geekhack

geekhack Projects => Making Stuff Together! => Topic started by: mkawa on Thu, 09 May 2013, 12:12:46

Title: The Living 3D Printing Thread
Post by: mkawa on Thu, 09 May 2013, 12:12:46
ATTENTION NETIZENS

this is now a thread ALL ABOUT 3D PRINTING


MEMBERPRINTERSWILL PRINT FOR YOU?
epicepee kessel mini
vvprostock delta (from kit)no
damorgueREDACTEDNO TITANIUM FOR YOU
CPTBadassREDACTEDNO DMLS, ABS, PLA, NYLON, STEEL, ALUMINUM, TITANIUM, ETC. ETC. ETC. ETC. :|
__red__unknownNO (idea)
Title: Re: a call for folks who have operated extrusion head 3d printers
Post by: noxwood on Thu, 09 May 2013, 23:49:38
So you're specifically looking for dual-extrusion? Are you willing to tinker with the build, or do you want it ready out of the box?

Unfortunately I can only help with the hardware stuff, not quite familiar with the different slicing softwares etc. The reprap forums should be great for that, though.
Title: Re: a call for folks who have operated extrusion head 3d printers
Post by: mkawa on Fri, 10 May 2013, 09:10:31
haven't decided how much tinkering would be appropriate. total DIY is going to take too long to ramp up, so repraps (the prusa iX, basically) is almost certainly out of the question.

MBI r2x is a definite candidate. it looks like it can make OK prints OOTB but it needs a fair amount of hacking (more stable bed, better loaders and extruders, some other basic stuff) to really print high quality models quickly. one huge upside though is the large user community and amount of open source compatibility.

cubex 2-head is also looking like a definite candidate. it's not clear that the third head really gets you much other than a larger price. it seems like a better turnkey solution, but the software is more proprietary etc.

there are tradeoffs everywhere, basically.
Title: Re: a call for folks who have operated extrusion head 3d printers
Post by: mkawa on Fri, 10 May 2013, 11:01:50
just noting that any experience reports, from professional level sintered down to lowest end FFM/FDM is welcome. (AHEM, DAMORGUE ;))
Title: Re: RFC: a call for folks who have operated extrusion head 3d printers
Post by: damorgue on Fri, 10 May 2013, 13:02:40
I take it you want to buy one? Purpose is sort of important as a deciding factor.

The ones based on extrusion melts the plastic which means that they use thermoplastics. These are then not very resistant to heat after printing and usually have a large glass transition phase. This means that not only can they melt depending on their usage scenario, they will transition to their liquid stage well before reaching their melting temperature.

There are also thermosets, another category of polymers which don't melt in the same way, and are instead cured to make them hard. Typically they start out with a resin and then cure it with light. From what I have seen, 3D printers which use these offer far more exact and detailed prints than those with nozzles can accomplish.

They all differ in: maximum printable size, speed, tolerances, cost of material/print, cost of machine, possible geometry.
Yes, the geometries which are possible differ slightly as they handle overhang differently. Some can deal with it by placing the part to be printed in a certain rotation, but some shapes are just not possible with certain methods.
Title: Re: RFC: a call for folks who have operated extrusion head 3d printers
Post by: mkawa on Fri, 10 May 2013, 13:17:41
Well, might as well make it public: I am buying one for usage by the greater geekhack community so that we have a 3d printing resource that is significantly cheaper than shapeways. usage will be big stuff like keyboard chassis and small stuff like extremely complex keycaps.

As I stated elsewhere we will also be opening a sister site to geekhack -- gearhack which will focus on wheeled transport, and there are many applications there, ducting, casing (lithium iron phosphate batteries are becoming my second serious project other than the ssk..).

certainly for keyboard usage we have no temperature issues. for car usage, abs tends to have enough heat resistance in MOST cases, polycarb is used sometimes in extreme cases or vinyl/TPU. In very extremely cases we'll have no choice but to go with eg shapeways' polyamide.


----


The problem with the other FDM printers you're mentioning is that buy-in is far greater than our budget, and the print accuracy is above what we need to bootstrap printing for the community. keyboard chassis can _almost_ be made with laser cutting only. (obviously we've seen some issues with this, particularly with metals). BUT only fairly boring designs can be made with laser cutting (you have the discretization issue among others), and milling is a process that i think is actually inappropriate (with alu i think) for keyboard chassis.
Title: Re: RFC: a call for folks who have operated extrusion head 3d printers
Post by: damorgue on Fri, 10 May 2013, 13:29:37
Quite a few prints are required to make one worth the investment when compared to buying a few prints from Materialise, Shapeways or similar, so increasing the usage to another field as you mention is probably a good idea.

I started to think that which I mentioned on polymer types wouldn't be relevant as I would have guessed at key caps or SSK revival case. Key caps want small parts with high accuracy in an abrasion resistant polymer. The other usage scenarios you mention will probably require larger parts with less accuracy in polymers which resist chemicals, vapor and temperature.
Title: Re: RFC: a call for folks who have operated extrusion head 3d printers
Post by: mkawa on Fri, 10 May 2013, 13:33:35
the way i posed the RFC is really by constraint of budget. we can only afford an FFM and a ABS/PLA printer right now with at most two heads. it will be "good enough" for a lot of the work we do here, and some other stuff which i'm working on via email until gearhack launches.

in the future hacking it up to do TPUs and other weird **** would be awesome, and/or raising enough to buy a serious FDM or SLS machine, but at the moment these are out of our price range. as you well know, the higher spec the machine the more expensive time costs for good reason. your machines for example are out of our price range to use for even small prints, must less buy (hah!)
Title: Re: RFC: a call for folks who have operated extrusion head 3d printers
Post by: mkawa on Sat, 11 May 2013, 17:21:26
this is coming together. if you want to be involved, please play around with makerware and set it to the replicator 2x :D
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: berserkfan on Sun, 12 May 2013, 00:40:18
I just want to voice support for Mkawa and what you guys are doing. 3D printing is truly the direction to go; it will greatly reduce the need for lengthy group buys and not being able to do something if there is not MOQ/ causing the original leader of the group buy to buy more sets in order to meet MOQ.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Tue, 14 May 2013, 11:59:28
order is in. t-8 weeks to delivery.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: CPTBadAss on Tue, 14 May 2013, 12:06:28
You....you're crazy Kawa.....And I like it  ;). Cannot WAIT to see what comes out of this
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Tue, 14 May 2013, 12:22:47
needs: programmers to help me make a faster skeinforge (translate it into a nicer typed language, basically)
           modelers to make stuff
           models that are well suited to 3d printing
           people who are willing to go bananas

as part of my actual work work, i will very likely be working on a gcode tolerance estimator and validator. a good benchmark suite and a clean gcode generator will be imperative.

otherwise, it's going to be a relatively high quality 3d printer whose services will be available to the community at much lower than market margin (which is anywhere between 5-10x and 20x). proceeds will be reinvested in the community (3d scanner, other tooling, etc.)
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Tym on Tue, 14 May 2013, 12:25:35
I have a little experience with 3D printing and can do basic stuff. If any one wants real nooby help feel free to ask. And I don't mind helping out in anyway I can
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: E TwentyNine on Tue, 14 May 2013, 21:16:27
Awesome idea.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Tue, 14 May 2013, 23:41:04
As Damorgue said, purpose plays a large part in which is best.

The Replicator 2 is a nice printer, it's certainly one of the more professional looking and the easiest to get up and running. You can certainly do much worse. Just beware the build area, I doubt it will handle much more than a GH60 case. I went with a Delta style system for that reason (the last of my parts arrive Thursday).

The biggest problem I see you face now is expectations.
Those who don't understand 3d printing tend to underestimate them, but those with some understanding of them, tend to greatly over estimate them. The claimed 100micron, due to the system, has to be done EXTREMELY slow and printing in general is slow to begin with.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Tue, 14 May 2013, 23:51:24
interesting interesting. i hadn't seen the delta systems, but there's very much a mill vs lathe thing going on here.

i don't know what your plans are regarding your printer, but we should do some same-model assembly tests and comparos to see how the two methods stack up. on the one hand, you have much bigger bounding box. otoh, your servos have to move things around that have variable mass over time and could potentially be pretty heavy.

regardless, lots of hacking to be done and stuff to make! joy!
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: dndlmx on Wed, 15 May 2013, 00:51:36
Dear GH, print some cases with HHKB-like layout for the next GH60 batch. kthxbai.  ^-^
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Wed, 15 May 2013, 00:54:34
if you build cad, the print will come
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Wed, 15 May 2013, 02:20:06
interesting interesting. i hadn't seen the delta systems, but there's very much a mill vs lathe thing going on here.

i don't know what your plans are regarding your printer, but we should do some same-model assembly tests and comparos to see how the two methods stack up. on the one hand, you have much bigger bounding box. otoh, your servos have to move things around that have variable mass over time and could potentially be pretty heavy.

I'm building a Rostock  (http://reprap.org/wiki/Rostock)(not a Max), which uses an external feeder and moves mostly just the nozzle and a bit of plastic as opposed to the entire bed, and extruder, because of that, my mass to move around is actually a whole lot less. This comes at the expense of added noise, especially if you go cheap on the bearings and alignment rods (which are expensive).

Being newer (only about a year really), there really isn't anything quite like a Makerbot yet available in Delta style. The closest thing is the Rostock Max (http://shop.seemecnc.com/Rostock-MAX-COMPLETE-3D-Printer-Kit-68398.htm),but it's nowhere near the professional looks (and build quality) of the Makerbot. If GraberCars releases the Cerberus (http://reprap.org/wiki/Cerberus), that might be comparable, but I don't know when or if that will happen. It's just too new of a design for manufacturers to really jump on yet.

As for distances things move, motor speed and distance isn't really the problem on any of them and it only plays in when building something tall regardless. Speed/Accuracy is actually more a matter of inertia. The heavier and faster you go, the sloppier things get, every bit of slack, becomes more and more exaggerated, so a lightweight head, pays off more and more as speeds go up. Deltas inertia is so low, that some of the latest ones are using fishing line instead of belts or threaded rods to move the sliders.


I'm planning on doing a GH60/GH60+ case, maybe a tkl case, I also want to make plugs for SP caps that allow o-rings to be used. There is a lot of random stuff I want to make, nothing in particular though. I also want to print some PLA to help make molds for casting aluminum, but that is a ways off really (PLA evaporates at those temps, so you print it, toss it into sand, and pour your metal). I got into it partly to get into this while it's still new, but it's also just for a new toy/project.


As for comparisons, when setup properly a modern Delta will outperform a Cartesian (axis based) printer in speed and quality. It just takes a lot more effort to get there. Deltas are barely a year old, so it's still under heavy development and lacks the documentation (they even lacked good software until recently). I can't see anyone really faulting your choice, it's an established, solid system, and one of even fewer with dual color. It's kind of like buying Intel, it's a safe choice. I went Delta mostly for the build volume and I fell in love with watching them work. I also enjoy a challenge and so far, just getting the parts, has been a challenge. Shady sellers, bad parts lists... It's been a hassle and I have yet to assemble a single part, not to mention being about 40% over the designers estimated costs (I did add some improvements, but I also got some things cheap or free).


Regardless, the more of these we have available, the better off we are, and having two different styles available is even better since each style has it's pros and cons (your sealed chamber is a definite plus and you get some nice proprietary software).



Couple things...
I didn't know this until recently, but PLA needs to be kept extremely dry (no humidity!) or it will not print well. Apparently some Chinese manufacturers are not shipping it in sealed bags. So you need to watch where you get it from, and be prepared for storing it. ABS is fine out in the open, however dirty filament is always an issue (even straight from the factory). Many make sponge holders to clean it as it comes off the reel. Shop around, Makerbot plastic is EXPENSIVE, I paid $28 shipped (from the US) for what they charge $48 plus shipping for (3d printer store prices vary greatly!).

Due to the cost of Kapton tape, you will probably want to invest in a glass plate. Glass tends to hold PLA and ABS, but you need a certain type of glass. Otherwise it can break from the heat. If not, you will be buying lots of Kapton tape and blue masking tape (for PLA). Glass and hairspray is a better solution (Aqua Net is the recommended one I think).

Another thing you may want to look into soon is a Lyman Filament Extruder, these let you recycle plastic or buy plastic in bulk for half the price. Considering your plan, you could go through a lot of waste and this would recoup a lot of expense. At $30-$50 per Kilo of filament, it won't take long to recoup costs on one.

There is now wood grained (pretty impressive stuff actually) and soft/silicone style filament available. There is also plans available for making a Sharpie holder that colors the filament before you melt it. This isn't as bright as colored filament,  red Sharpies on white tends to create pink, but works to alter color slightly. The results are better than you might expect.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Wed, 15 May 2013, 08:09:57
1) the advantage of the alum plate with the MBI r2x is that the plate is cheap. if it scratches (and they use teflon not kapton) or warps, you just buy a new one at the tune of 75$. building a glass surface plate is much easier said than done, especially if you want to heat it (ie, you can't heat a glass plate uniformly to reasonable temps without risking cracking etc.

2) all polymer filaments need to be kept dry. build a dry box. i will be documenting my dry box build here. maybe we can split the cost of a huge amount of bulk dessicant? on second thought, let's definitely do this. if you run your printer indoors (and you should to avoid rapid cooling and weird air movement, you will also need a serious odor remover along the lines of my solder fume extractor, but with better static pressure performance (ie, ****tons more charcoal). again, i think we can split some costs here.

3) looking at different options for DIY filament. for now, i'm sticking with MBI because the costs still work out to be extremely good and they can provide the necessary tolerances.

4) did not know about the filament dying. we are definitely going to need a living 3d printing thread to document a lot of this stuff as we find it. a lot of what i will be focusing on though is the software toolchain, understanding it deeply, rewriting large parts of it and then implementing an experimental framework for work reasons.

so damn excited!!
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: metalliqaz on Wed, 15 May 2013, 11:09:13
needs: programmers to help me make a faster skeinforge (translate it into a nicer typed language, basically)
           modelers to make stuff
           models that are well suited to 3d printing
           people who are willing to go bananas

If there comes a need, I can help with circuits and embedded programming.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Krogenar on Wed, 15 May 2013, 14:56:05
Just don't print any guns, mkawa.  :))
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Wed, 15 May 2013, 19:02:11
that was the first thing boost asked for
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: metalliqaz on Wed, 15 May 2013, 19:30:30
Why 3D print a crappy-ass gun when you can go to Cabela's and buy an heirloom piece for a few hundred bucks more?
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: SmallFry on Wed, 15 May 2013, 19:31:56
I counter your argument with a "Why not?"
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: CPTBadAss on Wed, 15 May 2013, 19:36:22
This is GeekHack, we do stuff just for the "Why not" factor :P

Seriously though, I'd like to propose a project for this printer. MX-to-Alps adapters so I don't have to hunt for caps so hard for my Alps board!
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Wed, 15 May 2013, 19:39:34
hope you're planning on putting SA profile caps on those :))

yah, it should be able to pump those out though.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: SmallFry on Wed, 15 May 2013, 19:45:07
I seem to recall Mr. Interface's 3D ALPS to MX adapters breaking.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Wed, 15 May 2013, 21:26:38
Why 3D print a crappy-ass gun when you can go to Cabela's and buy an heirloom piece for a few hundred bucks more?
More?

Considering the price of a 3d printer, the real gun is cheaper, mine is up to $700 in parts (almost $100 in nuts and bolts alone!), and the one Mkawa is getting is about $3000. You still need about $30 in plastic as well.

I don't know typical gun prices, but I'm sure $700 would get you one (used maybe?), and $3000 certainly would.

If you plan on having someone make it for you... Forget it, you need a firearms manufacturers license to do that.


I counter your argument with a "Why not?"
Because it could bring the Justice Department to your door. Because it could blow up in your face the first time you shoot it. Hobby 3d printers aren't always known for the strength of the finished item. Particularly if you don't get the settings right, your plastic got exposed to moisture, or you just got cheap filament.

Mostly, because it was meant as a technological demonstrator. It wasn't meant to really be used, it was meant to show off 3d printing as well as scare gun manufacturers and anti-gun nuts alike. You have to admit, it's impressive when you can anger both gun lobbyists and anti-gun lobbyists equally, and at the same time.

hope you're planning on putting SA profile caps on those :))

yah, it should be able to pump those out though.

You would probably be disappointing with 3d printed keycaps. Not only are they not smooth, but the last one I saw who tried, the stem broke.

As for pumping them out... a Keycap with a decent finish, just a guess, but at least 5 minutes each. You also need another 5-15 minutes to heat up the bed and nozzle before you can even start and similar cooldown before removing it. A full keyset, even doing several at once, could easily take all day.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Thu, 16 May 2013, 08:40:31
talked to a guy with a nice thick southern accent about dry boxes; found the perfect shell: http://www.usplastic.com/catalog/search.aspx?search=75063&page=1

lolzzzzz
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Krogenar on Thu, 16 May 2013, 09:25:48
that was the first thing boost asked for

(emails mkawa 3d models for handcuff keys)
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Tym on Thu, 16 May 2013, 09:31:38
that was the first thing boost asked for

(emails mkawa 3d models for handcuff keys)

Anyone see the Big Bang Theory where they bought a 3d printer? I hope no-one thinks about doing what Howard nearly did. Also we need plastic copies of Glissbro and CPTbadass
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: CPTBadAss on Thu, 16 May 2013, 09:34:29
Whoa whoa whoa, why do we want plastic forms of me Tym?  :eek:
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Tym on Thu, 16 May 2013, 09:35:30
Whoa whoa whoa, why do we want plastic forms of me Tym?  :eek:

I mean of your avatars 0.0 Slow down there! :P

Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: jdcarpe on Thu, 16 May 2013, 09:42:55
John Malkovich was making plastic guns long before 3D printers were around.

Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: CPTBadAss on Thu, 16 May 2013, 09:44:20
Whoa whoa whoa, why do we want plastic forms of me Tym?  :eek:

I mean of your avatars 0.0 Slow down there! :P

Of my avatar? Oh man, I'd totally get behind that ^__^
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: JPG on Thu, 16 May 2013, 09:52:01
needs: programmers to help me make a faster skeinforge (translate it into a nicer typed language, basically)
           modelers to make stuff
           models that are well suited to 3d printing
           people who are willing to go bananas

as part of my actual work work, i will very likely be working on a gcode tolerance estimator and validator. a good benchmark suite and a clean gcode generator will be imperative.

otherwise, it's going to be a relatively high quality 3d printer whose services will be available to the community at much lower than market margin (which is anywhere between 5-10x and 20x). proceeds will be reinvested in the community (3d scanner, other tooling, etc.)

What type of programming skill do you need? Which language you want to use? What's your time frame target?
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Thu, 16 May 2013, 12:23:51
a couple possibilities: 1) rewrite skeinforge in a highly disciplined dialect of C. use Clang for enlightened compilation and analyze the llvm. 2) rewrite skeinforge in a Java 4. Use wala for enlightened compilation and analyze the bytecode. 3) rewrite skeinforge in haskell or ocaml (ie, some ML dialect). hack up ghc or ocamlc (I have extensive experience in the latter, and access to enough experience to get going in the former) to do enlightened compilation. analyze the AST (afaik the lowest IL in both compilers is just an AST).

advantages and disadvantages to all options. will have to think on this one. If you're a phd applicant, I encourage you to apply to either UCI or UCLA's (latter is iffy) PL program to participate in this. If you do though, you need to let me know first because I will have to write the grant to fund you ;). Otherwise, you're welcome to pop in on the github anytime as we work. :)
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: JPG on Thu, 16 May 2013, 20:02:41
a couple possibilities: 1) rewrite skeinforge in a highly disciplined dialect of C. use Clang for enlightened compilation and analyze the llvm. 2) rewrite skeinforge in a Java 4. Use wala for enlightened compilation and analyze the bytecode. 3) rewrite skeinforge in haskell or ocaml (ie, some ML dialect). hack up ghc or ocamlc (I have extensive experience in the latter, and access to enough experience to get going in the former) to do enlightened compilation. analyze the AST (afaik the lowest IL in both compilers is just an AST).

advantages and disadvantages to all options. will have to think on this one. If you're a phd applicant, I encourage you to apply to either UCI or UCLA's (latter is iffy) PL program to participate in this. If you do though, you need to let me know first because I will have to write the grant to fund you ;). Otherwise, you're welcome to pop in on the github anytime as we work. :)

My java skills are far and I am not into compilation, but well, even if I can't do much on this project I'll follow it because it's very interesting and who knows, maybe I'll be able to give so help at some point!
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: berserkfan on Fri, 17 May 2013, 07:33:38
You know, for us non-Americans with no 'democratic' access to guns, you people have 'freedom' aplenty thanks to the NRA.

Every dictator hates the idea that his slaves could free themselves anytime.

That said, America is so awash in guns, sometimes foreigners think that every grandpa and grandma is toting as well. Duh, why doesn't NRA offer delivery service like pizza hut and vending machines for ammo? Guns are more American than Apple Pie, the Uncle Sam symbol, the Star Spangled 50-star banner and the White House (guns predate all of them)!

Why 3D print a crappy-ass gun when you can go to Cabela's and buy an heirloom piece for a few hundred bucks more?
More?

Considering the price of a 3d printer, the real gun is cheaper, mine is up to $700 in parts (almost $100 in nuts and bolts alone!), and the one Mkawa is getting is about $3000. You still need about $30 in plastic as well.

I don't know typical gun prices, but I'm sure $700 would get you one (used maybe?), and $3000 certainly would.

If you plan on having someone make it for you... Forget it, you need a firearms manufacturers license to do that.


I counter your argument with a "Why not?"
Because it could bring the Justice Department to your door. Because it could blow up in your face the first time you shoot it. Hobby 3d printers aren't always known for the strength of the finished item. Particularly if you don't get the settings right, your plastic got exposed to moisture, or you just got cheap filament.

Mostly, because it was meant as a technological demonstrator. It wasn't meant to really be used, it was meant to show off 3d printing as well as scare gun manufacturers and anti-gun nuts alike. You have to admit, it's impressive when you can anger both gun lobbyists and anti-gun lobbyists equally, and at the same time.

hope you're planning on putting SA profile caps on those :))

yah, it should be able to pump those out though.

You would probably be disappointing with 3d printed keycaps. Not only are they not smooth, but the last one I saw who tried, the stem broke.

As for pumping them out... a Keycap with a decent finish, just a guess, but at least 5 minutes each. You also need another 5-15 minutes to heat up the bed and nozzle before you can even start and similar cooldown before removing it. A full keyset, even doing several at once, could easily take all day.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Fri, 17 May 2013, 07:44:09
you can make a plate full of adapters/keycaps in a single run of the printer
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: E TwentyNine on Fri, 17 May 2013, 09:51:46
needs: programmers to help me make a faster skeinforge (translate it into a nicer typed language, basically)
           modelers to make stuff
           models that are well suited to 3d printing
           people who are willing to go bananas

as part of my actual work work, i will very likely be working on a gcode tolerance estimator and validator. a good benchmark suite and a clean gcode generator will be imperative.

otherwise, it's going to be a relatively high quality 3d printer whose services will be available to the community at much lower than market margin (which is anywhere between 5-10x and 20x). proceeds will be reinvested in the community (3d scanner, other tooling, etc.)

What's the current deficiency with skeinforge?   How slow is slow?
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Fri, 17 May 2013, 12:06:47
a two-color skeinforge print at 100u did not terminate over the course of a day on my 4ghz i7 in makerware. this was for a 2"x2" cube

the other issue is that python is ridiculously hard to analyze, so the rewrite would be for work reasons as well.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Fri, 17 May 2013, 17:09:36
you can make a plate full of adapters/keycaps in a single run of the printer
If they fit on the build surface, but you are still looking at 10 hours or more, especially with decent quality.
On a 10+ hour run, that leaves a lot of time for an error to sneak in and if it does, it will wreck all of them.



The last parts arrived today! Woohoo!
Now I just have about 16 hours of hand fitting 200 parts together with limited instructions. LOL
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: lazerpointer on Fri, 17 May 2013, 18:11:52
As Damorgue said, purpose plays a large part in which is best.

The Replicator 2 is a nice printer, it's certainly one of the more professional looking and the easiest to get up and running. You can certainly do much worse. Just beware the build area, I doubt it will handle much more than a GH60 case. I went with a Delta style system for that reason (the last of my parts arrive Thursday).

The biggest problem I see you face now is expectations.
Those who don't understand 3d printing tend to underestimate them, but those with some understanding of them, tend to greatly over estimate them. The claimed 100micron, due to the system, has to be done EXTREMELY slow and printing in general is slow to begin with.

I have a dream that one day we can live in a nation, where all the Cherry caps can get along with all the ALPS boards...

http://deskthority.net/workshop-f7/cherry-to-alps-adapters-t4934.html


[attachimg=1]
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: CPTBadAss on Fri, 17 May 2013, 18:20:52
Flip I suggested this earlier too :D
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Fri, 17 May 2013, 19:57:40
these should be printed undersized on a coarse setting on their side in PLA. to avoid rafts or other supports, the cherry cruciform will be highly tapered orthogonally to the way that MrInt has tapered his, and the alps end should taper and have dimples chunked out as it hits the bottom of the switch socket. this way, the adapter has all its sheer strength vertical to switch, and focused at the joint between the two cruciforms.

even injection molded in abs, you'd have trouble with that very naive design. if you were injection molding, you'd actually want a pretty soft TPU for this. on that note, injection tooling for this wouldn't be that expensive. if it weren't for the height issue, you'd be better off with universal MX cruciform caps (the alps socket is so bad regardless..). *shrug*
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Sat, 18 May 2013, 01:19:55
these should be printed undersized on a coarse setting on their side in PLA. to avoid rafts or other supports, the cherry cruciform will be highly tapered orthogonally to the way that MrInt has tapered his, and the alps end should taper and have dimples chunked out as it hits the bottom of the switch socket. this way, the adapter has all its sheer strength vertical to switch, and focused at the joint between the two cruciforms.


The reason for this, for those who aren't aware is that 3d printers have a "grain" similar to wood. The lines you often see on 3d prints actually run all the way through and are a weak point. Too low of heat and they will split with very little effort, but even with proper heat it's a weak spot, so you have to orient the design to account for this in situations where strength can be an issue.

Someone already tried something like this and it broke for that exact reason.



--------------------------------
5 hours of hand fitting plastic parts... My fingers are raw.
There's another 3 hours in woodwork as well.

And all I have is a massive pile of expensive parts (around 200!). LOL
Actually, all of the small parts are assembled into modular sections just waiting to be quickly fastened together once I get the plywood frame supports finished tomorrow. After that, comes wiring.

The person I got my plastic parts from had a rather sloppy printer, making for a lot more work than I should have needed to do. One was even off enough that a screw split some of the plastic even after running a drill bit through it. It's long tedious work.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Sat, 18 May 2013, 02:16:35
once the r2x comes in, we can reprint a some of your more egregious parts. i would also consider redoing the plywood eventually with heavier material. the light weight of the outer frames of the diy printers are a classic "bad thing". the error introduced by the movement of a head is inversely proportion (to some reciprocal function) of the weight of the frame. this is why bridgeport mills weigh several tons.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Sat, 18 May 2013, 17:04:56
once the r2x comes in, we can reprint a some of your more egregious parts. i would also consider redoing the plywood eventually with heavier material. the light weight of the outer frames of the diy printers are a classic "bad thing". the error introduced by the movement of a head is inversely proportion (to some reciprocal function) of the weight of the frame. this is why bridgeport mills weigh several tons.
The parts all fit now, so no worries there, just took some elbow grease.  The wood isn't nearly as much of an issue on a Rostock Delta as it is on Cartesians as it's not really applying much force to it. Newer Deltas are eschewing wood, but not because of wood being problematic, but that they created simpler/cheaper designs that no longer require it.  I could have started there, but I wanted the extra build volume of this style.

Having the ability to fabricate your own parts, and the ability to see where things can be improved is quite nice, I'm already drawing up plans for a custom design of my own using no wood and taking ideas from other designs as well as my own ideas.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Sat, 18 May 2013, 23:49:20
i'm not really seeing what the gcode coordinate system has to do with stability of the electromechanicals, but maybe i'm missing something. can you link the cartesian version? maybe it will make things more obvious for me (is it that the delta mostly rotates its platform like a lathe, so the stray forces that cause error are torsional?)

imo, you can almost never go wrong by making a cnc machine's frame denser. the gcode is computing without taking into account positioning error (generally, although i thought i saw a small correcter module in skeinforge), and those errors stack up in a long run.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Sun, 19 May 2013, 06:54:12
Makerbot is a Cartesian style printer, as it uses one motor per axis (two for one of them for vertical I think), that is Cartesian. Makerbot, Prusa, etc, all use that design, which is based on a milling machine. Yours is just a well put together kit that eliminates the wood, which is problematic on those.


A Delta is not a Cartesian, it's not even based on a milling machine or a lathe, it's based on an assembly line robot. Have a look, here  (http://www.youtube.com/watch?v=AYs6jASd_Ww)is a Rostock Delta being tested, and another  (http://www.youtube.com/watch?v=SJwn6IDB06M)printing.

As you can see, the mass being moved and how it's being moved is entirely different. It's not only lighter, but half of what is being moved, is only traveling in a vertical direction. I believe it's less than 1/8th of a pound actually being swung around in a Rostock, while on a Cartesian, it's several pounds that gets pushed side to side, forward and back.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Sun, 19 May 2013, 08:11:04
here's a video with an actual filament head:
feature=fvwp&NR=1 :P

yes, i can see that the forces exerted are significantly different.. i don't think that you're fundamentally looking at less weight at the print head though. in fact, i think that with the long swingarms, you're looking at more weight per print head. curious that there's no fan on the delta's head. i'm guessing it can only do PLA?

the major difference that i can see is: when an arm move _down_ on a pillar and then stops, the deceleration-causing-error is countered by the platform the machine sits on, which, assuming the thing isn't on a bar stool or something ridiculous, is pretty resistant to movement. the equivalent is Z-axis movement downward on a cartesian design, which probably carries the least error.

BUT! i still assert that there are going to be weird torsional forces causing hard to predict error, and that minimizing that error requires a heavier construction. imagine a more common movement in which two servos move up and one moves down. when the servos moving up stop, they're going to cause horizontal movement (some nasty wobble, potentially!) on their pillars, and there will be torsion on the top-platform, which is in a pretty precarious position, being so high (if it's heavy, that woble is only going to get worse, if it's light, it won't resist the torsion). and that's without even looking at the forces on the swingarms, which are definitely non-zero, and swingarm "droop" is going to introduce error as well.

HENCE, heavier, thicker everything (except for the print head) will increase precision. this is also true with the cartesian printers. the exact parts that should be heavier and thicker are slightly different, but sturdier load-bearing bits will still be required to increase ultimate precision with this printer, same as any other.

re: print-head weight. you could minimize print-head weight on a cartesian unit as well, but the eternal battle with these moving-head ffm printers is to increase flow precision, number of output and input nozzles, and temperature stability and that takes heavier print-head components. it looks like the rostock head design happens to be very minimalist, but that's orthogonal (lol) to the mechanical positioning/coordinate system.

although i will note that one benefit of the minimalist design of the rostock is that you have your printer _now_ and i have to wait 7-8.5 more weeks. lol!
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Sun, 19 May 2013, 16:17:24
They print ABS as well.
Fans are dependent on the head and the environment...  Some heads need fans, some don't. Some guys get away with none, others bolt on a fan and others place a desk fan next to it blowing across the entire build area. With your sealed chamber you are more likely to need one.

Yes, you can minimize print head weight itself on a Cartesian as well, however, it's less effective. You still have to move the entire print carriage, including alignment rods and motors, so while you can save a few ounces, which helps, you still have to move the entire carriage carrying it.


Rostock quality is mostly dependent on the rod end connections, the better they are, the better your print. The original rods were terrible and people switched to RC car rod ends for a bit, but the latest is magnetic ball ends and the prints are spectacular.

This is from a Rostock Max (wood framed) with an E3d head/.40 nozzle/no cooling/ABS/heated glass bed/magnetic rod ends.
Seems good enough for me.  :) (Pic and vid by Flateric)
Video of first print after upgrading arms (http://www.youtube.com/watch?feature=player_embedded&v=WN9a8Pi1qSQ)
Up close.
(http://vmroms.com/mypics/3d/file.jpg)
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Sun, 19 May 2013, 20:56:42
abs probably requires a beefier head. the first head you linked had no sinking. second head is pretty sweet. ideally you don't want to draft across the print area, even if you have a heated glass bed. the slower the cool the better.

question though: how are these guys doing their heated glass beds? just really thick planed glass multipoint heating and very slow warmup?

i will point out that a thick glass bed will weight your printer down pretty damn well.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Mon, 20 May 2013, 03:20:44
Like real life, some heads are better than others.

Many are using Borosilicate glass, because it doesn't shatter when heated uneven. Some have found soda-lime glass (green window glass) also works. it doesn't necessarily need to be thick. Others just risk it and run normal glass. Some just tape over the heater.

There seems to be no set standard for needing a fan or not, or even where or how many. The trick is to find what works for your printer/hardware combination and environment. What works for one, won't for another. One says he needs a heated cabinet, another will say he wants a fan... It's trial and error.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Mon, 20 May 2013, 09:04:30
a perfect recipe for repeatable manufacturing :D

can't wait to see the first print from your box, leslie!!!
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Mon, 20 May 2013, 13:09:52
oh man, i think you've infected me leslie. a delta max design could be incredibly helpful for certain kinds of projects here. for example, the really long build area could end up working extremely well for keyboard cases (which otherwise have to be cut up and then fastened together).
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Mon, 20 May 2013, 17:39:16
oh man, i think you've infected me leslie. a delta max design could be incredibly helpful for certain kinds of projects here. for example, the really long build area could end up working extremely well for keyboard cases (which otherwise have to be cut up and then fastened together).
:)
I love watching the Deltas work, it's just amazing to see them function, it's almost organic.

Like I said earlier, that length is why I went with this, space to do a gh60 (and TKL), of course it has to be done vertical but it should work with some scaffolding, and eventually two at a time to reduce that, if I make them for others. I don't plan on keeping the Rostock as my only printer for long, I plan some upgrades for it, but I also want to make a Cerberus derivative, which has a 400mm high build area, large enough for a TK.

I don't have a problem with the Cartesian/Reprap/Makerbot design, I just like the Delta design better. It uses less desk space, has more room, and just looks so futuristic. I kind of look at it as the second generation of home based 3d printing. However, time will tell if it becomes the more dominant design.  There are a lot of people invested in the style you have but many are also switching over as the design becomes more stable. The Rostock itself is only about a year old and it was extremely revolutionary. Many doubted it would even work and even claimed it was fake.


If you do decide on another, especially a Delta, I would recommend looking at either a Kossel or a Cerberus (both are still in development by the designers). Both are as cheap or cheaper than a Rostock. The Kossel has a similar build area as your Makerbot, but makes for a real nice, and cheap Delta that performs extremely well (and MUCH quieter!!!), I passed on it only due to build area size. It's about $100 less to build than a Rostock, and is the second design from the same guy who designed the Rostock. Cerberus is the work of a Lotus kit car designer who redesigned the Kossel and Rostock to form his own printer. It has an even larger build area than the Rostock for a similar or slightly less price.

Other options are Mini Rostock, which can be done for pretty cheap as well and would make for an excellent second printer for smaller items. If I start making things that sell, I plan on one of these. Parts are easy and cheap to get/make, including pre-cut Lexan panels instead of plywood (Ebay has these). The biggest drawback is the size (of course) and the noise... The linear bearings on Rostocks are VERY NOISY! Many recommend printing ABS bearings to replace them. Which isn't a bad idea anyhow as it prolongs the life of the rather expensive rods (quality rods for a full size can run from $90-$180!). The rods are why the Rostock Max, Cerberus and Kossel were designed the way they are now.

All of this is open source (including most of your Makerbot), so you can swap over parts, use yours as reference, and of course, build another entirely. Like I said, your second can be a lot cheaper if you D.I.Y. it.

Oh.
I forgot about another printer earlier, turns out there is a pre-build Delta and of decent/non-wood quality. It's called Spiderbot (http://www.spiderbot.eu/). They are still getting going, and their build area is smaller, and you would have to import it, but it's a nice, pre-built all metal Delta for a decent price. If I remember right, their base kit is $1200 after exchange rate and the top end was $1800. I like it better than the Rostock Max, but if it means saving $1000, I'd rather just build one myself.


If it wasn't so expensive to operate, I would build a stereo-lithographic printer as my next. These are the ones that use a laser to cure resin, they have incredible resolution. The printers themselves aren't any more expensive (you can use a Blue-Ray laser and you need no extruder). The problems start once you get finished building it and find that the resin costs 25 times more than ABS.  :eek:
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: PointyFox on Mon, 20 May 2013, 18:10:47
oh man, i think you've infected me leslie. a delta max design could be incredibly helpful for certain kinds of projects here. for example, the really long build area could end up working extremely well for keyboard cases (which otherwise have to be cut up and then fastened together).
:)
I love watching the Deltas work, it's just amazing to see them function, it's almost organic.

Like I said earlier, that length is why I went with this, space to do a gh60 (and TKL), of course it has to be done vertical but it should work with some scaffolding, and eventually two at a time to reduce that, if I make them for others. I don't plan on keeping the Rostock as my only printer for long, I plan some upgrades for it, but I also want to make a Cerberus derivative, which has a 400mm high build area, large enough for a TK.

I don't have a problem with the Cartesian/Reprap/Makerbot design, I just like the Delta design better. It uses less desk space, has more room, and just looks so futuristic. I kind of look at it as the second generation of home based 3d printing. However, time will tell if it becomes the more dominant design.  There are a lot of people invested in the style you have but many are also switching over as the design becomes more stable. The Rostock itself is only about a year old and it was extremely revolutionary. Many doubted it would even work and even claimed it was fake.


If you do decide on another, especially a Delta, I would recommend looking at either a Kossel or a Cerberus (both are still in development by the designers). Both are as cheap or cheaper than a Rostock. The Kossel has a similar build area as your Makerbot, but makes for a real nice, and cheap Delta that performs extremely well (and MUCH quieter!!!), I passed on it only due to build area size. It's about $100 less to build than a Rostock, and is the second design from the same guy who designed the Rostock. Cerberus is the work of a Lotus kit car designer who redesigned the Kossel and Rostock to form his own printer. It has an even larger build area than the Rostock for a similar or slightly less price.

Other options are Mini Rostock, which can be done for pretty cheap as well and would make for an excellent second printer for smaller items. If I start making things that sell, I plan on one of these. Parts are easy and cheap to get/make, including pre-cut Lexan panels instead of plywood (Ebay has these). The biggest drawback is the size (of course) and the noise... The linear bearings on Rostocks are VERY NOISY! Many recommend printing ABS bearings to replace them. Which isn't a bad idea anyhow as it prolongs the life of the rather expensive rods (quality rods for a full size can run from $90-$180!). The rods are why the Rostock Max, Cerberus and Kossel were designed the way they are now.

All of this is open source (including most of your Makerbot), so you can swap over parts, use yours as reference, and of course, build another entirely. Like I said, your second can be a lot cheaper if you D.I.Y. it.

Oh.
I forgot about another printer earlier, turns out there is a pre-build Delta and of decent/non-wood quality. It's called Spiderbot (http://www.spiderbot.eu/). They are still getting going, and their build area is smaller, and you would have to import it, but it's a nice, pre-built all metal Delta for a decent price. If I remember right, their base kit is $1200 after exchange rate and the top end was $1800. I like it better than the Rostock Max, but if it means saving $1000, I'd rather just build one myself.


If it wasn't so expensive to operate, I would build a stereo-lithographic printer as my next. These are the ones that use a laser to cure resin, they have incredible resolution. The printers themselves aren't any more expensive (you can use a Blue-Ray laser and you need no extruder). The problems start once you get finished building it and find that the resin costs 25 times more than ABS.  :eek:

So instead of costing $0.001 per key, it will cost $0.0025?   :eek:
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Mon, 20 May 2013, 19:06:46
So instead of costing $0.001 per key, it will cost $0.0025?   :eek:

The material alone for a GH60 case would cost roughly $175, instead of $7 for ABS. You still have printer time on top of that.

I'm not sure about you, but I would rather pay $100 and get an aluminum case than spend $250 on a plastic one.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: TheQsanity on Mon, 20 May 2013, 19:15:46
Do you need a scanner as well?
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Parak on Mon, 20 May 2013, 21:34:11
Dibs on printing test samples of modernized Model F bits!
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Mon, 20 May 2013, 22:49:57
the thing that gets me about the rostock and what i would fix, is that it's not truly polar. this is why the tie rod ends are such a large source of error. in order for it to be a truly polar design, _the bed has to rotate_. those circular movements with the head are a mess of error stacking because they're approximating a bed rotation, by turning a single instruction over one variable into a mess of discretized instructions over three variables, each instruction of which accumulates a non-zero error factor.

this goes back to what i said before about this being a mill vs lathe thing. it's exactly analogous, except the action of the head is additive instead of subtractive.

ok, out of engineering-theory-land and into practice.

unfortunately, my next geekhack tooling contribution is going to be another cartesian piece -- a cnc multi-axis mill (a small sherline, NOT a bridgeport, cptbadass :P). Leslie, i would encourage you to keep on the polar express, so to speak, because frankly, circular objects like that awesome twizzler you showed, are best made on polar lathe-like additive machines like the rostock (but rotate the bed!!! it's the key to increased accuracy! if a lathe is too foreign to you, think of it as a spirograph; it's the exact same concept).
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Tue, 21 May 2013, 02:32:40
Not an engineer so I missed why you were referring to a lathe before, I thought you were talking about something else.

Anyhow.
The offset and such is all fixed through software. If you can compensate to make it flat, I'm sure the circle is no more difficult.

The errors people get from the rods, is from slack in them. Linear rods aren't always perfect and linear bearings are terrible. many have ordered and gotten some that ground grooves into their new rods they were so tight, others wobbled excessively. However, it's slop in the rod ends where the most errors come from. The original design has to be hand fitted, for all 24 connections. It's a hassle, and even if you do that, it has them pivoting on threads. Not exactly a recipe for precision.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Tue, 21 May 2013, 06:42:19
Belts are on, motors are in, I still need to mount the extruder and the spool somehow and then I'm all set for electronics, which will probably happen once get done with work tomorrow.


Enough room for a TKL with room to spare.  ;)
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Tue, 21 May 2013, 11:08:51
HMMMM some intriguing stuff here XD

http://www.mcmaster.com/#glass-stock/=mue6y7
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Tue, 21 May 2013, 15:08:15
HMMMM some intriguing stuff here XD

http://www.mcmaster.com/#glass-stock/=mue6y7
Yeah, but how does it change when heated... does it warp or expand?

Seems borosilicate isn't as expensive as people make it out to be. I saw some last night for about $20. McMaster isn't exactly known for good, low quantity pricing.

Here is a good size piece.
http://www.amazon.com/Borosilicate-Glass-3D-Printer-inches/dp/B009CHPMOG
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Wed, 22 May 2013, 19:02:19
75$ shipping :P

what McM does is source quality components. (and they also have a local warehouse for every major metro area :D)

also i was specifically looking at the glass-mica ceramics. they have relatively high thermal conductivity compared to pyrex, which gives a much more even platform temperature with fewer heating devices under the plate. they also have ridiculously high temp tolerances, which you would expect out of ceramic. yet, they're machinable and so could be surfaced using good lapping and grounding technique.. quite interesting!!
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Thu, 23 May 2013, 01:39:15
MCM may be good, but wanting $30 per linear rod (I needed 6) and $20 per bearing (I needed 12) was a bit on the expensive side.
Even nuts and bolts were 3 times the price.

I haven't looked at glass-mica, but for even heating. most guys are putting two thermisters at opposite ends, and if your heater covers the entire surface, you should get relatively even heating. With your aluminum bed, that shouldn't be an issue.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: TotalChaos on Thu, 23 May 2013, 02:00:15
Can either of your printers print with soft materials?

Something along the lines of 10A Rubber?

Or can they only print hard ABS plastic?
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Thu, 23 May 2013, 10:39:51
Can either of your printers print with soft materials?

Something along the lines of 10A Rubber?

Or can they only print hard ABS plastic?

negative. shrinkage is crazy with these materials, and their melt points are way too high for FFM printers.

MCM may be good, but wanting $30 per linear rod (I needed 6) and $20 per bearing (I needed 12) was a bit on the expensive side.
Even nuts and bolts were 3 times the price.

I haven't looked at glass-mica, but for even heating. most guys are putting two thermisters at opposite ends, and if your heater covers the entire surface, you should get relatively even heating. With your aluminum bed, that shouldn't be an issue.
what McM is good at is high quality very precise materials. this makes pricing look pretty bad at low MOQs but it's actually pretty good because the guys on ebay and amazon that are selling rods are not selling rods that are as precisely cylindrical as the McM parts.

that said, onlinemetals is also pretty good for bulk shapes, and their low MOQ pricing is pretty good too. i'd go to them before i went to the ebay guys.

then again, i am a pathological perfectionist. take it as you will ;)

Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Thu, 23 May 2013, 16:23:12
Can either of your printers print with soft materials?

Something along the lines of 10A Rubber?

Or can they only print hard ABS plastic?


I'm not sure how stiff 10A rubber is, but there is filament that replicates silicone.  There is also a plastic/software combination that replicates wood, including the grain. It's pretty impressive.

I haven't seen prices on either as they have only just come out.

what McM is good at is high quality very precise materials. this makes pricing look pretty bad at low MOQs but it's actually pretty good because the guys on ebay and amazon that are selling rods are not selling rods that are as precisely cylindrical as the McM parts.
I used VXB Bearing, they have quality rods and bearings for about half MCM's price. The rods I got were good, the bearings, meh. I plan on printing replacement bearings anyhow.

I wouldn't buy linear rods or bearings without a recommendation, not for a Rostock. The rods are too important and expensive. My next will use rails though, it's much cheaper.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: TotalChaos on Thu, 23 May 2013, 16:46:48
Can either of your printers print with soft materials?

Something along the lines of 10A Rubber?

Or can they only print hard ABS plastic?

I'm not sure how stiff 10A rubber is,
Seems plenty stiff to me.  To stiff actually.  But I figure its better for me than plastic.

Quote
but there is filament that replicates silicone.
Yes I saw that mentioned on some random website.   Of course there are a lot of different types of silicone at all different hardness levels.   When I hear "silicone" the first thing I think of is "boobs" and at first I was thinking that would be too squishy to print keycaps out of... but I did some more research and at least some silicone should be strong enuff to hold up.


Whenever someone is ready to start experimenting just let me know and I will send u $$$ to buy silicone filament and u can experiment with printing some keycaps.

If you can print a couple of keycaps that reach the zone of usability then I would be interested to pay u to print a full set (or 3, since I figure they might wear out after a year of usage.  Some silicone lasts a lot longer/shorter than other.)

For Keyboard Science!  ;D
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Thu, 23 May 2013, 19:48:19
silicone's melt point is insane, and rubber doesn't flow plus there's the melt point issue. there are urethanes that have reasonable melt points (an MBI head will _hard stop_ at 230c) but shrink like crazy and tend to be more poly than urethane and hence have hardnesses on the order or like 60-90A. 10A is a very tall order for an extrusion head.

for these kinds of materials, casting a gross shape and then machining it down via a mill or lathe is probably a much much better option.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Sat, 25 May 2013, 01:46:13
The silicone like stuff is like automotive silicone, it would work as a coating on keycaps, but not the keycap itself and you really need a dual extruder or a lot of time and patience tweaking to do it with a single.


As for temps, many heads use teflon or peek, which is a limiting temp factor, well under 300c.
Trinity or E3d heads are all metal and I can handle temps up to about 400c  (I think the Trinity is a tad lower). Beware though, if you do try it, you now have to worry about things around it, mounts, belts, etc... By 400c, lots of things start to melt.

On mine, I can change the head mount (effector) to aluminum and/or add a small heat shield and I'm set. I plan on getting an E3d head as soon as they come back in stock and I may do the aluminum effector.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: CPTBadAss on Sat, 25 May 2013, 07:23:30
Can you explain a little about how a dual extruder head helps print/extrude silicone? Does it spread the heat out between two heads?
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: agodinhost on Sat, 25 May 2013, 10:39:53
This is from a Rostock Max (wood framed) with an E3d head/.40 nozzle/no cooling/ABS/heated glass bed/magnetic rod ends.
Seems good enough for me...
Good enough? Gosh, it's almost perfect as far as I can see, geee ...
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Sat, 25 May 2013, 16:34:56
Do you need a scanner as well?
I think we missed this one, sorry.

No, you don't, you can download files already made or make your own.
In terms of scanning, you can buy a scanner, use a still image camera and stitch them together to make a 3d image, use stills as the basis for a 3d image, or use a video still frame the same way.

The latest method though is using an Xbox Kinect, they are having great results from that, and the new HD version has people really excited because the added detail will make scans far better.


Can you explain a little about how a dual extruder head helps print/extrude silicone? Does it spread the heat out between two heads?

You don't need dual head to do silicone (it's actually a plastic that feels like silicone), however if you were to make keys from it, it would be far too soft and floppy. My thinking was with dual head, you could build a regular key underneath and make a coating of silicone over the top, similar to rubberized keys.

I was thinking it could be done with a single head by just doing it in a separate operation, but odds of pulling it off are just too slim, time consuming, and just an insane way to do it. A second head isn't that difficult or expensive to add anyhow (about $75 for me). Once I get mine running how I want, I will likely do it.

Here is one (http://www.youtube.com/watch?v=MlMTFr9qu9Q) silicone like plastic, it's a bit stiffer than the other I saw. The other I saw is soft like Gummi Bears.


Also, I heard last night, a company is making a salt filament, so you can print in salt and another is making a water dissolving filament, which can be used to make internal support structures and then then dissolve in water when finished with no residue or distortion.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: CPTBadAss on Sat, 25 May 2013, 17:52:04
Ah that kind of dual head. I thought there was a new technology I wasnt aware of. But thanks for the info! Ive been keeping up with this thread since my work has introduced me to SLA/SLS/Metal 3D printing. Ive wanted to learn more about the Makerbots and hobby side of 3D printers.

/me goes back to lurking and learning
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: TotalChaos on Sat, 25 May 2013, 18:30:29
Do you need a scanner as well?

Back when I studied 3D scanners, I couldn't find a single one that was high enuff resolution to scan Keycaps or keyswitches accurately.

 


Can you explain a little about how a dual extruder head helps print/extrude silicone? Does it spread the heat out between two heads?
You don't need dual head to do silicone (it's actually a plastic that feels like silicone), however if you were to make keys from it, it would be far too soft and floppy.
Soft and floppy is what I want.  Of course they need to support their own weight and the stem is kinda small.  And given how small keycaps are I figured we might have to make them with an extra thick stem and maybe an extra thick top so they would have the required strength and rigidity.

Quote
My thinking was with dual head, you could build a regular key underneath and make a coating of silicone over the top, similar to rubberized keys.
Aha! ur so devious!  ;D
Very interesting idea


Quote
I was thinking it could be done with a single head by just doing it in a separate operation, but odds of pulling it off are just too slim, time consuming, and just an insane way to do it.
I doubt it would ever be accurate enuff trying to use 1 head in 2 totally different construction passes.


Quote
A second head isn't that difficult or expensive to add anyhow (about $75 for me). Once I get mine running how I want, I will likely do it.

Here is one (http://www.youtube.com/watch?v=MlMTFr9qu9Q) silicone like plastic, it's a bit stiffer than the other I saw. The other I saw is soft like Gummi Bears.
Gummi Bears support their own weight.  That's what I need.  Of course Gummi Bears are cheating and have 10x the thickness of the wall of a keycap stem. 


If there was such a thing as a material that was strong in one dimension while being soft and squishy in the other dimension that could work perfectly.  Horizonatlly rigid while being squishy vertically would theoretically absorb all the shock of bottoming out.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Sun, 26 May 2013, 03:18:52
Soft and floppy is what I want.  Of course they need to support their own weight and the stem is kinda small.  And given how small keycaps are I figured we might have to make them with an extra thick stem and maybe an extra thick top so they would have the required strength and rigidity
You cannot thicken the stem much at all as it must go into the top of the switch housing.


Quote
I doubt it would ever be accurate enuff trying to use 1 head in 2 totally different construction passes.
Actually a few companies are working on quick, auto change systems right now. One is close to production. It works on CNC machines, no reason it can't here, the problem is making it cheap enough.

Quote
Gummi Bears support their own weight.  That's what I need.  Of course Gummi Bears are cheating and have 10x the thickness of the wall of a keycap stem. 
The only way is to layer it over something stronger.

Quote
If there was such a thing as a material that was strong in one dimension while being soft and squishy in the other dimension that could work perfectly.  Horizonatlly rigid while being squishy vertically would theoretically absorb all the shock of bottoming out.
That is one of the wonders of 3d printing, like fiberglass, how you layer things and how solid you make it, can make things flexible in one way and stiff in another. They are making mini plastic leaf springs that work, it's just a matter of figuring it out.

Instead of making the stem connect to the top of the cap, leave a small gap, and use flexible attachments coming off the sides. It would work, the big question would be durability. On the attachments, the red would act as a spring. Besides durability, you have quality, feel, and you still need to figure out how strong of a spring you need, and it may need a guide so the cap doesn't flop to the side or something, but the basic premise is there.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: TotalChaos on Sun, 26 May 2013, 20:14:51
Great ideas u have Leslieann!

I have put away my silly ideas for a 100% rubber/silicone keycap.

I think it would be easiest to simply glue whatever extra shock absorbers on top of a normal cheap keycap.  I can glue some padding on top myself and call it a day...


 Or we could glue 4 small springs on top of a keycap with a square piece of plastic mounted/glued on top.  Technically, I would think a spring should be mounted onto a nub/column of some sort.  Seems like just gluing a spring to a flat piece of plastic... that the glue would break after 10,000 keystrokes.  Tho I am not claiming to be a glue expert or anything.  But we can't mount a spring onto a nub without also lengthening the spring to take that into account, then we end up with a rather tall keycap.  Luckily I don't mind tall keycaps.  ;D
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Mon, 27 May 2013, 00:18:30
(https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQCqzI3Br-9Lcyag-WujmSHLI4_EortT5kBxQAeNV-aVaRffjz42A)


210mm x 210mm x 325mm build area
It's probably going to make it's (horrible) first print shortly. Then it's on to fine tuning.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: TotalChaos on Mon, 27 May 2013, 04:35:50
Tell us how noisy it is.  :)
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: vvp on Mon, 27 May 2013, 06:57:45
Probably a lot till linear ball bearings are not replaced with bushings.
Leslieann, do you have diagonal rods longer than the common 25cm? Because if not than you cannot do 21cm x 21cm square, it is more a circle with about 24cm diameter. The one I can get to is not finished yet and it has 25cm diagonal rods.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Mon, 27 May 2013, 14:13:15
Show Image
(https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQCqzI3Br-9Lcyag-WujmSHLI4_EortT5kBxQAeNV-aVaRffjz42A)



210mm x 210mm x 325mm build area
It's probably going to make it's (horrible) first print shortly. Then it's on to fine tuning.
pics!
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Findecanor on Mon, 27 May 2013, 17:44:52
The latest method though is using an Xbox Kinect, they are having great results from that, and the new HD version has people really excited because the added detail will make scans far better.
I visited a startup company not long ago: Volumental (http://www.volumental.com/). You use Kinect, a browser plugin (Windows and Mac only) and their servers do the computation. When it was demonstrated to me, uploading and downloading took most of the waiting time. The result is a mesh and a texture map.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Mon, 27 May 2013, 18:19:27
Tell us how noisy it is.  :)
Actually, since I got the better bearings and rods, it's not that bad. It's similar to the square tube railed ones on Youtube, such as Cerberus and Kossel.

Probably a lot till linear ball bearings are not replaced with bushings.
Leslieann, do you have diagonal rods longer than the common 25cm? Because if not than you cannot do 21cm x 21cm square, it is more a circle with about 24cm diameter. The one I can get to is not finished yet and it has 25cm diagonal rods.
Yeah, it's a bit smaller especially since my heated bed is smaller than that as well. A more realistic number right now is 150mm-180.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Wed, 29 May 2013, 04:51:42
First print.

A 10mm crooked cube. LOL
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: PointyFox on Wed, 29 May 2013, 22:05:40
First print.

A 10mm crooked cube. LOL

Oh God.. WHAT HAVE YOU DONE?!
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Thu, 30 May 2013, 11:21:41
taking potatocam to a whole new level lol
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Krogenar on Thu, 30 May 2013, 11:23:44
taking potatocam to a whole new level lol

Leslieann printed a potato!

But hey, something printed, it's a start!
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: vvp on Thu, 30 May 2013, 15:18:24
First print.

A 10mm crooked cube. LOL

Oh God.. WHAT HAVE YOU DONE?!

The fan is not doing a good blow job or the parts are too hot.
Just a guess  :rolleyes:
Anyway, nice progress!
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Thu, 30 May 2013, 15:30:19
can you illuminate (lol) how you did your heated plate? materials etc? i want to (but may not get around to) playing around with rotating heated mica/silicate beds. the canonical example of an object that will print well in a polar system and not a cartesian is the simple cylinder (whereas the cube, or worse, the high ratio rectangle) is the vv example.

i will definitely start by playing with mica-silicate non-rotating beds though, so definitely, parts, bom, measurements, etc. (reminder: pick up a type-k probe and fluke adapter or dedicated unit for precise contact measurement -- IR is going to pick up and average too much of the bed, exactly what you don't want when you're measuring uniformity).
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Thu, 30 May 2013, 16:28:40
taking potatocam to a whole new level lol
The lens was blurry, it's a tiny object, and there was movement in frame, not a good situation for any potato cam.

Anyhow, I got in a rush to capture the moment, but as Krogenar said, it printed. lol

can you illuminate (lol) how you did your heated plate? materials etc? i want to (but may not get around to) playing around with rotating heated mica/silicate beds. the canonical example of an object that will print well in a polar system and not a cartesian is the simple cylinder (whereas the cube, or worse, the high ratio rectangle) is the vv example.

i will definitely start by playing with mica-silicate non-rotating beds though, so definitely, parts, bom, measurements, etc. (reminder: pick up a type-k probe and fluke adapter or dedicated unit for precise contact measurement -- IR is going to pick up and average too much of the bed, exactly what you don't want when you're measuring uniformity).
I got a PCB based heat bed (which is smaller than my build area) along with belts/pulleys, Arduino, sd adapter, and endstops in a smoking combo deal on Ebay.

I covered it with green glass and Aqua Net hairspray (make sure it's cold or it will look like Michael Jackson's hair). Also you want to cover anything such as mechanicals to avoid the spray as it can gum things up. I sprayed some on a paper towel and wiped it onto the surface 5 prints so far without having to reapply. I use 8 clamp type paper clips to hold it around the perimeter and ensure good contact as the pcb's are never flat.

PCB beds heat faster, cost more and use more power, mine plus glass and clips takes about 7 minutes to heat up, but I think I need a stronger PSU, as the heat system cycles I can see my LED build area lights flicker a touch. My bed alone is sucking up about 11 amps, plus the 5 for the rest of the system really taxes the PSU the little PSU I'm using (I have 1 or 2 spare amps on an old, used psu). I also had to add a fan to the Arduino as the heater was overloading the circuits.

No matter how round you try and make something, you have to remember that you are working in digital, at some point you hit the pixel level and it will simply not get anymore round. Although, I'm seeing it, despite being digital, if you slow down the jerk movement and run a few degrees cooler/more fan, you can actually round the corners. At least on a Delta. While making the cubes, a few corners on a few levels ended up rounding due to the speed of the arm jerk versus the speed of filament extrusion. I ended up with a really nice rounded corner.

As for temps, I fired a few temp probes on my bed, one I crushed two were damaged while adding heat shrink (thermistors are damaged by an open flame, but soldering irons are fine...) so I am using a 10k resistor from an old pc fan I had laying around. It's quite inaccurate, however I'm having no issues with the bed temps, I just kinds guessed on a how off it might be and it works fine, it's off by about 2-3 degrees at room temp, so I set it 6-8 degrees below target temp, How did I get that, well, for each degree after that, it gets increasingly longer to heat up, and I got tired of waiting and just decided to print and see what happens. LOL It worked.

Point is, don't worry about temp accuracy, find a temp that works. Nozzle size, filament type and even filament brand will change what temps work best. On a .5 nozzle, I get flow around 220c, but I print at 235c. On a .35 nozzle I don't even see flow until 240 and print at 245. When you go too high on either plastic, you can smell it and when it's too low, it won't do anything. My experience so far has been that it should slowly drool when it gets near the right temp and a full nozzle.


To get started, worry more about getting things running right, instead of trying to have it all figured out and measurement-wise perfect. Nothing on these is perfect, and you will probably just over complicate it. You are going to probably spend a long time just figuring out the best temps, nozzle, and THEN you get to play with extrusion settings. Precise temps are the least of your worries and are something easily figured out through trial and error, and are in fact best figured out in that manner. I have heard of ABS varying from 215 to 260 for best melting point. Like I said before, forget the precise number, find what works for you and your combination.


I had the same problem with my first saltwater aquarium, I went all out with all sorts of expensive equipment and I just over complicated it. I downsized and went to a simple all in one, with nothing special and had a great working tank. Same with the printers, get what you REQUIRE and figure out where to go from there.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Sat, 01 June 2013, 08:02:57
Quote
I got a PCB based heat bed (which is smaller than my build area) along with belts/pulleys, Arduino, sd adapter, and endstops in a smoking combo deal on Ebay.
using a pcb as a uniform filament... BRILLIANT!!

Quote
I covered it with green glass and Aqua Net hairspray (make sure it's cold or it will look like Michael Jackson's hair). Also you want to cover anything such as mechanicals to avoid the spray as it can gum things up. I sprayed some on a paper towel and wiped it onto the surface 5 prints so far without having to reapply. I use 8 clamp type paper clips to hold it around the perimeter and ensure good contact as the pcb's are never flat.
buy a granite surface plate at your local machine shop shop, knife shop, or carpentry shop. lap the glass on the plate. the glass is much heavier than the pcb and as long as it's thick enough (it's thick, right? if not, buy a thicker one and run more current through the pcb) will not be deformed by the pcb.

Quote
PCB beds heat faster, cost more and use more power, mine plus glass and clips takes about 7 minutes to heat up, but I think I need a stronger PSU, as the heat system cycles I can see my LED build area lights flicker a touch. My bed alone is sucking up about 11 amps, plus the 5 for the rest of the system really taxes the PSU the little PSU I'm using (I have 1 or 2 spare amps on an old, used psu). I also had to add a fan to the Arduino as the heater was overloading the circuits.

No matter how round you try and make something, you have to remember that you are working in digital, at some point you hit the pixel level and it will simply not get anymore round. Although, I'm seeing it, despite being digital, if you slow down the jerk movement and run a few degrees cooler/more fan, you can actually round the corners. At least on a Delta. While making the cubes, a few corners on a few levels ended up rounding due to the speed of the arm jerk versus the speed of filament extrusion. I ended up with a really nice rounded corner.

As for temps, I fired a few temp probes on my bed, one I crushed two were damaged while adding heat shrink (thermistors are damaged by an open flame, but soldering irons are fine...) so I am using a 10k resistor from an old pc fan I had laying around. It's quite inaccurate, however I'm having no issues with the bed temps, I just kinds guessed on a how off it might be and it works fine, it's off by about 2-3 degrees at room temp, so I set it 6-8 degrees below target temp, How did I get that, well, for each degree after that, it gets increasingly longer to heat up, and I got tired of waiting and just decided to print and see what happens. LOL It worked.

Point is, don't worry about temp accuracy, find a temp that works. Nozzle size, filament type and even filament brand will change what temps work best. On a .5 nozzle, I get flow around 220c, but I print at 235c. On a .35 nozzle I don't even see flow until 240 and print at 245. When you go too high on either plastic, you can smell it and when it's too low, it won't do anything. My experience so far has been that it should slowly drool when it gets near the right temp and a full nozzle.


To get started, worry more about getting things running right, instead of trying to have it all figured out and measurement-wise perfect. Nothing on these is perfect, and you will probably just over complicate it. You are going to probably spend a long time just figuring out the best temps, nozzle, and THEN you get to play with extrusion settings. Precise temps are the least of your worries and are something easily figured out through trial and error, and are in fact best figured out in that manner. I have heard of ABS varying from 215 to 260 for best melting point. Like I said before, forget the precise number, find what works for you and your combination.


I had the same problem with my first saltwater aquarium, I went all out with all sorts of expensive equipment and I just over complicated it. I downsized and went to a simple all in one, with nothing special and had a great working tank. Same with the printers, get what you REQUIRE and figure out where to go from there.
HMMMM... interesting point about not-needing uniformity... as much as the right temp at the center (where you're mostly printing)... food for thought.

as far as power supplies are concerned, find a local neckbeard-run electronics surplus place. they'll have more power supplies there than you can shake a very large stick at for way way cheap.

i just made the mother of all purchases at adafruit to play with arm-based motor and filament controllers. will be going back for more once the beaglebone black run comes in (NEED MOAR JTAG). you can also get all kinds of crap on ebay. look for way used brand name units (lambda, delta, sparkle -- no really, these are brand names), especially ones originally made to power huge RF transmitters, as they're cheap and least likely to blow up on you.

Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Sat, 01 June 2013, 16:22:13
The glass is flat, the PCB isn't, as for bent glass, the way a  Delta works, it's always constantly adjusting because as far as it's concerned there is no such thing as flat really.

As for the power supply, I have TONS of them in the basement, I just don't want to change it out yet.


Status update:
My prints are getting better, I'm actually starting to get close to usable items. I have my scale down, so a 10mm cube is actually 10mm. Flow rate appears to be my last big hurdle, I think.

Belts are a pain... They need to be TIGHT. One person said basically it should sound like an upright bass guitar when you flick them. I made 3 of these (http://www.thingiverse.com/thing:12513), and they make it a lot easier to get that last bit of tension, though I may actually have made them too tight at this point, noise shot way up on one carriage, so I will have to check.

Oh, and I figured out, as soon as you sit down to make something, before anything else, start warming up the bed.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Sat, 01 June 2013, 17:51:10
glass has low thermal conductivity. i agree.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Tue, 04 June 2013, 23:43:51
on that note, i got two material samples in today:

1) borosilicate 0.125" thick sheet
2) alumina ceramic 0.025" thick sheet

the borosilicate is clearly going to be much easier to machine. it should basically lap flat just like glass. which is good, because this sheet is _not_ flat.

the ceramic requires diamond tooling iirc to machine, so what you get is what you get flatness wise. however, the flatness of this sample is reasonable, and more importantly, it conforms quite easily to my surface plate and apparently requires a huge amount of bending force to crack or otherwise break. thermal conductivity is fantastic. i could see a sandwich where the top layer is a very thin layer of alumina ceramic, the middle layer is a filament carrying a ton of current, and the bottom layer is something very flat, but not thermally conductive. not only would this heat quickly and uniformly, but it would be almost impossible to damage.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Wed, 05 June 2013, 01:21:21
Yes, Ceramic will need diamond tooling.

You are going to spend a ton of time making a super flat bed, then heat it up to 80c (which can cause things to shift), inside a heated box (again, things shift), and then you plan to lay down plastic, which warps like CRAZY as it cools.

Even if you could print a keyboard case flat, ABS would prevent you from doing so. Any more than a few inches and by the time you get a few layers, as they start to cool, they will shrink, pulling the ends up. Experts actually only recomend a 10cm length tops because of the warpage.

Take a look here:
This guy is awesome.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Wed, 05 June 2013, 02:31:47
first of all, i actually think that we should just do large objects in PLA. unless there's some material reason why we need to print something in abs we should just print it in PLA, period.

second, i think we need to recall high school physics: there are two kinds of effects that we refer to as errors in any process; there is stochastic error, this is the isometric shrinkage that causes surface abnormalities and roughage in FFM printing, and there is systematic error, which causes distinct geometrical errors in the shapes that are printed via FFM. how is this relevant? flatness of the surface plate is an attempt to minimize systematic error, and heating the surface plate is meant to reduce stochastic error. however, it's important to note that the error factors introduced by these two flaws in the manufacturing process are not independent!

in particular, as i think i ranted about earlier today, every damn thing is stochastic! some things are just lucky enough that their random error variables have tiny short tails and low variance. i will admit that i didn't watch that dude's entire youtube rant, but my feeling is that he's not analyzing his sources of error; just pointing out that you can never remove the error completely is not a productive use of one's time. so here's my feeling. we can do a lot better than what's contained in the reprap wiki and/or what's commercially available. yes, i'm going to spend a ton of time experimenting and hopefully build a flat plate that stays flat when you heat it to 100C or so. then, i'm going to lay down PLA on it in layers, and hopefully the thing that comes out is going to be incrementally closer to my CAD than the thing that was produced before i sat down and thought really hard about the sources of error in the original design :D

if not, i'm sure as hell going to understand the issues better, and nothing's going to stop me from trying again :))

ps, can you tell i'm going stir crazy from having my printer another month out? :))
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Wed, 05 June 2013, 19:55:37
Reducing error is good, don't get me wrong, but I just think you are going a bit extreme on a system that is only really capable of .1mm (.003in) accuracy under the best of circumstances.

As for PLA vs ABS, PLA isn't as strong, nor are the colors as vibrant, however, I hear it's great to work with.


Looks like I finally got mine dialed in other than scale.
I may need to add an extra cooling fan to the head to sharpen up my corners a tad, but otherwise my prints are looking quite good.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Wed, 05 June 2013, 20:22:19
PLA is only incrementally less strong than ABS, and remember that an object that's printed FFM is going to be way way less dense than an object that's molded under high pressure. as everyone is constantly pointing out, the defects in the bulk material are HUGE, much bigger than the 0.1mm that _the stepper motors only_ are capable of.

instead of thinking "well, this is a low accuracy manufacturing method, screw it", think "ok, how do i reduce my other error sources to get to the fundamental accuracy (computational and electromechanical) that this manufacturing method is capable of".

if we were talking about that cool but weird heated filament pen i might be like "yah, screw it, we're limited by the human hand", but stepper motors and computational units can be incredibly accurate. the only thing holding FFM back is the introduction of bulk defects from physical sources; otherwise, it's actually a pretty damned accurate way of making things..
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Thu, 06 June 2013, 03:13:52
PLA is actually quite a bit more brittle. Number-wise they may seem similar, but in actual use, it's quite a bit different. I watched a Youtube video of a guy messing with and breaking both, ABS fared much better. PLA is also fickle in terms of moisture and we have high humidity here. Installing and removing filament after each job is cumbersome, you can't just pull it out of the extruder when finished.


As for the accuracy,
Of all the things in your printer effecting quality, you are focused on the part that is already the most accurate part in the entire machine and where you will see the absolute least (if any) gains. You can't even level the bed to the level of accuracy you are after. Accuracy is good, but focus it on something that will visibly make your prints better. I can't tell you where that is on a cartesian, probably belt tension or something, but it's certainly not the bed accuracy.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Thu, 06 June 2013, 09:01:46
abs is actually way more fickle in terms of humidity. i think i mentioned earlier, but dry box.

bed accuracy is huge because it's systematic, and shrinkage is one of the biggest issues, especially with abs.

ps: steppers and threaded rods
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Thu, 06 June 2013, 16:05:40

Everything I have read says exactly the opposite about humidty. PLA is soy and corn based and just soaks it right up. ABS is more heat fickle and while humidity bothers it, it's nothing like PLA. Strength and humidity were why I started with ABS.

Bed accuracy can be huge, but again, it's already the most accurate item in the printer. You are targeting the most accurate item hoping to help make up for the shortcomings of everything else, which are known to be quite inaccurate.

Until you deal with the other inaccuracies, you can put the most accurate bed known to man, but it won't make a lick of difference in your prints. This goes triple since you have yet to even try the printer and see just how many things are going to cause trouble before you even start putting down plastic.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Thu, 06 June 2013, 22:06:14
neither material is hydrophilic, and bed accuracy (flatness and cooling issues) is the least accurate part of a threaded rod-based printer FOR PRINTS FRIENDLY TO ITS COORDINATE SYSTEM

what actually happens with polymers is that water gets between the polymer chains, and becomes a defect in the bulk filament. between PLA and ABS, ABS is the stickiest water-wise, and hence has the most problem with this, in addition to having the worst shrinkage and thermal behavior. PLA was championed earliest for FDM and FFM printing because a) lower temperature resistance and property change points means it's most stable while cooling and b) less sticky in terms of water. further, even if you do get water in the filament, you don't need to heat it as much to get the phase change and hence the water produces fewer defects in the printed material and is less problematic when the filament hits the heater. that said, any bulk polymer filament should be stored in a dry box.

the head position on a cartesian printer is by far the most accurate part of the printer. it's completely analogous to a CNC mill. as long as your stepper motors are accurate, your rods are accurate, and the head itself is fixtured with enough force, basic controls can position the head to near the 0.1mm the threading and steppers are capable of. (note that at this point all i'm talking about is moving to the point and then sitting there)

your printer has a completely different set of error sources; your head positioning depends on tie rods and bearings, and apparently the tie rods are attached to belts at some point? completely different, and a source of much more error for certain types of operations.

for example, consider the g-code execution of printing a cylinder on your machine vs a makerbot. the makerbot is going to have positioning issues due to computation accuracy, nasty inertial forces all over the place, etc. your machine has fewer fewer movements to make, and can take code in polar coords (the point of that design). further, the inertial forces are going to look completely different. in this case, your bed accuracy is going to play a larger part and my bed accuracy is going to play a smaller part in the printing error.

now, consider the g-code execution of printing a cube on both machines. the makerbot is going to be happy as a ****ing clam. only one motor's going to have to move at once, and now the bed accuracy is a BIG DEAL. your machine is going to be pretty unhappy.

make more sense now?
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Thu, 06 June 2013, 22:21:27
I still don't buy it, I don't think it will hurt, but I still doubt it will do much.
The plate you are are getting is already considered one of the better ones in the industry. I'm not saying it can't be better, but have serious doubts that making it better is going to do much. It;s not like your printer comes with a plywood bed.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Thu, 06 June 2013, 22:38:39
the makerbot alum plates cost 75$. the idea is that you use them for a little while until the heating and cooling cycles warp the metal or the teflon coating nicks or worse. then you throw it out. even so, it's a plate that's too thin to even bother machining flat, even if it had uniform heating (the corners have a tendency to "wing out"). it is one of the better in the cottage maker industry, but the cottage maker industry just doesn't have a lot of resources at the moment (although we're here right now working to change that :D). the makerbot solution is nice because it's "good enough" for a "long enough" lifetime, and then it's easily replaceable. and note that even then, you have a tilting table under the bed that you have to use to try to level your printing space for each job, or else, as i was told by an MBI rep "yah, your prints will probably warp otherwise. we recommend a [tolerance] height gauge and adjusting the table every few prints".
u
let me put it this way. a bridgeport 3-ish axis cnc mill costs 70 grand without even the gcode compiler, and its weight is measured in portions of tons. when you want to make a circular hole in something with a bridgeport, if at all possible, you take a machine bit the diameter of the hole you want to make, and you drill out that hole directly, because it's not quite accurate enough to make a circle anywhere near as accurate with a smaller tool.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Thu, 06 June 2013, 22:45:33
christ, i'm totally rambling at this point.

let's see your new prints!!
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Sat, 08 June 2013, 01:27:40
the makerbot alum plates cost 75$. the idea is that you use them for a little while until the heating and cooling cycles warp the metal or the teflon coating nicks or worse. then you throw it out.
WTH!?
Okay, I get it now, that's insane.  I wouldn't play that game either.

I'll post some fresh prints in a bit, I am ordering magnetic arms this weekend, which will help, but at the moment I had to recalibrate things as I redid my upper and lower plates because the old ones were done in a rush (and were quite off).

Other issues:
The cheap aluminum pulleys I got were complete junk and stripped out. I found while replacing one, that it was rocking about 1/8th turn on the shaft. It's amazing how good my prints were, all things considered.

I'm still working on getting correct scale and final calibrations on things. I got a new Extruder, put in a cooling fan and duct and just getting things squared away, but the prints are getting better. I did a hollow cube earlier and it came out fantastic (needed more fan), but before getting a picture, I broke it apart to see how it looked inside. My bridging inside was good, as was the strength, so I know my retraction and cooling is pretty much dead on.

I'm going to get some PLA next week as well and see how that goes. I also plan on getting another head soon. I bought this one with the intention of using it only to get a handle on things as the one I wanted was out of stock. I need to adjust my P.I.D. tonight too (no idea what it is), so I get better heating on my bed and head. As it is, I'm pushing the little power supply quite hard by the time I run lights, heaters and fans.

This is what happens when you build from scratch though, and it's interesting.


I will admit, if there is one thing I dislike about deltas, it's the calibration. Getting it to print flat, at the right scale, and the right height... It's like groundhog day.  Make a firmware adjustment, home all the towers, measure and adjust, make another adjustment to firmware, home all the towers, measure and adjust, wash rinse, repeat until the towers all match the bed center. Any time you change one thing, every measurement change. You can't just do it once and be done, so you spend hours, going up, going down, upload, measure, up, down....

And it gets worse, these measurements are supposed to done while hot. So while you are sliding a bit of paper under the hot head, you are trying not to bump it with your knuckles, while watching the screen, and clicking the mouse to move the axis. During all of this,  your fingers are insulated from the 80C bed, only by a thin bit of paper. NOT FUN.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Sat, 08 June 2013, 05:47:50
Potato cam time...

TL:DR
Left is latest print @ 2x speed, on the right is my very first print.



I know some of you are probably wondering why I'm still tuning this thing. Well, first off, as mentioned I made some changes, had some problems... This is a home built machine built from (rather loose) open source plans, and I can be a bit obsessive at times.

Anyhow...
On the right, is the first thing/cube I printed. A 10mm solid cube (why solid?) printed with a .5mm nozzle, it was 20% over sized (.0785in) and, well, just look at it. It leans, no uniformity... This was a result of bad frame alignment, loose belts, and what I later found was a pulley that was holding on for dear life and several rods weren't tightened up all the way. But hey, it printed so I was happy at the time, I finally had something, regardless of how horrible it was,  to show for all the money and effort.

On the left is the latest, yes, I know the top infill isn't great (I was experimenting)... However, it was printed at twice the speed as the one on the right with a .35mm nozzle, and is completely hollow, the walls are only 1mm thick and it won't fall apart like the one on the right has done, it takes a pair of pliers to crush or damage it.  It's also within one thousandth of an inch of what it is supposed to be, I think I can cut that in half and possibly triple the speed with some changes. Maybe your super bed isn't so crazy after all! It wasn't until I got my calipers and I converted my numbers to inches that I realized. Now I'm kind of shocked to be honest, I really didn't expect that sort of accuracy. Maybe it's time to stop fooling with it and print something for real.

The one corner looks bad (as does one on back corner) for a couple reasons. The corner you are seeing happens to be where the head was stepping up. On something this small, the loops are small and so the previous layer hasn't cooled quite enough to compensate for the added time of the head being there while moving up and adding more hot plastic, so you get a slight melted look. The back side suffers because my fan doesn't reach it as well, I just installed it today and may add a second of a deflector to redirect the air back there. I had two fans before but with no ducting and was getting worse results with two, larger fans than I am now. Some of this can be fixed by adding a pause between layers, but that can leave the head sitting in a bad spot, lowering temps, more air flow and more... That's part of the problem though, every problem has 10 solutions, each with different results that may impact something else, so there is a lot of trial and error.

Anyhow, there is very clear progression there, in fact, if you ignore the heat issues (due to size) and my poor infill (again, I was experimenting), my prints are better than the parts on the printer itself at this point and only getting better.


Edit: I just noticed the picture makes the new one look like it tapers in at the bottom, so I checked it with my calipers, it's showing a difference of .0005in between the two. While I have doubts that my El Cheapo caliper is even that accurate, I can live with it.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Sat, 08 June 2013, 09:12:55
you're getting there. that's not bad for abs

PID algorithm: http://en.wikipedia.org/wiki/PID_controller

it's the simplest control algorithm
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Sat, 08 June 2013, 17:07:35
Thanks. :)
I'm pretty happy with it, Just a little more and I think I will consider it done.

Then I'll start working on my next one. LOL
I have a sneaking suspicion this one may be sold by the end of the month. I have some people interesting in getting a printer, and I'm pretty sure at a meeting I have later this month that I could probably sell it to finance the next one pretty easily. If so, I'll be building a Cerberus or Kossel next (I will whether I sell it or not!).


There are a LOT of pitfalls doing it from plans.
If anyone is considering it, research, research, research. It's easy to get lost or over spend.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Mon, 10 June 2013, 09:50:07
IT SHIPPED!!!! IT SHIPPED!!#@*)(#)*(@!)(*#!(*)@#()* ao ewxzcirwewsklj ao wzxirwskjlhakj aso excited i can"t even type!?!?!?!?!#!#()_#!)(_#!
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Mon, 10 June 2013, 17:45:23
Awesome!

I have some PLA coming, magnetic arms (better precision) and a stronger power supply. The latter is something I hear yours actually can benefit from as well.

I have 17 amps (old PSU), the board uses 5amps and the bed uses 11... supposedly. However, when I flip on my LED lights I can see them flicker depending on system load, so I have a 20 amp coming to replace it. Plus, the bed struggles to warm up when I have even the slightest breeze. In fact I was getting some airflow from my Arduino cooling fan and that was hurting heating times even. I have never gotten it over 80C. I built a guard to redirect that air and it helped, but more amperage is needed. The current PSU is a noisy little bast*rd anyhow. I have seen three of these power supplies and not a single one has a good fan in it.

I thought I blew up a motor or driver the other night as well, the driver modules are just fickle. Too much power and they overheat or cause the motor to click, too little and the motor won't move. I think it was fine, but I ramped up the power to stop it clicking, which only made it worse. I think the real problem is I may have a clogged nozze. Weee...
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Mon, 10 June 2013, 18:22:09
i have power supplies. christ i have a lot of power supplies. i also live 10 minutes away from allelectronics

power supplies will not be an issue.

clogged nozz's suck!! datavac to the rescue? :D
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Mon, 10 June 2013, 18:39:43
i have power supplies. christ i have a lot of power supplies.
I do too, however finding one that can push 18+ amps, wasn't in the scrap pile. :(

I got a nice low profile one with 20 amps for $20, it's overkill, but I would rather be over powered than under.


I got the bed up to 80 finally. I swapped back to my .5mm nozzle, and still having some feed issues and retraction problems. Just not quite set right I guess. One of those instances where a pre-built would be a lot easier to deal with, but, meh.  I did this as an experiment, albeit an expensive one, but you have to pay to play.

Also, if you haven't tried it, try Tinkercad. It's not a fantastic cad program, but you can knock out simple stuff extremely fast.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Mon, 10 June 2013, 19:35:51
forcing myself to learn solidworks. yuck but what're you gonna do
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: kmiller8 on Mon, 10 June 2013, 19:41:31
Hey, I just bought a 3D printer too! can I join the party OuO
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Acetrak on Mon, 10 June 2013, 20:11:39
mkawa I can give you free lessons np
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Mon, 10 June 2013, 20:59:54
Here is a tip, when trying to trouble shoot, keep a log of changes you made...

My extrusion issues have been solved, I found a small setting I had changed waaaaay back trying to solve a different problem. I fixed the other problem, but this was haunting me now. I'm thinking of calling this printer "Butterfly effect", because any minor change you make, can have HUGE results elsewhere.

The air nozzle I'm printing looks FANTASTIC, bridging is good, no lift, no overhangs, no odd noises, no droops, no melting, it's just soooo smooth. This is with a .5 nozzle, .35 layer height, 60mm per sec print speed (average speed for a cartesian).


Yes, I'm swooning, it's the best print I have made so far, and it's with my large nozzle and a higher speed than I have been using. This is what I have been aiming for.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Thu, 13 June 2013, 18:20:34
I like PLA... for about 5 minutes, then my print head shaft gets too hot and clogs the whole works. This stuff is REALLY, REALLY temperature fickle.

I have reconfigured my fans 4 times now trying to get it to work with no luck. Best I have managed is about 10 minutes of printing with it.  All this time I thought my extruder was underpowered, it's not, in fact I snapped off more than half the metal teeth in my Bowden tube press fit connector.  So apparently, I've been battling this head from the start.

I get fantastic prints at slow speeds, then as the teflon liner warms up, it gets worse, and worse and worse, until it just clogs entirely. I had it printing at 200mm a second and after 10 minutes it couldn't even manage 1mm per 30 seconds. By the way, watching a delta at 200mm per second is awesome(!) but wow do things to to shaking. LOL

Oh, I don't mean the printer, don't get me wrong, it was swaying and shaking, but it was printing great, it was more than capable. No, it was shaking the desk, which in turn was reverberating into the floor. You would have thought someone was having some extremely hardcore sex, during an earthquake, while on PCP. Needless to say, I didn't let it run like that for long. Something would give under that kind of punishment.

Sooo, next paycheck, I'm ordering a new head. This was only meant to be temporary, but E3d heads are still a 3week wait (been that way for weeks). Trinity has a good one as well, but theirs is meant for 3mm, not the 1.75 I use. The only other all metal one I found, doesn't have a built in bhowden attachment. I'm starting to consider just making my own, they aren't that complex really. In the meantime I may order up a J-Head and see how that does, unfortunately, those too lack a bowden attachment.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Tue, 18 June 2013, 09:09:32
holy crap

(https://dl.dropboxusercontent.com/u/24794081/_DSC9520.JPG)
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: linziyi on Tue, 18 June 2013, 09:10:28
:O it's in colour! Thought 3d printing can't include colours in it
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: vvp on Tue, 18 June 2013, 13:55:00
:O it's in colour! Thought 3d printing can't include colours in it

Even the cheap DIY 3d printers can do colors. The question is why would one bother with it?
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Tue, 18 June 2013, 16:51:30
holy crap
Damn that came out great, I'm a bit envious at how easily you got up and running.

Watch out for shrink on ABS, it's like dunking a hot guy in freezing water if your bed temp isn't above 90C.  :)



PLA is a nightmare to get right, it turns out I broke both 120psi pneumatic fittings that hold the bowden (feed) tube. Seriously, the fittings hold 120 psi, and I snapped the hell out of both of them.  :eek:

When they broke they not only jammed my nozzles, one piece also jammed the entrance to the print head. What stinks is I kept redoing my fan layout, thinking the PLA was clogging. It was, however it wasn't a temp issue, it was metal in the feed system causing excess pressure, which allowed the PLA to overheat.

Now that everything is cleaned out, I'm printing ABS like a champ (even that had begun to clog after 5 minutes of printing). I have two new fittings on the way, and I'm reworking my fans a little more to hopefully get PLA flowing good. I'm finally able to start making things other than small simple stuff.



I found out a few other things.
I upgraded the PSU from a tired 17amp unit to a new 22amp, added a larger heatsink (with heat sink compound) to the Ramps board, and increased the awg size on my bed from 18awg to 16awg. WOW what a difference. I immediately saw a huge change in how the bed heats up, and no more light dimming when the lights are on. However, this unveiled a new issue... The new PSU showed I was still undersize on wiring and the wires were heating up bit enough to burn, but quite warm, had I still been using the 18awg, I'm sure I would have melted something. I put 14awg wires on the bed and not only are the wires cold, but the bed heats twice as fast as it used to.

I did some checking, I was on 18guage wires and according to some charts, for a short run, 18awg will handle 11 amps. However, I had issues even with 16awg. This tells me that either some of the wire size charts are wrong, or the bed is pulling more than 11 amps. Before, it would take 15 minutes or more to reach 75c, and that was with no fans (sometimes it struggled even with that), now it heats up to 90c in about 5 minutes, even with a small fan blowing across the glass .  :D

I also insulated my head (currently in the garage drying), and I have the parts for my magnetic arms, which will clean up slop, but I need to buy new JB weld as the stuff I have I think is bad, it didn't hold very well at all. Once I get PLA flowing I'll finish the magnetic arms, and then I will be off and running with good accuracy.  I still want   better head, but now that it's not as much of a hurry now that I know the head wasn't the main problem. I can always use the old one for another color. I just need another Nema motor and bowden tube.

Oh, and I did finally get the PID done, but I have to redo it again now that I changed the wires and insulated the head.


I hope no one has the wrong idea, I built mine from scratch from a newer design. It's bound to take some tuning and tweaking. While Mkawa is printing great, he spent a lot more to do so. I wanted the newer style and the experience of working from scratch, mine was as much about the journey as it was about the destination. Both methods work and eventually (with luck) arrive at great working printers, we just took different routes. Some of my issues were my fault, others were luck of the draw, some are due to lack of documentation. I'm sure Mkawa is happy with his, as am I with mine.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: Leslieann on Tue, 18 June 2013, 16:53:48
Even the cheap DIY 3d printers can do colors. The question is why would one bother with it?

Two colors allow for lettering or designs to be placed on objects.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Tue, 18 June 2013, 18:41:03
rule of thumb is to run twice as many wires as the theoretical max. the theoretical max assumes no defects in the bulk wire (whether stranded or solid). this is _never_ the case. defects raise resistance, which causes dissipation in the wire (resistive losses = power expended in wire = hot wire). also pay close attention to the specs you're reading as theoretical maximums. they may be ratings at something like 60C, which is way too hot for practical runs of wire.

it's a bit like speccing power supplies. switching supplies are typically happiest at 50% max steady-state load @ 40-50C. raise the temperature or load and you're likely making some semiconductor or dieletric very unhappy for short, or worse, long periods of time. you're also typically increasing noise and ripple, which can cause problems through the circuit that the rail supplies if you're say, analog or mixed signal and psrr is not impeccable.

anyway, this is all a roundabout way of suggesting that you consider investing in more tooling than product, leslieann. at the moment, you're so focused on making a print that you're not really sure what, where, or how everything is working. it seems to me (and feel free to correct me if i'm wrong) that you're attempting a print, guessing a fix, attempting another print, guessing another fix, etc. i may be too far in the other direction, but i don't like to start the machine until i have concrete properties and measurements in my head and can validate what _should_ happen. then, i can stop things and perform a control step the second i see something i don't expect. this has nothing to do with starting from a kit vs a built machine; although i am also surprised the built machine was able to pump a few small things out so easily, i can guarantee you that it's not all wine and roses.

that said, the first thing i'm doing right now is actually building a mount for a dial indicator so that i can do a regular topographical map of my build plate(s). believe it or not, the carriages and driver for such are pretty damn good, even with a few belts in the mix (doh! i was wrong about that one, only the Z axis is a threaded rod), and the build platform is definitely the limiting factor for me.

based on the first map i'm going to have to decide whether to try lapping, different materials, holders, etc. interestingly, the rep2x plate approach is to raw _cast_ (i'm guessing it's a gravity cast from the look of it) an aluminum plate. this is interesting because ideally you would actually want a forged plate to maximize uniformity of expansion, and then you would want to machine the finish to get verifiable flatness at room temperature. of course, as i said before, 75$ for a new plate, so a raw gravity cast it is :P. hilariously, the factory even misaligned the kapton tape (they use full on kapton instead of just teflon, ironically; the film probably costs more than the plate), so i have a gigantic seam running across the tape where one roll ended and the other began. you can actually see this in the traffic cone, although i'm not sure if i got it in the picture.

anyway, one of the goals of this project is to develop a new machine that, as i said before, uses truly polar gcode and construction. one of the nice side-effects of the traffic cone test print (included on an sd card with the machine!) is that you can see the computational approximation in the "circular" cone. this was pleasantly surprising, as going into this, i was sure that physical error would dominate computational error everywhere.

ok, novel over. fun awaits! feel free to ping outside the thread if you want to powow on really gritty specifics leslieann!
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Tue, 18 June 2013, 18:42:44
hah! i just remembered why i bought tack-spray the other day. i have a sheet of teflon from mcmaster i was going to play around with (after cutting new mouse feet out of it :P). yesss!
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: tsangan on Tue, 18 June 2013, 18:51:15
Everyone can join in on this fun too now!

http://www.kickstarter.com/projects/pirate3d/the-buccaneer-the-3d-printer-that-everyone-can-use
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: CPTBadAss on Tue, 18 June 2013, 18:56:36
Noooo, kawa, post more stuff here. I love this thread!
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: kmiller8 on Tue, 18 June 2013, 19:00:27
Everyone can join in on this fun too now!

http://www.kickstarter.com/projects/pirate3d/the-buccaneer-the-3d-printer-that-everyone-can-use

I had one of the $250 pre-orders on that, but the build area was too small, and the delivery date is too far out for me.

Some other cheap options.

makibox (http://makibox.com/) starting at $200, shipping sometime within a few months. (I think it's fully assembled)
printrbot (http://printrbot.com/) starting at $300, shipping sometime this month at best. (Kit/fully-assembled for more)
solidoodle (http://store.solidoodle.com/) starting at $500, ships in a few weeks (fully-assembled)

Those are all the "cheap" ones I've found and would consider buying.

/me has looked a lot into the options out there before making his decision.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Tue, 18 June 2013, 19:01:55
Noooo, kawa, post more stuff here. I love this thread!

dude, i have a real metals project that i need your help on (design, FEA and machine time). email a bro.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: mkawa on Tue, 18 June 2013, 19:03:03
great list kmiller. this is now officially the living 3d printing thread.
Title: Re: The Living 3D Printing Thread
Post by: The_Beast on Tue, 18 June 2013, 19:06:35
The soliddoodle is a decent printer. It took a while for my friend to set his up and get all the settings right, but now that it is, printing is really easy
Title: Re: The Living 3D Printing Thread
Post by: PointyFox on Tue, 18 June 2013, 19:09:15
We have a Solidoodle at work and the thing looks like garbage.  It's held together by parts made from 3D printers and various kinds of tape.  Also whatever that gold stuff is on the platform is also chipping off.  It could be the fault of whomever built or is running the thing. 
Title: Re: The Living 3D Printing Thread
Post by: linziyi on Tue, 18 June 2013, 19:10:50
What differentiate the $2000+ printers from the $300+ ones?
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Tue, 18 June 2013, 19:11:50
don't forget the upcoming photocuring printers. i can't remember the name of any of them at the moment but the basic idea is that you take a resin that cures under UV, you point a projector downward at a tub of the stuff, and you slowly raise/lower whatever it is you need to raise or lower to form a solid object.

basically the practical method behind additive manufacturing is to take a material that transitions between phases of matter (solid, liquid, gas, plasma), and bring from a non-solid to a solid in a controlled, compounding matter. this differs significantly from subtractive manufacturing in that you usually take a big old brick of solid stuff and hack away at it until it looks like you want it to. one was invented by cavemen. THE OTHER BY MEN AND WOMEN OF THE MODERN SPACE AGE
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Tue, 18 June 2013, 19:12:36
What differentiate the $2000+ printers from the $300+ ones?
the same thing that differentiates all expensive from cheap tools: precision and accuracy.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: kmiller8 on Tue, 18 June 2013, 19:14:14
great list kmiller. this is now officially the living 3d printing thread.

here's some more

Makerfarm RepRaps (http://makerfarm.com/) has kits ranging from $520 to $585, but doesn't come with powersupply/glass, so it's a bit more than that
Rostock Max (http://shop.seemecnc.com/) is a delta-type printer of $1000
Mendel Max (http://store.makerstoolworks.com/printer-kits/) $1600 but one of the most solid reprap designs and a sexy looking printer
MakerBot (http://store.makerbot.com/) $2200 "standard" for FDM-type printers (honestly a lot of cheaper ones can print similar quality, but after a lot of calibrating)

Obviously these are just a few of the options available, but these (to me) are some of the best kits and 3D printers.
Title: Re: The Living 3D Printing Thread
Post by: kmiller8 on Tue, 18 June 2013, 19:17:02
don't forget the upcoming photocuring printers. i can't remember the name of any of them at the moment but the basic idea is that you take a resin that cures under UV, you point a projector downward at a tub of the stuff, and you slowly raise/lower whatever it is you need to raise or lower to form a solid object.

The popular one is the Form1 (http://formlabs.com/) ($3300)
But there are DIY methods that would cost around $700

The big problem with these types of printers, is that the resin is very expensive, however the print quality is quite a bit better than FDM printers can achieve.
Title: Re: The Living 3D Printing Thread
Post by: kmiller8 on Tue, 18 June 2013, 19:22:28


people                 3d printers owned                     will print for you?
-------------------------------------------------------------------------------------
leslieann              rostock delta (from kit)               no
mkawa                makerbot rep2x (from box)         not yet! debugging!
kmiller8               still deciding                              duh, no



kmiller8 got a makerfarm reprap 8" :)
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Tue, 18 June 2013, 19:31:20
the ultimaker is the current reprap produced design (reprap seems to be a loose-knit developer community at this point, and "the reprap" seems to refer more to the designs they product than any particular machine). that design looks quite nice.

power supply-wise, my recommendation is to search for HUGE used tdk lambda, meanwell, elpac, B&K, et&c supplies on ebay, then go to your local electronics surplus store and get a passive power supply tester. in my case, that's an 8 ohm 18" long piece of ceramic with wire embedded in it (next time i go i expect to find a 1ohm. if not, there will be blood). it will apparently sink 300W without catching on fire, but i'm somewhat doubtful, and regardless if i need to seriously test something past 150W i'll probably just put it on top of 12" long aluminum extrusion from same store and aim a fan at the combo. throw your voltmeter across it and eyeball that the voltage stays reasonably constant. remember, it's a voltage source, so if it starts to fail, the voltage will fluctuate (then it might explode, so put some glasses on or something).

now, just making a used power supply source a huge amount of current is NOT a full functional test. ideally you want to measure ripple under across the load range, etc. etc. etc. etc. well tough. if you really needed that kind of precision, you would buy new and it would cost you thousands of dollars instead of about a hundred bucks. hence, my recommendation is to buy a supply rated for 3x or so of the current you expect to actually use in steady state, and to not exceed 60-70% of rated peak current.

that said, modern switchmode supplies are incredibly efficient, reliable, and being pumped out by the buttload AS LONG AS you're ok with 12vdc. in particular, the makerbots run on 24vdc, and stringing switchmode supplies serially across a common AC ground naively is NOT OK. it's possible, but the results will not be pretty, and switching power supplies are cheap. in fact, they exist only because they're so cheap, so just find one that provides the power source you want as cleanly as you need.
Title: Re: The Living 3D Printing Thread
Post by: linziyi on Tue, 18 June 2013, 19:34:12
What differentiate the $2000+ printers from the $300+ ones?
the same thing that differentiates all expensive from cheap tools: precision and accuracy.

I heard that replicator x2 is "professional grade" 3d printer, so it must have insane accuracy... But for the cheaper ones, are they still reliable for easy tools like screws, nuts and blots?

***I know maybe this is not a very good question since most people only have dealt with one 3d printer***
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Tue, 18 June 2013, 19:37:29
"professional grade" 3d printing is currently limited to 10-60k$ machines. formiga, stratasys, and so on make high accuracy high volume SLS and FDM printers that can print in multiple materials at much higher temperatures. the makerbot, cubex and all the diy printers we're discussing are all hobbyist grade. there is a high degree of experimentation required to print useful output with all these devices, and the only two materials that can be printed thus far are PLA and ABS (and then only filament)
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Tue, 18 June 2013, 22:30:03
don't forget the upcoming photocuring printers. i can't remember the name of any of them at the moment but the basic idea is that you take a resin that cures under UV, you point a projector downward at a tub of the stuff, and you slowly raise/lower whatever it is you need to raise or lower to form a solid object.

basically the practical method behind additive manufacturing is to take a material that transitions between phases of matter (solid, liquid, gas, plasma), and bring from a non-solid to a solid in a controlled, compounding matter. this differs significantly from subtractive manufacturing in that you usually take a big old brick of solid stuff and hack away at it until it looks like you want it to. one was invented by cavemen. THE OTHER BY MEN AND WOMEN OF THE MODERN SPACE AGE
Resin is 15x the cost of ABS, I looked at building one.
The printers costs similar, but the resin costs will kill you.


anyway, this is all a roundabout way of suggesting that you consider investing in more tooling than product, leslieann. at the moment, you're so focused on making a print that you're not really sure what, where, or how everything is working.

It's just what you are seeing based on what I write. I'm kind of trying to document some of the things I ran into trouble with.

I actually researched a lot and do test, measure and retest. Part of the issue, is as I mentioned, documentation. One place will say one thing, and another will say something else. Being open source a lot things are kind of like comparing Red Hat to Ubuntu. You get info from one that doesn't work with the other. As such you get a lot of conflicting info or even out dated info.

Your kit was built the same way, however they already went through all of the process of working out the kinks.
This is also why working machines fetch a decent amount of money.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Tue, 18 June 2013, 22:34:40
What differentiate the $2000+ printers from the $300+ ones?
Replicator 2x is more of a high end home printer. It's no more accurate than any other as it's all similar systems. It's just a Prusa or Mendel in a fancy box with better documentation and all the bugs worked out.

Cheaper ones have smaller print sizes, and depending on model, more or less tinkering required to make quality prints. Some also require special filament, which is normal filament, just wrapped in a fancy overpriced package. Speed can also be a factor in price.

The biggest thing though, is how much do you want to tinker. As one company says, "A sense of adventure required".
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 19 June 2013, 00:09:59
don't forget the upcoming photocuring printers. i can't remember the name of any of them at the moment but the basic idea is that you take a resin that cures under UV, you point a projector downward at a tub of the stuff, and you slowly raise/lower whatever it is you need to raise or lower to form a solid object.

basically the practical method behind additive manufacturing is to take a material that transitions between phases of matter (solid, liquid, gas, plasma), and bring from a non-solid to a solid in a controlled, compounding matter. this differs significantly from subtractive manufacturing in that you usually take a big old brick of solid stuff and hack away at it until it looks like you want it to. one was invented by cavemen. THE OTHER BY MEN AND WOMEN OF THE MODERN SPACE AGE
Resin is 15x the cost of ABS, I looked at building one.
The printers costs similar, but the resin costs will kill you.
completely different error profile, scale and purpose. resin photocuring has the potential to model additive photolithography. you're unlikely to want to make a safety cone with it (and you would have some definite trouble doing so anyway since you're relying on a chemical reaction that may or may not be malleable in terms of color), but you might want to make a the exoskeleton of a tiny robotic swarming bee.

the root of empiricism is trying to gain some understanding of the (inevitably stochastic) mechanisms behind physical processes, and then (or if you still don't quite get it) measuring until you have a reasonable approximation of the distributions on the inputs and a reasonable approximation of the process. as i've been pointing out incessantly, the mechanisms behind additive printing are completely analogous to those of subtractive printing with substantially different inputs.

Quote
It's no more accurate than any other as it's all similar systems. It's just a Prusa or Mendel in a fancy box with better documentation and all the bugs worked out.
only in my wildest dreams. a few bugs are worked out such that you can print a traffic cone when you unwrap the box (or at least you may be able to). anyway, as i also have said incessantly, error analysis and correction is all incremental. a bridgeport is just a sherline in a fancy 3-ton box (this is not an exaggeration). but the weight of a bridgeport is essential to reduce specific kinds of error and produce the kinds of extremely high tolerance parts that power the increasingly efficient internal combustion engines and composite molding tooling that the modern world is made out of.

Quote
Cheaper ones have smaller print sizes, and depending on model, more or less tinkering required to make quality prints. Some also require special filament, which is normal filament, just wrapped in a fancy overpriced package.
what is filament? it's wire made out polymer? what's the composition of that polymer? what is the typical shape is the extrusion? what is the tolerance of the bounding diameter of the filament? the word fancy hides the details that drive the incremental improvements that need to be made to achieve that incrementally higher accuracy and precision that may be boring to some, but is extremely important in empirical science.

here's an example: the composite parts in a reprap designed machine are often made on other FDM machines to relatively low tolerances and necessarily lower material properties (FDM is not yet very good at making hard dense objects). makerbot inc invested in injection molding tooling to create denser, harder and higher precision composite components that fulfill more or less the same functionality. they invested in a casting mold for aluminum plates to make low thermal resistance platforms that can be machined flat (but of course they don't do that part, sigh. this is, btw, a very definite bug) and have relatively uniform thermal expansion properties. it's not fanciness. it's engineering. (well, i guess if you consider engineering nothing but fanciness you are wrong but only misguided -- there is nothing fancy about engineering. it is a horrid slog of tiny incremental changes, and it's also tedious and hard).

anyway, the point is, the difference between expensive manufactured things or expensive tools and cheap things/tools is all in accuracy and precision, either in manufacturing or some sense of error. there are some things that are completely cosmetic, but it's actually much rarer than you might think. fun example: the difference between a louis vuitton monogrammed hangbag manufactured to specification and the much more common cheap knockoff is the following:

grade and source of leather (softness, thickness, uniformity of grain, lack of polymer or composite filler)
panels are cut, aligned and sewed according to strict specification:
  seams must meet strength requirements
  distance between threads within tolerance
  not a single symbol can be cut off
  every symbol is at least some distance alpha of the edge of every panel once sewed

yes, it's a handbag, and machine-formed polyester will often fulfill the same functionality for a while, but vuitton bags are the kind of thing that are designed and manufactured expressly to be preservable and usable after sitting in peat moss for thousands of years, while loosely sewed polyester will last about as long as it takes for me to get it to it and mangle it in one of my crazy experiments.

i insist a lot of things, but i particularly insist that we respect the incrementalism of manufacturing on this board. this is a forum centered on exotic electromechanical switch designs for computer keyboards. incremental changes matter here. on this forum, fanciness matters.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 19 June 2013, 00:52:35
now that i've gotten that lecture out of my system, can someone link dox's cad files?
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Wed, 19 June 2013, 01:43:34
What is filament? it's wire made out polymer? what's the composition of that polymer? what is the typical shape is the extrusion? what is the tolerance of the bounding diameter of the filament? the word fancy hides the details that drive the incremental improvements that need to be made to achieve that incrementally higher accuracy and precision that may be boring to some, but is extremely important in empirical science.
You missed what I was after there.

Go look at the Cube printer Office Depot sells, it's $1200 and designed only to use their filament, which cost far more than regular filament. People have hacked it to work with regular filament spools and it has no problem printing with it. The company does all they can to keep you buying their filament, just as HP and Lexmark do all they can to limit you to only their ink and not using refils. While it does give them some quality control, there is nothing special about it except putting more money in their pocket.


And if you think you bought a Bridgeport, you're going to be disappointed. You seem to have this idea that yours is somehow vastly superior, when I reality, yes, it's better than most, but injection molding doesn't improve everything. The accuracy and strength of the parts on mine wouldn't benefit one iota by being injection molded or even being machined from aluminum (except maybe the upper and lower plate). Accuracy, strength and tolerances are great, but only where it counts. You could align your bed to the wall with a micrometer and make the frame out of solid aluminum on a Bridgeport, and while cool and would last 1000 years,  it won't actually make you sleep any better once the cool factor wears off.

I think you have been reading and buying into the sales literature a little too much.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Wed, 19 June 2013, 04:16:55
... all the diy printers we're discussing are all hobbyist grade. there is a high degree of experimentation required to print useful output with all these devices, and the only two materials that can be printed thus far are PLA and ABS (and then only filament)

And nylon and maybe more. But yes PLA and ABS are the common ones.
Title: Re: Buying A 3d Printer for Geekhack (I Am)
Post by: vvp on Wed, 19 June 2013, 04:58:52
PLA is a nightmare to get right, it turns out I broke both 120psi pneumatic fittings that hold the bowden (feed) tube. Seriously, the fittings hold 120 psi, and I snapped the hell out of both of them.  :eek:
This is interesting. Lets assume 120psi is the typical rating for pneumatic fittings used in DIY 3d printers.
That means the force rating of the fitting is about 10 N. Typical extruders (for 1.75mm filament) push with force in the range of 10 - 15 N. So we are overloading the fitting a bit. But still looks like your fitting had a defect since the safety factor should be at least 2.
Or you pushed the filament with significantly higher force.
Thanks that you document the problems you experienced. It is an interesting reading.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Wed, 19 June 2013, 05:18:34
What differentiate the $2000+ printers from the $300+ ones?
I would like to know too. The point is that companies charge whatever the market will bear. What they charge is unrelated to how much effort is behind the product and what is the product value to users. There is only a lower limit on price. That is the cost of producing the product. If the 3d Printer market is commoditized then you can expect that the price corresponds to the value. Is this true for the current 3d Printer market?
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 19 June 2013, 08:45:11
... all the diy printers we're discussing are all hobbyist grade. there is a high degree of experimentation required to print useful output with all these devices, and the only two materials that can be printed thus far are PLA and ABS (and then only filament)

And nylon and maybe more. But yes PLA and ABS are the common ones.
very cool. this is only a little higher than the temp that the MBI filaments are locked at, but that's a software limitation. i suspect there's some fudge that would allow 240C and maybe a tiny bit more without melting anything important.

and leslie, the MBI machines aren't even sherlines; have you seen the machining on one? they are very well made, and subtractive printing is something that is pretty well understood at this point. i just went into detail on how half my "turnkey" machine is totally bogus and i have to put hundreds into measurement, tooling and elbow greay to improve my heated bed ON TOP of the thousands that MBI spent to produce the heated beds.. the point i was making was exactly what i said, and abstract from our specific printers. we're still rolling caveman style here in 3d printing land, i'm afraid. even the 60 grand sintering machines are nowhere near as precise as a bridgeport (although the cost is appx the same).

hell, if damorgue wasn't under more NDAs than most apple employees, i'm sure he'd have some fun stories to tell us ;)

Title: Re: The Living 3D Printing Thread
Post by: damorgue on Wed, 19 June 2013, 09:58:15
You guys might be interested in Euromold and similar trade shows. A lot of manufacturers showcase stuff there. What is the diameter of your current nozzle and filament mkawa?

(http://i.imgur.com/w0up81R.jpg)
(http://i.imgur.com/28whHVe.jpg)
(http://i.imgur.com/j86aSt5.jpg)


Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 19 June 2013, 11:18:03
rename it califormold and come to the us damorgue. i can't make anything with the word euro in it right now :P.

the filament is 1.75-1.8mm. nozzle is .4mm. also, grrr. have you guys built enough machines that we can get some time on them yet? :D
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Wed, 19 June 2013, 12:27:45
0.4mm was actually a fair bit lower than I had imagined. It should allow for some fairly intricate stuff. Was the cone printed from your machine? Can it stop ejecting the plastic and do separate parts without a connection between them?
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 19 June 2013, 15:03:19
yes and yes
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Wed, 19 June 2013, 15:26:59
What softwares are you using. You spoke of writing some stuff earlier, and I was just wondering what formats it supports.I am assuming that you input .stl files which it turns into code for the movement of the nozzle?
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 19 June 2013, 16:25:58
the only open source gcode generator that i know of right now is skeinforge. i'm planning on rewriting skeinforge for the purpose of rigorous analysis using formal methods. i'm also hoping to look at some of the open source CNC mill and lathe compilers as well. if you know of any other FOSS manufacturing compilers or can NDA me in on anything, i'm happy to explain to you what the goals and methods of this research are.

note additionally that the code i'm looking for isn't limited to compilers. i want SVD style stuff as well. if your stack involves signal processing or controls (especially exotic [read: non PID] algorithms), i would be overjoyed to have a look at it.

oh, and to answer your question, right now i'm using the full makerbot/makerware toolchain. they have a stack that's derived from skeinforge, replicatorg and sailfish (all FOSS) but a bit more plug and play with their devices. i plan on branching out once i have a better handle on things though. i am thoroughly armed with JTAG and remote gdb and not afraid to use it.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Wed, 19 June 2013, 17:15:37
PLA is a nightmare to get right, it turns out I broke both 120psi pneumatic fittings that hold the bowden (feed) tube. Seriously, the fittings hold 120 psi, and I snapped the hell out of both of them.  :eek:
This is interesting. Lets assume 120psi is the typical rating for pneumatic fittings used in DIY 3d printers.
  • 120psi (i.e. about 827kPa) pressure rating
  • a bowden for 1.75 filament has about 2mm radius
That means the force rating of the fitting is about 10 N. Typical extruders (for 1.75mm filament) push with force in the range of 10 - 15 N. So we are overloading the fitting a bit. But still looks like your fitting had a defect since the safety factor should be at least 2.
Or you pushed the filament with significantly higher force.
Thanks that you document the problems you experienced. It is an interesting reading.
Glad to see some good come out of my posts.
As I have said, half the reason for building it was for the experience and there has been no shortage of that. :))

I actually broke both fittings (one at each end). At the moment the hot end fitting is holding with only half the teeth, the extruder end only has 3 or 4 teeth left I think (though I probably broke more late last night), I so am using a clamp/contraption of zip ties to hold it in place until replacements arrive. Unfortunately both are raising hell with retraction.

I ordered a J-Head this morning. Last night after I thought I had dealt with my cooling issues, the head jammed again. I'm starting to think the head I have is just complete crap. I insulated the very end of the head, and have a 50mm fan blowing right onto the Peek. I have seen people printing PLA with this head using a single 25mm fan.

I would consider it possibly being the filament, but the jams happen as things heat up over time. If I make lots of small 10 or 15 minute prints in ABS with cool down time in between, it runs fine, which is why I was able to make calibration cubes and such, but after 20 minutes or so, heat makes it way up the head and it clogs. On PLA it takes about 5 minutes less.


It's easy to get in over your head with a  D.I.Y. and I expected some. Actually, where I got stuck most was not where I expected, two were documentation problems (updated board, and bad instructions), and the head should simply work, but doesn't. Everything else was either finding a good tutorial, or figuring it out through logic.


By the way, I swear, I'm buying stock in a zip tie manufacturer, I've gone through around 200 so far (who needs duct tape!). I wonder, will the universe implode if my zip tie amount exceeds dollar amount?

and leslie, the MBI machines aren't even sherlines; have you seen the machining on one? they are very well made, and subtractive printing is something that is pretty well understood at this point. i just went into detail on how half my "turnkey" machine is totally bogus and i have to put hundreds into measurement, tooling and elbow greay to improve my heated bed ON TOP of the thousands that MBI spent to produce the heated beds..
I consider what you have to be more like a Cadillac with all the bells and whistles. The fact that you already found a bunch of issues (many of which go back to the design it's based on) just reinforces that idea.

As for the rest of my response, it sounded more of a lecture aimed at me than a complaint about your printer, your post after only furthered that belief.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 19 June 2013, 20:31:11
the posters in this thread have many years of engineering experience combined, leslieann. you can choose to ignore their suggestions, but it sounds like what you're doing isn't really working for you, so we have offered them.

fwiw, the first thing i would do about your extrusion head is buy or build a multi-input temperature readout device (fluke is overkill, extech is about right, no-name is not worth it. you will be using this a lot. velleman offers reasonably priced kits, although i think they still use PICs -- yuck. sparkfun or adafruit might have a more modern kit using an atmel MCU...), a number of contact (type K is imo the de facto standard) thermocouples with nice high thermal limits and reasonable accuracy (+/-10C is probably fine), and a roll of kapton tape, then measure the temperatures up and down your head device from the nozzle up to and including the feed tube coupler.

i'd also buy a very high quality and small DC clampmeter that can measure the amperage feeding all the power devices in your chain non-contact. these things generally push too much current for general purpose ammeters. this will cost serious money, as you'll want to be able to measure relatively small (10s of amps) currents with it, and the cheap ones are basically useless until you're pushing car motor starter current (3-500A). keep in mind that these all use hall effect (basically they're measuring the B field perp to the current), so you want a small, sensitive clamp. i haven't had the greatest luck with these so i can't offer more specific suggestions.

the only thing i can really tell you is that i generally don't buy constructed things if i can construct something comparable myself with reasonable effort, as i have far more invested in tools than i do in _stuff_. that said, i do admire your tenacity and persistence. you'll get there, but i will insist that it might take a bit of a change in perspective if you want to get there sooner rather than later.
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Wed, 19 June 2013, 21:23:07
I don't know much about code and software I am afraid. Looking forward to see what you guys will and end up with though.

Because thermocouples rely on measuring the voltage drop though it, they are sensitive to induced currents. Just keep it in mind when you place the wires along or around other strong electronics. Also, be sure to have the cold junction at a sufficient distance where you can be sure that the temperature remains fairly constant. Two points which you were probably already aware of but can easily be forgotten and may lower their accuracy.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 19 June 2013, 22:52:50
totally forgot about that actually. good points damorgue.

also, i find it odd that only mechengs really know and understand controls and tolerances and yet when they inevitably get turned into digital computations, it's completely up to a CS or worse, an EE to implement, and we know nothing about controls. it's quite silly actually, and points to a huge gap in both curriculums.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Wed, 19 June 2013, 23:55:59
the posters in this thread have many years of engineering experience combined, leslieann. you can choose to ignore their suggestions, but it sounds like what you're doing isn't really working for you, so we have offered them.

fwiw, the first thing i would do about your extrusion head is buy or build a multi-input temperature readout device (fluke is overkill, extech is about right, no-name is not worth it. you will be using this a lot. velleman offers reasonably priced kits, although i think they still use PICs -- yuck. sparkfun or adafruit might have a more modern kit using an atmel MCU...), a number of contact (type K is imo the de facto standard) thermocouples with nice high thermal limits and reasonable accuracy (+/-10C is probably fine), and a roll of kapton tape, then measure the temperatures up and down your head device from the nozzle up to and including the feed tube coupler.

i'd also buy a very high quality and small DC clampmeter that can measure the amperage feeding all the power devices in your chain non-contact. these things generally push too much current for general purpose ammeters. this will cost serious money, as you'll want to be able to measure relatively small (10s of amps) currents with it, and the cheap ones are basically useless until you're pushing car motor starter current (3-500A). keep in mind that these all use hall effect (basically they're measuring the B field perp to the current), so you want a small, sensitive clamp. i haven't had the greatest luck with these so i can't offer more specific suggestions.

the only thing i can really tell you is that i generally don't buy constructed things if i can construct something comparable myself with reasonable effort, as i have far more invested in tools than i do in _stuff_. that said, i do admire your tenacity and persistence. you'll get there, but i will insist that it might take a bit of a change in perspective if you want to get there sooner rather than later.

I don't exactly see how that equipment would have helped except confirm what I already knew.
The engineer sees things as an engineer, solve it with scientific testing and equipment, it's what you know. It reminds me of an astronaut joke. Nasa spent millions making a pen that writes in zero gravity, Russia used a pencil.

The parts I got were an assembled Arduino, Ramps board, and an industry standard heated bed. I have no interest in doing SMT electronics, so I bought them pre-assembled. You can't do everything yourself, you pick your battles and know your abilities.


As for the head, I found some the issue with the print head. The teflon liner shrank, probably from heat, apparently, it's a common but little discussed issue with this head. The other problem was too much retraction, I was sucking up a blob of filament into the teflon and getting stuck. I used a bit of my bowden tube to replace the teflon insert, and cut way back on retraction and I'm back to getting okay enough prints that I can make my J-Head mount and possibly even the magnetic arm parts I need.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 20 June 2013, 09:08:25
while we're telling engineering jokes..

engineers come in all shapes, sizes and competencies. there were many brilliant engineers employed by the soviet union. there were also the engineers that designed the yugo. there were many brilliant engineers employed by public and private entities in the US. there were also the engineers that designed the ford pinto. :))
Title: Re: The Living 3D Printing Thread
Post by: CPTBadAss on Thu, 20 June 2013, 09:22:10
also, i find it odd that only mechengs really know and understand controls and tolerances and yet when they inevitably get turned into digital computations, it's completely up to a CS or worse, an EE to implement, and we know nothing about controls. it's quite silly actually, and points to a huge gap in both curriculums.


My school tried to integrate the programs but I had no interest in learning any code until I started working on boards here.

And all these engineering jokes...I never heard the Pencil vs Pen one before
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 20 June 2013, 09:28:38
...and the first engineering joke i was ever told :P

Quote
Several professors were asked to solve the following problem: "Prove that all odd integers are prime."
Mathematician: 3 is a prime, 5 is a prime, 7 is a prime, 9 is not a prime - claim is false.
Physicist: 3 is a prime, 5 is a prime, 7 is a prime, 9 is an experimental error, 11 is a prime ...
Engineer: 3 is a prime, 5 is a prime, 7 is a prime, 9 is a prime, 11 is a prime ...
Title: Re: The Living 3D Printing Thread
Post by: linziyi on Thu, 20 June 2013, 09:34:01
...and the first engineering joke i was ever told :P

Quote
Several professors were asked to solve the following problem: "Prove that all odd integers are prime."
Mathematician: 3 is a prime, 5 is a prime, 7 is a prime, 9 is not a prime - claim is false.
Physicist: 3 is a prime, 5 is a prime, 7 is a prime, 9 is an experimental error, 11 is a prime ...
Engineer: 3 is a prime, 5 is a prime, 7 is a prime, 9 is a prime, 11 is a prime ...


......I don't get the joke..?
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 20 June 2013, 09:40:23
it's often told in a way that's less kind to the mathematician:

Quote
Mathematician: 3 is a prime, 5 is a prime, 7 is a prime, therefore, by induction all odd numbers are prime.
Physicist: 3 is a prime, 5 is a prime, 7 is a prime, 9 is an experimental error, 11 is a prime ...
Engineer: 3 is a prime, 5 is a prime, 7 is a prime, 9 is a prime, 11 is a prime ...

to explicate the joke: the mathematician uses formal reasoning to make a dumb mistake. the physicist convinced herself a priori of something and then looks for any and all evidence that it may be true and trots it out. the engineer... he is just dumb. :D
Title: Re: The Living 3D Printing Thread
Post by: linziyi on Thu, 20 June 2013, 09:43:06
-_- didn't see the induction part
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 20 June 2013, 09:44:02
the first version didn't have it!
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 20 June 2013, 13:07:33
also, just fyi, the cadillac of home 3d printers: (yes, that's the power supply under there)

Title: Re: The Living 3D Printing Thread
Post by: vvp on Thu, 20 June 2013, 13:10:15
the only open source gcode generator that i know of right now is skeinforge. i'm planning on rewriting skeinforge for the purpose of rigorous analysis using formal methods. i'm also hoping to look at some of the open source CNC mill and lathe compilers as well. if you know of any other FOSS manufacturing compilers or can NDA me in on anything, i'm happy to explain to you what the goals and methods of this research are.
http://slic3r.org/
AGPLv3 license
AFAIK, it is only for 3D printing.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Thu, 20 June 2013, 13:21:13
it's often told in a way that's less kind to the mathematician:
Quote
Mathematician: 3 is a prime, 5 is a prime, 7 is a prime, therefore, by induction all odd numbers are prime.
...
to explicate the joke: the mathematician uses formal reasoning to make a dumb mistake.
He should have used COQ or some other theorem prover ...
... and his error would have been much more peculiar  :))
Title: Re: The Living 3D Printing Thread
Post by: vvp on Thu, 20 June 2013, 13:24:34
As for the head, I found some the issue with the print head. The teflon liner shrank, probably from heat, apparently, it's a common but little discussed issue with this head. The other problem was too much retraction, I was sucking up a blob of filament into the teflon and getting stuck. I used a bit of my bowden tube to replace the teflon insert, and cut way back on retraction and I'm back to getting okay enough prints that I can make my J-Head mount and possibly even the magnetic arm parts I need.
What was the too big retraction? What retraction do you use now?

Edit: Hmm, J-head seems to be quite short compared to what I saw at the printer I can get to. I do not know how it's head is called.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Thu, 20 June 2013, 17:04:00
Okay, here is a perfect example of the weird stuff I see online while researching things...

A VERY common claim is that "you need gear reduction for extruders, especially for 3mm" and "Direct drive is barely strong enough for 1.75mm filament".  I just looked at a store where they claim their stepper, which is a rather strong Nema 17 is "Suggested for only 0.5 mm hot-ends".

How much more strength do you need if the motors are already breaking other parts of the system. The only thing I can think of is that some of the motors people buy are junk.

At any rate, yes, you do want gear reduction for 3mm, because every step of the motor pushes tons more filament giving you less control. Some guys are even doing it on 1.75 for the same reasons.

What was the too big retraction? What retraction do you use now?

Edit: Hmm, J-head seems to be quite short compared to what I saw at the printer I can get to. I do not know how it's head is called.
J-Heads have about 20 different versions, some longer than others. Some use cartridge heaters, others have a different Peek end. They aren't just revisions, sometimes they are just options. Seems a bit much to me.

I was doing fine with 10mm retraction (which is default), this was fine, everything worked well, until I switched to PLA. When the PLA jammed, it broke the bowden clamp/fittings (and damaged the hot end's teflon liner). When I went back to ABS, I was trying to contend with the fittings having slop, and added extra retraction to compensate.

The extra retraction ended up moving hot ABS into the teflon which was already damaged from the PLA clogs. I think this was why my cooling was ineffective as well, since I couldn't overpower the hot abs heating it from inside. While I did inspect the tube when I unclogged the PLA, all I could see was a stain on it. It looked and felt fine. By the time I replaced it, it was requiring a lot of force to push filament through.

By replacing the tube, turning down temps and turning down retraction, I was able to get a dirty print that should hold the J-head when it arrives tomorrow. However by the end of the night, one bowden fitting had died completely, and the nozzle was just one clog after another. Those fittings really raised hell, I was pulling out metal bits of the fitting in chunks and I think they may have scratched the teflon liner, which not only gave the ABS something to grab, but also the shavings would have caused the nozzle to clog as well.

I never intended to keep the hot end even this long, but my work is often feast or famine (self employed), and the last 2 weeks have been slim so I had to conserve. Next week, will probably be feast again as I know I have at least one big $$ build and install.


Just some of last nights nights carnage (bits of the fitting I have pulled out).
|
|
V
Title: Re: The Living 3D Printing Thread
Post by: vvp on Fri, 21 June 2013, 07:33:02
The Rostock here does not have any problems with direct drive extruder. It uses 0.45Nm stepper with drive wheel radius of about 4.5mm. That represents force of about 100N. Should be plenty for 1.75mm filament and 0.5mm nozzle. It does not show any problems when printing at 6cm/s.

Here is an interesting info about forces required from an extruder cold end.
http://airtripper.com/1338/airtripper-extruder-filament-force-sensor-introduction/
Unfortunately he does not specify his nozzle and the filament.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 21 June 2013, 16:00:18
this thing is boss: http://www.amazon.com/Extech-SDL200-4-Channel-Thermometer-Logger/dp/B000CDMQIE/ref=sr_1_3?ie=UTF8&qid=1371847857&sr=8-3&keywords=datalogging+thermometer

also, if you want a single device that will read a huge number of temperatures though, an arduino uno mega r3 with an adafruit datalogging shield and like 8 of the MBI amplifier kits will boss the **** out of that

http://store.makerbot.com/type-k-thermocouple.html (x8)
http://store.makerbot.com/thermocouple-sensor-v1-0-kit.html (x8)
http://www.adafruit.com/products/50 (x1)
http://www.adafruit.com/products/1141 (x1)

for power, just find a 5v wall wart from your junk box, surplus store, etc.

Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 21 June 2013, 16:03:18
the only open source gcode generator that i know of right now is skeinforge. i'm planning on rewriting skeinforge for the purpose of rigorous analysis using formal methods. i'm also hoping to look at some of the open source CNC mill and lathe compilers as well. if you know of any other FOSS manufacturing compilers or can NDA me in on anything, i'm happy to explain to you what the goals and methods of this research are.
http://slic3r.org/
AGPLv3 license
AFAIK, it is only for 3D printing.
this is brilliant! thank you!!!
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Fri, 21 June 2013, 17:07:09
I use Slic3r (mainly because it's simple and I learned on it), but you will want to use something to verify the code. It's known for not always doing things right and I've had several things I fed into it and come out withing entirely different. Like a horseshoe shape coming out as three cylinders...

When that happens, run the design through Netfab  (http://www.netfabb.com/cloud/)or Willitprint (http://willit3dprint.com/) and then rerun Slic3r. That fixed the ones I had issues with.



So last night I got to thinking about my setup before I tried PLA, and decided to tear the whole head/extruder assembly apart and start fresh based on how it was when I started. I tore everything apart, blow torched the nozzle, checked all the teflon, cleaned the extruder, and then I disconnected the fan. I pulled even more metal bits out of the system, I don't think I will ever use that type of fitting again, what a mess.

I ran a few extrusion tests and found with heat soak, that a temp of about 235 managed to extrude okay. So after a lot of false starts I have it printing again,  albeit VERY VERY slow. I'm getting a great quality print (when it pushes filament), but what do you expect at 15mm per second, which is all the system can manage it seems. I have the extruder power turned down so as not to blow out the bowden fittings again and the combination just can't push filament fast. At least it's printing and I can make a good mount for the J-head, I only hope it can finish as it has a habit of messing something up dead center of a print job.

I got the J-head today (it's tiny! much smaller than my current head) so once I get a good mount done, I will fire that up and put some of this mess behind me. Even if I have to go hand fab a mount from aluminum, it WILL be running this weekend if I can help it.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 21 June 2013, 17:08:23
I use Slic3r (mainly because it's simple and I learned on it), but you will want to use something to verify the code. It's known for not always doing things right and I've had several things I fed into it and come out withing entirely different. Like a horseshoe shape coming out as three cylinders...
that is so perfect for my project i literally want to cry with joy right now.

sounds good leslieann. slowing down is NOT a bad thing in any way, both the head and your methodology. increasing motor speed introduces a ****load of physical error, not to mention makes it much harder to deal with temperature issues etc. etc. etc. etc. etc. 235C is about the right temp for the filament. what i haven't been understanding is why you have so much heat and pressure in your extrusion system in general. if you've been trying to get it REALLY hot and then trying to cool it down REALLY quickly so that you can print uber fast, that would explain quite a bit.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Fri, 21 June 2013, 17:11:02
The Rostock here does not have any problems with direct drive extruder. It uses 0.45Nm stepper with drive wheel radius of about 4.5mm. That represents force of about 100N. Should be plenty for 1.75mm filament and 0.5mm nozzle. It does not show any problems when printing at 6cm/s.

Here is an interesting info about forces required from an extruder cold end.
http://airtripper.com/1338/airtripper-extruder-filament-force-sensor-introduction/
Unfortunately he does not specify his nozzle and the filament.

Interesting, I skimmed it a bit but will go back and read more of it.
He did mention the head, under a picture, it's a J-Head V9 clone (J-head is an open source design and tons of people are making them, some good, some not so good and in many wild variations).

His filament is 1.75mm based on the pictures (scale of teflon vs other parts of the extruder). I have an Airtripper extruder, works well, but it's much more complicated than some of the newer designs.


Edit: and of course the head decided to act up mid print.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 21 June 2013, 17:20:42
also the latest news on my end is that i have everything back together and i'm printing a bunch of traffic cones to use to push through the carpet under my machine + random pieces of acrylic that the machine sits on. it turned out that the machine was totally not level at first because it was missing a little rubber foot from the factory (HAH), and on top of that, all i really have to mount it on is 40lbs of random acrylic and a berber carpeted floor. so, traffic cones.

few reasons for this: my head to plate tolerances right now are around +-0.1mm and my head to head (remember, two heads) tolerances are about 0.05mm. with abs and a 0.4mm head, i should actually be able to do about 0.1mm slice heights, but obviously something's going to give here, and it does; i can't print on high qual because the head that the gcode is not targeting keeps running into plastic cooling on the bed. i now have a dial indicator with theoretical accuracy of about 0.003mm, and i've printed half the mount that can position it on the heads. i need to design the other half, print it, then bring my head to plate tolerances down as low as i can get them. how low is that? no frickin clue, but am excited to find out!

measurement!
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Fri, 21 June 2013, 17:23:49
I use Slic3r (mainly because it's simple and I learned on it), but you will want to use something to verify the code. It's known for not always doing things right and I've had several things I fed into it and come out withing entirely different. Like a horseshoe shape coming out as three cylinders...
that is so perfect for my project i literally want to cry with joy right now.

sounds good leslieann. slowing down is NOT a bad thing in any way, both the head and your methodology. increasing motor speed introduces a ****load of physical error, not to mention makes it much harder to deal with temperature issues etc. etc. etc. etc. etc. 235C is about the right temp for the filament. what i haven't been understanding is why you have so much heat and pressure in your extrusion system in general. if you've been trying to get it REALLY hot and then trying to cool it down REALLY quickly so that you can print uber fast, that would explain quite a bit.

Slowing down is fine, but when it takes an hour to do what would normally take 15 minutes and it fails 45 minutes in, it really stinks. Most of my prints were done at around 40mm per second, that isn't exactly blazing fast to begin with. I'm down to 10mm now, and all in an effort to just get a print to finish and it's still not working very well.


I wasn't trying to heat it fast and then cool it, I was trying to maintain a stable temp through the print. I've determined that the problem is heat soak on the hot end. The Peek and internal teflon heats up, increases pressure on the filament and things come to a halt. If I lower temps and speeds, it takes longer to heat soak but still does. If I increase temp it heat soaks faster, either way, I don't get any further with a print job. Fans do nothing, insulation on the head did little. The head just heat soaks the same no matter what.


Oh, another thing about Slic3r, it will change direction mid bridge. As in it will go out over thin air, and make a u-turn. Interesting to watch, but doesn't work very well. LOL It doesn't always take into account what it's doing when it does it.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 21 June 2013, 17:30:42

I wasn't trying to heat it fast and then cool it, I was trying to maintain a stable temp through the print. I've determined that the problem is heat soak on the hot end. The Peek and internal teflon heats up, increases pressure on the filament and things come to a halt. If I lower temps and speeds, it takes longer to heat soak but still does. If I increase temp it heat soaks faster, either way, I don't get any further with a print job. Fans do nothing, insulation on the head did little. The head just heat soaks the same no matter what.
wait wait wait. slow down here turbo. i'm not sure what you mean by heatsoak, because i've only heard it used for what i imagine is a different meaning (heatsoaking in automotive terms is the process of thermal migration. with big old cast motor blocks it takes a long damn time for heat to spread). my guess on what you're saying is that you have filaments that you're pushing current through, and you have a thermistor somewhere (where?), but you have very little control over the temperatures in the head for some reason? the way this typically works is that you have a big fat filament, you have a simple controller (my meche friends keep telling me variants of 'i wasn't even aware there was an alternative to PIDs?!' sigh), and you feet the thermistor and the filament voltage into the pid with the filament voltage as the variable and the thermistor as the control target, yah? does this describe what you're doing? if not, please describe what it is that you're doing.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Fri, 21 June 2013, 17:33:54
also the latest news on my end is that i have everything back together and i'm printing a bunch of traffic cones to use to push through the carpet under my machine + random pieces of acrylic that the machine sits on. it turned out that the machine was totally not level at first because it was missing a little rubber foot from the factory (HAH), and on top of that, all i really have to mount it on is 40lbs of random acrylic and a berber carpeted floor. so, traffic cones.

few reasons for this: my head to plate tolerances right now are around +-0.1mm
You should be able to get head to plate down to about .0025mm, I'm down to about that. I'm also getting similar accuracy in x and y, so long as my belts are tensioned right. Still getting the hang of how often and how tight they need to be. This is still with sloppy arms.

As for a level machine...
I have personally witnessed a Thing-O-Matic swung completely upside down upside down while printing without error. Suffice to say, a sturdy table is more important than how level it is. Just make sure your internals are properly aligned to each other.
 
Traffic cones for stands? CUUUUTE!  I want pics! :)
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 21 June 2013, 17:39:59
i know right!

40lbs of acrylic is sturdy unless it's big flat pieces sitting on berber carpet. the idea is yes, not to be absolutely level, but to keep the whole 80lb combine from moving during a print. it turns out berber carpet is not very rigid :P
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Fri, 21 June 2013, 17:42:48
wait wait wait. slow down here turbo. i'm not sure what you mean by heatsoak, because i've only heard it used for what i imagine is a different meaning (heatsoaking in automotive terms is the process of thermal migration. with big old cast motor blocks it takes a long damn time for heat to spread).

My head has a peek tube, then a teflon liner, and then an inner teflon liner to adapt it to 1.75mm. The heat is migrating from the head, into the inner teflon liner, and starts to soften the ABS while still inside the teflon. The peek and 1st liner prevent a fan from cooling the inner liner.

I have pulled it out mid print (teflon and filament) and the teflon was scalding hot, and found the clogged ABS inside it. Basically the inner liner is only cooled by filament passing through it. I just pulled it again, and the ABS is melted 3/4ths of the way up the head, and even the bowden fitting at the top is warm.

I really hate this head.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 21 June 2013, 17:44:30
can you draw or link some kind of diagram s'il vous plait? i have ****ty spatial intuition
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 21 June 2013, 17:49:20
more pics of the cadillac. note the extremely high tech enclosure lid :))

Title: Re: The Living 3D Printing Thread
Post by: BLJ Consulting on Fri, 21 June 2013, 17:58:12
with molding machines "heat soak" is a term given to the wait time at start between when the thermocouples read the correct temperature and the entire screw and barrel can reasonably be assumed to be up to that temperature.  So, more or less what you said with the added element of potentially unmelted plastic waiting to snap the delicate screw head assembly.  Turn the screw before heat soak and you risk a 1 millisecond failure that take 2 hours and $1000 to repair.



I wasn't trying to heat it fast and then cool it, I was trying to maintain a stable temp through the print. I've determined that the problem is heat soak on the hot end. The Peek and internal teflon heats up, increases pressure on the filament and things come to a halt. If I lower temps and speeds, it takes longer to heat soak but still does. If I increase temp it heat soaks faster, either way, I don't get any further with a print job. Fans do nothing, insulation on the head did little. The head just heat soaks the same no matter what.
wait wait wait. slow down here turbo. i'm not sure what you mean by heatsoak, because i've only heard it used for what i imagine is a different meaning (heatsoaking in automotive terms is the process of thermal migration. with big old cast motor blocks it takes a long damn time for heat to spread). my guess on what you're saying is that you have filaments that you're pushing current through, and you have a thermistor somewhere (where?), but you have very little control over the temperatures in the head for some reason? the way this typically works is that you have a big fat filament, you have a simple controller (my meche friends keep telling me variants of 'i wasn't even aware there was an alternative to PIDs?!' sigh), and you feet the thermistor and the filament voltage into the pid with the filament voltage as the variable and the thermistor as the control target, yah? does this describe what you're doing? if not, please describe what it is that you're doing.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Fri, 21 June 2013, 18:21:40
Here is the head as it's assembled I left off the top mount.

Also here is a picture of the inner liner as it was when I pulled it out a minute ago.
As you can see the ABS melted 21mm up into the liner, and that is not counting the retraction. It should not be capable of melting that far up the tube.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 21 June 2013, 18:38:25
ah, yes, so it's the same thing. in the case of engines, the thermistors are in the coolant, and possibly in the oil (ideal, but apparently predictive models are the new in thing to save 30$ on the fitting and thermistor), but you have a huge amount of metal which is waiting to change size by a very significant amount, and oil which will not be pressurized or viscous enough to fill the final size tolerances of that metal until it reaches temp. i think we can beat you on this one, because rebuilding an engine takes about a hundred man hours, most of it measurement, parts replacement and re-machining of THE ENTIRE BLOCK (well, the active parts anyway). in the best case, the combustion chamber tolerances become so out of whack that the block just cracks in half in a big explosion and then you simply buy a newly manufactured engine in a crate.

anyway, i think i see where i was misunderstanding now. her temps are all out of whack. the things she wants to be cool are hot and the things she wants to be hot are cool. it does seem to be a design problem. that said, if she finds that slowing the process down (allowing more time for temperatures to reach steady state -- ie, allowing more time for heatsoak to do its thing), what i would guess is that there are two possibilities: first is that the design is fundamentally slow. my new understanding of what's supposed to happen here is that the filament is supposed to feed through the teflon liner WITHOUT hitting glass transition, then hit the filament, at which point it melts so that it can be squeezed through the nozzle. hence, what is happening is either that the teflon is getting too hot (your theory, leslieann) and causing the abs to hit transition too early OR the abs is not moving quickly enough at some/any point, and the filament at the heater is getting hot enough to melt the filament all the way up the teflon tube. now the tricky bit is that it seems to me that once either of these things happens, both will happen, and then the whole thing will blow up.

which seems to be what's going on.

that sound about right?

edit: ooh, diagrams! looking now.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 21 June 2013, 18:47:16
is that blackened bottom part where the teflon slides into the peak? or does it actually slide into the heater (because that is bad.)
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Fri, 21 June 2013, 19:09:31
hence, what is happening is either that the teflon is getting too hot (your theory, leslieann) and causing the abs to hit transition too early OR the abs is not moving quickly enough at some/any point, and the filament at the heater is getting hot enough to melt the filament all the way up the teflon tube. now the tricky bit is that it seems to me that once either of these things happens, both will happen, and then the whole thing will blow up.

which seems to be what's going on.

Yes, now you got it.

The teflon does butt up against the brass nozzle, but they all do (otherwise it creates issues). The difference is that this end uses a huge metal end/head which encapsulates both teflon sleeves. There is no way to even begin cooling the teflon until it reaches the Peek material. This makes for a very large transition area for filament.

On my current head, the aluminum end/head itself is 25mm tall before it reaches the Peek, not counting the brass nozzle. On my new J-Head, there is 8mm of brass (not counting the nozzle), and then immediately goes into Peek. That is a a huge difference in how much you are heating up and how much heat you are trying to contain.


is that blackened bottom part where the teflon slides into the peak? or does it actually slide into the heater (because that is bad.)
That black strip is actually where the bowden tube clamped it, before I used it as a new liner. You can ignore that.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 21 June 2013, 19:27:06
The teflon does butt up against the brass nozzle, but they all do (otherwise it creates issues). The difference is that this end uses a huge metal end/head which encapsulates both teflon sleeves. There is no way to even begin cooling the teflon until it reaches the Peek material. This makes for a very large transition area for filament.

here is the problem i have with this. teflon is a thermal insulator (among plastics it's certainly not the best, but it also has a very very high melt point and is slippery, so i think it's a good choice of materials here). that means that it's hard to heat up, but that also means that it's hard to cool down. it should not be getting hot, period. correct me if i'm wrong, but i believe what you just said is that the teflon does extend into the heated metal portion (unless the brass nozzle extends all the way up into the peek -- it is not clear from the diagram. imo this is a design error to me (but a fixable one). ideally, you want an instant transition from solid to very not solid when you hit the heater. that means no thermal insulator ever between heated portion of head and not-heated portion of head and then infinite amounts of current into the heated portion such that it is a theoretically constant 230C or so (ie, instaneous thermal recovery).
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Fri, 21 June 2013, 19:50:18
I see the problem being the temperature gradient from the heat block which you want to keep hot and the teflon and PEEK which you want to keep cold. When you start up, you can basically not input enough heat into the heat block as that is the limiting factor for speed, and the PEEK remains as a barrier making the temperature gradient sharp. Once you approach steady state, that temperature barrier smooths out and you get a wider gradient which begins to affect the teflon and the parts higher up causing things to melt prematurely.

If you were to maintain a sharp temperature gradient, then the heat input could be increased, thus allowing a more rapid build speed and decrease the risk of clogging before it reaches the nozzle. The way this is usually achieved is by a better insulator (mostly delays the point where the gradient reaches through, which isn't suitable for long builds) or you apply a barrier which removes heat, ie a cooling block. The cooling block would need to be compensated by increased heat input, but it alloows for the temperature gradient to be sharper.

This is what I gather from your descriptions.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Fri, 21 June 2013, 20:03:30
here is the problem i have with this. teflon is a thermal insulator (among plastics it's certainly not the best, but it also has a very very high melt point and is slippery, so i think it's a good choice of materials here). that means that it's hard to heat up, but that also means that it's hard to cool down. it should not be getting hot, period. correct me if i'm wrong, but i believe what you just said is that the teflon does extend into the heated metal portion (unless the brass nozzle extends all the way up into the peek -- it is not clear from the diagram. imo this is a design error to me (but a fixable one). ideally, you want an instant transition from solid to very not solid when you hit the heater. that means no thermal insulator ever between heated portion of head and not-heated portion of head and then infinite amounts of current into the heated portion such that it is a theoretically constant 230C or so (ie, instaneous thermal recovery).

Here is a pic on the internals and how it works.

The innermost teflon actually slides into the nozzle as far as shown (6.5mm).
The outer teflon layer butts up against the end of the nozzle (represented here by the blue tube thingy).


It looks like the nozzle design was originally for 3mm filament and they simply added more teflon to adapt it to 1.75mm. This is common, and would probably be fine were it not for the teflon sliding into the nozzle.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Fri, 21 June 2013, 20:08:56
If you were to maintain a sharp temperature gradient, then the heat input could be increased, thus allowing a more rapid build speed and decrease the risk of clogging before it reaches the nozzle. The way this is usually achieved is by a better insulator (mostly delays the point where the gradient reaches through, which isn't suitable for long builds) or you apply a barrier which removes heat, ie a cooling block. The cooling block would need to be compensated by increased heat input, but it alloows for the temperature gradient to be sharper.

This is what I gather from your descriptions.
Correct

The E3d all metal hot end maker claims a transition from solid to melted in 3mm. This head starts at probably 5mm-10mm, but as time goes on, it stretches to about 25mm transition zone which is when things clog.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 21 June 2013, 20:22:03
darmogue breakin it down. basically you either need to keep your cool end cooler while keeping the hot end constant or v.v.

i would go with heatsinking your hot end and applying more power to it. reason: things with high thermal conductivity are thermodynamically more malleable. that's what thermal conductivity means
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Fri, 21 June 2013, 20:30:30
darmogue breakin it down. basically you either need to keep your cool end cooler while keeping the hot end constant or v.v.

That was my idea while back, but if I run it cooler, it means printing slower.
In the end, I can run hotter and faster or cooler and slower, either way, I end up clogging at the same point in a print.


As for the heatsink idea,
I insulated the end of the head, blocked off all drafts, and put two 50mm fans blowing onto just the Peek. It didn't help. So I'm done with this head. I just need to get a mount printed (trying it in parts) and I can throw this in the spare parts bin and use a better head.
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Fri, 21 June 2013, 20:34:21
You  will need to remove heat from the PEEK by any means possible. I was trying to think of a good way to divert heat away from there, but the problem is that it moves around and any extra size and weight like heatsinks or connections in the form of hoses to the moving entity will carry disadvantages.

Just to confirm, with that model it is the head which moves around and not the build, correct?
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Fri, 21 June 2013, 20:41:49
You  will need to remove heat from the PEEK by any means possible. I was trying to think of a good way to divert heat away from there, but the problem is that it moves around and any extra size and weight like heatsinks or connections in the form of hoses to the moving entity will carry disadvantages.

Just to confirm, with that model it is the head which moves around and not the build, correct?
Correct, it's a Rostock Delta.

I thought about watercooling the Peek, but decided it's just not worth the effort.

At least one company is looking into the idea though. You could get by with a pair of 1/4in tubes to transport the coolant.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 21 June 2013, 21:03:40
i would rank "exploding head" as a bigger problem than "adding some inertial error" and start adding heatsinks. cheap extrusions are plentiful at any electronics surplus store
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Fri, 21 June 2013, 23:38:17
i would rank "exploding head" as a bigger problem than "adding some inertial error" and start adding heatsinks. cheap extrusions are plentiful at any electronics surplus store
Yes, but water cooling is so geek chic!  :cool:

Actually one of the reasons they are considering water cooling is due to size constraints, fitting two hot ends and effective cooling into a Delta effector can be a challenge.

I considered it simply because I probably have everything I need to do it just sitting on a shelf.  ;D Though I would hate to see what would happen to my glass plate if it sprung a bad leak suddenly while the bed was at 100c.

A major issue is mounting a heat sink, any idea what sticks to Peek and is thermally conductive? I have no idea, not that I went looking. The best idea I had (other than watercooling) was to cut the Peek down to a sliver of itself and thread on a chunk of finned aluminum onto it. Then I started thinking well, why use Peek at all, just use a thin aluminum tube up to some fins. At which point I started contemplating just making my own all metal head...

At what point do you say enough of this, and just buy something known to work better. I don't mind making things and fooling around, but sometimes the results are just not worth the effort you put in. I think I spend a whopping $40 on the hot end, with bowden assembly, and it was only meant for short term use. My only real complaint is that I already replaced most of the parts I planned on keeping (the bowden assembly).
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Sat, 22 June 2013, 04:48:40
Woot!
First print, new nozzle (a .35), and WOW what a difference.

With conservative settings and no pre-test, I was printing at my old speed again and my infill is already better than almost all I did with the old nozzle.  It's not perfect and I still need to dial things in, but it's like someone switched the game from hard to easy.

Unfortunately Slic3r is up to it's old tricks, trying to switch directions in mid air, but hey, things are looking up.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sat, 22 June 2013, 05:37:22
Here is an interesting info about forces required from an extruder cold end.
http://airtripper.com/1338/airtripper-extruder-filament-force-sensor-introduction/
Unfortunately he does not specify his nozzle and the filament.

Interesting, I skimmed it a bit but will go back and read more of it.
He did mention the head, under a picture, it's a J-Head V9 clone (J-head is an open source design and tons of people are making them, some good, some not so good and in many wild variations).

His filament is 1.75mm based on the pictures (scale of teflon vs other parts of the extruder). I have an Airtripper extruder, works well, but it's much more complicated than some of the newer designs.

He uses a modified Airteripper too and somewhere else he mentions that it is not good for 3mm filament. So even from that we can assume 1.75 filament. No idea what material was used, since temperatures he is trying seem too hot for PLA and cold for ABS. Does J-Head V9 come with different nozzle sizes? Or is it only 0.5mm? .... I'll try to ask these things on his web directly.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sat, 22 June 2013, 05:54:01
few reasons for this: my head to plate tolerances right now are around +-0.1mm and my head to head (remember, two heads) tolerances are about 0.05mm. with abs and a 0.4mm head, i should actually be able to do about 0.1mm slice heights
I read somewhere (cannot find the web page now) that bed leveling should be precise to 1/5 of the layer height used.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sat, 22 June 2013, 08:11:44
i'd much prefer a full order of magnitude (cold) to give me enough fudge for thermal expansion, but you would probably need a runout meter that was accurate to 5 sig figs and a jig that was machined to be accurate to that degree as well, which i definitely do not have
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sat, 22 June 2013, 08:14:57
what was the opening diameter of your old nozzle, leslieann?
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sat, 22 June 2013, 13:08:35
my tiny family of traffic cones to push through the silly carpet. :D

anyway, i'm noticing that i'm getting the most inertial error on small y movements. the makerbot slicer's gcode generator doesn't slow down for these high frequency small distance back-and-forth y-movements and it's definitely causing some error -- you can see the whole 80lbs shaking when it does this. interestingly, the y-axis is driven by two belts due to some odd motor placement. thinking..
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Sat, 22 June 2013, 15:26:56
He uses a modified Airteripper too and somewhere else he mentions that it is not good for 3mm filament. So even from that we can assume 1.75 filament. No idea what material was used, since temperatures he is trying seem too hot for PLA and cold for ABS. Does J-Head V9 come with different nozzle sizes? Or is it only 0.5mm? .... I'll try to ask these things on his web directly.
His temps could be a thermister not reading quite accurate, but also some ABS melts higher, some melts lower.

I didn't know there even was a J-head V9, but being open source and a clone, it could be something else just renamed. I thought officially the newest was a V5. They do come in various nozzles, but J-heads aren't very friendly towards this it seems.

Direct drive pushes too much filament per step with 3mm, particularly on nozzle sizes below .5. All that head pressure is hard on the stepper as well.

what was the opening diameter of your old nozzle, leslieann?

Oops, the new one is .35, could have sworn it was .4, now I need to check what I put in settings.

On my old nozzle I had a .35 and a .5. I bought the .5 for initial setup and the .35 for later, but when things went downhill, I went back to the .5 in hopes of getting things working again.


my tiny family of traffic cones to push through the silly carpet. :D

anyway, i'm noticing that i'm getting the most inertial error on small y movements. the makerbot slicer's gcode generator doesn't slow down for these high frequency small distance back-and-forth y-movements and it's definitely causing some error -- you can see the whole 80lbs shaking when it does this. interestingly, the y-axis is driven by two belts due to some odd motor placement. thinking..
That's hilarious, it's a bummer you didn't print them with a smiley face.  :))

That sounds like my issue when I cranked my print speed (waaaaay) up. I didn't get errors, but what a racket and I feared things might break.
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Sat, 22 June 2013, 15:34:29
Print a triangle lying down to get a frequency range and try to find at which frequencies it resonates and grows larger. Then try to dampen those by or avoid them. Or just make everything heavier by stacking bricks on top of the machine.

Hmm, Your cone will have the problem of high frequency turns any way you place it in a cartesian coordinate system and limit the amount of planes it can move in simultaneously. Can the raster pattern be changed to a circular one instead? I believe you are already doing the contours that way.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sat, 22 June 2013, 19:54:31
the slicers aren't smart enough to avoid certain frequencies. they aren't even smart enough to not do that stupid high frequency oscillation in the first place. (although i imagine i'll do my part to fix this in the fullness of time). i am actually going to put bricks on top of the machine, but i can't currently put anything truly heavy on top of the machine because of my carefully designed cardboard box lid highlighted in earlier photos. once the acrylic lid comes in, i'm going to redesign my current fume extractors (variations on the priority mail design from my DIY solder fume extractor thread) so that the fans are firmly mounted on the wall and push air through flexible tubing into 20-40lbs of charcoal distributed on top of and around the machine. the cutesy little traffic cones are also going to have to turn into much shorter spikes + sorbothane to lower the frequency of the whole system. the traffic cone thing was just convenient because one of the sample models is that traffic cone, and i had already printed one or two to test the machine.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Sun, 23 June 2013, 18:04:15
I was getting fantastic ABS and PLA prints, and then things started acting funny again.

On the ABS, I couldn't push filament through the bowden tube, and checking everything, I found my filament is 1.9mm. It wasn't that big at the start of the roll. A bit of checking shows ABS does absorb water (though PLA is worse) and when it does, the filament can swell (how much depends on the grade). Our humidity has been up to nearly 90% (yes, it's terrible). I tried baking the filament, but that did nothing to reduce the size. I'm still not sure if it's a matter of manufacturing, humidity or both, but it looks like I have at least a pound of useless filament.

I do keep the filament in ziplocks with silica gel, but that does nothing while I'm using it. I heard of at least one person built a semi-airtight chamber for his rolls, with only a small hole for the filament to exit just before entering the extruder, I may do that along with buying some better filament and building a fume extractor.


The PLA, was great last night, I was actually starting to see why people like it, I got two really nice rod ends from it, then went to bed. Today, I go to make more, and nothing works. Nothing changed, and yet it refuses to push filament through the nozzle. I cranked up temps, and extruder pressure, still no luck.  I just don't see how it works one minute and a few hours later, simply refuses to work despite nothing changing (and yes, I checked the filament diameter). I can get it hot enough to be drooling out the nozzle, tell it to print and it dries up in just a few minutes. Like I said it worked great last night. Now I get nothing.

I could strangle this thing sometimes.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sun, 23 June 2013, 20:12:39
http://airtripper.com/1338/airtripper-extruder-filament-force-sensor-introduction/
Mark responded. He used 1.75mm PLA, nozzle size of 0.4mm. That means all the important data are there now.

Not sure whether I should feel bad about how filament is handled here. It is just thrown on a bench. It did not change diameter from the time I checked it (so it is stable at 1.7mm for at least 2 weeks). It is ABS. Typical humidity over here is in the 50-60%.

Is your filament nice and straight even when it is already pushed through extruder cold end (airtripper). The airtripper (as delivered) in the rostock here was bad. The plastic hole into which the filament is pushed did not start just after the gear and had big diameter (abut 4mm). This led to bowing of the filament especially when there was bigger amount of retracements. All the bowing created a sinusoid like wave on the filament in the bowden which led to occasional motor skipping.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Mon, 24 June 2013, 03:32:42
My filament comes out of the extruder about as curved as it goes in.
So long as it stays under 1.85 or so, it will get through the bowden just fine and work, above 1.85 and it starts creating too much drag (enough that I can feel it's shard to push).

I replaced my Airtripper, it worked well, but SeeMeCNC recently came out with a pretty nice extruder (EzStruder), and when on sale it wasn't much more than the hobbed drive pulley I needed ($9 for the pulley, $25 for the extruder with pulley). It's had quite a few good reviews by people who had seen and used it. It's small, plenty of torque and dead simple to change filament, I like it a lot. I wouldn't mind putting a geared stepper motor on it though, just to slow it down a bit.

The only time I saw a problem with filament and the extruder was when the motor go so hot that it softened the PLA. Otherwise, my extruder has been great.

I'm starting to wonder if the filament is just worse than I thought. On the plus side, if that's the case, and i am doing okay with it, it means things should be great once I do replace it.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Mon, 24 June 2013, 05:35:52
I got to thinking, if it's the moisture, I'm in trouble because even if I buy better filament, I would have issues. What annoyed me as well, was people storing it out in the open without issue, while I was being careful to re-bag it every chance I got. I can believe it can swell some, but if it did lots, there would be a lot of bad products out there as mine is about 13% over size.

When I realized how much, percentage-wise, it really bugged me and made me start thinking of a way to find out. I knew my filament varied some, I measured when I got it in several places and I saw it go from 1.68 to 1.78, so I had a baseline at least.

I went digging for old filament in my work area and the garage. I found a piece that has been in the garage for over a week or more, and... It measured 1.69. So.. If ABS does swell, it's probably very little, my guess would be less than 1%.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Mon, 24 June 2013, 06:14:02
I do not know. I used only ABS and the filament is in the rage 1.68-1.70 all the time but mostly 1.70mm.

The only thing which is not OK with it is that when starting a print the extrusion is "bloby". See change in the extruded material amount when printing a skirt. It has 4 strings and the outer one (the top) has clearly visible blobs about every 4 mm. This typically goes away when a skirt is finished, sometimes it lasts even during a part of the first layer. Sometimes the filament connecting the blobs is extremely thin even to the extend that it disappears and I only get a sequence of about 1mm long blobs  :rolleyes:

Maybe it is not a filament error.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Mon, 24 June 2013, 10:24:05
that looks like your cold end is too cold or your platform is not heated..
Title: Re: The Living 3D Printing Thread
Post by: vvp on Mon, 24 June 2013, 13:57:03
that looks like your cold end is too cold or your platform is not heated..
I doubt it is that. I think the temperatures are already stable when I start printing skirt. My guess would be that when printer is not running for a longer time them some gas bubbles get into extruder (somehow) and till they are expelled I get the blobs. Always after a while the extruded filament is nice and even.

Btw. I thought for a long time that Rostock design is the most easy to bed-level, but with the right software support. Looks like the support is arriving now. I have even written down the equations for automatic bed leveling myself but I did not get to the implementation of the HW  and the testing. Anyway I do not need to do it now since it is already done:

At least incorrect tower positions, diagonal rod length, incorrect top endstops, and z-axis length should be easy to compensate for (so one would not need laser cut top and bottom plate). No idea yet what kind of errors are compensated in the video.
Title: Re: The Living 3D Printing Thread
Post by: OkGold on Mon, 24 June 2013, 14:02:40
hey guys, so does anyone have Cherry keycap models? I really dig the ALPS adapters, genius
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Mon, 24 June 2013, 17:43:45
I do not know. I used only ABS and the filament is in the rage 1.68-1.70 all the time but mostly 1.70mm.

The only thing which is not OK with it is that when starting a print the extrusion is "bloby". See change in the extruded material amount when printing a skirt. It has 4 strings and the outer one (the top) has clearly visible blobs about every 4 mm. This typically goes away when a skirt is finished, sometimes it lasts even during a part of the first layer. Sometimes the filament connecting the blobs is extremely thin even to the extend that it disappears and I only get a sequence of about 1mm long blobs  :rolleyes:

Maybe it is not a filament error.

While sitting the nozzle can build gas bubbles and ooze a bit, giving an inconsistent print at first, that's one of the reason you use brims and skirts and such, it clears out the nozzle. Using a skirt, or doing a small amount of extrusion just before starting your print, brings fresh, solid filament into the nozzle.





I'm going to contact the supplier tonight about the filament and see what they say. The seller claims an oval shape is normal due to how they roll it, however, mine is round, it's just HUGE. When half the roll is 1.98 and 1.99 round, of course it has issues in a 2mm ID bowden tube. The seller and manufacturer also claims .1mm accuracy.. riiight. I know it's cheap filament, but I would like to at least get most than a quarter pound out of the 4 I have.  Luckily, I'll be near the seller Friday and may just stop in and show them.


Oh, and I found out the issue people have with direct drive on 1.75, bowden tube systems...
This setup seems okay for .5 nozzles (which I saw), and is what most people start with. However, once you decrease the nozzle size, head pressure goes up and in order to continue pushing filament, it takes lot of power, which can overpower the pneumatic fittings, and overheat the motors. Even the best Nema 17's can just barely push a .35 nozzle without getting quite warm hot.  Which is exactly what I have been experiencing.

I suspect the motor or driver gets hot and loses power. With PLA it can get hot enough to soften the PLA as it passes the drive gear, and soft PLA in telfon doesn't push nearly as easy.

So I'm looking at gear reduction systems, drivers and a clamp system for the bowden possibly.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Mon, 24 June 2013, 18:33:53
that looks like your cold end is too cold or your platform is not heated..
I doubt it is that. I think the temperatures are already stable when I start printing skirt. My guess would be that when printer is not running for a longer time them some gas bubbles get into extruder (somehow) and till they are expelled I get the blobs. Always after a while the extruded filament is nice and even.

sorry, i misread this. i thought all your extrusion looks like this. i can definitely imagine weird startup effects that would cause this, but just program your slicer to extrude enough garbage to get into steady state before starting on the part; imo easier to do that than debug startup effects. (they're a bit like caching startup in compute systems..)

Quote
Btw. I thought for a long time that Rostock design is the most easy to bed-level, but with the right software support. Looks like the support is arriving now. I have even written down the equations for automatic bed leveling myself but I did not get to the implementation of the HW  and the testing. Anyway I do not need to do it now since it is already done:

At least incorrect tower positions, diagonal rod length, incorrect top endstops, and z-axis length should be easy to compensate for (so one would not need laser cut top and bottom plate). No idea yet what kind of errors are compensated in the video.

very cool. frankly, there's no reason you couldn't do the same thing with a euclidian design. the limitations at the moment are largely budgetary.

and leslieann, re: the tolerances on your filament, not to say i told you so but... ;)

we should identify the _good_ filament manufacturers here. frankly, the MBI stuff is obviously being made in china now, so we can isolate the good extruders at factories in the same way that we isolate the good keycap molder factories over there... after all, a filament extruder is basically the front end of an injection molder with a tool at the end that extrudes long strands of filament in a very controlled way (rather than a big old mold under pressure..)
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Mon, 24 June 2013, 22:08:43
and leslieann, re: the tolerances on your filament, not to say i told you so but... ;)

we should identify the _good_ filament manufacturers here. frankly, the MBI stuff is obviously being made in china now, so we can isolate the good extruders at factories in the same way that we isolate the good keycap molder factories over there... after all, a filament extruder is basically the front end of an injection molder with a tool at the end that extrudes long strands of filament in a very controlled way (rather than a big old mold under pressure..)
One of the bigest complaints I have heard with cheap filament is size., so I did check it when I got it and before buying the PLA. The first 10% of the ABS was decent, I wouldn't have said it was great, but it served it's purpose, it was only as I got further into the roll that things went south.  Had I seen it this bad, I wouldn't have ordered the the PLA. It too seems fine many meters in, but it's not like you can easily unroll a pound of filament and check.

As for good ones, here are two lists.
http://reprap.org/wiki/Printing_Material_Suppliers
http://forum.seemecnc.com/viewtopic.php?f=36&t=754
Based on recommendations (and shipping location) I have 1lb or ABS and another of PLA coming from Ultimachine, should be here tomorrow (I hope).

Also, take a look at this, you think my filament is bad?
http://richrap.blogspot.com/2012/06/jammed-frggn-nozzle-30doc-days-1518.html
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Tue, 25 June 2013, 00:24:53
Is he serious about the ball bearings? Holy crap, that isn't even some slight contamination, that is like their machine breaking down and releasing balls from its bearings into the material. I wouldn't touch that with a 12 gauge shotgun.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Tue, 25 June 2013, 00:32:51
yah, i like how he refers to the bearing as "a contaminant". a bearing is much much more than a contaminant. that's like "oh, pieces from the grinder just kind of fall into the material, AND WE LEAVE THEM IN IT". the real question is, what do they do with the grinder?
Title: Re: The Living 3D Printing Thread
Post by: vvp on Tue, 25 June 2013, 03:45:16
I'm going to contact the supplier tonight about the filament and see what they say. The seller claims an oval shape is normal due to how they roll it, however, mine is round, it's just HUGE. When half the roll is 1.98 and 1.99 round, of course it has issues in a 2mm ID bowden tube. The seller and manufacturer also claims .1mm accuracy.. riiight. I know it's cheap filament, but I would like to at least get most than a quarter pound out of the 4 I have.  Luckily, I'll be near the seller Friday and may just stop in and show them.
When a filament is not round or when diameter changes over the length of the filament then the filament should be thrown to a garbage bin and the supplier should not be used again.
Even 0.1 mm accuracy for 1.75 mm filament can mean that the volume pushed through nozzle is almost 12% more (or almost 12% less) than the slicer expects. The error seems high to me.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Tue, 25 June 2013, 03:46:26
hey guys, so does anyone have Cherry keycap models? I really dig the ALPS adapters, genius
http://www.thingiverse.com/thing:79673
Title: Re: The Living 3D Printing Thread
Post by: OkGold on Tue, 25 June 2013, 09:39:42
So what's the market like here? are people interested in getting adapters/keys/etc? or is it just something people are messing around with?
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Tue, 25 June 2013, 09:49:23
we're messing around so that we can deliver you guys cool custom stuff! best of both worlds hooray!
Title: Re: The Living 3D Printing Thread
Post by: kmiller8 on Tue, 25 June 2013, 13:02:19
Well I got my kit yesterday... Got everything assembled except the extruder because I'm missing a few bearings. Hopefully by the end of the week I'll be printing.
Title: Re: The Living 3D Printing Thread
Post by: SpAmRaY on Tue, 25 June 2013, 16:55:41
Well I got my kit yesterday... Got everything assembled except the extruder because I'm missing a few bearings. Hopefully by the end of the week I'll be printing.

topre keychains!!  :-X
Title: Re: The Living 3D Printing Thread
Post by: kmiller8 on Tue, 25 June 2013, 18:31:16
topre keychains!!  :-X

no? those will be laser cut... There's isn't a good enough finishing method on FDM 3D printing that I'd feel comfortable selling as a finished "professional" product.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Tue, 25 June 2013, 19:08:09

people                 3d printers owned                     will print for you?
-------------------------------------------------------------------------------------
leslieann              rostock delta (from kit)               no

This information  is incorrect.
Mine is not a kit, mine is built from scratch.
Also, I have no problem printing for others, once I have everything worked out.



When a filament is not round or when diameter changes over the length of the filament then the filament should be thrown to a garbage bin and the supplier should not be used again.
Even 0.1 mm accuracy for 1.75 mm filament can mean that the volume pushed through nozzle is almost 12% more (or almost 12% less) than the slicer expects. The error seems high to me.
I agree, but he also needs to know he is selling utter garbage.

I agree and disagree with you about the .1 accuracy.  On one hand, yeah, it's a hassle, on the other hand, how much are you willing to pay to get higher accuracy? If it's not effecting the print, it's not worth a massive price increase.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 26 June 2013, 01:01:53

people                 3d printers owned                     will print for you?
-------------------------------------------------------------------------------------
leslieann              rostock delta (from kit)               no

This information  is incorrect.
Mine is not a kit, mine is built from scratch.
Also, I have no problem printing for others, once I have everything worked out.


oh, good point. could you put one dense post together that summarizes your build? plans, BOM, some brief description of anything that needs to be fabbed, any specific issues you had early on that we haven't been beating to death for the last n pages... ;)

going on plans and sourcing your own parts is something that should be discussed more. a lot of the reprap plans are more like loose recipes (ie, get _some_ kind of stepper motor with at least these specs...) that provide room for a lot of budgeting etc... if the rostock is like that, a more detailed post on your build would be very education.

for my part, i'm going to start this week on my completely exploratory delta-like design with a simple rotary table this week. just putting an ARM on it, taking some measurements, putting bed material, taking some measurements, heating it up, taking some measurements... yes, this is what i do for fun.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Wed, 26 June 2013, 01:46:34
oh, good point. could you put one dense post together that summarizes your build? plans, BOM, some brief description of anything that needs to be fabbed, any specific issues you had early on that we haven't been beating to death for the last n pages... ;)

going on plans and sourcing your own parts is something that should be discussed more. a lot of the reprap plans are more like loose recipes (ie, get _some_ kind of stepper motor with at least these specs...) that provide room for a lot of budgeting etc... if the rostock is like that, a more detailed post on your build would be very education.
Yeah, I can do that, and yes, the Rostock is exactly like that... I get things like this:
"Fasteners: Stainless steel, mostly M3 (some M4 and M8)."
That was why I said your kit has a lot of bugs worked out, mine is ALL bugs. LOL
Here is the wiki page for it: http://reprap.org/wiki/Rostock


Hmm...
I'm debating if it might be better to do it as a separate thread, and make it a bit generic as well. Sort of a "so you want to build a 3d printer" type thing.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Wed, 26 June 2013, 03:50:54
I agree and disagree with you about the .1 accuracy.  On one hand, yeah, it's a hassle, on the other hand, how much are you willing to pay to get higher accuracy? If it's not effecting the print, it's not worth a massive price increase.
You are right, there is no reason to pay more when it is not needed.
The rostock here is the old one as defined in the wiki: http://reprap.org/wiki/Rostock
I do not own it. It was from a kit. The kit had few bad parts: too loose filament guide on airtripper (fixed by inserting a piece of bowden in it), defect on the heatbed copper traces (fixed by soldering), universal joint holes should have been smaller, obsolete and unfinished build instructions.
It prints ok at low speeds (at most 50 mm/s), 0.3 mm layer height, external perimeters at about 10-20 mm/s.
Filament is from the same source as the kit. It looks fine so far. It's diameter is still in the rage 1.68-1.70 mm. But only about 10% of the spool is used so maybe the quality will deteriorate later :rolleyes: or maybe not  :). 1kg of filament was for 24 ... and now it is 25 ... long life for inflation!
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Wed, 26 June 2013, 06:19:19
As I expected, a "build a 3d printer primer" came in at over 2600 words and that's before I add bb code and links and final edit. LOL



The rostock here is the old one as defined in the wiki: http://reprap.org/wiki/Rostock
I do not own it. It was from a kit. The kit had few bad parts: too loose filament guide on airtripper (fixed by inserting a piece of bowden in it), defect on the heatbed copper traces (fixed by soldering), universal joint holes should have been smaller, obsolete and unfinished build instructions.
It prints ok at low speeds (at most 50 mm/s), 0.3 mm layer height, external perimeters at about 10-20 mm/s.
That's the same Rostock I have, just done in parts by me, no kit. Yeah, the instructions stink. LOL My next will be a Cerberus or oversize Kossel.

Two things determine print speeds on a delta (actually three), the head, and the arms. The u-joints are worthless junk, I never even installed them. Traxxas rc car rod end system can be cobbled together for $12 (Or bought for about $40), I used 3/8in oak, and cut the heads off some fasteners to attach the rod ends. Or, go one step further, and spend the $50 and convert to magnetic rods (http://forum.seemecnc.com/viewtopic.php?f=54&t=1704&sid=8a592fead4b0c9a4ad4a68a8a102d0f5).

On mine, I consider 50mm per second slow, that is my baseline troubleshooting speed. I only go below that when there is a problem (which is all the time at the moment).

If my extruder could keep up, at .3 mm layer height I could easily print at 80-100mm a second without any noticeable quality loss and even ran mine up to to 200 (just to try it) and saw only a little loss in quality. Magnetics should exceed even that, however the momentum it generates shakes the heck out of everything (it seemed like a good size earthquake was happening) and as I said, my extruder motor can't handle it. I suspect I would probably need a more powerful heater to keep up that rate for long as well. I'd love good quality at 120-160mm, which is very fast for a cartesian.

If you have good arms and head, there is only one other thing that causes poor prints on a Rostock and that's the belts. They need to be TIGHT! They should sound like an upright bass guitar when you pluck them. Seriously!  It took me a while to figure out how tight they actually needed to be.

I use three of these (http://www.thingiverse.com/thing:31991), they make tensioning the belts much easier. These  (http://www.thingiverse.com/thing:26361)are probably a bit better but will add mass to the system. I'm probably going to make a mesh of the two designs soon.
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Wed, 26 June 2013, 07:29:11
If you are all crazy and want to make huge modifications, then there are always lead screws and linear actuators based on them.

A smaller change you could make: The larger the wheels, the less influence you will get from flex in the drive belts. You sort of gear it up, then add the tolerance and then gear it back down again, also gearing down and lowering the influence from the added tolerances in the middle of this transmission.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 26 June 2013, 09:27:50
the MBI unit is a good candidate for leadscrews actually. the Z dimension is already driven by a very long very nice leadscrew. the Y two-belt design i was talking about _could_ be a single belt driving a leadscrew... the X dimension is pretty accurate with a single belt.

the rotary table i'm picking up is stepper directly driving the table via a leadscrew. it's the sherline 4"
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 26 June 2013, 09:28:32
i've updated the OP to reflect everyone's sourcing a bit more properly. when you get your novel up i'll link to it leslieann :))
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Wed, 26 June 2013, 15:39:23
A smaller change you could make: The larger the wheels, the less influence you will get from flex in the drive belts. You sort of gear it up, then add the tolerance and then gear it back down again, also gearing down and lowering the influence from the added tolerances in the middle of this transmission.
Larger pulleys, while they do have less belt influence, make for less positioning accuracy. Though 200 steps per mm is probably a bit on the excessive side.  :))
Title: Re: The Living 3D Printing Thread
Post by: vvp on Thu, 27 June 2013, 05:37:24
Leslieann, I replaced u-joints yesterday with .... much more tighter u-joints. Hopefully it will last for a while. Hell, it was possible to move the platform by few millimeters without any movement on the carriages. I was surprised it printed so well (at slow speeds). I guess gravity forced the platform to the same position. It looks like even when the joints are total crap, rostock can print quite well if it is set to very low speeds.

Belts produced a bass tone from the beginning. They should be ok. They were tightened the way wiki proposes: tighten manually, put it down shorten them a bit more and force them back. Seems to work well enough.

There were separate instructions with the kit. They were not much better than what is on the wiki  :rolleyes:

What I want to point out is that if you go with a kit it is not much better than sourcing everything yourself.

There are new carbon tubes here for over a week now and some sample ball-joints from an RC Model shop. So there is a plan to replace the diagonal rods with something better. Still waiting for more ball-joints and tools to make left-hand threads.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Thu, 27 June 2013, 06:09:18
Would not leadscrews mean slow movements? Leadscrew will slow down your system (compared to pulleys) about 30 times. It may mean getting steppers which can accelerate more quickly to keep the print speeds up.

The new Mini-Kossel levels bed repeatedly to 0.02 mm and there is no reason it would be slower than standard rostock. So you get speeds up to 20 cm/s and low speed accuracy of 0.02 with belts cheaply. Hmm, cannot even quickly find what is typical elasticity of GT2 timing belts.

Can leadscrew compete? Probably yes ... with beefy enough motors :)
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Thu, 27 June 2013, 06:15:53
Yes, they will not reach the same speed as easily, but you get reliable and consistent tolerances with increased speed. If you need to have acceleration and retardation distances for movement with bands, and in cases where there is no room even wait for the oscillation to dissipate, then the total time might be the same with a slower but far more exact lead screw.

I agree that is it most likely overkill though but this consistency, which then also allows the head to output a very constant flow, could be another factor to make the builds more consistent. This rather than having to continuously have to adjust the output rate to match the irregular movement caused by a band system.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Thu, 27 June 2013, 06:25:00
Woot!
I managed to print PLA for several hours today.. my junk filament no less.
I got my magnetic arm cups made, and I even made the main body of my gear reduction system, a near 4 hour print job. Longest print job I have run so far. Of course, 20 minutes later on another print job, I jammed the head again. lol I had to babysit and crank up the driver amperage, which meant adding a fan on the motor and driver... But it worked. Oh well, my Ultimachine filament arrived, I just have to start using it. Once I got printing, I didn't want to stop it.

The gear reduction looks great, the bearings fit, I just need to see if the herringbone gears mesh right... Unfortunately, the main gear has an issue in Slic3r, Willitprint never works for STL files, Netfabs service is down and I can't even get Tinkercad to correct the issue. Oh well, the head jammed just before I was ready to print it anyhow.

If it works, I will get it on Thingiverse, as it can be used with the Airftripper and with the SeeMeCnc Ezstruder. It uses the same bearings as the Airtripper and gives an approximate 3:1 reduction. I also have to print the carriages for the new magnetic arms, I may print those while working on fixing the herringbone gear, but I want to get the reduction done first as I will get more benefit from that.


VVP,
I did the belts that same way (figured it out through trial and error), but found that little tensioner made it much easier. Simply give the end of the zip tie a tug and it was done. I think, my belts are settling finally, though.

Also, another way I overcame slop was I added hair ties (stiff rubber bands) to tie the rods together. This took out a lot of the slop that tightening bolts couldn't. Laugh all you want, it works well. It would probably work on u-joints too. I did each pair, top and bottom then I did from leg in a pair to on leg in the next pair at the effector. So I have a complete circle from one to the next at the effector. It made quite a difference.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Thu, 27 June 2013, 06:28:12
when you get your novel up i'll link to it leslieann :))
First version is up (3500 words  :-X)
http://geekhack.org/index.php?topic=45210.0
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 27 June 2013, 07:50:14
finally got the bed as level as it will get with an indicator gauge, but i forgot to check head to nozzle clearance (or offset that appropriately) FACEPALM.

the result: [attach=1]

oops.
Title: Re: The Living 3D Printing Thread
Post by: JPG on Thu, 27 June 2013, 07:55:24
finally got the bed as level as it will get with an indicator gauge, but i forgot to check head to nozzle clearance (or offset that appropriately) FACEPALM.

the result: (Attachment Link)

oops.

Damn, I hope it wont cost you that much!

[attachimg=1]
Title: Re: The Living 3D Printing Thread
Post by: BLJ Consulting on Thu, 27 June 2013, 09:24:20
finally got the bed as level as it will get with an indicator gauge, but i forgot to check head to nozzle clearance (or offset that appropriately) FACEPALM.

the result: (Attachment Link)

oops.

ouch.  Good thing you got that extended warranty
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Thu, 27 June 2013, 23:15:51
finally got the bed as level as it will get with an indicator gauge, but i forgot to check head to nozzle clearance (or offset that appropriately) FACEPALM.

the result:

oops.
I assume that's (only) the Kapton tape... Ouch.
If I had to rely on Kapton, I'm not sure I would have even bothered building a printer, the price of that stuff is just silly. I have yet to buy any, and I would prefer to never need to.

As for the head crash, been there, done that, pretty much the same exact way. LOL I'm amazed I haven't broken my glass doing it.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Fri, 28 June 2013, 05:39:37
Update...
First off good PLA is AWESOME! It comes out like mudd, soooo nice.

Second...
Cheap Filament? What cheap filament?  *giggle*

Say what you will, but my printer ROCKS!
My gear reduction is done, and it needs some work, HOWEVER....  Filament either goes through the nozzle or, well, there is no "or"... (okay the filament COULD be chewed to bits).  I geared it down by about 3:1 and WOW. It will just about push your finger through the bowden tube and nozzle now. I have it doing decent quality printing at almost 100mm a second using the junk filament I could hardly print with before and the extruder motor is not skipping, I even turned the amperage way down! (It is getting a bit warm at these speeds though). Oh yes, this printer is rocking now!

A little work and this gear reduction will be ready for prime time. It will work on Airtrippers, SeeMeCNC's Ezstruder and pretty much anywhere it can fit. When I get it done, it will be open sourced, but even in crude form (holes are off), it rocks! I have yet to even try it with the good filament.

Here is a shot of it doing about 100mm per second, .35mm nozzle, .25 layer height, junk filament, hair tied tie rod ends, and zero tuning on the new extruder. The blobs on the first layer is due to bad retraction )I haven't adjusted it for the retraction yet) and an odd first layer for the part. Lots of start and stops and the stuff to the far right is actually support material only, it actually looks much better in person.

For a first run at that speed and junk filament, I'll take it!
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Fri, 28 June 2013, 06:55:06
Congrats. Could you show us some close up pics of the finished print, or preferably one printed with the good filament once you do? If I understood you correctly, that was still with the bad filament.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Fri, 28 June 2013, 07:29:44
Thanks! :)
Tomorrow, I will take some of what printed and after I rebuild the reduction and use better filament.

I actually stopped the print about 20 minutes after the picture. The misalignment and torque of the reduction system was enough to damage my extruder(!) and misalign the filament being pushed so I stopped it before any serious damage could occur.

I need to redo it with a little more precision, the gear mesh was great, it was even relatively quiet (due to using ,the herringbone gears) but some screw holes were off and the pinion set screw rubbed the body. It was a great first test though, I was really impressed. When done, I would recommend anyone with direct drive to put it on, it really makes a big difference. I won't go back to direct drive once I get it working.

I will probably design a whole extruder around it at some point.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 28 June 2013, 11:03:46
NOICE!

DAMAGE REPORT: all kapton damage on the plate (it was a very very very very tiny error), and i suspect the brass nozzles are plan softer than the hard anodize on the alum anyway. right side nozzle is still DEAD ON 0.4mm. fantastic. left nozzle looks a little worse. definitely took the brunt, averaging closer to 0.5mm (my caliper is only accurate to about 0.04mm though in practice, and probably less on the extruded filament because it's still definitely compressible)

note that as per MBI support, the extruder nozzles as of the r2x and future models are integral to the heater core. they are a press fit with way more force than previously, which is nice because it means uniform temperatures, but you can't swap out nozzles anymore. i didn't as how much a heater core would be because i was advised to check tolerances on the parts first. phone support argued with each other for a bit about whether the brass was harder than the alum alloy they used or not, but i guess now we know! i suspect without the hard anodize the results would have actually been different. quite interesting actually. i suspect the change in tolerance on the left nozzle will end up getting lost in other noise.

kapton is ridic expensive through mcmaster (in low quantities basically) but ebay has it cheap direct from asia and MBI sells a nice wide roll at a very reasonable price. 5.7"x~22y for 25$. 0.1mil not bad at all.

MBI support also feels that the the gantry forces produce up to about 0.15mm of unevenness in the center of the plate (downward) and the plate itself is specced to like 0.2mm flatness (which frankly is not very flat). official assembled flatness tolerance is like 0.3mm. what's interesting is that because the heater is quite good, you can make up for some of that tolerance by moving a bit slower, as that squishes the layers more densely as you extrude, so it all works out surprisingly well. my feeling as well as theirs.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Fri, 28 June 2013, 17:11:32
Here is the print from last night on macro... Yes, that is the paper grain you can see in front of it.

This was at 88mm per second (I checked the numbers).
Near the top you can see where the extruder itself started to fail. The left side shows the detail most clear, I'm in a rush to get out the door at the moment.


Also, while I was, and still plan on making a universal gear reduction, the Berry Tripper (http://www.thingiverse.com/thing:86631) his is pretty close to what I had planned for my own version. I'll be printing off the last parts I Need later tonight.

For those with direct drive, make one of these, and set steps per mm to 340 (should get you within 1mm)
Title: Re: The Living 3D Printing Thread
Post by: kmiller8 on Fri, 28 June 2013, 22:47:16
(http://i.imgur.com/w6IVWpC.jpg)

It begins :D
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Sat, 29 June 2013, 00:55:21
I found out that last night I was printing with a loose belt (I'm working on better tensioners) and my heated bed was sliding 3mm side to side (screws came loose).

I just looked at that picture again,  doesn't do it justice, that color makes it hard to see.
Title: Re: The Living 3D Printing Thread
Post by: kmiller8 on Sun, 30 June 2013, 20:14:53
I printed a sheep :D

(http://i.imgur.com/lNIukAX.jpg)

This is me testing 50 micron print level, it came out pretty good for one of my first prints, and especially my first print of this layer size with my machine.
Title: Re: The Living 3D Printing Thread
Post by: __red__ on Sun, 30 June 2013, 20:21:07
Awesome guys, wish I hadn't been away so long so I could have commented as this went.

I print PLA at 220mm/s but at ridiculously thin layers so it still takes a while.


__red__
Title: Re: The Living 3D Printing Thread
Post by: BLJ Consulting on Sun, 30 June 2013, 20:48:31
How thin is ridiculously thin?
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Sun, 30 June 2013, 21:10:12
Interesting thing about printers...
Switch two wires and suddenly everything prints mirrored (don't ask!  :rolleyes:)

So I got my modded Berry Tripper extruder printed in PLA (I redesigned it to use a larger bearing i had on hand)... and forced the bearing in a little tight and SNAP! Next version... I redid it, and all went well, except I switched to ABS, and my temps were a tad low, and while assembling it, it delaminated some (still usable though). GRRRRRR I (stupidly) went to the Ultimachine PLA and didn't test for optimal temps. Something I did with their PLA. These are near 3 hour prints only to see them bad in 5 minutes. So I took another, reinforced it, and got my ABS temps right this time, with luck it will come out right.

The new extruder sounds like a drowning cat when it retracts. LOL But it works great. No more direct drive for me. Currently printing at .2mm without a complaint from it and running nice and cool. I got to see what .1mm is like the other night... Very smooth.


A note about Ultimachine filament, I found a few others using it locally the other night. All feel the same way I do about it, it's fantastic stuff. Also, if you live in the central US, it usually arrives in 1-2 days.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Mon, 01 July 2013, 05:43:28
Nice, and my filament went from good stable 1.7 mm to 1.61 mm, I guess at the end of the spool it will be like a sewing thread :) It is probably a good idea to check filament diameter each day before printing.

Also I tried the latest Marlin firmware from https://github.com/jcrocholl/Marlin.git (2013-06-11 22:33:58) and it does not work well. Movement is jerky around the center of the heatbed.

Uff, and I found that it is hard to make the first layer stick if its layer height it lower than 0.2 mm. I read many times things like: "Make first layer thin to make it stick." It looks like it may be true but there is a lower limit. This was ABS @ 230C on kapton tape on glass @ 110C.

Did any of you try sandblasted glass?

Ridiculously thin (and also slow) is 0.025 :) http://richrap.blogspot.sk/2012/01/slic3r-is-nicer-part-3-how-low-can-you.html
Title: Re: The Living 3D Printing Thread
Post by: Tym on Mon, 01 July 2013, 06:19:38
Could you guys 3D print another 3D printer?
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Mon, 01 July 2013, 06:44:58
Could you guys 3D print another 3D printer?

That is the idea of several of them. None of them can be printed entirely of course. There are many mechanical parts which require metal, higher tolerances and such but where many parts can be printed after you have bought a base kit.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Mon, 01 July 2013, 06:45:25
have been avoiding glass (yes even pyrex) for its horrible heat conductivity.

red! what are you printing on? hackerspace printer or your own? hooray! another inductee!
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Mon, 01 July 2013, 15:00:49
Nice, and my filament went from good stable 1.7 mm to 1.61 mm, I guess at the end of the spool it will be like a sewing thread :) It is probably a good idea to check filament diameter each day before printing.

Also I tried the latest Marlin firmware from https://github.com/jcrocholl/Marlin.git (2013-06-11 22:33:58) and it does not work well. Movement is jerky around the center of the heatbed.

Uff, and I found that it is hard to make the first layer stick if its layer height it lower than 0.2 mm. I read many times things like: "Make first layer thin to make it stick." It looks like it may be true but there is a lower limit. This was ABS @ 230C on kapton tape on glass @ 110C.

Did any of you try sandblasted glass?

Ridiculously thin (and also slow) is 0.025 :) http://richrap.blogspot.sk/2012/01/slic3r-is-nicer-part-3-how-low-can-you.html
I usually only go to about 95c,  with hairspray on green window glass.
So long as it hasn't been a while since I sprayed it, I have to wait for the glass to cool to almost room temp before I can pry the ABS, off even at .2 (I haven't tried .1).

PLA on my glass at 60 with hairspray is actually a fight to get off, no matter the temp. I have had it stick so bad that I had to heat cycle it in order to be able to remove it without breaking something.



have been avoiding glass (yes even pyrex) for its horrible heat conductivity.
So long as I don't have a fan blowing on it, my bed is up to 95c in about 7or8 minutes.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Mon, 01 July 2013, 19:05:02
thermal recovery
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 04 July 2013, 00:45:34
speaking of thermal recovery, pla is bizarre and has a weird glass transition window and degradation point. the rep2x firmware doesn't handle it well at. all.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Thu, 04 July 2013, 03:06:20
can you be more specific? what do you mean by degradation point?
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 04 July 2013, 08:15:32
at 230C i'm getting blobs of PLA stick in my head. my _theory_ is that these blocks have gotten way too hot and depolymerized, because they get wildly stuck in the head -- they stop flowing no matter how much power the heatercore pumps into them.

http://en.wikipedia.org/wiki/Thermal_degradation_of_polymers

that said, the rep2x heatercore design is just not well suited for PLA. it gets way too hot. i've found a magic temperature that seems to preserve flow, but even this is starting to fail as the head fills up with degraded polymer (note to self, clean the heads out).
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 04 July 2013, 09:31:15
i've ordered some turnkey solutions for the ABS issues, and some provisions for taulman nylon. we'll see how this goes. need to clean out the heads this morning as well, and soak the nozzles in some solvent for a bit (ideally). lots of carbon on those. hah!
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 04 July 2013, 11:14:29
couldn't get the heatercores out. I bet I missed a bolt that's mounted on the underside.. crap, i did. anyway, they didn't come out like I expected them to, so i just cleaned the upper tube section from the top with copious amounts of solvent and light brushing. looks pretty clean now actually!
Title: Re: The Living 3D Printing Thread
Post by: vvp on Thu, 04 July 2013, 12:32:35
thanks mkawa
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Thu, 04 July 2013, 16:21:45
at 230C i'm getting blobs of PLA stick in my head. my _theory_ is that these blocks have gotten way too hot and depolymerized, because they get wildly stuck in the head -- they stop flowing no matter how much power the heatercore pumps into them.
230c for PLA is way too hot and will clog your head for sure, that was part of the problem I was having.

One thing I later found was let the head cool to room temp, then push some ABS through (at ABS temps) and it would clear it out.



Also, solvent will eventually clean things out, but leaves residue, meaning they will clog again soon enough probably.
This  (http://www.youtube.com/watch?v=6bTfl35zlHE)is my preferred method for cleaning them out. So far, I have yet to need to clean my J-head, but I cleaned my old head all the time due to issues. Beware the alcohol fumes, they can get you drunk or sick quite fast. It can also catch fire.
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Fri, 05 July 2013, 06:18:00
I stumbled across this  (https://sketchfab.com/show/cnTC9viItfZ1fdT811NgEVafw1S)which might come in handy when trying to explain something. It could make things a bit easier to point to something etc.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 05 July 2013, 07:08:32
at 230C i'm getting blobs of PLA stick in my head. my _theory_ is that these blocks have gotten way too hot and depolymerized, because they get wildly stuck in the head -- they stop flowing no matter how much power the heatercore pumps into them.
230c for PLA is way too hot and will clog your head for sure, that was part of the problem I was having.

One thing I later found was let the head cool to room temp, then push some ABS through (at ABS temps) and it would clear it out

Also, solvent will eventually clean things out, but leaves residue, meaning they will clog again soon enough probably.
This  (http://www.youtube.com/watch?v=6bTfl35zlHE)is my preferred method for cleaning them out. So far, I have yet to need to clean my J-head, but I cleaned my old head all the time due to issues. Beware the alcohol fumes, they can get you drunk or sick quite fast. It can also catch fire.
heat stress of doing that would destroy my entire head quite quickly. makerbot r2x nozzles are not replaceable.

also the r2x firmware happily told me to extrude PLA at 230C :facepalm:

yes i cleaned mine out with solvent and a brush for the upper head and abs for the nozzles.

i only have a couple spools of PLA an honestly the r2x handles abs so beautifully that i just stuck them in a bag until i get further into design of the Geekhack True Polar (tm). up early so i'm going to build up my arduino uno motor shield and rotate some leadscrews :D
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Fri, 05 July 2013, 15:52:06
Quote from: leslieann
heat stress of doing that would destroy my entire head quite quickly. makerbot r2x nozzles are not replaceable.

also the r2x firmware happily told me to extrude PLA at 230C :facepalm:

i only have a couple spools of PLA an honestly the r2x handles abs so beautifully that i just stuck them in a bag until i get further into design of the Geekhack True Polar (tm). up early so i'm going to build up my arduino uno motor shield and rotate some leadscrews :D

Ahhh yes, I forgot about that, which is why so many replace it with a J-head.
Mine does ABS quite well as well, other than fumes, I have no issues with it.

i have not seen any discussion of moving to j-heads in the r2x discussions. the j-head is based on the MBI mk4 design which also used a teflon sleeve, PEEK section and then brass screw-on nozzle. the r2x heads are a significantly different design which is optimized for more uniform diffusion of heat. they are all-metal, with iirc an aluminum, unjacketed inside but pressed outside into a large aluminum block. the exposed barrel is then taped to a heater filament which is of a material i don't know, and then a brass nozzle (although it seems to have been hardened so maybe it's an odd alloy or something) is pressed either into the barrel or around it. the whole exposed barrel is surrounded more metal of some kind and then jacketed to just above the nozzle ending with a ceramic block.

basically, it seems like their goal was, "get hot, stay hot". this makes it absolute **** for printing PLA, but pretty beautiful for ABS.

the only thing i've seen people complain about is the filament retailer design. there are those who insist that the spring is not strong enough. i _think_ the issue is that they're running out of spec filament through it, as mine look plenty strong and hold extremely well. they may also be clogging their heads trying to run PLA through and then jamming ABS in without cleaning out and lubing the delrin plunger section. overall though, people seem pretty happy with the heads.

the only major changeout i've seen for the heads is an aluminum carriage specifically for running over 260C. at those temps, the carriage itself starts to melt (ack!), and all hell breaks loose. this temp is required for extruding the cool taulman vinyl filament, and is definitely unsupported by MBI (but looks tres cool).

the plates on the other hand..


note from kawa: ack, i hit edit when i meant to hit quote. AAAAAA sorry leslieann :( :( :(
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 05 July 2013, 18:34:26
heat stress of doing that would destroy my entire head quite quickly. makerbot r2x nozzles are not replaceable.

also the r2x firmware happily told me to extrude PLA at 230C :facepalm:

i only have a couple spools of PLA an honestly the r2x handles abs so beautifully that i just stuck them in a bag until i get further into design of the Geekhack True Polar (tm). up early so i'm going to build up my arduino uno motor shield and rotate some leadscrews :D

Ahhh yes, I forgot about that, which is why so many replace it with a J-head.
Mine does ABS quite well as well, other than fumes, I have no issues with it.


Update on my printer:
Switching to a geared extruder was the best thing I could have done. Good filament or bad, it will push it. It really made life easier... Except during filament changes.  Oh, and I will never buy loose 1lb filament again, what a hassle to deal with.

My biggest problem now, is the perfectionist in me. I redesigned the carriers for mine, and I cannot count how many revisions I've done, but I have over a dozen prints of the part (at an hour each) sitting in the scrap bin. Granted it's only the third part I have designed, but between finding what works and what doesn't, accounting for shrinkage, and just changing how I want certain things has lead to many, many changes. Last night when i finally got what I think was finally it, Slic3r decided it no longer wanted to properly slice it. Cura, Kisslicer and Skeinforge want to run my extruder in reverse,
ahahahaa this cracked me up so hard i couldn't read the rest of the post

what the hell?! i hope to god that's a simple switch in the config file somewhere. christ! i guess it isn't such a bad thing that they're all written in interpreted languages.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Fri, 05 July 2013, 20:22:26
It seems most slicer programs run the extruder opposite to Slic3r, the only thing I can figure is that the Repeteir firmware may be confusing them, I'm not sure. It's an easy mechanical fix, just flip the wire on the Ramps board, however that means swapping the wire every time I swap slicers. I would like to get it working on all of them.


Famous last words of a 3d printer owner... "You know, it would be so easy to just fix that one little part..."  30 hours and 12 prototypes later you find something else to "easily fix".
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sat, 06 July 2013, 01:23:22
flip it in software not hardware
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Sat, 06 July 2013, 04:47:12
flip it in software not hardware
If I could find where, I would.
Firmware would work, but again, that still means messing with it every time I change slicers.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sat, 06 July 2013, 08:30:59
It seems most slicer programs run the extruder opposite to Slic3r, the only thing I can figure is that the Repeteir firmware may be confusing them, I'm not sure.
It cannot depend on firmware. Slicer can generate G-code without printer even connected. It cannot query firmware. It must be because of slicer configuration. If you use absolute coordinates for extruder then you can easily check the G-code. Look whether the E Values are increasing when progressing further in the G-code file.

The only thing how it could depend on firmware is when you slice from within some other program (e.g. pronterface) and that program would modify config setting for slicer based on the connected printer.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Sat, 06 July 2013, 15:53:26
It cannot depend on firmware. Slicer can generate G-code without printer even connected. It cannot query firmware. It must be because of slicer configuration. If you use absolute coordinates for extruder then you can easily check the G-code. Look whether the E Values are increasing when progressing further in the G-code file.
Actually, you hit the mail on the head, or darn close.
Last night I found out that Repetier defaults Slic3r to use absolute coordinates, while others use relative.  I had no idea what that setting did at the time so I left it alone, everything worked, so I didn't mess with it. This probably explains why Skeinforge never worked either, I knew it wasn't extruding, but didn't realize the reason was that it was probably spinning backwards. My old Extruder was, at times, hard to tell if it was spinning at all until I marked the pulley.


For anyone looking for it, it's in Slic3r Configuration/Printer settings/general/mid page and it is a check box labeled "use relative E-distances:"
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sat, 06 July 2013, 18:16:13
quite weird. this doesn't even seem like it should exist. what does an absolute extruder coordinate represent? position on the great strand of life?

ps, 12 hours into a 16 hour build and lovin' it!
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Sat, 06 July 2013, 23:48:11
quite weird. this doesn't even seem like it should exist. what does an absolute extruder coordinate represent? position on the great strand of life?

I have no idea. LOL

12 hours into a 16 hour, eeek!
I try to break things up if I can, but that has to do with patience and the need to babysit the printer up til now. If it wasn't for the fact that I plan to rip the heart out of it tonight (swapping to magnetic arms), it would just about be ready for prime time.


I changed that switch, and swapped the motor wiring. Slic3r works fine, going to try Cura on the next print and see how it does.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sun, 07 July 2013, 00:34:59
actually i just had to swap the filament spool on the fly. i was just letting it run and realized it was down to the last few feet of filament on the spool. good thing, because i'm pretty sure it just air prints if you run out
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sun, 07 July 2013, 04:51:15
quite weird. this doesn't even seem like it should exist. what does an absolute extruder coordinate represent? position on the great strand of life?
I read that at the beginning they did not know what is better. Absolute or relative. So they implemented both options in firmware. Slicers added an option for this to support firmware. Allegedly, almost everybody uses absolute coordinates nowadays and support for relative ones is obsolete.
Title: Re: The Living 3D Printing Thread
Post by: Tym on Sun, 07 July 2013, 04:59:37
Question (Serious): What do you guys use your 3D printers for? Because whenever I see people showing off theirs, they just generally print random crap they don't need. Just for the fact they say they have a 3D printer.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Sun, 07 July 2013, 06:42:16
Changed to relative and successfully printed with Cura.


actually i just had to swap the filament spool on the fly. i was just letting it run and realized it was down to the last few feet of filament on the spool. good thing, because i'm pretty sure it just air prints if you run out
Yes, it will most certainly air print. More than a few people have made filament sensors to tell them when it runs out.


I read that at the beginning they did not know what is better. Absolute or relative. So they implemented both options in firmware. Slicers added an option for this to support firmware. Allegedly, almost everybody uses absolute coordinates nowadays and support for relative ones is obsolete.
This runs counter to what I just ran into and what I read in the reprap.org wiki (http://reprap.org/wiki/G-code#M82:_set_extruder_to_absolute_mode).
Cura and Skeinforge both use relative by default, and the page I read made a specific note that Repetier/Slic3r was odd is using absolute by default. I had to switch to relative in order to get those others working.


Question (Serious): What do you guys use your 3D printers for? Because whenever I see people showing off theirs, they just generally print random crap they don't need. Just for the fact they say they have a 3D printer.
I have seen similar, however, I know at least two who use them to generate income. One is planning on leasing out his latest to local businesses.

Keep in mind, one reason you only see trinkets being made when people show them is a matter of time. Mkawa just said he was 12 hours into a 16 hour print, that's not THAT uncommon, a 30 minute print is actually a very small object. Making a simple flat keychain can take 20 minutes or more. You don't want to start a 3 hour print only to have to pack up after 2 hours. For a demo, you want something you can do fast and show results. Hence, you only see trinkets when showing them off to people. A big print on a 3d printer is like watching paint dry, and can take just as long.



As for me, my reasons for getting one was actually three-fold.
1. To get an understanding of them, my business is computers and I wanted to be ahead of the game when these become more mainstream (I actually had family members asking why I didn't have one yet, cost was the reason). While I did gain a lot of knowledge I also learned that they are a long way off for my customers. Though I still think manufacturers should be looking at them seriously.
2. To tinker. Computers, tech, and fabrication are a hobby, so this is right up my alley.
3. GH60. I couldn't find a case for a reasonable price so I said heck with it and spent 4000x more in order to build my own. Yes, this sounds rather stupid, but, take into account #1&2. I don't like buying tools just to buy tools, I like having a goal and reason in mind (this could have been reason 3 I guess lol). So yes, instead of waiting and buying a used case for $20 or so, I spent $800+ on a printer to do it myself, but at the same time gain a new tool and understanding of a new technology.


As for what I am using it for and will be using it for beyond that, so far, all I have made was a few keychains, calibration cubes and parts for my printer. Really, so far, it's done little more than consume a lot of plastic (Feed me, Seymore!). BUT... Remember, most people spend months and months putting these together and calibrating them (particularly if done from scratch like mine). Mine reached that point in the first month or a little after, I've spent the rest of the time making improvements and troubleshooting, but I'm about ready to move on. It's technically dialed in, most problems now are me making mistakes, not the printer, or me tearing it apart to make a better part that will make it better and requiring more calibration. My printer will probably never be "done", but it's pretty good at this point and about to make a giant leap forward (had a print error so my mag arms are still not installed).

Besides Jailhouse Blues shims (which I have made some failed prototypes of) I want to make spacers for SP keys so that o-rings will work, JB switches really benefit from o-rings. I also want to make some new feet for my Filco/Vortex case (I want a specific height). Other things include a bluetooth speaker mount for my MTB (I hate headphones and buds and they are stupid to wear while exercising as they cause serious hearing damage), mini ITX computer cases, a robot (or should I say another), tool holders/organizers for my garage (screwdriver racks, wrench holders), redo the control center/panel on my desk, SSD mounts for my computers, a dock for my phone/weather station*, and some Hermit crab shells (why not?). I'm also looking into an easy way to run my printer off of the 7in  Android tablet I have, and if so, I would make a mount for it (I know how, it's just not efficient or fast). I also have people asking for printer parts, phone cases and more.

Those are the easy things off the top of my head, I actually have a decent size list sitting on my file server.
I also plan on making a white case for my KBT Race, one that is low profile and made of actual white plastic (instead of natural and painted!). I'll probably replace the DAS keyboard I use for my KVM with a custom cased QFR, if the GH60 doesn't take that spot. Depending on reception, I may offer limited runs of the cases. Yes, they would be plastic, but I can do things a mill can't, and yes, my printer can do TKL cases, in fact, with a little work, I could do a full TK. I also have BIG plans for an old Model M I have sitting around, but you will have to wait for me to get that project underway before I unveil that one. I also may make a custom mouse, but that needs to be way off in the future when I have a greater understanding of cad and 3d printing as that requires a lot of complex curves.




*I used an old Evo 4G and loaded it with an Android weather station app reading off a weather station that is two blocks away.  It was a cheap free way to get a weather station on my desk.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sun, 07 July 2013, 07:24:19
mine is for geekhack to make **** with
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sun, 07 July 2013, 09:12:47
I read that at the beginning they did not know what is better. Absolute or relative. So they implemented both options in firmware. Slicers added an option for this to support firmware. Allegedly, almost everybody uses absolute coordinates nowadays and support for relative ones is obsolete.
This runs counter to what I just ran into and what I read in the reprap.org wiki (http://reprap.org/wiki/G-code#M82:_set_extruder_to_absolute_mode).
Cura and Skeinforge both use relative by default, and the page I read made a specific note that Repetier/Slic3r was odd is using absolute by default. I had to switch to relative in order to get those others working.
LOL, you made me to search for my source: http://www.renosis.net/Skeinforge-41-guide.html
The relevant part:
Quote
I am told by Tonokip (a firmware author) that the reason the absolute and relative options are there, is, at the time of implementation, they were weighing the advantages and disadvantages of each mode. So both are options are there, however, pretty much everyone uses Absolute mode now.
I guess that means it is not really settled what is going to be used more.
Title: Re: The Living 3D Printing Thread
Post by: xecut on Sun, 07 July 2013, 09:31:46
is it possible to use it for printing keycaps?
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Sun, 07 July 2013, 10:29:18
is it possible to use it for printing keycaps?

Possible: Yes. Suitable: No

The FDM printers of today will have troubles with getting a good enough  stem mount as well as create a nice surface. If you treat the parts after printing, for instance with acetone or sand them manually, then you can get a nice outer surface. I recon the stem fitting will remain a bit troublesome though, but probably possible. SLS and SLA are far better suited for printing parts with small details such as key caps.

I am looking forward to seeing some interesting cases and all kinds of projects come to fruiting because of these though.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sun, 07 July 2013, 14:19:22
the cruciform should really be low pressure molded and pressure fit into a circular housing in the printed cap. reliable cruciforms are possible with FFM machines, but with current designs, the rest of the keycap design interferes too much with a high detail bit in the center of the object.. gcode compilers will have a much easier time printing these in two pieces or, since the cruciform is always exactly the same, a precise mold can be made and the stem and cruciform bonded to the cap after the fact.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Sun, 07 July 2013, 14:31:05
There are several challenges with keycaps actually.

1. As Damorgue said, strength. Keys are injection molded under high pressure, making the plastic much more dense.
2. Surface finish, again as Damorgue said, you can do some smoothing, but these are digital printers and most people print with layer heights closer to .2mm, which sounds small, but still leaves quite visible lines showing each level. It's kind of like building with bricks, one level at a time rather than carving and sanding.
3. While you can use a lower layer height and smaller nozzle, they increase print time drastically. A full keyset at normal settings would take much of a day as it is.
4. Color, most people only have the ability to print one color (I only need another motor to do dual and plan on getting one).
5. Shape is a big one... remember, everything is built from the ground up, this presents some challenges since keys are hollow. If you print them right side up, the center stem would either be too long, or the sides a bit short. If you do it upside down, you either will make a flat key, or your surface finish will be horrible.

Basically you can do it, but most people would be unhappy with them with current hobby level printers. It could be done quite well with STL (Stereolithography), which uses a laser and a special polyurethane, I even considered building one, and while cheap to make the printer, your prints are all a dull yellowish color and a keyset would probably run you a few hundred dollars in fluid. It's about 15x more expensive than printing with ABS as you need special chemicals.

SLS (laser sintering) has been used to make keys, and they offer a nice, though different surface finish and were made in metal, however, hobbyists are only just starting to find ways to do those cheap. The lasers alone are typically somewhere around $30k. Again, as with most 3d printing, you only get one color.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sun, 14 July 2013, 11:26:04
pretty happy with how this one came out:

(https://dl.dropboxusercontent.com/u/24794081/2013-07-12%2018.00.54.jpg)
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Sun, 14 July 2013, 11:54:06
Looking sharp there mkawa, literally. Although a rather simple part, performance such as flatness and small radii are showcased well. How did you print the coloured areas Where they added on top after when you had switched the filament and the part had cooled down or had you timed the colours in some way?

Edit: I believe suka over at DT (possibly at GH as well?) works for [SLS machine manufacturer]. I am not entirely sure but at least I think he has some sort of connection to them at least.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sun, 14 July 2013, 17:45:05
i printed a coarse setting print of the M with the natural parts of the left side (that's one solidworks part). we then did a very quick two color print of two of the slashes using the dual head extruder. while that was printing, we placed a third slash on the makerware plate, assigned it to one of the heads, aligned it to be exactly flush with the previously printed parts, and as soon as those parts finished, i immediately told the makerbot to reheat everything, we deleted the first two slashes in makerware, changed one of the filament rolls and printed the third slash before the first two had a chance to cool. as a result, all three slashes bonded to each other to make a single plastic part with only a very small gap where the makerbot started the second teal print of the third slash. this part was then press-fit into the left side of the M backpiece. there is no glue or slurry resin used to attach anything. it was just multiple carefully dimensioned prints and a filament quick-change.

maybe a link could be discreetly handed to suka for this thread? ;)

he is, like you, damorgue, probably NDA'd up, but anything he can share, again, like you, is gold for us hobbyists ;)
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Sun, 14 July 2013, 18:55:03
Looks great, makes me miss my 3 series.
Title: Re: The Living 3D Printing Thread
Post by: suka on Mon, 15 July 2013, 02:39:19
I have already been monitoring this thread since the beginning mainly because of personal interest in the technologies employed and the planned projects here. Although I do indeed posess some additional knowledge and experience in the field of SLS there is probably no overlap at all between my current field of work and the challenges presented herein, so I am afraid I cannot be of any technical help even with or without any NDA :-(
In my own (and also some other) threads I have always been an avid proponent of the advantages of laser sintering that I have experienced during my creations - fast prototyping results, accurate and durable parts and the possibility to obtain unique designs without any minimal order markups for a reasonable price. But as a tinkerer and hobbyist myself I absolutely love to see the 3D-printing alternatives gain traction and become affordable and known to a broader audience - under different circumstances I am sure I would already own one myself...
Until then all I may provide are the experiences I made in my various keyboard projects - so if you have any questions in regard to plates, caps or adaptors feel free to ask  :)

Keep up the good work (and moreso the detailed write-ups on your experiences!), really interesting stuff!
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Mon, 15 July 2013, 07:38:24
welcome suka!! damorgue is also NDAd up and mostly familiar with sintering. he just throws in his general engineering knowledge as we screw around. no one here is expected to be an expert in anything -- we're just having fun :D

again, welcome! please feel free to ask questions and offer whatever advice you can think of :)

also, if your NDA allows you to contribute CAD and/or print things in FFM, my printer is now available for general use ;)
Title: Re: The Living 3D Printing Thread
Post by: CPTBadAss on Mon, 15 July 2013, 09:30:37
I'm just going to float this out there. Today I learned that Plastic Splinters Suck. I was getting trained on the 3D printer and while handling the models, I managed to get two plastic splinters.

Edit: I was sitting at my desk for like 15 minutes digging them out with a knife. I think I've scared my co-workers. More incredibly interesting news about me at 11. :P
Title: Re: The Living 3D Printing Thread
Post by: ITzNybble on Mon, 15 July 2013, 09:34:38
I'm just going to float this out there. Today I learned that Plastic Splinters Suck. I was getting trained on the 3D printer and while handling the models, I managed to get two plastic splinters.

Are they worse than like a fiberglass splinter?
Title: Re: The Living 3D Printing Thread
Post by: CPTBadAss on Mon, 15 July 2013, 09:39:20
My experience with fiberglass splinters is that they break up and it's annoying to get ALL the bits out. At least the plastic splinter stayed together...
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Mon, 15 July 2013, 09:41:26
first aid protip: before you go digging into your skin with a knife to get a splinter out (or just to cut yourself -- hey, it's not my business) get a HOT lighter, butane preferably, and light the blade up. it will sterilize it. the lighter will leave some carbon on the blade edge. just leave that there. trying to get it off will contaminate the blade.
Title: Re: The Living 3D Printing Thread
Post by: CPTBadAss on Mon, 15 July 2013, 09:44:07
I hope hand sanitizer and hand soap work just as good as fire 'cause that's what I had.
Title: Re: The Living 3D Printing Thread
Post by: ITzNybble on Mon, 15 July 2013, 10:07:59
first aid protip: before you go digging into your skin with a knife to get a splinter out (or just to cut yourself -- hey, it's not my business) get a HOT lighter, butane preferably, and light the blade up. it will sterilize it. the lighter will leave some carbon on the blade edge. just leave that there. trying to get it off will contaminate the blade.

MANMODE!!!!!
Title: Re: The Living 3D Printing Thread
Post by: Tarzan on Mon, 15 July 2013, 11:52:28
first aid protip: before you go digging into your skin with a knife to get a splinter out (or just to cut yourself -- hey, it's not my business) get a HOT lighter, butane preferably, and light the blade up. it will sterilize it. the lighter will leave some carbon on the blade edge. just leave that there. trying to get it off will contaminate the blade.

Plus this way you can tell people the resulting scar was your attempt at a jailhouse tattoo.

 :p
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Mon, 15 July 2013, 15:49:51
I hope hand sanitizer and hand soap work just as good as fire 'cause that's what I had.
they don't, you're screwed.

also, the buddy i printed the M logo for took this:

(https://dl.dropboxusercontent.com/u/24794081/image%20%283%29.jpeg)

for a sense of scale. hah!
Title: Re: The Living 3D Printing Thread
Post by: kmiller8 on Mon, 15 July 2013, 19:23:18
Possible: Yes. Suitable: No

The FDM printers of today will have troubles with getting a good enough  stem mount as well as create a nice surface. If you treat the parts after printing, for instance with acetone or sand them manually, then you can get a nice outer surface. I recon the stem fitting will remain a bit troublesome though, but probably possible. SLS and SLA are far better suited for printing parts with small details such as key caps.

I am looking forward to seeing some interesting cases and all kinds of projects come to fruiting because of these though.

I spent an hour or so tweaking a stem capable of FDM printing and this is what I came up with.

(http://i.imgur.com/6qiV3Im.jpg)

Using a raft, I've had a 100% success rate (Out of 10 caps or so). With the only finishing being squeezing a small screwdriver in each stem hole to widen them abit and if necessary shaving a little off the wider sides so it can slide in and out of the switch housing.

Obviously it's like you said, not 100% perfect but as long as you're gentle with them I don't see why they wouldn't be able to hold up :D

I attached the STL file for the basic cap I've been using to stick penises on and print

[attachurl=1]
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Tue, 16 July 2013, 09:17:41
no one's saying they can't print the stem, but you'll get much better repeatability casting the stem and printing the rest of the cap.
Title: Re: The Living 3D Printing Thread
Post by: kmiller8 on Tue, 23 July 2013, 21:38:46
For a "living" thread this is pretty dead.

cheggit this converter I made to make MX ALPS compatible

It works ok, I had to print it at like 90% the model size and SUPER SUPER SLOW, but it kinda works after a little post processing.

(http://i.imgur.com/d8WEe3E.png)
Title: Re: The Living 3D Printing Thread
Post by: meiosis on Wed, 24 July 2013, 00:49:17
For a "living" thread this is pretty dead.

cheggit this converter I made to make MX ALPS compatible

It works ok, I had to print it at like 90% the model size and SUPER SUPER SLOW, but it kinda works after a little post processing.

Show Image
(http://i.imgur.com/d8WEe3E.png)


Quite smart indeed, perhaps try Mx to topre, I believe there would be an elevation issue between a design like that? (Keycaps raised a bit higher)?
Title: Re: The Living 3D Printing Thread
Post by: vvp on Wed, 24 July 2013, 03:00:02
For a "living" thread this is pretty dead.
Only diamonds are for ever ... and not even those ... I guess :)

My 3d-printed u-joints did last about 12 hours of printing before some noticeable slack developed. So I can confirm that they are a piece of ****.

I looked in more detail how Mini Kossel bed leveling works. It is measuring the bed Z-height at regular rectangular grid (currently it is 7x7). This gives error terms. The error term for a particular point in XY plane is computed using linear interpolation. So if your bed is badly distorted then your part will be distorted just the same. It is still good to define geometry somewhat correctly so that the interpolation error is not big. And with really bad geometry z-probe deployment/retract would not work too.
Title: Re: The Living 3D Printing Thread
Post by: SpAmRaY on Wed, 24 July 2013, 07:20:02
For a "living" thread this is pretty dead.

cheggit this converter I made to make MX ALPS compatible

It works ok, I had to print it at like 90% the model size and SUPER SUPER SLOW, but it kinda works after a little post processing.

Show Image
(http://i.imgur.com/d8WEe3E.png)


I'm sure you've seen the thread over at DT but in case not similar project, although not currently active

http://deskthority.net/workshop-f7/cherry-to-alps-adapters-t4934.html
Title: Re: The Living 3D Printing Thread
Post by: kmiller8 on Wed, 24 July 2013, 07:35:52
I'm sure you've seen the thread over at DT but in case not similar project, although not currently active

http://deskthority.net/workshop-f7/cherry-to-alps-adapters-t4934.html

#inspiration #RIPMrInterface

Quite smart indeed, perhaps try Mx to topre, I believe there would be an elevation issue between a design like that? (Keycaps raised a bit higher)?

You're correct

(http://i.imgur.com/HSkky8T.jpg)
Title: Re: The Living 3D Printing Thread
Post by: kmiller8 on Wed, 24 July 2013, 09:12:53
Oh, put me down as willing to print. PM me ideas or .stl files and we can work out costs :)
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Wed, 24 July 2013, 12:12:13
I made some converters along with mrinterface, but they were found to be too tall. It remains an option if we ever make a custom alps board, where we could make a deeper case which would enable us to use converters and MX caps. I am away from home, so can't really send it atm though, but it looks very similar to yours kmiller8.
Title: Re: The Living 3D Printing Thread
Post by: kmiller8 on Wed, 24 July 2013, 12:59:02
I made some converters along with mrinterface, but they were found to be too tall. It remains an option if we ever make a custom alps board, where we could make a deeper case which would enable us to use converters and MX caps. I am away from home, so can't really send it atm though, but it looks very similar to yours kmiller8.

yeah, like I said above, I was inspired by MrInterface with the design, but trust me, I took all the measurements and drew up the model myself. Also there is definitely an increase in height, here's an example pic I took.

(http://i.imgur.com/HSkky8T.jpg)
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Wed, 24 July 2013, 21:14:53
A warning to those with deltas... When moving, or adjusting the head, if you have a glass bed, lower the head down first.

While the head will stay up under normal circumstances, when adjusting a belt, or being transported, the head can fall. I took a chunk out of my glass bed the other day. No head damage, and it's only like $15 to replace the glass, but... Ooops.  I'm not sure if it was during calibration (head crash), belt adjustment or while I was transporting it, but one of the times the head hit the glass it made a small crack and when I printed over it, the plastic pulled up the glass shard with it.


As for the thread, many living things have periods of dormancy, it doesn't mean they are dead.
I've been busy rebuilding much of my printer. I'm redoing  part of the frame, moving some electronics, adapting an auto-leveling system and designed a new extruder. Which so far the first version has worked great, just need some minor changes, it's self loading (unlike Airtrippers, which are iffy), can't bind up (nowhere for it to go), and tiny as heck. All of which I hope to have on in the next few days. Basically, it will be nearly an entirely new printer from just a couple weeks ago. I've been working on and designing dozens of new parts to go on, if it it isn't electronic, it's probably being replaced.


I'm also going to build a cabinet, I was just going to build a fume extractor, but after seeing this (http://hardware.slashdot.org/story/13/07/20/2149212/3d-printers-shown-to-emit-potentially-harmful-nanosized-particles), I want something I can make nearly airtight and blow out an exhaust duct directed out a panel under a window.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 24 July 2013, 23:36:06
i ordered some parts for my r2x and now i have to post the following mostly negative review. SIGH. x-posted to https://groups.google.com/forum/?fromgroups=#!forum/makerbot which is a pretty cool group regardless of whether you have a makerbot or whatever else.

Quote from: me
Hi folks,

Relatively new rep2x owner here. I received my r2x in June-ish, and have been racking up the build hours since then. I swear I have had more fun with this in the last month than I had in the first 3 years of grad school (wait, those were terrible by any stretch.. sorry, I'll try to think of a better analogy as this review 'evolves').

So far, this review is unfortunately universally negative. Bottleworks delivered quite quickly considering these are parts machined, presumably, in the US, and I'm well aware of how expensive machine time in the US is. However, what I received were a) very roughly machined aluminum parts. In particular, the build plate base machining was clearly optimized for speed above all else. the arms were similar. there was no final fine finishing cut on any part and many parts have larger nicks and irregularities that show a general lack of respect for detail. I understand that the price of these parts is very low, but unfinished aluminum with very rough cuts is kind of the worst of all worlds. aluminum oxidizes in weird ways if you don't finish it, and with the HBP in particular, one needs to be quite careful about the flatness tolerances, as the use of an aluminum base plate means that you will have to deal with thermal expension, even if the very top layer of the build plate is borosilicate. for about the same price (when they have stock, which is another matter entirely), MBI's gravity cast alu plates are at least flattened to 0.3mm, and their injection molded ABS arms are precisely sized, even if they warp out into nowhere land after about 50 hours of build time. (they are cheap, fwiw!)

3 more points that i feel are necessary to warn people about before i end this bit of the review (but i will be installing at least some of the parts, so there will be updates! hooray!)

1) the bearings that are included at 10mm ID, 19mm OD LM10UU linear ball bearings with printed retaining rings. this would be all well and good if the r2x (and possibly the r2? i have no idea) used steel Z-stage support rods. however, they actually use 10mm ceramic coated alum aka feather shafts. everything i've read about feather shafts recommends using frelon sleeve bearings and not ball bearings. i have seen this many many times from every vendor of these rods. note that MBI uses sintered bronze bearings. while not frelon, they are definitely softer than steel balls. my understanding is that the deal here is that while the ceramic coating lowered coefficient of friction, it is not quite as hard as a steel rod (which are typically rockwell C60 or so), and if the 10-20-micron RMS ceramic coating wears off, all you have left is some pretty soft aluminum. in short, you're going to have a bad day. now, because he specifically cut the arms for LM10UUs, you can't use the MBI bearings, unlike carl's alucarrier. the MBI bearings are 15mm OD, which is a more common bearing size for 10mm IDs. to be fair, bottleworks' product description specifically states this, but it still took me by surprise when I took everything apart and started taking a closer look at all the MBI and bottleworks parts.

that said, these arms and retaining rings should fit a number of other vendors' frelon sleeves quite well. i've ordered what's in stock, but may just wait on lead time if i find a particular nice set that needs to actually be manufactured. fortunately, it seems that MOQs are pretty low in the bearing industry. in particular, SPD and QBC both have highly compatible parts in their catalogs.

2) i pretty firmly believe that the heater wattage on this kit should be upped. i tossed just the aluminum base with heater and unidentified insulation (corners are sealed with what looks like RTV silicone, mostly a black fiberglass looking weave). just measuring surface temperature on the alu base with an unrestricted 130w into the unit, it had a significantly hump at about 67C, and it was clearly struggling to get hotter than that. stick a borosilicate plate on top with a thermal conductivity about 2 orders of magnitude less than aluminum and you're going to have a bad day. also, despite the heater basically covering the bottom surface, i got an odd 5-ish C gradient from the center of the unit to the corners. mcmaster carries a silicone backed 270w 24v 6x9 unit that i may end up swapping in for this

3) THIS IS PROBABLY THE MOST IMPORTANT POINT:

i have gotten zero post-sales support from bottleworks. worse, my questions were at first answered with highly defensive appeals to volume ("i have hundreds of kits out there <snip several paragraphs in which questions are not answered>|") then when i repeated the questions i got ("i'm not going to argue about this" when i didn't recall arguing about anything at all). finally, his ultimatum was that i must send the kit back to him and if they were sent back in the state they were sent, he would refund me because i was a 'hypochrondriac' of some kind due to my HBP measurements. i simply stated the conditions that the HBP base were tested under, and i got back, verbatim "ok kid". in short, not only should you expect no post-sales support, but if you do contact him, prepare to be berated and insulted at frighteningly short cycle times. in fact, i'm still receiving emails from him. his last email could easily be seen as a threat of some kind, as it involves him mentioning personal information of mine out of context and with no other content in the email. thankfully, i am an internationally published researcher, run geekhack.org, a 23k user webforum, and generally have zero fear of doxing, but there you go. if you order, don't email him after you get your parts. you're going to have a bad day.

so that's it for now. i will be using what parts i can salvage from the kit, hand finishing parts, etc. i had to disassemble my bot anyway to replace both heads (i cut one of my initial plate levelings too close early on scraping them pretty badly, and the heads were growing increasingly out of tolerance as i printed the crap out of them :D), and my initial horizontal Z gantry plate, which now says "makerbot" on the front (it's really really warped), so except for the vague threats from this vendor, i'm actually a pretty happy clam. hell, even his insults are better than grad school. also, to be fair, i leveled one shot at B about me being an actual engineer. it was in the heat of the moment, and i apologize to the fellow.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 24 July 2013, 23:43:04
i like this part of that /. post best: "The emission rates were similar to those measured in previous studies of several other devices and indoor activities, including cooking on a gas or electric stove, burning scented candles, operating laser printers, or even burning a cigarette."

lol.

anyway, if i'm reading this right, there's not much we can really do about the UFPs but fully ventilate the area, or use a fairly effective fume hood that ejects to atmosphere. hepas don't go down to nm scale, and my cheap charcoal is basically useless unless the stuff is much larger and non-inert. your dryer vent idea is probably the best, leslieann. i'll probably just open the window more often during long prints. i have nowhere obvious to route air to without opening a window, so i might as well just open the window more often and point a box fan at it or something

alas, this is also morbidly funny because i was just arguing with someone about the ABS smell, and my position was that it couldn't possibly be vaporizing. d'oh!
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Thu, 25 July 2013, 00:54:13
Yeah, I'm not entirely sold on the articles merits.  An electric stove? Seems a bit ridiculous, but I worry about how much crap I breath every day as it is (I don't have the best lungs to begin with). The part that worries me isn't just the particles, but chemicals that could be in some of that plastic, particularly the ABS, which is known not to even be good to breath the dust from while sanding.



I'm going to aim for a negative pressure system, sucking air from inside the room through the cracks, and venting out a panel I'll put under the window, which will be closed. While not perfect, this should suck out or at least seriously reduce not just the smell, but also the particles and it has to be better than the single fan I have blowing air in from an open window.



As for your review, it doesn't sound THAT bad, new technology and all, until you remember that this was a near $3000 printer you bought, from a company considered/claiming to be one of the premier personal 3d printer builders.  At which point, I just want to shake my head.  Sadly, I have run into far too many companies like that. They act all tough online, but act like they are still working from their garage and everyone is out to get them. I've had multi-million dollar D.O.D. suppliers act that way as well. I don't get it, it helps no one.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 25 July 2013, 01:16:02
that is a review of "bottleworks makerbot accessories", which is a company i won't bother linking here, NOT makerbot, who has been absolutely wonderful. today i called makerbot international and asked "what are the Z support rods made of and the support person literally had an answer in 5 minutes." i've quizzed them on hardness of their factory parts, materials, material properties and tolerances of all kinds of junk, and had hour long conversations with them on the economics of their Z gantry design.

tldr; makerbot international (now stratasys makerbot international i guess) is super awesome and makes an incredible little product with some small but annoying flaws but is more than happy to work with you to tweak everything they make.

bottleworks aka bc technologies sells replacement parts for the makerbot products and berates you and insults you if you ask questions after you pay him for them.

there is another fellow named carl who sells makerbot replacement parts (only a couple so far, he has tackled the far easier problems and does not claim to solve all of the makerbot problems; in fact he claims to solve none of them. he just wanted to print taulman nylon so he made the one part you need to make to do that). he is awesome. he is perfectly happy to chat about his products and other people's products. we started talking about mice for reasons i don't remember at all, and it led to me thinking very deeply about signal processing hardware architectures in consumer mice, much to carter's chagrin :D.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Thu, 25 July 2013, 03:36:52
that is a review of "bottleworks makerbot accessories", which is a company i won't bother linking here, NOT makerbot, who has been absolutely wonderful.
Ahh, okay, I wondered why things weren't adding up.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 25 July 2013, 11:34:47
oh, that reminds me, my machine is down, and actually it's been torn down to the frame, while i put together parts to rebuild the z axis and plate better, faster, etc. etc. i _believe_ this stuff should be showing up tomorrow, and i should have it back together by the weekend. i'm also replacing the head, and i've learned how to calibrate the head bits a bit better, so i should be able to tighten my tolerances pretty significantly when it comes back up.

edit: i'm mentioning this because NOW, when my machine is down, i'm getting a bunch of printing requests. bug me again next week!
Title: Re: The Living 3D Printing Thread
Post by: CPTBadAss on Thu, 25 July 2013, 11:44:59
Alps to MX adapter inserts please kawa!
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 25 July 2013, 11:47:44
OH SURE MR I CAN PRINT ANYTHING I WANT AND WORK NEXT TO 100 MACHINES, I WILL PRINT YOU TINY BRITTLE ADAPTERS :|

yah yah next week
Title: Re: The Living 3D Printing Thread
Post by: CPTBadAss on Thu, 25 July 2013, 12:08:17
Print anything I want? Maybe. Work next to 100 machines? Just two. Do I get to keep anything? No...

:|
Title: Re: The Living 3D Printing Thread
Post by: sparkhack on Thu, 25 July 2013, 12:56:59
I'm new here and registered because of the review that I read on Makerbot Operators Google Group.  I was curious to know if you had any other upgrades installed?  Which ones do you feel are needed to make the Replicator 2X perform reliably?

Thanks

i like this part of that /. post best: "The emission rates were similar to those measured in previous studies of several other devices and indoor activities, including cooking on a gas or electric stove, burning scented candles, operating laser printers, or even burning a cigarette."

lol.

anyway, if i'm reading this right, there's not much we can really do about the UFPs but fully ventilate the area, or use a fairly effective fume hood that ejects to atmosphere. hepas don't go down to nm scale, and my cheap charcoal is basically useless unless the stuff is much larger and non-inert. your dryer vent idea is probably the best, leslieann. i'll probably just open the window more often during long prints. i have nowhere obvious to route air to without opening a window, so i might as well just open the window more often and point a box fan at it or something

alas, this is also morbidly funny because i was just arguing with someone about the ABS smell, and my position was that it couldn't possibly be vaporizing. d'oh!
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 25 July 2013, 15:34:24
i've done a lot of little things, but most of it is measurement-based. for example, i have measured what is either t_loss at the head or inaccurate heatercore thermistors on my initial heads (measured: 190C, reported 230C). i measured the t_loss on the factory HBP (measured: 80C, reported 110C). after consulting with some polymer experts, i determined that the measured values are actually basically what one wants for the process and cooling temps.

i designed a clearance and leveling jig for a mitu 5 series indicator gauge, which as you can see in previous pages i made a pretty fundamental mistake on at first ;P, but ultimately got me some pretty good results with the factory HBP. however, the factory HBP has a tendency to warp with repeated heat cycles, despite the heat being fairly even, the thickness and density is not, because it is a gravity cast piece. i am playing around with different options there at the moment.

however, if you page back a bit, i've gotten some really fantastic small parts out of the r2x right out of the box. the M logo i printed with my friend is sweet, and the little cones are super cute. the biggest problem AND design feature of the makerbots is that because the designers knew they could not design a super flat heated build plane with their budget, they instead designed a suspension system that tries to mean out at +/-0.4 to 0.5mm or so. note that this length is a randomly directed vector, because of the jiggling, so sometimes it will take repeated tries to get a good print, and very long prints can sometimes not turn out quite as you'd like.

that said, i was weighing it against the cubify printers (discussion also in this thread very early on), and i definitely think i made the right decision. it make take a tweaking to get incrementally better parts out of the bot, but if i've learned anything from interviewing machinist after machinist, it's that every single damn machine is like this. it takes 20 years to become a shopmaster even in a full multi-axis high-spec cnc shop for a reason. the world is infinitary and quite stochastic, and we have to take it as it is :)
Title: Re: The Living 3D Printing Thread
Post by: DamianGTO on Thu, 25 July 2013, 16:45:42
Well I'm new here and I did read some page of this tread.
I did see that some had issues with the rep2x with PLA.
I have fund out after many test that the PLA do like the wall on the heat chamber to much.
After some time it will be to much and the printer start to air printing, due the clogging.
But I also fund out there is a very simple way to fix this.
I use PTFE oil or some high grade cooking oil and put that on a bit of the filament when I start to printing.
I also use that after I have cleaned it all out.
I also put a little extra when I do long prints.
This has solved the problem and the PLA do not clog anymore.
My theory is that the PLA get stuck to the walls and its get harder and harder for the PLA to melt and flow like it should be, but with the oil that is on the wall( i think) the PLA can not stick to the wall and the flow will be better.

Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 25 July 2013, 16:53:35
hmmm... i didn't try the ptfe lube with the PLA because i suspected the problem was that it was depolymerizing (which of course it would if it did get stuck to the heatercore). i will have to try this. if you still have mineral oil in your heads though, you wash them out with solvent (iso alcohol is a pretty safe one), as i think mineral oil doesn't react nicely with the brass nozzles. a little ptfe lube should be fine though, and the worst effect it can have is slightly lower the temperatures in-head when printing ABS, but ABS tends to flow extremely well, so i suspect that won't be an issue.

if you read elsewhere, the PTFE oil we like best here (no, in fact, WE WORSHIP IT) is dupont's krytox basic lubes, 102, 103, etc. the base is a polymer oil, which separates it from many ptfe dry lubes (which are very light petro oils with ptfe nanoscale particles). and it can be combined with the krytox line of greases to get like literally any viscosity. also the friction coefficient, it is so low. SO LOW
Title: Re: The Living 3D Printing Thread
Post by: DamianGTO on Thu, 25 July 2013, 17:05:05
hmmm... i didn't try the ptfe lube with the PLA because i suspected the problem was that it was depolymerizing (which of course it would if it did get stuck to the heatercore). i will have to try this. if you still have mineral oil in your heads though, you wash them out with solvent (iso alcohol is a pretty safe one), as i think mineral oil doesn't react nicely with the brass nozzles. a little ptfe lube should be fine though, and the worst effect it can have is slightly lower the temperatures in-head when printing ABS, but ABS tends to flow extremely well, so i suspect that won't be an issue.

if you read elsewhere, the PTFE oil we like best here (no, in fact, WE WORSHIP IT) is dupont's krytox basic lubes, 102, 103, etc. the base is a polymer oil, which separates it from many ptfe dry lubes (which are very light petro oils with ptfe nanoscale particles). and it can be combined with the krytox line of greases to get like literally any viscosity. also the friction coefficient, it is so low. SO LOW

Well I love PTFE to. HAve used it in many different thing and has always had a good results  ;D
I also do use PTFE on the outside of the nozzle. It make so the plastic will not stick to it when printing if there is some plastic that do not be where it should be. ;)

Im not sure I have used that brand yet, but I guess I need to look it up if they have it here  :cool:
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 25 July 2013, 17:16:34
it's CRAZY EXPENSIVE. i will be buying it in bulk and dispensing small usable quantities for reasonable prices in the nearish future (note i do about a hundred things at once, so dates are pretty malleable in my head. FAIR WARNING!)

you can get really expensive tiny amounts from mcmaster too just to try. we should be able to vend it here for about a quarter of that price though, and with a handy set of dispensers :D

also, crazy awesome tip on ptfe outside the nozzle to keep the crap from building up. oh man, you should see my old heads. i have NO IDEA how the hell half of that crap got all the way up there (BOST, YOUR CHANCE AGAIN!!)
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Thu, 25 July 2013, 17:17:11
edit: i'm mentioning this because NOW, when my machine is down, i'm getting a bunch of printing requests. bug me again next week!

Speaking of which, I might put in a request for a new shell for my mouse. I need to fix a few things that didn't turn out that great last time though.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 25 July 2013, 17:18:27
estimate about a week of downtime. hashbaz is in town, and several other things might delay me and my various shipments.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 25 July 2013, 18:47:13
i expanded on the suspension system comment on the makerbot users group. i think this is actually what's going on there:

Quote from: me
the MBI engineers basically knew they couldn't build a flat, stable (ie, non-moving) z-stage with their budget. hence, they had two goals: first, when you can't make something solid, you try to control the oscillations, so they went with a suspension system and tried to dampen its frequency with every parts and material choice. second, they obviously thought hard about the temperature cycling, and wanted to protect this suspension system as much as possible from exposure to heat. hence, gravity cast aluminum for the HBP; it's cheap, and easy to make flat since it's so soft. personally, i've lapped mine down (the last time i was less dumb and did it near op temp), 2-3 times. the heater for thin aluminum is also pretty cheap and can be low wattage, even covering a large build plate. then, they tossed two layers of a fiberglass/aerogel like substance (but again, a cheap one) under the heater and threw a thin alum sheet in with the leveling nuts. on the bottom side of that, they tossed some pretty hard springs (note: measure K). and nuts for leveling the plate. some brilliant dude even made their business card a feeler gauge for optimal nozzle to plate clearance. HAH!

now, z gantry. in the center is a long buttressed plate with some reasonably hard resin. i'm guessing it's about gf20 and PPO or PO. this has a high temp resistance, plastic transition way above the heater temp, and high tensile strength due to the glass fiber. basically, its young's modulus is high, and it shouldn't yield. unfortunately, it seems to over time. my gantry plate with several hundred hours of build time (at least?) is very much convex. so, final question: why the abs arms? i think it's actually because they were trying to lower the oscillation frequency with the arms and the feather shafts. the feather shafts have a lower modulus of elasticity than steel shafts do, as do abs arms vs PO + gf20 arms. basically, they wanted the gantry plate to stay as good a leveling reference as possible (ie, they wanted it to deform as little as possible) so they made the arms and the shafts the path of least resistance for oscillation so that the kinetic energy of the plate bouncing around is dissipated as far away from the plate as possible. if you think about it, the alternatives are a) the frame. this is basically all bad. b) the gantry plate. this is exactly what you don't want.

what i think i am going to try to do with my bot is actually to transfer that oscillation to the frame and then to dampen is as much as possible in the frame. there are two ways to do this. first is to make it heavy as sh*t. i've done a bit of that already, in that my bot sits on 40 pounds of acrylic and under another 5lbs. the second thing to do is to plate the sides with material that adds weight but also dampens oscillation. one upside to this is that the one can also improve on the heat insulation goals of the side plates as well. i have some stuff i'm going to play around with for this, since steel is cheap, and heavy, and if it doesn't work out i can always make other crap with it.

as for the HBP flatness issues. it's a bit of a myth that glass is naturally flat (i can't tell you how many times i've seen this on the various printing sites and it bugs me to no end...), but i'll lap down some borosilicate -- might as well start with the bottleworks stuff, and see how well it works out.

for small parts, i'm just going to use high alumina ceramic. it's not that expensive in small pieces, it's ridiculously hard (it's basically sapphire powder in binder, compressed then fired), and it has metal-like thermal conductivity properties if porosity is controlled while having basically 0 thermal expansion.

for large parts, i have no idea. lots of power applied directly to thick surface ground silicate maybe? silicate is at least cheap... it's hard to really say what's best from a hobbyist perspective, which means there's plenty of room for experimentation :D
Title: Re: The Living 3D Printing Thread
Post by: DamianGTO on Fri, 26 July 2013, 08:37:51
i expanded on the suspension system comment on the makerbot users group. i think this is actually what's going on there:

I think there is an error in this. The plate under the aluminium, where the leveling screws are, is made of stainless steel. I do have 3 build plate here and all are the same, ;)
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 26 July 2013, 14:10:48
ah, that i didn't pick up on. care to guess what alloy? something like t316 24ga would make a lot of sense. it's quite inexpensive to produce and has extraordinarily high yield strength without much weight.
Title: Re: The Living 3D Printing Thread
Post by: DamianGTO on Sat, 27 July 2013, 10:03:11
ah, that i didn't pick up on. care to guess what alloy? something like t316 24ga would make a lot of sense. it's quite inexpensive to produce and has extraordinarily high yield strength without much weight.

No idea what kind it is. Not my field  :))
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sat, 27 July 2013, 10:13:35
CPTBADASSSSSSSS YOU ARE NEEDED
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sat, 03 August 2013, 23:28:29
if you have cad ready to go, now would be a good time to email me.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Tue, 06 August 2013, 01:18:54
(https://dl.dropboxusercontent.com/u/24794081/2013-08-05%2007.44.33.jpg)

WHERE ARE YOU CAD?!?!?!
Title: Re: The Living 3D Printing Thread
Post by: Krogenar on Tue, 06 August 2013, 10:43:54
[attachimg=1]
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Wed, 07 August 2013, 16:13:09
So I just about have my printer rebuilt... Less wood, belt tensioners, magnetic arms and auto leveling (should be running tonight).
Interestingly, getting rid of the wood sides for some metal tubing actually cut down on the noise by about half! It was shocking to hear the difference. Between those and using good bearings and slides, mine isn't even a quarter as loud as the ones I've seen on Youtube. So if anyone has or wants to build a Rostock, get good bearings and slides, and figure out how to eliminate the wood sides. It will look and run better, and will be much quieter.

The magnetic arms are, while have yet to actually print with them, a disappointment and I'm seeing why a lot of designers are staying away from them. Don't get me wrong, there is zero slop, and it's a proven system. My issues stem from the fact that it makes the assembly much heavier, heavy enough that if the effector (head) is off center, it will slowly droop to center when power is off. This tells me I added considerable weight as it used to stay well put, which is against the idea behind the delta printer in the first place. The other issue I have is you can't just simply grab the effector and move it out of your way without risking it coming detached, I've had it happen a few times. They are also a PAIN IN THE NECK to build. While the second is only a personal issue, the latter is why no one is designing deltas with magnetic arms as they are quite fickle to get right, with luck, someone will start mass producing them or something, though I'm not sure I will stick with them even if they work due to the weight, which could mean slower, though more accurate parts. I think I can get the same accuracy through lighter, cheaper, more secure methods.



Using what all I have learned from my current one, I've re-engineered 90% of it already, I'm drafting plans for a replacement.
The new machine (which will use no wood) should have a 300mm diameter x 450mm tall build area, this will let me (just barely) build a GH60 case flat on the bottom, and a full size TK case on end.
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Wed, 07 August 2013, 16:54:08
this will let me (just barely) build a GH60 case flat on the bottom, and a full size TK case on end.

Could you explain how you will print the tkl vertically? Just curious how your machine manages sudden horizontal surfaces without anything underneath.
Title: Re: The Living 3D Printing Thread
Post by: Tym on Wed, 07 August 2013, 16:59:46
Question: I have had alot of stuff printed with nylon, but a new company im trying to work with is offering ABS is that the same, different? Stronger etc?

Ive honestly no idea, thank y'all
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Wed, 07 August 2013, 17:31:24
this will let me (just barely) build a GH60 case flat on the bottom, and a full size TK case on end.

Could you explain how you will print the tkl vertically? Just curious how your machine manages sudden horizontal surfaces without anything underneath.

Depends on how far out you have to go and how your fans are set.
Here is an article on bridging.
http://www.3dgeni.us/a-bridge-too-far/
While you could say that's supported at each end, you have to jump that gap before it connects. Obviously you can go further with something at the other end, otherwise it droops, but you can go out horizontal more than you would imagine. I've managed 3/8in without anything on the other end. It needed some cleanup, but it worked. Usually anything over 1/8in and I try to make some sort of support that will snap off clean after it's done. Once I get a working case, I was planning on doing as many as possible as pairs, so they support each other when done vertically rather than use support material. That or make the upper and lower case together to support each other, depending on design.

Here is a video of bridging, showing what I mean about it cooling as it leaves the nozzle and how it traverses horizontal.

Question: I have had alot of stuff printed with nylon, but a new company im trying to work with is offering ABS is that the same, different? Stronger etc?

Ive honestly no idea, thank y'all
Nylon is far more flexible and less brittle than ABS. ABS comes in more colors.  Your keyboard case is ABS as are most doubleshot keycaps. Nylon is most commonly used in rope.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 07 August 2013, 20:11:01
in the realm of thermoplastics can currently be extruded, nylon is at the top of the temperature food chain. it has the highest glass transition and highest melting temp. this means that it has more temperature versatility for certain applications. for example, underhood applications are generally much better off with nylon (most nylons are approved for automotive underhood use, whereas most abses are not). however, nylon and abs aren't really very similar past the fact that they're both polymers. they're actually like wildly different polymers with wildly different material properties nad structures.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Thu, 08 August 2013, 03:30:27
That brings up a good point, if you print nylon, you have to be EXTREMELY careful unless you have an all metal hot end.

The melting point/printing temp of nylon is 240c, and the teflon liners on most hot ends begin giving off nasty fumes at 250.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 08 August 2013, 09:55:10
ptfe melts at 260 (that is, MELTS, not enter glass transition), which is why you don't regularly want to be getting PTFE that hot and nylon is NOT for printing in these printers.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Thu, 08 August 2013, 16:13:22
ptfe melts at 260 (that is, MELTS, not enter glass transition), which is why you don't regularly want to be getting PTFE that hot and nylon is NOT for printing in these printers.
E3d and Trinity heads can handle it, there are a few other all metal ends as well, they were designed to be capable of it.
E3d currently has a 4 week lead time on pre-orders and Trinity is on hold (medical reasons and have yet to release a 1.75mm version).

You can do it on regular heads, you just need to be very careful and it's highly recommended that you have some really good ventilation.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 08 August 2013, 16:27:03
you're probably talking about the lower temp taulman with the process temp of 245. there is another taulman nylon with a process temp of 260. please please please don't try to print that stuff with a head that has ptfe in it!
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Thu, 08 August 2013, 17:29:03
you're probably talking about the lower temp taulman with the process temp of 245. there is another taulman nylon with a process temp of 260. please please please don't try to print that stuff with a head that has ptfe in it!
Yes, the 240-245c... (depends who gives the number)
Personally, I don't think I would try either one with a ptfe head, just not worth it.



By the way, mine is alive once again and already ran off one set of Vortex adapters.
Magnetic arms aren't as impressive as I expected, that could be due to the work I did on my ball ends previously to eliminate slop. However when the magnetics start doing infill... THE NOISE! OMG! Tons of chatter.

Oh, and I will never again own a 3d printer without belt tensioners. Sooo much easier to deal with.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 08 August 2013, 19:25:37
you automatic belt tensioners now? or are they manual? automatic belt tensioners rock. so. hard.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Fri, 09 August 2013, 03:38:22
As for as the materials: PTFE is not an option, but PEEK or FEP may work (with proper heads).
Here is some discussion about it: http://forums.reprap.org/read.php?1,65051,201484
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Fri, 09 August 2013, 06:04:48
you automatic belt tensioners now? or are they manual? automatic belt tensioners rock. so. hard.
Not automatic, but I have been thinking about it.
The Rostock in standard form uses zip ties to just tie the belts up. You have to clip the zip tie to re adjust the belt any time it slips or stretches and on these the belts stretch quite a bit being as long as they are, how many you have, and how much mass the system can generate.


And so the magnetic arm saga comes to a crashing end.
So I got one print out of the magnetic ends (a set of green Vortex universal plate adapters), nice quality, though not a massive improvement. After that finished, I noticed my effector (head mount) was a bit tilted. It didn't effect the print, it just annoyed me as it looked sloppy, and being easy to remove I took it off and started looking for the cuplrit. One of the steel balls wasn't quite sitting right and as soon as I tried to mess with it, the ball pulled right off. Grrrr. Getting them to stick (using JB weld), and getting them all precise has been the bane of people trying these. I spent a lot of time getting everything right, including testing a few types of epoxy. They were holding when I finished, so I can only imagine that the system must have gotten torqued pretty good at some point during assembly.

I wasn't that happy with them anyhow. While they were nice when performing maintenance, and at speeds under 50mm per second, they were great, but the rest of the time they weren't worth the hassle or money it took to make them. Doing infill at 60mm+ made a racket, if I moved the head by hand, there was a good chance the thing would disconnect, and it was heavy enough to droop with the motors off (I figure it doubled the weight of the assembly). Meaning I had to take extra care when moving it, since the head parks at the top.

I can re-use a few bits, and I can copy the belt tensioners onto a rod end carriage without much trouble. I think I'll stick with my tie rods with bands to keep them tight for my new printer. It's more secure, lighter, and MUCH more quiet. It also handles a LOT more speed. I had this one printing nicely at 180mm per second the other night and doing well. A week ago I had it at 240mm per second, but my prototype extruder was having trouble keeping up.  All told, I had about $80 and 2 weeks of my spare time wrapped up in this, between the tensioners, carraiges, effector and rods, all of which I had to either build from scratch or completely redesign.

Sometimes it's the journey, not the destination (hmm, road trip sounds good!).
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 14 August 2013, 19:16:38
where are these MX to alps adapters that i am supposed to be churning out?
Title: Re: The Living 3D Printing Thread
Post by: SpAmRaY on Wed, 14 August 2013, 19:19:38
where are these MX to alps adapters that i am supposed to be churning out?

Yeah for real! Prototypes or bust!
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 14 August 2013, 19:22:10
or the spliney ergodox case?

my bot is so lonely :(
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 15 August 2013, 14:35:47
HOLY CRAP THIS ERGODOX CASE IS HUGE
Title: Re: The Living 3D Printing Thread
Post by: kmiller8 on Thu, 15 August 2013, 22:38:13
mkawa I will print

y wont u update OP

mkawa pls
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 16 August 2013, 01:29:14
i need to confirm that you will print objects that aren't dongs km
Title: Re: The Living 3D Printing Thread
Post by: Glod on Sat, 17 August 2013, 00:18:03
how did the ergodox case go?
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sat, 17 August 2013, 00:35:58
it's just too big for my bounding box. i've done some pieces like this at say a 45 degree angle, but the printer ends up spending 8 hours building scaffolding and then 7.5 hours in it turns out that one small detail piece (like the fastener holes on his design) breaks off due to a small error that would have to be designed out and the whole print is a bust.

if i had the source files with splines i could cut the design into printable pieces, but only the steps and stls are provided on the ergodox page. i've pinged dox to see if he has time to cut up the design himself (it's very much conducive to it) and beef up certain structural parts (since the price per cm3 of my prints are at least an order of magnitude less than shapeways), so we'll see. if anyone is in contact with him, feel free to mention that i'm trying to produce them in a limited bounding box and can actually provide parts under acrylic costs, but i need either source to cut up, or cuts made by him on his original solid part.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sat, 17 August 2013, 00:43:46
as for the mx alps adapters, i can draw them up myself, but just haven't had the time. if someone has a solidworks part in progress, that would be ideal. the big thing is that i want to try to add some tolerances to the part drawings, optimize for certain kinds of common errors that affect density and tensile strength, and then tune the gcode a little better to see if we can actually FFM these out of ABS or if there's just no way to get the flexural strength we need. if worse comes to worse, i have the capability of printing taulman 645 nylon now, which has much better yield strength than any abs formulation that is currently being accurately filamented.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Sat, 17 August 2013, 06:16:35
it's just too big for my bounding box. i've done some pieces like this at say a 45 degree angle, but the printer ends up spending 8 hours building scaffolding and then 7.5 hours in it turns out that one small detail piece (like the fastener holes on his design) breaks off due to a small error that would have to be designed out and the whole print is a bust.
How big are they?
If they can fit into a 400mm diameter, I should have you covered shortly.   :thumb:
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sat, 17 August 2013, 06:44:12
if i had the source files with splines i could cut the design into printable pieces, but only the steps and stls are provided on the ergodox page. i've pinged dox to see if he has time to cut up the design himself (it's very much conducive to it) and beef up certain structural parts (since the price per cm3 of my prints are at least an order of magnitude less than shapeways), so we'll see.

You do not need dox. You can cut stl files in openscad (and I guess in other CADs too). Just load them as an object in openscad (use import("abc.stl");) and then use intersection operator to select the pieces to print. Use union to beef the parts you want stronger. Export pieces to stl, slice, print and glue together.
Title: Re: The Living 3D Printing Thread
Post by: MOZ on Sat, 17 August 2013, 07:24:48
it's just too big for my bounding box. i've done some pieces like this at say a 45 degree angle, but the printer ends up spending 8 hours building scaffolding and then 7.5 hours in it turns out that one small detail piece (like the fastener holes on his design) breaks off due to a small error that would have to be designed out and the whole print is a bust.
How big are they?
If they can fit into a 400mm diameter, I should have you covered shortly.   :thumb:


You'll be good in that diameter for the classic design.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 21 August 2013, 10:13:05
thinking of picking up the makerbot scanner so that people can sculpt and send then have molds printed. thoughts? obviously it depends on price point and whether they actually release it this week like they promised BUT i think they're targeting around 1k, which is barely within budget, and it would allow a great number of cool things to be done.
Title: Re: The Living 3D Printing Thread
Post by: CPTBadAss on Wed, 21 August 2013, 10:17:55
thinking of picking up the makerbot scanner so that people can sculpt and send then have molds printed. thoughts?

I don't understand what this does. You can scan a part and it makes the mold negatives?

where are these MX to alps adapters that i am supposed to be churning out?

Looked for 30 minutes one night trying to find the files. They don't seem to exist and kmiller8 won't give up his files so I guess we're gonna have to ask Mr. Interface or someone will have to model them.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 21 August 2013, 10:28:08
you scan a part using their camera + dual laser system and it provides you with an stl. you can extrapolate from that STL to make a solid or you can print it directly using their slicer. if you were extrapolate out the STL into a solid with splines you could do an inversion to make a mold in CAD software.

the adapters are just not that hard to model. i say someone take the hour that's needed and just draws them off of the datasheets in solidworks, annotating the model with the datasheet tolerances.
Title: Re: The Living 3D Printing Thread
Post by: CPTBadAss on Wed, 21 August 2013, 10:35:11
you scan a part using their camera + dual laser system and it provides you with an stl. you can extrapolate from that STL to make a solid or you can print it directly using their slicer. if you were extrapolate out the STL into a solid with splines you could do an inversion to make a mold in CAD software.

That's awesome. I'd love to see what comes out of that if you do get one of the scanners

the adapters are just not that hard to model. i say someone take the hour that's needed and just draws them off of the datasheets in solidworks, annotating the model with the datasheet tolerances.

If that's a ploy to get me to 3D model at home, it's not going to work :P
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 21 August 2013, 10:40:09
it's not a ploy. IT'S AN ORDER SON
Title: Re: The Living 3D Printing Thread
Post by: CPTBadAss on Wed, 21 August 2013, 10:42:22
SON, GET ME A COPY OF SIEMENS NX THEN.
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Wed, 21 August 2013, 10:56:48
I could otherwise recommend sculpting in software directly. Zbrush and Blender both have some tools for it. They have made the process quite similar to sculpting irl.

I have also noticed that many seem to want things which already exist on their caps (darth vader, iron man, a hand etc). These you don't even have to model as you could find them and just copy paste and attach to a cap.


Edit: Do you need help slicing the ErgoDox mkawa? When you wanted the adapters to be made, did you mean a mold for them or the adapters themselves?
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 21 August 2013, 11:07:07
1) yes, someone please slice the ergodox for me. i am the worst cad operator ever.

2) adapters themselves. we'll resort to molds if we absolutely cannot get the ultimate tensile strength we need by printing them directly. casting presents a boatload of issues (degassing etc).
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Wed, 21 August 2013, 11:08:58
Double, single or no sloped case? Also, best way to slice it would probably be with a slight overlap.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 21 August 2013, 11:11:06
slice the single models into two pieces, it seems like the thumb positions are the easiest place to slice. just run a seam across there and subdivide into two models

if you could do both the sloped and no-slope i can print both and i suspect there will demand for both
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Wed, 21 August 2013, 11:15:22
What did did you mean by through the thumb area? Diagonally?

This is what I thought you meant at first: http://i.imgur.com/PpA9wiR.png
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 21 August 2013, 11:24:14
that works, but you're right, if you did that you'd want overlap. yes, i was thinking diagonally. let me take a quick screenshot of what the model looks like w/rt to my print box
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 21 August 2013, 11:30:00
(https://dl.dropboxusercontent.com/u/24794081/Capturevert.PNG)

vertically it sticks up several cm above my z limit

(https://dl.dropboxusercontent.com/u/24794081/Capturehorz.PNG)

horizontally, it is in the danger zone (YEAAAAAAAAAAAAA DANGER ZONE). but barely doesn't fit.
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Wed, 21 August 2013, 11:47:17
Damn, so close (http://i.imgur.com/U3zEShC.png)

Could you draw a line where you think it would be best? Is there any particular slice which allows more to be printed at the same time? http://i.imgur.com/E3zco1V.png
Title: Re: The Living 3D Printing Thread
Post by: fydo on Wed, 21 August 2013, 11:49:11
I could otherwise recommend sculpting in software directly. Zbrush and Blender both have some tools for it. They have made the process quite similar to sculpting irl.

I was actually just thinking of this the other day. Is there a "known good" model of a basic MX keycap that one could use as a starting point for such modeling? I don't want to have to worry about tight/loose fitting stems, etc.

Thanks in advance!
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Wed, 21 August 2013, 11:54:12
I could otherwise recommend sculpting in software directly. Zbrush and Blender both have some tools for it. They have made the process quite similar to sculpting irl.

I was actually just thinking of this the other day. Is there a "known good" model of a basic MX keycap that one could use as a starting point for such modeling? I don't want to have to worry about tight/loose fitting stems, etc.

Thanks in advance!

I have a few rows modelled, but the stem fitting depends on the machine tolerances, surface roughness as well as material. If they are made in metal, they will flex less and will have to be looser than in plastic. If the surface is rough/smooth, then the stem will grip more/less as well. I have a test block which I could send to get printed first, after which you know more. It looks something like this: http://i.imgur.com/73pKJ.jpg

Edit: You may not  notice it in the image, but the size of the gaps vary slightly. One side it won't enter at all and on the other it is a bit loose.

I have got to finish the remaining profiles some day.

Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 21 August 2013, 16:04:18
anywhere around here would be nice. just printing a single case is the goal at this point.

(https://dl.dropboxusercontent.com/u/24794081/Capturecut.PNG)
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Wed, 21 August 2013, 16:39:00
What adhesive will you use? Just wondering how large to make the cut. 0.5mm? Better to make to hold the parts in place, and fill up too large of a gap than to not make it large enough.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 21 August 2013, 17:18:29
with abs one can use any number of adhesive. ye olde cyanoacrylate works fine, so do most epoxies. the most effective adhesive tends to be abs slurry either fresh with maybe 25% acetone mixture still keeping it moist, or relatively dry, with very very acetone keeping it pliable. however, my thinking was that there is enough clearance under the board that a true mechanical connection can be constructed in a dovetail style and the adhesive inserted in the middle. this will also keep alignment consistent. this is why i pinged dox for the original solid files, so one doesn't have to do a lossy triangular transformation.. however, i think he's moved on from this design and is busy ;)

sorry, abs slurry is just abs degraded with acetone to make an abs-like resin, or at least a resin that is very attractive to full abs polymers.
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Wed, 21 August 2013, 17:37:06
Try these for now: http://www.sendspace.com/filegroup/G51glpXUwVtIPPnGiSGYjQ

Edit: The hook acts as a bit of support for bridging when printing as well.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 21 August 2013, 18:15:15
printed is down today. as usual, there is some hardware i'm putting in and tinkering with before the next print. i'm also loading a custom conf'd compile of sailfish onto the machine asap due to some bugs i seem to be hitting in the MBI firmware (they are close cousins, so it's mostly to tweak some stuff i've talked to dan about and to get better instrumentation during the print)
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 22 August 2013, 14:22:05
so... the makerbot digitizer came out. you guys have a scanner right damorgue? what's your feeling on this thing? it looks like it tries to do a ton of interpretation  SORRY INTERPOLATION from a camera image.

i happen to know enough about vision to know that that can be wildly unsuccessful

laser distance measurement = good. camera distance measurement = bad.
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Thu, 22 August 2013, 15:04:38
I would agree that they are better, but for many applications the tolerances you get out of a camera can be sufficient. I actually scanned my mouse using my own home camera. I did some testing, and the more pictures you used the more the result narrowed down and approached a steady state which wasn't that far off the real deal. I would not scan an object which requires tight tolerances. Usually, those shapes are easier to describe, and can be measured and recreated with caliper instead. Organic surfaces are rarely that exact, but much harder to measure and model, hence the use of scanning and rather low demand on tolerances.

A quick issue I see with makerbot digitizer is that it only takes pictures at one height. Sure, it will rotate the object, but you won't get any pictures from above, or from below.

If you were to scan a cup, it wouldn't see the hole at the top very well, and the cup would be filled. I guess it looks at it slightly from above, so it would be able to determine that there is at least a shallow hole, but it could only determine it like an inch deep or so. This is a limitation of the lasers as well since they won't light into concave surfaces very well, assuming the camera only captures the light frequency they emit. That thing is built to scan a sphere, the less the object resembles a sphere, the more problems it will have.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 22 August 2013, 15:08:53
ah, good point. you really want that scanning rig on a polar axis like most other true scanning rigs..

i guess the question is what could we use it for? it can only scan the outside OR inside of a keycap, so you have to do some modeling to get the full solid (like a cup), it seems like it's best for uncomplicated solids

but in that case you can actually use vision-based methods, heck, if it's destructive you can shine IR at it and put IR reflective material on it (or like the kinect, just heat it up) to get quite a bit of distance information
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Thu, 22 August 2013, 15:30:42
It illustrates the importance of planning your scans. In that particular rig it would probably be best to scan the cup lying on its side for instance. If I were to scan a cap, I would hang it from a tiny string to ensure that all important sides are shown. You can of course stitch two scans together, but that can be troublesome. In the particular case of a key cap, I would probably model the stem anyway, since the fitting is so important. You won't be able to accurately scan the tiny hole without a very expensive machine.

With the recent popularity of sculpting your own keycaps in clay, a scanner would come in handy though. Scan them, digitally replace the stem to one with fine tolerances and then print them.

Edit: I forgot to mention something quite important regarding camera scanning reflective and shiny objects. USE POWDER! Pretty much any powder will do. Flour or talk (baby) powder works nicely to make an object matte and gives a far better representation.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 22 August 2013, 15:32:36
that's what i was thinking

that said, they come out better cast, honestly. it's a bigger pain to get rid of all the striations and crap, and abs isn't the most paintable thing in the world
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 22 August 2013, 15:33:49
i'm very hesitant until we can come up with a really good use case for it now. we need a small mill way more than we need a scanner
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Thu, 22 August 2013, 15:35:30
Shapeways actually offers stainless steel which isn't very expensive. For reference, a Cherry MX keycap cost like $11 in stainless steel last time I checked, $2.3 in their white cheapo plastic, $2.7 in black and $2.8 polished white.

i'm very hesitant until we can come up with a really good use case for it now. we need a small mill way more than we need a scanner

True that. There are plenty of software for using your home camera to make decent scans
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 22 August 2013, 19:22:06
a sherline 5400 series can work with shapes that would cost as much as a sherline mill to have shapeways make ;)

it is nice to know that shapeways can do non-casted non-precious metals now though.
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Thu, 22 August 2013, 19:27:49
I haven't read up on them too much, but their gold plated and other plated varieties appear quite cheap as well. I doubt it is real gold at that price, but the plating does look nice and shiny. Bronze plated matte could go well with those brown kits that were recently run.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 22 August 2013, 19:40:54
shapeways scales at the size of eg a single cap, but for larger objects like complex chassis shapes, you're using way more material than they seem to want you to use. a small mill can handle these things, but naturally requires some amount of operator expertise, etc. at a certain point, if your object IS millable, you're better off paying a real machinist to mill it out anyway. i'm guessing their process (previously they could only cast soft metals but i'm guessing if they can so stainless now they have a DMLS machine) will not provide bulk material nearly as strong as that produced from billet material by a good machinist.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Fri, 23 August 2013, 17:12:16
shapeways scales at the size of eg a single cap, but for larger objects like complex chassis shapes, you're using way more material than they seem to want you to use.
Shapeways warns not to go under 3mm for wall thickness in structural parts, even in metal.

Their prices are a bit strange, while I can sort of see how a lower corner of my new printer would cost me $650 for stainless, I fail to see how it's worth $240 to make it in ABS.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Fri, 23 August 2013, 17:16:49
My extruder decided to become a royal pain the butt, so I'm struggling to get the frame connectors printed. Its a 4 hour print at 120mm per second and I keep failing around the 2-3 hour mark, but here is a mockup of the print surface size. It will be able to print the keyboard dead center with a couple CM to spare

Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 23 August 2013, 17:45:22
that is really tight.

are you sure it wouldn't be better to print it vertically with some supports?
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Fri, 23 August 2013, 18:28:06
that is really tight.

are you sure it wouldn't be better to print it vertically with some supports?
That is just a rough quick layout.

I did the math before I started, by the numbers,  it will do 360mm diameter within the triangle, which is the size of the keyboard.  The arms can extend beyond the triangle about 15%, though but not in a perfect circle. It will clear an TKL.

Even if it doesn't, for about $100 I can double it, and for $150 I can triple the size of the build platform.   :)) Unfortunately, I'm pushing the size limits of my desk even with this.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 23 August 2013, 18:34:53
you're also looking at flatness issues. silicates have flatness tolerances too
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Fri, 23 August 2013, 19:46:13
The new printer has an auto level function that is being built into it. It can probe points on the bed and give a readout as to how far off they are. On small builds it probably won't be an issue, but on larger ones, if I can't dial them out, I can use PVA or HIPS to build a flat, soluble surface to build on top of.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 23 August 2013, 20:45:10
i'm not sure how you're supposed to dial out random variation in bed height. do you have a flexible bed with some kind of periodic ? from some pictures somewhere (which may have been kirkle's who knows :X) it looked like you had a large PCB heater and a piece of silicate clipped to it. i'm a bit confused how you would dial out flatness variation. something that's hard and not flat is pretty much hard and not flat. you can't really do much about it. if it's flat, but the plane is tilted, you can level it to a more expected normal, but if your surface is warped you're going to have to get fancy with rafts and compression to prevent the warpage from propagating into your print. oddly, i sometimes get better vertical prints then horizontal prints this way (but my original factory plate got pretty darn warned after ~100 build hours -- the MBI guy had a good laugh at it).
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Fri, 23 August 2013, 20:48:40
I think the idea is to assume that the head travels in a flat plane and let it build more where it has measured the surface to be further down. The first few layers will flatten and the unevenness won't propagate throughout the build. Sort of a "build a flat surface on top of the uneven one"-method.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Fri, 23 August 2013, 22:09:42
Damorgue has it.
If you assume the head is traveling in a flat plane, you can use PVA to make a flat surface to build upon and then disolve it in water. The idea is use the auto level to get it as flat as possible, but if there is still too much variation, use PVA.

The autolevel is pretty neat though, once you get it calibrated, you don't have to keep calibrating when an adjustment is made elsewhere. People are able to get accurate enough that they are printing thin PLA objects on bare glass.

Take a look:
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sat, 24 August 2013, 04:23:27
Leslieann, do you have different auto-levelling than the one created by Johann?

Because Johann's auto-levelling does not correct for the curved print-bed as Damorgue proposed.
Johann's code curves everything exactly the same way as the bed is curved. Actually this is an important feature of Johann's code because it allows to correct for slightly incorrect tower positions and diagonal rod length. This is a great feature since one does not need to have exact rods and top/bottom plates and prints will still work well enough and there will not be issues with first layer not sticking. But incorrect tower positions and rod length specification in firmware lead also to second order errors in layer flatness. That means printer does not know what is flat i.e. you cannot assume head is moving in a flat level. This second order error is only linearly approximated at 7 points in each axe direction. So you do not want tower positions / rod length too wrong so that the approximation works well enough (and so that the probe deploy/retract can position head well enough).

I know only 3 approaches to delta bed levelling:
1) Johann's - this is what most people know about.
2) Math based one. It is currently not completely automated but there is some proof of its feasibility. Here is more information about it: http://forums.reprap.org/read.php?178,237655,237789#msg-237789
3) Manual one i.e. the tedious one. Most delta calibration descriptions do not bother with incorrect tower positions but the thread above has some hints here: http://forums.reprap.org/read.php?178,237655,237789#msg-237789

Mkawa will not like Johann's approach but I think it is good enough. Thick mirror is flat enough if you mount it only in 3 points (so that you do not expose it to forces which can bent it). Really if your keyboard case is only as bent as a mirror is then it is a already a win. Especially considering how easy to use is Johann's bed levelling. And mirror does not get curved more after few hundreds of uses. My experience is that once delta gets levelled it stays that way (if you are not replacing printer parts).
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Sat, 24 August 2013, 07:52:08
I'm using Johann's, and yes, I understand it's abilities and limitations.
I plan on using the auto level to help double check my settings (and set head height). I still plan on setting rod lengths and such to achieve flat, to me, that is part of the process of tuning a delta. I don't like the idea of trying to dial out a huge error made in construction by using software, fix the problem first or at least as much as you can. Auto level should assist you in getting a good print, not compensate for a terrible build.

You pretty much covered my thoughts regarding the glass, which is what my build surface will be.
It's a plastic case, that's going to be sitting on a desk, which I''m willing to bet isn't nearly as flat as the print surface the case was built on. 
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sat, 24 August 2013, 08:38:46
very interesting, and makes PLA much much more attractive when its material properties aren't an issue. it's basically heated beds make everything a moving target and significant degrade the measurement device at HBP temps.

but what's really interesting about this is that it's basically a useful version of the gauge check from subtractive printing. what i've been told by experienced tradesmen machinists is that gauge checks are useless because

a) they increase cycle time too much, but this bed topology only has to be mapped out at most once a print and probably much less often than that, because unheated beds just don't warp all that much as build time accumulates

b) if the indicator ever measures runout over tolerance, you have to toss the part -- say you're boring something out and the machine does a gauge check on the bore diameter and it's too large. oops, can't get that material back. that's now scrap. this might be useful while testing gcode but in production the best it can tell you is that you need to stop production and rewrite your gcode.

c) with low warpage material you can just keep adding until variation of object is within tolerances. like you said leslieann, you can dial in a raft based on your topo, and if your remeasurement is still out of tolerances, just add more material! pretty much all the low temp low warpage materials are water soluble, so bam!

holy crap i fell asleep while i was writing this last night. anyway, nice
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sat, 24 August 2013, 08:45:47
Leslieann, do you have different auto-levelling than the one created by Johann?

Because Johann's auto-levelling does not correct for the curved print-bed as Damorgue proposed.
Johann's code curves everything exactly the same way as the bed is curved. Actually this is an important feature of Johann's code because it allows to correct for slightly incorrect tower positions and diagonal rod length. This is a great feature since one does not need to have exact rods and top/bottom plates and prints will still work well enough and there will not be issues with first layer not sticking. But incorrect tower positions and rod length specification in firmware lead also to second order errors in layer flatness. That means printer does not know what is flat i.e. you cannot assume head is moving in a flat level. This second order error is only linearly approximated at 7 points in each axe direction. So you do not want tower positions / rod length too wrong so that the approximation works well enough (and so that the probe deploy/retract can position head well enough).

I know only 3 approaches to delta bed levelling:
1) Johann's - this is what most people know about.
2) Math based one. It is currently not completely automated but there is some proof of its feasibility. Here is more information about it: http://forums.reprap.org/read.php?178,237655,237789#msg-237789
3) Manual one i.e. the tedious one. Most delta calibration descriptions do not bother with incorrect tower positions but the thread above has some hints here: http://forums.reprap.org/read.php?178,237655,237789#msg-237789

Mkawa will not like Johann's approach but I think it is good enough. Thick mirror is flat enough if you mount it only in 3 points (so that you do not expose it to forces which can bent it). Really if your keyboard case is only as bent as a mirror is then it is a already a win. Especially considering how easy to use is Johann's bed levelling. And mirror does not get curved more after few hundreds of uses. My experience is that once delta gets levelled it stays that way (if you are not replacing printer parts).
i think it's a useful advance. sure, it's not perfect, but that's the whole point of mentioning that larger beds give you a higher probability of hitting flatness tolerance issues.

the fact is everything manufactured has tolerances (that's what i think about 99% of the time these days), so "good enough" methods to approximate what those tolerances are and to compensate for them are invaluable.

Title: Re: The Living 3D Printing Thread
Post by: vvp on Sat, 24 August 2013, 12:03:32
I still plan on setting rod lengths and such to achieve flat, to me, that is part of the process of tuning a delta.
Good thinking.
Johann's method fixes the most noticeable error with incorrect calibration (rod length, tower positions). It fixes the z-error. Everybody notices that easily since the first layer does not stick well. But Johann's methods does not fix errors in X-Y plane at all. And the errors in specification of rod length or tower positions in firmware will lead to errors in X-Y plane direction too and on some places of the bed the dependence is first order and therefore the most significant.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sat, 24 August 2013, 12:11:55
it's really hard to get the rods right on a rostock style design, you have flex on those long rods, and so on and so forth. but obviously there are issues with a cantilever style design or rectangular design as well
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sat, 24 August 2013, 12:12:31
error is a fact of life. to deal with it, you first characterize it, then think really hard, and work around it basically.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sat, 24 August 2013, 13:52:10
Actually the more I'm exposed to rostock the more I like it. It is a bit un-intuitive ... well because it is not cartesian. But any part precision errors (I encountered so far) have a nice recognizable footprint on the errors in bed z-level height or in the printed parts. So once these things are learned, it is not a big issue. But it takes some time. It has also rather long bowden. So few more quirks to learn there too. But that is about it.

When I was discussing rod errors I always meant diagonal rod length error (the 6 rods from carriages to the platform holding hot-end). It is not hard to make them precisely equal with a jig. But their final common length will vary a bit between different machines since most people will make a jig by just drilling a piece of wood (no fancy tools).

There should not be any noticeable deformation in the diagonal rods. Forces on them are in the direction of their long axe. Carbon fibre rods are plenty strong for that.

But it would be interesting to find out how much the smooth rod towers bend at the common accelerations. This will be X-Y position dependent too. But lets do a quick and dirty check here. The print head (with diagonal rods) is only about 180g on the machine here. Maximum acceleration is set to 4m/s. So the maximum side force at the tower is around 1N (I'm ignoring a lot of things here* but it is about right). I guess it will bent a bit under 1N. I put a 200g pliers (i.e. 2N) on the rod and I'm not sure I noticed a change/bent or not. Which, I bet, must only mean I'm blind like a bullet :)

Getting towers exactly equidistant is actually very easy and cheap (by drilling both top and bottom plate at once with a drill press - which is a common tool). With the help of the math in the reprap forum (or doing it all manually) you can actually get a very precise rostock at low accelerations even without laser cutting and other high precision tools.

* max acceleration is specified for the carriage movement but the side forces will be from the platform/diagonal rod movements
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sat, 24 August 2013, 14:50:55
there's nothing weird about non-cartesian. lathes are used for every circular subtractive application in the world and they are cylindrical. very high axis count mills do all kinds of funky **** with coordinate systems for minimizing error (although it's mostly manual BUT I WILL FIX THIS). what's weird about the rostock design is how nonstandard the coordinate system is, and the fact that the it takes euclidian instructions and then does something weird with it, and the very large number of different error sources. euclidian machines have just a couple of error sources that are HUGE. rostock designs have tons of slightly smaller error sources (although depending on your implementation they can be quite large).

also the really tricky bit about the rostock is that your error is so hugely dependent on minimizing head weight. but as we move to higher and higher temp material extrusion, it's going to get increasingly hard to maintain that weight.

quite the conundrum!

that said, it's good to see the rostocks get some traction and also bill steele's cylindrical design (which i'm actually really angry that he's trying to patent because it's so freaking obvious; COME ON, THE LATHE IS BASICALLY PRIOR ART). but anyway
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Sat, 24 August 2013, 21:19:02
I haven't actually been using a heated bed lately.

I have been trying to nail down the process as it's not as easy as printing with one. I originally planned a heated bed for the larger printer, but when I started seeing the wattage I cringed. 200-800 watts depending on how fast I want it to heat up. There was also warp issues I wanted to avoid. While I disliked the heat it produced, the last straw was when the fet in my Ramps board died. I had to heat the bed in stages. While I finally replaced it, I think I damaged a trace. Grrr. I honestly think it was bad from the start, I have always had issues with that fet running extremely hot. At any rate, it;s nice to not have to wait on the bed every time I print, but like I said, it is more hassle.


I'm with VVP on the deltas.
While I initially picked it for the build volume, easy of build, and frankly I liked how it looked and worked. You can look at plans, see them operate, but it's not until you start using it and modifying it that you really start to see just how genius the design really is. It's adaptability is amazing.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sun, 25 August 2013, 09:45:24
my printer is now down because i semi-bricked my mightyboard (the at90 is still working but the 1280/2560 seems to be trying to boot off of garbage). there's a programmer but windows serial device drivers are freaking impossible to a) use b) get working correctly. migrating the whole setup over to my laptop so i can unbrick the thing using an operating system that works.

FUNNY STORY. i first tried to do this in a linux VM, but the windows driver somehow got in the way of the virtualized device (the bus is still virtualized, even if the device is directly connected to the VM) and produced garbage. NT8 WHY YOU SO STUPID
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sun, 25 August 2013, 09:46:16
did you know: NT7 and NT8 heap layout randomization is pseudorandom based on exactly 256 possible pseudorandom seeds

THEY HAVE TEAMS OF SECURITY PEOPLE ON CAMPUS

I HAVE MET AND TALKED TO THEM

CHRIST
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sun, 25 August 2013, 09:46:59
THEY HAVE A BOOKLET WITH THAT EXAMPLE IN IT AND THE WORDS: "don't do this. it doesn't work"

AAAAAAAAAAAaaaaaaaaaaa.......
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sun, 25 August 2013, 15:04:28
sigh. the in system programmer is just refusing to talk over the at90. who the **** knows why. i ordered a jtag for atmels because i hate them so much anyway i just know i'm going to end up needing to breakpoint the **** out of this and everything else i do with them once i do get this thing unbricked.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Sun, 25 August 2013, 17:57:59
Win 6,7,8 all have serious problems with serial over usb, Android developers see it a TON on cell phones when trying to unbrick them.  Those and router hacking. Getting that system to pass through a VM... yeah right. lol It can work, but it's next to impossible and even less likely to work even if you do. Windows USB implementation is terrible enough as it is, combine it with crap Chinese/Indian programmers and wide open USB specifications and you're just begging for problems.

I keep a pair of older dedicated laptops, one with XP, another with Linux on it sitting on a shelf just for those situations, because you can't count on Win7's sub/serial connections.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sun, 25 August 2013, 19:28:08
windows device drivers have problems, period. the fact that you can't do simple txrx is about as endemic as it gets.

anyway my mac running avrdude is very obviously not able to reach the avrisp on the 1280, and the at90 seems like it's working. it's reporting the correct everything and it's acting like a proper tty, so i suspect that it's just that replicatorg did something incredibly stupid to the fuse bits on the m1280 and i'm going to have to jtag my way out of it at high voltage.

for a moment today i was contemplating just calling and ordering a revH board tomorrow (the june mightyboard was revG) but then i remembered how much i HATE ATMEL8 MCUs and that i'd rather spend months wiring the thing up to a beaglebone and writing an entirely new firmware with dnewman and jetty than have yet another stupid at8 board cluttering up the apartment.

fun fact: the mightyboard firmware no longer uses ANY ARDUINO ANYTHING (mostly thanks to dcn and jetty). the only reason the board is still based on an arduino schem and running on an at8 is because of backwards compatibility. i love the guys and gals at makerbot, but this is something that needs to be FIXED LAST YEAR
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Sun, 25 August 2013, 20:54:05
You're in way over my head. Well, not entirely, I've done enough of that, to where if I need a Jtag, I know that even if I fix it, it will soon be on my list of things I want replaced.

I'm waiting for Beaglebone to get easier, a bit more onboard power would be nice, plus I would like to get a setup where I could use a cheap, used cell phone or tablet to control things. Yes, I could do it now, I even have the parts, but it's more convoluted to accomplish.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Mon, 26 August 2013, 13:32:28
hate to burst your bubble but writing an arm + neon firmware from scratch is going to need about 10x more jtag than flashing a board that's just jumping to garbage in the nvram after boot. many many decisions need to be made. the bbone right now only has one bootable OS, somewhere between a 2.4-ish to 2.6-ish kernel angstrom distribution. the arm core on the cortex is quite unique in that it's one of the first to implement the neon simd isa; the tegra and snapdragons have the most popular data parallel isas in the embedded world at the moment, so you need a compiler. then, you need to figure out what the hell kernel to run. currently, linuxcnc and EMC tend to use these pcie to gpio/pwm/txrx cards to control steppers, all running under a pre 3.0 linux with the fairly standard rt extensions (iirc this is just some tweaking to priorities, and scheduler quantums and not true rt.)

oh crap, fell asleep during this post too. anyway, it's all complicated. waiting to hear back from makerbot; they have an updated unbricker that should actually work
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Mon, 26 August 2013, 16:21:07
oh crap, fell asleep during this post too. anyway, it's all complicated.

LOL
Actually a guy in the deltabot Google group has Beaglebone working, sounds like he has it setup pretty well and shared a lot of how he got it done. It didn't sound all THAT bad, but I didn't dive in too deep on it.



I did some research on the glass for my printer...
While there is no official set standard, the common accepted policy on tempered glass is that there should be no more than .0005in tolerance.  Works for me!



Oh, I figured out that the Kossel delta calculator is off for my printer.
Because it uses linear guides on top of the upright rails (which reduce the print area) and slightly different frame connectors, it's not accurate for mine. Now that I have the parts all designed and the connector printed and mocked up, it looks like I should have between 17inches (430mm) and about 19inches(480mm) diameter depending on where in the build volume you measure. I found an 18in (460mm) tempered glass table top on Amazon for $62 (free shipping!) that I'll be ordering later this week. It's 3/8in thick, so it should stay in place and not flex too much.  ;D Instead of a paper weight, I'll have a printer weight.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Mon, 26 August 2013, 22:07:29
i don't believe armgcc supports neon yet, and there's generally a huge difference between being able to move some steppers around and having a high tolerance, smart, fast, stable machine controller. linuxcnc allows the former to happen pretty quickly -- dcn and some other fellows have gotten the reprap style machines there already. but there's a long way to go still and a heck of a lot of buggy code to write first ;)
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Mon, 26 August 2013, 22:10:34
hey, want to see 200ish print hours can do to the z-threaded rod on a replicator? :D

(https://dl.dropboxusercontent.com/u/24794081/_DSC9725.jpg)

quick proud of this one, frankly.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Tue, 27 August 2013, 00:12:55
What did you do? Gnaw on it?  :))
I have 250 hours on mine, though maybe only 1/4 of that is actually printing (4 pounds of filament), everything looks fine wear-wise.

Not that I haven't broken or damaged anything though, casualties thus far:
2 printed pinions (gear reduction, one overheated and warped, the other just broke, too thin)
1 printed spur (gear reduction, I didn't reinforce the bolt hole enough)
1 extruder (delaminated at a stress riser, redesigned and printed at higher temp, working great)
3 stripped belt pulleys (garbage, stripped before they got tight they were free, and I know why)
2 bowden fittings and some teflon lining (crappy filament)
1 Ramps board (hot bed trace, it had a bad FET, which I then made worse using an old soldering iron, still works, just no hot bed)
Took a chip out of my print bed (I flipped it over, head fell while I was tensioning a belt)


I know of at least one person using Beaglebone on a delta with Linuxcnc, but yeah, it has a ways to go, and beyond the effort I'm willing to expend.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Tue, 27 August 2013, 01:34:34
linuxcnc isn't quite there yet, even on really fast amd64 chips with the dedicated gpio cards on pcie that dnc tells me he uses. the commercial packages are still just way better. at the most basic level, linuxcnc, rtlinux, etc are all total hacks. once, long ago, the linux kernel was simple enough that you could rip out the scheduler and redesign the api to give deadlines and so on and so forth. we're long past the point where this is possible though. kernel.org's kernels only kind of work because so many people beat on them and the fundamental api was designed properly from the beginning (for a situation where millions beat on something but still everything is wrong because of stupid crap that was seeded 15 years ago, see ntkern). the scheduler is a nightmare and tied like a shoelace around the entire kernel. because of aforementioned reguilar and frequent beatings, the kernel works for many people very well but only as an interrupt driven multi-user monolith.

it's super ironic that rick rashid is now captain of the good ship windows, because the original mach microkernels were exactly what you want in a modern RTOS for machine control. ironically, even darwin, the only thing that can even kind of claim to be a mach-based kernel has so much BSD running privved that it's also effectively a monolith now, and of course the scheduler in any monolith is going to be a huge nightmare.

sigh. anyway, yah, i eat stainless steel acme rods for breakfast and then apparently grind up the brass travel nuts for a snack. problem? :D
Title: Re: The Living 3D Printing Thread
Post by: JPG on Wed, 28 August 2013, 07:20:45
Hi all 3d printer. I just saw https://www.massdrop.com/buy/magic-plastic-pellets on massdrop (it's some plastic pellets you can melt and shape to make anything).

Anyone know if they are good? Maybe it could be used to make keycap stuff like Binge handmade marvels?

Waiting on Kawa's explanation of all of this plastic properties  :rolleyes:
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Wed, 28 August 2013, 08:22:54
It is some polymer in pellet form, by the looks of it a thermoplastic with a low glass transition temperature but rather high melting point. I don't think it is a thermoset. Be aware that in order to cast it, you may need a significantly higher temperature to get it liquid and even then it may not be suitable as it is probably designed to have a very large glass transition span to be easier to craft for regular folks. It is thus probably easier to craft directly in, rather than cast.

I could recommend buying old vinyl records for close to nothing as another source of fully dense thermoplastic.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 28 August 2013, 09:28:31
Hi all 3d printer. I just saw https://www.massdrop.com/buy/magic-plastic-pellets on massdrop (it's some plastic pellets you can melt and shape to make anything).

Anyone know if they are good? Maybe it could be used to make keycap stuff like Binge handmade marvels?

Waiting on Kawa's explanation of all of this plastic properties  :rolleyes:
this is also called instamorph and has a bunch of other trade names. i have a big bottle that i used to make dong-shaped objects (just kidding, that was just a shout out to the d-squad and kirkle!). it's fun stuff. you just dump a bunch into boiling water, pull it out and treat it like clay until it cools down.

see look! i don't always go into atomic detail! :D
Title: Re: The Living 3D Printing Thread
Post by: SpAmRaY on Wed, 28 August 2013, 09:51:11
Hi all 3d printer. I just saw https://www.massdrop.com/buy/magic-plastic-pellets on massdrop (it's some plastic pellets you can melt and shape to make anything).

Anyone know if they are good? Maybe it could be used to make keycap stuff like Binge handmade marvels?

Waiting on Kawa's explanation of all of this plastic properties  :rolleyes:
this is also called instamorph and has a bunch of other trade names. i have a big bottle that i used to make dong-shaped objects (just kidding, that was just a shout out to the d-squad and kirkle!). it's fun stuff. you just dump a bunch into boiling water, pull it out and treat it like clay until it cools down.

see look! i don't always go into atomic detail! :D


going off topic of 3d printing, well unless you count molding this by hand to be 3d printing ;)

but could this be used to patch up a chopped up keyboard case?
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 28 August 2013, 09:56:20
maybe? it only bonds to other plastics while hot and it doesn't necessarily bond all that well. That said, it's very malleable and bonds much better and sets much harder than clay or bondo or any other fiber fiill stuff, and you can always epoxy it into place. it's also super cheap. i would just go for it :D
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 28 August 2013, 09:56:50
also just buy it off amazon as instamorph. no need to gb it. it's so cheap!
Title: Re: The Living 3D Printing Thread
Post by: SpAmRaY on Wed, 28 August 2013, 10:00:17
also just buy it off amazon as instamorph. no need to gb it. it's so cheap!

Yeah I actually ordered some off Amazon just to experiment with earlier ;)
Title: Re: The Living 3D Printing Thread
Post by: domoaligato on Thu, 29 August 2013, 22:24:26
Does anyone happen to have a 3ds max file for a cherry esc key?
Title: Re: The Living 3D Printing Thread
Post by: vvp on Fri, 30 August 2013, 04:06:22
Leslieann, did you use Berry tripper at the end?
I'll need to change extruder too. So I'm looking for some bastard child of Airtripper and Wades/Greg.
Something which uses gears and hobbed bolt but has filament guide and clamp as airtripper.

My computation that the direct drive should be enough was wrong. I didn't know that when a stepper is using micro stepping then it's actual torque is only about 70% of the nominal rating.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 30 August 2013, 09:17:54
i managed to brick a mightyboard. oops
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Fri, 30 August 2013, 09:18:40
i managed to brick a mightyboard. oops

Any idea when you might have a working printer? :)
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 30 August 2013, 11:40:04
they're sending me out another one (oh god makerbot support is amazing, i can't even begin to describe how thankful i am for the things they've comped me). i suspect this is going out fedex home (although my last shipment they upgraded me without comment, because they're THAT awesome.) so mid next week. the everything mechanical is ready. at this point i'm just waiting for a mightyboard.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 30 August 2013, 11:42:24
btw, repg is what started this whole mess. i triggered a bug in repg that set my atmega1280 lockbits to 0x00 (NO MORE PROGRAMMING FOR YOU) and had to jury rig a high voltage serial reprogram using a jtagice3 which explicitly doesn't support it. this first involved a 12v battery that fried the manual reset switch and then finally a 1hz function generator set to 0-12v on the rst pin.

that said, by the time i got the lock bits unset, it was too late, no matter what i loaded on to the m1280, i got no boot from the board.

conclusion: be extremely careful with repg-r22 and mightboard rev Gs. it does the wrong thing in spades.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Fri, 30 August 2013, 16:38:26
Leslieann, did you use Berry tripper at the end?
I'll need to change extruder too. So I'm looking for some bastard child of Airtripper and Wades/Greg.
Something which uses gears and hobbed bolt but has filament guide and clamp as airtripper.

My computation that the direct drive should be enough was wrong. I didn't know that when a stepper is using micro stepping then it's actual torque is only about 70% of the nominal rating.
Berry Tripper is a Wades gear reduction combined with Airtripper, and yes, I'm using it.  Other than sometimes having to "aim" the filament into the output hole, it works fabulous.

I have designed a new micro, easy loading, geared extruder, but it's been bogged down with minor problems. It's close, but still needs some work and my attention has been focused on the new printer instead, so I've been using the Berry Tripper.


Go geared, you won't regret it.
It's a bit noisier and a bit bulkier, but it really does make things easier. I went back to the Ez Struder the other night, out of curiosity, I like that little thing, but wow, did it lack the power and precision of the geared extruder.

By the way, if you do use the Berry Tripper, the steps per mm with most hobbed gears is right about 340 per 100mm. With such a high number, being off a tad isn't as much of an issue compared to direct.


i managed to brick a mightyboard. oops
Don't do that.  ;D
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 30 August 2013, 16:49:40
fwiw, i'm not exactly sure what bricked it, but the initial problem is that idiotic repg set all the lock bits on my atmega1280 either after, before or while putting garbage all over the flash memory. i bought an atmeljtagice3 to try to ISP or JTAG my way out of this mess, but unless you spend 600$ on the AVRONE, you don't get high voltage programming through the dongle. so i did what any red blooded hacker would do: found the reset pin and applied 12v to it. unfortunately it turns out the reset pin basically sinks to ground and i ran about 10A through it, frying the reset switch. once i realized this (magic smoke from batteries is bad), i strobed the pin at 13v with a function generator instead and was able to reset the lock bits via ISP with the ICE3. however, something in my 1280 was still clearly not happy (i suspect the bootloader was corrupted in an unrecoverable way, set non-write and then permanently fused). so i had to pull the thing off the board anyway. because i don't have any smd rework tools i pulled about 8 pads off while doing this because lead free solder and solder wick ARE NOT FUN and NOW I HATE ATMEL EVEN MORE.

thankfully MBI is awesome and is sending my a new board. hooray!
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 30 August 2013, 16:52:27
m1280s are cheap, thankfully, so i'll replace those pads with very carefully applied copper tape and throw a new chip on. SIGH. on the upside, atmel studio is actually not that bad. i expected much worse.
Title: Re: The Living 3D Printing Thread
Post by: domoaligato on Fri, 30 August 2013, 18:23:09
Does anyone happen to have a 3ds max file for a cherry esc key?

Please?
Title: Re: The Living 3D Printing Thread
Post by: MOZ on Fri, 30 August 2013, 18:31:38
Does anyone happen to have a 3ds max file for a cherry esc key?

Please?

If and when you find one, post it in the CAD resource hub please. Thanks.
Title: Re: The Living 3D Printing Thread
Post by: domoaligato on Fri, 30 August 2013, 23:07:03
I have found a few but when I open them in there respective program they come up blank. :(
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Sat, 31 August 2013, 00:37:38
Does anyone happen to have a 3ds max file for a cherry esc key?

Please?

I am inclined to not release mine until I have finished all the rows and 1u;1.25u;1.5u and so forth and is absolutely certain that they are correct. What are you going to use it for?
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sat, 31 August 2013, 03:35:23
Go geared, you won't regret it.

Yes, I am planning to. Maybe I could push airtripper more but I do not want to add fans on the stepper driver and the motor. Berry tripper uses M5 bolt and a hobbed pulley as airtripper has. I have only a hobbed bolt at hand. I'll probably design something which will fit nicely in the corner of the traditional Rostock. I do not want to unnecessarily limit the built volume at the extruder location.

mkawa: new OSS slicer:
https://github.com/Ultimaker/CuraEngine
https://github.com/daid/Cura
I did not try it myself. It did not install cleanly on archlinux and I did not bother fixing it.
Title: Re: The Living 3D Printing Thread
Post by: domoaligato on Sat, 31 August 2013, 04:03:59
Does anyone happen to have a 3ds max file for a cherry esc key?

Please?

I am inclined to not release mine until I have finished all the rows and 1u;1.25u;1.5u and so forth and is absolutely certain that they are correct. What are you going to use it for?

as a base to build custom keycaps on.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Sat, 31 August 2013, 16:59:46
Yes, I am planning to. Maybe I could push airtripper more but I do not want to add fans on the stepper driver and the motor. Berry tripper uses M5 bolt and a hobbed pulley as airtripper has. I have only a hobbed bolt at hand. I'll probably design something which will fit nicely in the corner of the traditional Rostock. I do not want to unnecessarily limit the built volume at the extruder location.
I put the extruder outside the wall, and then later replaced the wall with a tube. I used printed brackets to hold a tube at each back corner, and clamps to hold the extruder and spool mount. It not only resulted in a much more open look, but the frame was more stable as well.

The only wood left is the top and bottom.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sun, 01 September 2013, 06:29:20
I put the extruder outside the wall, and then later replaced the wall with a tube. I used printed brackets to hold a tube at each back corner, and clamps to hold the extruder and spool mount. It not only resulted in a much more open look, but the frame was more stable as well.

The next printer I'll do will be more open. I'm thinking about using iron and weld it. But that is far future. I'm lazy to modify what seems to work well enough. But I thought the same about extruder too. Higher print speeds changed that. Maybe I'll only add a support tube to what is already in there.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Tue, 17 September 2013, 16:47:03
 :mad: :mad: :mad: :mad: :mad: :mad: :mad: :mad:

So the other day I needed some ABS in a hurry for a project and I was out. I knew someone relatively close with some cheap stuff, while the cheap PLA ran okay, the ABS has been a nightmare.  Since then I've learned a lot and changed some parts out for better quality, more durable stuff. I haven't had a jam in months that I couldn't pin directly on myself or simple part failure.

So far I have yet to get more than a single layer from it but I've thrown away 15 feet of scrap. It jammed my new, and pretty much flawlessly operating head so bad that it may be ruined. It nearly broke my extruder, it did kill the bearing that was on the way out, and I'm starting to have doubts that this is even ABS at this point, because I have never seen ABS cook like that.

How the hell do people even use this stuff.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Tue, 17 September 2013, 23:30:52
with all due credit to MBI -- their ABS is high quality, meets tolerances, and processes well -- it's extremely hard to beat toybuilder labs. disclaimer: after discovering Joe/toybuilder was local, I tracked him down and we've become buds, but even so, his filament carries even higher dimensional tolerance than MBI's, and processes just as well. That said, there are definite differences in the ABS formulations. My general rule of thumb is that MBI abs has marginally higher tensile strength but lower yield and ultimate tensile strength, while toybuilder tends to be a carry higher yield strength but lower tensile, meaning it's a bit flexy but less brittle. Keep in mind that I've run mostly blue MBI ABS and mostly pink (yaaaa) TBL filament. This matters quite a bit, as the color additives have a very non-trivial effect on processing.

for dimensional tolerances, TBL filament is streets ahead. If you're having trouble with nozzle pressure, try out Joe's filament.

the only other vendor i've heard enough good things about to try out is ultimaker, but between toybuilder and MBI, i think i have access to every shade i could possibly need.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Wed, 18 September 2013, 20:40:53
I've been using Ultimaker,  with great results, I just needed some in a hurry and figured I would give it a second chance.

Also, color does effect the filament strength and temp required to melt and get good adhesion. It also varies if you are using a heated bed and if you are using a cooling fan or not. I have to be pretty precise on my cooling when doing ABS (particularly white), there is a fine line between a good print and getting no adhesion between layers.

I'll be ordering from Toybuilder soon.

MBI, no way in hell, they are insane on price.  Average price shipped to my door...
MBI $85
Ultimaker $55
Toybuilder $47
Generic $24

I can get generic next day, or local pickup (but it stinks for ABS and very limited colors, I may reserve it for when I need PLA in a  hurry). Ultimaker takes 2 days on average and decent colors. Not sure how fast Toybuilder would get here, probably 3 days, but they have a better selection and lower price.

What we need is someone like Newegg to start stocking good filament at a good price.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 18 September 2013, 22:17:14
crap, i had a post written out about this, and then i refreshed like an idiot. expect things to get more expensive, not cheaper. high quality filament is very difficult to make. economies of scale don't work; they actually work against you. it's not clear to me that FFM will end up as the dominant additive manufacturing technology. sintering is clearly the way forward at the high end, but at the low end, there are so many problems to solve and so few clean solutions. polymers are very complex things that thermoplastics are actually the trickiest polymers to work with because you have to make it wildly unstable, in the FFM case, TWICE while still maintaining chemical and material properties. not to mention you have to re-solve the discretized positioning problem with a tiny tiny budget. this is something that eats up people's lives still today, 40 years after it was first introduced; it's frankly still paleolithic.

but anyway, buy abs from joe, extrude and be happy for now. he's a great guy with a great product and selling it for price that are as low as this product will ever be.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 18 September 2013, 22:18:36
speaking of paleolithic, i'm very much completely useless today. what the hell is that mess up there. hah! bottom line, toybuilder gets all my business except for the exotic filaments right now. nylon!!!!!! yay

that said, i don't think MBI's pricing is all that bad, and their filament is good and they have a good color selection. if they have a color i want, i will buy from them in a second. also, the higher tensile strength may very well be coming with a higher glass transition or at least higher RTI. of course, no one is giving out datasheets (because they're not getting them from their suppliers very likely), but it's not hard to see some pretty big differences between output.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Thu, 19 September 2013, 17:04:04
that said, i don't think MBI's pricing is all that bad, and their filament is good and they have a good color selection.
$42 for a pound of extruded plastic? No.

It doesn't cost that much, sorry, no way in hell, not going to #$#%^#$ do it, that is Lego level pricing for extruded plastic. Almost all of it's coming from just a few suppliers in China.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 19 September 2013, 18:14:16
kg ma'am, not a pound.

plastic is a complicated beast. we think we know what it is because it's so malleable and easy to touch, but the more i learn, the more i realize how much of a miracle it is.

think about the etymology... metal is elemental. a single element, very difficult to work with, in fact NOT plastic except for the very rare and pure elemental metals. plastic should be named after its chemical composition, marginally or partially crystallized polymer chains packed tightly together. but instead we named it plastic because it was the first material we discovered that's malleable, that is plastic. we created it to make cool **** out of. it's malleable but strong. we can make it more or less malleable. we can make it more or less strong. it's up there with the wheel. so amazing!
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Thu, 19 September 2013, 18:22:00
kg ma'am, not a pound.

plastic is a complicated beast. we think we know what it is because it's so malleable and easy to touch, but the more i learn, the more i realize how much of a miracle it is.
I did per pound, I cut the price in half (1Kg= about 2.2 pounds)
You can buy virgin ABS pellets for $2-$7 per pound. Even at $10 per pound, $30 to extrude it is extremely expensive.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 19 September 2013, 19:17:49
You're welcome to process and extrude these ABS pellets you're finding on the spot market at those prices. I think you'll be surprised at what happens when you attempt to re-extrude the filament you produce (assuming you manage to produce usable filament at all :)) )

Context: I've had an extensive informal education at this point at the hands of several notable people. BLJ, who is frankly, a polymer genius, dcnewman, author of much of the sailfish and mbi mightyboard firmware which is used on not only the mbi mightyboard but ramps clones as well; he is, in addition to an excellent programmer, genius and gentleman, a degreed expert in polymer flow. Further, I regularly discuss injection molding with several friends who do polymer composites research as well as practitioners who own factories which do nothing but injection molding and extrusion. Finally, I have had some short discussions with spot market plastics dealers who have point blank told me that nothing is assured in the world of plastic unless you can trace the batch from point to point with nearly crytographic guarantees.

eta: i almost forgot to mention the honorable Mr. Chiu at TBL! great guy, converse regularly, has taught me much about doing business overseas, fulfillment, etc.

oh my god, and the fine folks at MBI! i've broken so many of their parts that everyone knows me by name at this point. i talk regularly about various aspects of machine performance; where things can be improved, what's going well and what's not, etc.

polymers!
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Thu, 19 September 2013, 19:21:05
You're welcome to process and extrude these ABS pellets you're finding on the spot market at those prices. I think you'll be surprised at what happens when you attempt to re-extrude the filament you produce (assuming you manage to produce usable filament at all :)) )
I'll find out soon, I know someone with a Lyeman extruder for this very purpose.

Will it work, I have no idea, but I refuse to pay $42 a pound for ABS plastic.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 19 September 2013, 19:26:05
i like your stinginess and gumption, but prepare for a fair amount of frustration :)
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Fri, 20 September 2013, 01:04:30
i like your stinginess and gumption, but prepare for a fair amount of frustration :)
I won't have to be first, I'll let the other guy figure it out first. LOL
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 20 September 2013, 09:56:40
YES! now you're learning! muahahahahahaha
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sat, 21 September 2013, 17:32:56
smallfry the rapid prototyping bot is back in business folks :)

(https://dl.dropboxusercontent.com/u/24794081/2013-09-21%2015.39.28.jpg)

HOORAY!!
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sun, 22 September 2013, 13:34:29
huge thanks to damorgue for cutting up dox's ergodox case for me. first test print!

Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sun, 22 September 2013, 13:36:00
and by that i mean the 10th test print, but the first to not completely fail ;)
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sun, 22 September 2013, 13:38:34
that said, i don't think MBI's pricing is all that bad, and their filament is good and they have a good color selection.
$42 for a pound of extruded plastic? No.

It doesn't cost that much, sorry, no way in hell, not going to #$#%^#$ do it, that is Lego level pricing for extruded plastic. Almost all of it's coming from just a few suppliers in China.

i can literally show you a dual extruded thing where the two colors have wildly different shrinkage, adhesion and every other mechanical property. ABS is not ABS is not ABS. there are as many formulations of ABS as there are particles in the universe (recall, this is the greek letter 'c'). they range from the truly ****, recycled-but-no-one-will-tell-you-that, to the direct from henkels or dupont or other certified master batch maker with extensive documentation on what it is made out of to measurement error to how it will behave when extruded (ONCE) within tolerances.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sun, 22 September 2013, 13:52:06
cool new autodesk tool for manipulating stls and step files directly: http://blog.123dapp.com/2013/09/introducing-autodesk-meshmixer-awesome-3d-remixes-at-your-fingertips

generates support WITHOUT slicing! hmm..
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Sun, 22 September 2013, 17:21:39
i can literally show you a dual extruded thing where the two colors have wildly different shrinkage, adhesion and every other mechanical property. ABS is not ABS is not ABS. there are as many formulations of ABS as there are particles in the universe (recall, this is the greek letter 'c'). they range from the truly ****, recycled-but-no-one-will-tell-you-that, to the direct from henkels or dupont or other certified master batch maker with extensive documentation on what it is made out of to measurement error to how it will behave when extruded (ONCE) within tolerances.
I'm still not paying MBI prices.


cool new autodesk tool for manipulating stls and step files directly: http://http://blog.123dapp.com/2013/09/introducing-autodesk-meshmixer-awesome-3d-remixes-at-your-fingertips

Great, now if they would fix 123Design... You know, the program meant for 3d printing, that can't import STL files. Who thought that was a good idea?   I'm not redoing everything I've designed from scratch just to use their program.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sun, 22 September 2013, 17:42:35
STLs are output files. meshmixer is a postprocessor like makerware or repg. you should not be working with solid meshes. you want splines to retain precision. sure, solidworks can import stls, but you literally are not allowed to manipulate them. same with rhino, even maya. no design package speaks voxel meshes. not even game programmers work with polygonal or voxel meshes at the design phase anymore. (in fact, gaming engines do dynamic rendering for LOD purposes but that's neither here nor there..)

you're free to pay any price you can find for filament, but be aware that a statement like "ABS costs X$ in y shape" is an inherently silly and wildly imprecise statement.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Sun, 22 September 2013, 18:06:36
STLs are output files. meshmixer is a postprocessor like makerware or repg. you should not be working with solid meshes. you want splines to retain precision. sure, solidworks can import stls, but you literally are not allowed to manipulate them. same with rhino, even maya. no design package speaks voxel meshes. not even game programmers work with polygonal or voxel meshes at the design phase anymore. (in fact, gaming engines do dynamic rendering for LOD purposes but that's neither here nor there..)

you're free to pay any price you can find for filament, but be aware that a statement like "ABS costs X$ in y shape" is an inherently silly and wildly imprecise statement.
STL's may be an output format, but it's standardized format that other 3d printer programs accept. It's a massive oversight in many peoples opinions.


As for ABS, we don't need aerospace quality.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sun, 22 September 2013, 20:37:59
anyone have a tiny ergodox? :D

(https://dl.dropboxusercontent.com/u/24794081/2013-09-22%2018.26.58.jpg)

abs is literally not used anywhere in aerospace. it's the easiest to fabricate, weakest reasonable plastic to work with basically. and the question, as you well know, isn't some fine tolerance issue, but whether your prints succeed or wildly fail. look at the above, for example. that's due to 2 things: 1) very tiny random striations in my x-motion rods due to my OEM bearings. 2) small amounts of degradation due to having to turn up the extrusion heat by _10C_ to get the jittery head to bond the working layer.

i also have a bent y idler pulley rod, but i think the jitter is largely due to the x-rods. the striations in the x-rod are small enough that i can't feel them, i can only hear them as the bearings slide across in certain situations. the last thing you want to add to that is tons of error somewhere in your polymer chains (ahahaha pun). it's freaking hard enough to FFM, why make it harder to save a few cents per gram.
Title: Re: The Living 3D Printing Thread
Post by: TheFlyingRaccoon on Tue, 24 September 2013, 18:22:29
Rowdy reminded my that I had drawn up a Cherry MX key awhile back. Figured I would print it and see how it worked. Only took 15 minutes to print!
(http://i.imgur.com/IlFN8WL.jpg)
(http://i.imgur.com/CBTb7XH.jpg)
Needs some light sanding but it came out great! I might engrave something with the CNC mill into it.
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Wed, 02 October 2013, 07:40:00
Put a neat object in my folder on your dropbox mkawa. Just something fun if you manage to figure out what it is :)
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 02 October 2013, 11:42:59
ooo, new models. still about a week out on the new rods i think.
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Wed, 02 October 2013, 15:19:33
Just some for fun parts. They have some interesting properties but no real function.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 02 October 2013, 18:49:10
yep, i see what look like two torture tests for an oscillating print head, and one material properties checking piece. good stuff.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Mon, 07 October 2013, 14:03:43
Leslieann,
What retrace feed rate do you use with your geared extruder?
I finally tried a geared extruder. But the retrace time did raise from about 0.05s to about 0.2s. This leads to significantly more visible puddles of plastic at the retrace locations. Slicer can hide them perfectly on the external perimeters but they are left visible on the single perimeter walls and the tops (slicer can do nothing about these) and perimeters of vertical holes (slicer can hide these but it does not - a slicer bug).

Do you still use 12V to power your steppers?
I cannot really turn the extruder stepper quickly enough to shorten the retrace time with 12V power.

The gear ratio is about 1/2.8 so I should not need so huge slowdown but it looks like it is needed to avoid skipping. But is not tuned well yet. I should be able to shorten the retract time to about 0.15s but I doubt it helps enough.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Mon, 07 October 2013, 16:24:37
Yes, I use 12v, not all boards really like 24v.

I put my retract as high as I can without the extruder motor skipping but yes, I still get some blobs here and there. Cura deals with it better, usually leaving them on corners where you can remove them easier (wire cutters and a nail file). Slic3r tends to put them right in the middle of a flat wall making it harder to smooth and hide. Another trick is try using a lower temp, the hotter your end, the bigger the blobs.

I'm using about 3:1, I thought maybe 4 would be better, but I'm considering making one with 2:1 and seeing if it does better on retraction. Power at 3:1 is more than enough, it's speed that's an issue, so 2:1 might do it. Unfortunately, no one makes an extruder with that ratio, so that means designing it and so far, I have not done well trying to design an extruder.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Mon, 07 October 2013, 17:39:42
The easiest and quickest is just swapping the gears in the extruder you use (Berry Tripper?).
The idea is something like this:
Code: [Select]
use <MCAD/involute_gears.scad>

gearAxeDist = 25;
tinyTeethCnt = 16;
bigTeethCnt = 32;
boreD = 5;
height = 8;
roughness = 0.1; //plastic surface roughness

gearPitch = (gearAxeDist-2*roughness)*360 / (tinyTeethCnt+bigTeethCnt);
echo("Gear Pitch [mm]: ", gearPitch/180*3.14159);

// tiny gear
translate([gearAxeDist+10,0,0])
gear(
  number_of_teeth = tinyTeethCnt,
  circular_pitch = gearPitch,
  gear_thickness = height,
  hub_thickness = height,
  bore_diameter = boreD,
  backslash = 2*roughness );

// big gear
gear(
  number_of_teeth = bigTeethCnt,
  circular_pitch = gearPitch,
  gear_thickness = height,
  hub_thickness = height,
  bore_diameter = boreD,
  backslash = 2*roughness );

As for as me, I do not know what I'll do. The stepper voltage to RAMPS can be increased up to 35V. With a bit of luck it may mean about 2.5 times the usable speed.
But I do not know whether it will not mean to replace the hotend resistor too and whether stepper current will  not need to be decreased to avoid pololu overheating and who knows what else. And moreover two power sources or a heatbed change too  :rolleyes:

My extruder (own design) kind of works. The code is parametric but has few hacks (and I bet a lot of bugs too (which will show up when different parameters are used)). It is not ready for release.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Tue, 08 October 2013, 21:57:39
The easiest and quickest is just swapping the gears in the extruder you use (Berry Tripper?).
The idea is something like this:
I actually use herringbone gears and found a generator for it, I just need to make them.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Wed, 09 October 2013, 05:21:49
I actually use herringbone gears and found a generator for it, I just need to make them.
Right, that is a normal gear with non-zero twist argument + add its other half using mirror transformation. But no need for that if you already have a generator  :)

I wanted to use them too, but at the end I realized my mounting makes sure that gears cannot move axially and standard gears are easier to work with.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Wed, 09 October 2013, 23:02:04
It's not the movement that's an issue, the herringbones run quieter.

Here is a generator.
http://www.thingiverse.com/thing:104165
Title: Re: The Living 3D Printing Thread
Post by: vvp on Thu, 10 October 2013, 04:28:41
It's not the movement that's an issue, the herringbones run quieter.
Ok, I did not know that. It is a good reason to use them.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Fri, 11 October 2013, 16:36:25
It's not the movement that's an issue, the herringbones run quieter.
Ok, I did not know that. It is a good reason to use them.
It's not just herringbone gears, it's why we use angular cut gears on everything we can.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 11 October 2013, 16:52:45
totally OT but i LOVE the whine of straight cut gears transferring huge amounts of power. rallycross cars are some of my favorite examples, because they push out HUGE amounts of torque with very very high shaft accel and decel. example:
feature=player_detailpage#t=81

hear that whine as the gearbox spins up? it's like music to me.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sun, 13 October 2013, 05:50:35
Well, straight gears on an extruder do not whine like that  :)
Why did they use stright gears?

I decided to try moving from 12V to 24V for stepper motors. I'll let you know the result. I guess it will be done in a month or so.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sun, 13 October 2013, 10:54:19
straight cut gears are more durable. more surface area per unit diameter
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Sun, 13 October 2013, 19:35:51
straight cut gears are more durable. more surface area per unit diameter
Actually, angular cut gears have more surface area and tend to run more smooth as they are always engaged, leaving them less prone to shock damage and giving them a smoother operation. In general, they tend to be considered stronger overall. The two main selling points on straight cut gears are that they're easier to produce, and they don't produce side loads. Another benefit is that when shaped properly, straight cut will have lower friction, however, this tends to equate to more noise, particularly as speed increases. Friction and ease of production is why race cars use them, while street cars use angular whenever possible for noise reasons.


As for the whine, straight cut are more prone to it however there is methods you can use to reduce it, such as dissimilar materials for each gear (I do this on herringbone), oil bath, tooth profile, pitch, speed and load. Given equal circumstances, straight cut will make more noise than angular. Speed is why most extruders are silent even with straight cut, the rotation speed is simply too low for much noise during normal printing, retraction and loading filament can still cause whine. Herringbone can also produce whine when run in reverse, or when misaligned. On my old nozzle, too much retraction caused my head to jam, so being able to hear the retraction was valuable at the time as I could tell when it was doing it too often and switch to another slicer, but was quiet the rest of the time. I kind of got used to it.



Personally, I just find them interesting,  I love mechanical stuff, and herringbone gears aren't something I've had any experience with so I wanted to try them, but I'll have to see how the latest ones turn out as they do have a dark side.  When misaligned, particularly in reverse, herringbones generate a massive side load. This side load can be enough to destroy small bearing races and extruders, I've destroyed two of each so far due to poorly printed gears. I had no idea the amount of side load they could produce.  The last gears and extruder I allowed for some float of the gears so they could keep themselves aligned properly and that seemed to solve it. I have better gears now.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sun, 13 October 2013, 22:24:02
woah, owned! hmmm.. let me think about this one a bit. i always thought that straight lines packed the most teeth into a cylinder.. (and by straight i mean an arc of 0deg, not like parallel to the cylinder straight, there could be some angle theta for which each ray is offset by theta, and an optimal theta for each cylindrical shape)

but my spatial reasoning is frankly ****. is there a really simple way for me to grock why arc cuts give you more surface area?
Title: Re: The Living 3D Printing Thread
Post by: vvp on Mon, 14 October 2013, 05:09:41
Based on this web http://www.roymech.co.uk/Useful_Tables/Drive/Gear_Efficiency.html
Efficiency of spur and helical gear is the same. But the site considers only gear losses. Axial force needs to be compensated for when helical gears are used. That compensation probably results in some loses.

I'll stay with straight cut gears. I like the fact I can put a gear on without moving gear axe away first.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Mon, 14 October 2013, 06:09:44
cptbadass's 3am musings agree with leslieann but couldn't remember why. something to stare at later.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Mon, 14 October 2013, 16:53:21
but my spatial reasoning is frankly ****. is there a really simple way for me to grock why arc cuts give you more surface area?
Very over-simplified answer...
The straightest distance between two points is a straight line, and a straight cut gear, is a straight line.



I'll stay with straight cut gears. I like the fact I can put a gear on without moving gear axe away first.
I'll probably go to them at some point, it would certainly make assembly easier.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Tue, 15 October 2013, 11:35:27
but my spatial reasoning is frankly ****. is there a really simple way for me to grock why arc cuts give you more surface area?
Very over-simplified answer...
The straightest distance between two points is a straight line, and a straight cut gear, is a straight line.



I'll stay with straight cut gears. I like the fact I can put a gear on without moving gear axe away first.
I'll probably go to them at some point, it would certainly make assembly easier.
yep, that was my immediate thought, but it's a packing problem, and straight lines are easier to pack, no?

Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Thu, 17 October 2013, 04:37:58
I believe it has more to do with the tooth profile necessary for straight cut to engage smoothly. You don't actually use the entire face.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Thu, 17 October 2013, 11:36:23
Well, at least based on what is in openscad MCAD library, there is no real difference between spur gears and helical gears. The profile is the same, it is just "twisted" in case of helical gears. Both kinds of gears engage only at a line. The difference is that for helical gears the line is not straight. I can see only 2 significant differences:
* helical gears generate axial force,
* helical gear engage at different phases of tooth touch point at the same time.

The second point actually can make a difference since involute gears transfer force without tooth sliding (rubbing each other) only at one point of the tooth engagement phase. That is when the teeth touch point is at the pitch circle. I would assume that at this point the power transition is the most optimal. Elsewhere the rubbing should waste some of the useful power. Although the moments (levers) of tooth engagement are the same in all the phases, the friction is changing. This can possibly introduce some variations in the power transition and therefore vibration and the "whine" of the spur gears.

The good think for helical gears is that same part of it is always at that optimal point (at the pitch circle).

Disclaimer: I'm not a mechanical engineer, I'm just "brainstorming" why involute helical gears may have something good to them.

But our geared extruders should be good enough with spur gears.

(http://upload.wikimedia.org/wikipedia/commons/c/c2/Involute_wheel.gif)
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 17 October 2013, 22:31:32
fantastic animation; thanks. i'm starting to see the intricacies. you really really have to model things as time variant in R^3, as the force vectors involved cannot be contained in any simple intuitive subspace. INTERESTING!
Title: Re: The Living 3D Printing Thread
Post by: vvp on Mon, 21 October 2013, 14:13:48
I did first test with 24V power source.
It allowed to increase maximum motor speed by about 60%.
Stepper driver pots did not need a change.
BANG_MAX/PID_MAX was reduced to 120 (still about two times the power so hotend heats up much quicker).
PID parameters need to be auto-tuned again.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sat, 09 November 2013, 10:07:01
OK, I like 24V 3dPrinter power source.

I made one by modifying regular PC power source so that it has floating ground and connected it to series with unmodified PC power source.

Anyway, I saw same schema of a PC power source and it looks like it should be easy to modify -12V rail so that it can handle high currents. Looks like only replacing two diodes, capacitor, stronger current leads and maybe using 3.3V coil in the final filter (if the original one has too small wire diameter, this would disable 3.3V output, but who cares). A floating ground modification would be needed too but that is trivial. After the change we could use -12V +12V rails for a 24V power source. It looks simple. Did anybody try it? Any experience?
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Fri, 15 November 2013, 17:59:07
You could probably get a 24v psu for cheap and smaller in size.
I need to look at what the Ramps board requires for higher voltage, it seems like a better way to go. However, if I do, I'll be buying a PSU, as what you're doing is a bit beyond my ability.


I strongly suspect my heated bed is the source of many of my problems.
Ramps is rated for 5amps max draw and the bed is rated for 10 amps, others get away with 16amps to power everything, my printer found 18amps to be underpowered, and actually destroyed a mosfet and a cheap Chinese 20amp PSU (all 3 had active cooling).



I have a question for you VVP
In a printer chat, someone claimed that the 3watt resister we use for hot ends actually draws closer to 40watts due to some "trick". When I asked how this worked, I got no response. Any ideas or is he just full of it like I suspect? And if he is correct, then what is the 40watt cartridge heaters actually pulling?
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sat, 16 November 2013, 08:55:03
Actually, I found one more power source scheme and that cannot have -12V rail strengthened easily as I proposed. So the idea is not that universal. I do not know which kind is more common. My guess would that the one which can have -12V strengthened. Anyway, it looks like one needs to check how his/hers particular PC power source is connected at the secondary side.

In general, off-the-shelf 24V power sources are easily available as 24V switching power sources for LED lights. They seem to top at about 350W which should be enough. I only consider adjusting PC power source since me (and probably almost everybody else) has some spare one from older PCs.

I use two small (SFX format) PC power supplies in series to get 24V. One of them is floating ground of course.

Most hotends use 3W wire wound resistor of 6.8Ω, axial leads, 13mm length, 5.6mm diameter. We mostly power it with 12V which gives us power of 12/6.8 ≅ 21W. Much more than the nominal 3W, but it does not really matter. The point is that resistor power rating is limited above all by how quickly it can get rid of heat. That is the reason the higher power resistors are bigger in size. Since our hotend resistors are surrounded by thermally conductive paste and inserted in a metal block they can get rid of heat much better than when they are simply soldered to a PCB. On a PCB it would have maximum 3W, in our hotend it can withstand 21W easily.
I actually power this 6.8Ω resistor with 24V which leads to maximum power of 24/6.8 ≅ 85W. And I did not have any problem with it yet. But notice this is the peak power. I use PID and limit the duty cycle to at most 120/255. That means that my maximum average power is about 86/255*120 = 40W. Which is just the power the guy mentioned. By the trick, he probably meant two things preventing baking our 3W resistors to ashes):
1) good heat transfer from resistor to hotend
2) limiting PID duty cycle if more than 12V power source is used.

Some people go from hotend resistor to heaters. This way they make sure that they really do not go over nominal values. I do not think it is needed. Wire wound resistor should be enough and they are cheap. Just make sure that heat is transferred well from the resistor to the hotend. Although I'm thinking about replacing the hotend resistor with a 15Ω one to limit peak currents and a chance they will induce something to thermistor wires. But I'm not in a hurry. The high currents I have there now do not seem to do any harm. So the replacement is just a quest for unnecessary perfection :) I'm not considering going for a heater.

The 40W cartridge heaters, if specified for 12V, should pull 40/12 ≅ 3.3A. They should have resistance about 3.8Ω. I do not think is it that great idea to use them, since they are more expensive. They will heat up your hotend sooner. I already achieved that by moving to 24 V, which gives me also higher speed on steppers (but I care only about extruder stepper speed).
Other advantage, I can think of, is that they are run on nominal values so they stay in warranty. I never heard of hotend resistor failure yet and it did not happen to me, so I think cartridge heaters are just vanity ... at least till I do not find some data confirming their usefulness :D Any wire wound resistor which just fits nicely in your hotend should be fine. If you care much find surge wire wound resistor (these can withstand short current peaks better) and look for the ones which are rated for the biggest temperature.

Edit: spelling.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Mon, 18 November 2013, 00:03:23
Thanks.
My understanding is people like the cartridge because it's easier to wire up and you can use a set screw to hold it in place against a mating surface without fear of destroying it. Also, it's been sold as producing more heat (higher wattage), but that appears to be fake.

Hmm, based on the math you provided, that means my heated bed is drawing just a bit more than the 10 amps claimed. The hot end wattage also means people using a 5amp power supply to power a Ramps board, Arduino, fans and hot end are actually very underpowered. That's one thing I dislike about open source, for all the good information, there is also lots of bad.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Mon, 18 November 2013, 05:16:42
I have RAMPS 1.3. It's wiki page claims 11A for heatbed (which is about right) and 5A for steppers and hotend (which is too small). Most motors (driven by the most common (green) pololus) can take about 1.3A without thermal shutdowns. So the minimum rating for motors and hotend should be 4*1.3 + 12/6.8 ≅ 7A. The fuse is somewhat low for this too (its holding current is 5A and tripping is 10A). If you are very unlucky you may have problems with fuse ... but you probably will not, the fuses are slow (like about 15s trip time at 25A).

Things change when you use e.g. 24V power supply instead of the common 12V. Steppers and hotend can handle it with a software change only (limiting hotend resistor duty cycle). But our 12V heatbed will not work reliably with 24V power supply. That would lead to about 22A of current and that is more than the fuse would safely allow without tripping (its tripping current is just at 22A), the MOSFET can handle it but would probably need a heat sink and the PCB traces and your wires would probably need strengthening too.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Mon, 18 November 2013, 20:41:20
I have RAMPS 1.3. It's wiki page claims 11A for heatbed (which is about right) and 5A for steppers and hotend (which is too small). Most motors (driven by the most common (green) pololus) can take about 1.3A without thermal shutdowns. So the minimum rating for motors and hotend should be 4*1.3 + 12/6.8 ≅ 7A.

That's about what I was thinking.
I'm going to step mine up to an 8 amp brick, that way I can also run a fan and lights.
Not sure what to do about the bed, I know the circuits are separate for the bed (Ramps 1.4), maybe it's possible to use a 24volt bed and leave the rest on 12volts. I don't really want a huge power supply attached, but I may do that but make it easily removed.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Tue, 19 November 2013, 05:46:26
... maybe it's possible to use a 24volt bed and leave the rest on 12volts.
Yes, it is. Though, you need a bed which will not pull more than 11A at 24V if you increase the voltage. If you have 12V only PCB heatbed then you need to switch it. I have seen a dual voltage (12V/24V) PCB heatbed. I think (not sure) it is still pulling about 10A at 24V option. If so then you would get a heatbed which heats up considerably faster. I personally do not care. When I heat it up I cover it with a piece of cloth and it is quick enough for me.
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Sun, 01 December 2013, 15:15:40
How is the quality nowadays on all you guys' machines? Any updates, are you all up and running?
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Mon, 02 December 2013, 00:04:12
Mine's fine, I just need to invest in better power. Most of my funds have been diverted to other things lately.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Mon, 02 December 2013, 01:21:48
i'm running and producing at about as high a rate as a rep2x is capable of. basically i print until i break something, i fix it, then when it comes back up again, i print until it breaks again and so on. basically, there are a lot of disposable parts in the replicator. it's a very clever design, and the disposable parts are remarkably good at light duty cycles. but i tend to push tooling limits, and _when_ the parts fail. they fail in very bizarre ways. i've had galling on "steel" rods with bronze bushings (chinese steel :|), huge amounts of warpage in the z-stage, and my current y-axis accuracy is well, pretty low. the only remaining original ABS parts in the machines are on their last legs and showing visible wear in the .5 to 1mm range in bizarre directions (vibration, i think). at this point i feel like i know the design well enough that i have a pretty good idea of what needs to be improved and what can stay consumable, but implementing major changes takes time

shrug

as far as machine capability, my biggest issue right now is just printing very small parts. temperature and movement control is just not advanced enough to get the kind of tolerances you need to print small parts --- the machine tolerances start running into the part size and then you end up with a whole bunch of failed builds.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Mon, 02 December 2013, 10:57:51
The Rostock here works fine. The print quality improved with every change to the original design:
1) Ball joints instead of the original universal joints. MP-Jet joints were used instead of Traxxas (no need to connect diagonal rods with springs). This helped the most.
2) Geared extruder, no problem with skipped steps, but it is still slow (the maximum print speed is about 5 cm/s), the hobbed bolt grinds the filament at higher speeds. This should be improved more.
3) Idlers were replaced. The original ones were based on 608 bearings. The new ones are from two MF148 (8x14x4 bearing with flange). Half turn of the belt was added (so that the belt touches the idler with the smooth side).

I also found I cannot print reliably thin and tall objects (e.g. 1 cm diameter, 20 cm height tube). After about 15 cm the printed object is bending and the surface is not perfect. At least that is what I think is happening. The material is ABS.
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Mon, 02 December 2013, 12:13:30
Feel free to test this (https://www.dropbox.com/s/i96ycw7twyfv3h7/Format%20and%20force%20test%201.stl) for me  :thumb:
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Mon, 02 December 2013, 17:38:26
you put that in the dropbox earlier right? i think i have it and have looked at it. i should have printed it before the extruder gearbox went out last week. i tried to revive it with replacement springs, but something else is wonky in the filament drivetrain. with MBI's design, you basically replace everything around a failed part when the part fails, and life is good, so i have new parts coming, but i think that one was too small (or was it?...) to print with my current limitations. basically, right now if i don't keep the filament moving very quickly, the drivetrain gets stuck. it's almost like the issue that the hot ends have with PLA (they're just too damned hot), but it's purely mechanical. the ABS is fine, and to clear the blockage you just push it on through and try your print again.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Tue, 03 December 2013, 11:14:06
It looks like a tough part to print using FDM. It will require a lot of support. Also that thin pillar few mm in diameter and long about 14mm would be a ***** to print. Especially when the printer does not have a fan and uses a bowden. It probably can be done with a lot of support and a different support material which can be dissolved away. Bowdenless printer would be better to get more precise material deposition especially on the small parts where blobs cannot be hidden inside the part.
I would try SLS or SL for this.
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Tue, 03 December 2013, 12:08:30
It is my intention to use SLA or SLS in the end, that is the reason for the thin pillar actually since they take advantage of anchors. I just wanted to test a few things with a cheaper method first, but I just figured out a way to accomplish the same test with a different model.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Tue, 03 December 2013, 14:19:36
aren't you trying to test the material? obviously an extrusion print isn't going to look anything like an SLS print from a material properties standpoint..
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Tue, 03 December 2013, 14:20:05
like those buttons i printed for you. you're going to get a lot less elasticity out of the sls version of those...
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Tue, 03 December 2013, 14:29:40
like those buttons i printed for you. you're going to get a lot less elasticity out of the sls version of those...

I have already printed those in other methods and they are fine :)

I am trying out a few solutions for the structure mostly. My intentions was to get rough estimates with FDM first though.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Tue, 03 December 2013, 15:05:10
good, but i wouldn't even bother printing in our materials to prep for sls. i mean just between two factories and runs of abs filament at the same print duty i can get two completely different bulk materials. heck, as you know, just between two colors from the same factory same run date, there can be a huge amount of difference, and that's just for abs.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Wed, 04 December 2013, 13:45:19
If you do not need all the free space inside the part then just design it solid (filled in) for an FDM test run. Sparse infill can be used so it is not a big deal whether the part has a big volume or not. As it is now, I would tell it is unprintable with a standard Rostock. Especially that thin pillar.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 04 December 2013, 14:49:55
shrug. i can print it with HIPs supposed. basically i'd print a solid HIPs block with your part in it.

hah!
Title: Re: The Living 3D Printing Thread
Post by: vvp on Wed, 04 December 2013, 17:20:31
Yes, that would work :)
It would be probably enough to surround the pillar with HIPs. I guess, it would not turn out very well anyway but at least it would be there. The rest could use also the standard support. It would be pain to remove it but it should be doable. But when using HIPs for the pillar then it can be used for all support.

Makerbot2 does not use bowden extruder so it should not have such a big problem with small parts which do not have enough internal volume to hide blobs in.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 04 December 2013, 18:21:03
the problem with long tall skinny parts, and really really small parts is collision. if a head collides with a printed bit of extrusion, bad stuff happens depending on how much support that part has w/rt stiction to the build plate (which is ultimately where all the forces into the part go while it's being printed).
Title: Re: The Living 3D Printing Thread
Post by: vvp on Thu, 05 December 2013, 03:19:14
Leslieann:
I just noticed that the 11A fuse for heatbed on my RAMPS 1.3 is rated for only 16V (the 5A fuse for steppers and hotend is rated 30V). Your RAMPS 1.4 is probably the same so if you would want to switch heatbed to a 24V version then you should change the fuse too.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Thu, 05 December 2013, 16:04:08
the problem with long tall skinny parts, and really really small parts is collision. if a head collides with a printed bit of extrusion, bad stuff happens depending on how much support that part has w/rt stiction to the build plate (which is ultimately where all the forces into the part go while it's being printed).
On tall thin stuff, I usually still a pad off to the side with a thin upright (1x or 2x nozzle diameter), this lends support and can be broken away relatively clean after printing compared to putting a pad and support on the thin wall.

Leslieann:
I just noticed that the 11A fuse for heatbed on my RAMPS 1.3 is rated for only 16V (the 5A fuse for steppers and hotend is rated 30V). Your RAMPS 1.4 is probably the same so if you would want to switch heatbed to a 24V version then you should change the fuse too.
Yeah, I have been reading up on it a bit more and saw that.
I need to get the new printers operational before I start messing with that, anyhow.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 05 December 2013, 16:19:57
with your bowden tubes.. have you guys tried using sacrificial walls and towers as a wiper mechanism?
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Thu, 05 December 2013, 17:43:07
with your bowden tubes.. have you guys tried using sacrificial walls and towers as a wiper mechanism?
I have my retraction down pretty well, to where I don't have a need really.

The thing with bowdens is you either need a lot of retraction or take out slop where you can. I run 10or13mm of retraction (I don't remember where it's set at the moment), and I place clips to take up slack in the pneumatic fittings, which can add more than 3mm of slop.

One issue I have seen though, is retraction needs to be fast, and anything much over 3:1 gear reduction and I can't retract fast enough. I have a prototype extruder I plan on trying that is 2:1 reduction to see if it gets better. I had an pg35l extruder motor but the 20:1 reduction was entirely too slow and I wasn't happy with it, or how hot it got. My 3:1 works well (it's from a 3mm extruder system), but 2:1 might be better for 1.75 systems.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 05 December 2013, 18:39:31
you don't have issues with creep out of the hot end at all with the bowdens? naturally we have gravity bringing a bit of extra melt down out of the nozzle and need to wipe every once in a while.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Fri, 06 December 2013, 02:56:48
you don't have issues with creep out of the hot end at all with the bowdens? naturally we have gravity bringing a bit of extra melt down out of the nozzle and need to wipe every once in a while.
It may be needed with dual extruder when one head is heated and does not print anything for a longer time. I did not try to use it but I think the wipe column is almost useless for single extruder rostock. Moreover it can be harmfull since it adds retracts which (if frequent) deforms filament and results in wrong extrusion amounts. The other point is that non-printing moves are quick and head is not pressurized during them. Hardly anything gets out of the nozzle because of gravity in such a short time (typically below 0.5s). The bigger problem is retract and retract reverse times. Depending how quick your extruder stepper is, these can take about 0.2s. But the important difference is that the nozzle pressure is rising/falling during these times. The filament is pushed to the hotend with forces around 20N (for speeds about 2.5 cm/s, 185C PLA). This value is about 2e5 times higher than the gravitational force for a bit of melted plastics in the nozzle. OK, 2e5 is the maximum at the time of retract start and retract reverse end only but still it is a huge number.

The consequence is that tiny blobs of material are deposited at the retract and retract reverse locations. Slicer can handle this easily if there is enough internal volume to hide them in. For very tiny parts there is not enough internal volume and it causes visible/measurable seem on e.g. thin walls. Thin pillars not only do not have the internal volume but also bent which is much worse problem actually. And if they are alone there is also problem with their cooling.

That is the reason I'm trying to get not only stronger extruder but also a very quick one. This also made me to go to 24V for the motors. It increased the usable extruder speed by about 60%. I actually expected speedup by 100% but it was not true. I do not know why I achieved only 60%   :confused:

Anyway, I believe the problem with tiny blobs during retract and retract reverse are mostly fixable with better slicers. The slicer should have some model to estimate how flow will change with the falling/raising pressure and move the head along the planned extrusion path acordingly. If the bowden friction is predictable enough (I hope it is) and the fluid dynamics in the hotend is predictable enough (I think it is) then this should be doable.

Edit: spelling.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 06 December 2013, 03:01:15
it's too hard to estimate flow changes. depends on material, actual hot end temperature etc. etc. etc.

that's the thing with steppers for extrusion. life would be much easier with simple dc motors..
Title: Re: The Living 3D Printing Thread
Post by: vvp on Fri, 06 December 2013, 03:11:40
I think it is hard to predict friction forces, maybe even impossible to predict them well enough for the prediction to be useful. But there is a chance the friction forces are small enough that errors here would not matter that much.
I think the situation in the nozzle itself should be predictable enough.  Reynolds number will be small. Heating and viscosity change related to it complicate it but my guess is this is doable.

Probably the most easy way would be to measure flow speed experimentally and just put the measured table in the slicer code. That is if we find the flow speed is repeatable enough for the same filament feeding speed changes.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 06 December 2013, 03:30:42
friction isn't the issue. filament pressure depends on density of your particular filament formulation and diameter of filament and a whole bunch of other things. for a given filament spool of high quality you should be able to experimentally determine these values, but it's a per-spool thing. the stepper error makes it even more complicated.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Fri, 06 December 2013, 04:52:27
You are probably right, if the filament does not get deformed in extruder to create waves in the bowden then the friction should not matter. And if it gets deformed the problem is in the extruder.

And the tables would depend on the filament. Maybe the dependence can be reduced to few parameters which would need to be calibrated for a given filament. But that means a lot of experimental measurements. Maybe trying a more theoretical approach (after experimentally verifying it works for one filament) is not that bad idea.

Regardless of all that, I'm not going to devote my time to this project. Thin structures are not that important to me :)
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Fri, 06 December 2013, 22:39:31
The consequence is that tiny blobs of material are deposited at the retract and retract reverse locations. Slicer can handle this easily if there is enough internal volume to hide them in. For very tiny parts there is not enough internal volume and it causes visible/measurable seem on e.g. thin walls. Thin pillars not only do not have the internal volume but also bent which is much worse problem actually. And if they are alone there is also problem with their cooling.

That is the reason I'm trying to get not only stronger extruder but also a very quick one. This also made me to go to 24V for the motors. It increased the usable extruder speed by about 60%. I actually expected speedup by 100% but it was not true. I do not know why I achieved only 60%   :confused:

Anyway, I believe the problem with tiny blobs during retract and retract reverse are mostly fixable with better slicers. The slicer should have some model to estimate how flow will change with the falling/raising pressure and move the head along the planned extrusion path acordingly. If the bowden friction is predictable enough (I hope it is) and the fluid dynamics in the hotend is predictable enough (I think it is) then this should be doable.

Better slicers help with blobs, but also faster retract speeds. I never had the problem until I went with a geared extruder. They were REALLY bad on my PG35L with 50:1 gear reduction. That's the reason for the 2:1 extruder I haven't gotten around to testing. People look at extruder power, but never speed, and in my experience, speed is just as important. 

As for your not understanding 24v motors not delivering double the power... Like every motor, they are optimized for a specific voltage and rpm. Any deviance can raise or lower rpm and power, but not at the same efficiency. I'm a bit surprised it's 60%, but not surprised you didn't get double.

Now you have me curious...
I was interested in 24volts for my bed mostly, but now, I'm wondering if maybe 24v on the motor side would allow me to go back to a direct drive extruder. The EZ Struder is a fantastic extruder, it juts lacks the power for any nozzle below .5mm.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sat, 07 December 2013, 08:00:40
Now you have me curious...
I was interested in 24volts for my bed mostly, but now, I'm wondering if maybe 24v on the motor side would allow me to go back to a direct drive extruder. The EZ Struder is a fantastic extruder, it juts lacks the power for any nozzle below .5mm.
Probably not. Depends on the speed you need for normal extrusion when printing. My guess is that your typical printing speed is 100 mm/s. With layer height of 0.3 mm and extrusion width of 0.6mm we get filament feed rate of (100*0.3*0.6) / (π*(1.75/2)) ≅ 7.5 mm/s. Typical filament driving pulleys have diameter 9 mm, and lets assume 200 steps per revolution, then we get stepping speed of 7.5/(π*9)*200 ≅ 53 steps per second. That is a too small number for driving voltage requirements. I have here a voltage/torque characteristics of a stepper (not a NEMA17). There is only about 3% difference between torques at 12V and 24V driving voltage up to the speed of about 70 steps per second.

Higher driving voltage does not help at low speeds because the motor torque depends on the magnetic field strength. Magnetic field depends on the coil current. And the coil current is limited/set by the stepper driver. This is for the static torque (zero stepping speed).

For raising stepping speed there is complication. Motor coils have inductance which limits the speed you can raise current in a coil for given driving voltage. The higher driving voltage the quicker you can raise the current. With higher stepping speed you may not be able to raise the current to the stepper driver limit quickly enough. Before you are able to raise the current it may even happen you actually already need to lover it because the next step is due. That means lower effective current with higher stepping speeds and hence also the lower torque.

Summary: Higher driving voltage allows you to achieve higher stepping speeds at the same output torque. If the driving voltage is higher than stepperMaxCurrent*stepperCoilResistance, then it does not increase the stepper static (holding) torque at all.

If you want to get a better idea about it, read the wiki page about RL circuit.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Mon, 09 December 2013, 16:27:13
It's not the low speed that's an issue, it's the high speed for retract that's the issue.

Interestingly, my Minebea (a division of Panasonic) steppers are actually much faster than the Kysan stepper, by almost double. If I push the Kysans extrusion speeds above 2200mm (per minute) the stepper goes wonky, meanwhile the Minebea can go up to about 4800mm per second. The Kysan however has about 1/3rd more torque. I'll have to see if it can spin the direct drive better and save the Minbea for the geared extruder.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Tue, 10 December 2013, 05:31:13
Higher voltage will give you significantly higher speeds for retract and retract reverse.
Higher voltage will increase your low speed (i.e. extrusion speed) torque only by an insignificant amount.

If your extruder skips steps while extruding filament (during normal printing speed without retracts) then higher voltage probably will not help. If your extruders skips steps during retract or retract reverse then higher voltage will probably help.

What exactly happens (what is considered high speed and what is considered low speed) depends on the resistance and inductance of the motor you are using. Quick and dirty estimate to get an idea. Whoever is expert on stepper motors feel free to fix errors and improve it.
For example one of my motors has resistance R = 2Ω and inductance L = 3.2mH. From this I get time constant of τ = L/R = 0.0032/2 = 1.6ms. Maximum current (without pololu current limiting) at U = 12V is 12V/2Ω = 6A. That is more than 3 times the maximum current the motor and the pololu can handle. So lets approximate the exponential (over which the current is rising) with a linear function I = k*t; where k = U/R/τ = U/L. The motor max current is about 1.5A. If we do not want to distort the square signal into a motor coil much (we want the low frequency idea) then the current raise time up to 1.5A should not be (lets say) more than 1/10 of the signal width. So for the signal width we get 10*t = 10*(I/k) = 10*(1.5/k) = 10*(1.5*L/U) = 10*1.5*0.0032/12 = 4ms. That is about 250 steps per second. Based on the previous post that means that I should expect only below 10% raise in torque for printing speeds below 100 mm/s (the signal distortion for this speed should be below 10%).
Btw. this also nicely explains why I got increase of only 60% in retract speed when I increased the voltage to 24V. There is probably still enough torque required during retracts that the linear approximation of the coil current rise does need to rise to maximum significantly before the coil current needs to be switched off again.

I wrote this ugly post mostly to brainstorm about it myself (the only 60% increase was bugging me). It is just a "on a napkin" computation which was done in a text editor instead. I posted it. Maybe somebody will fix the bugs in it :-)
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Tue, 10 December 2013, 19:41:37
When I say skipping steps, is it acts as though it's getting too many signals at once and doesn't know what to do.

By the way, I got the new printer built, I have to make one adjustment, an endstop screw is off 5mm, but still operates.
Current print area is 17in diameter x 18in high, which is more than enough for a TKL keyboard, a cheap ($20), minor change and I can easily do a full size.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Wed, 11 December 2013, 05:06:49
Cool. I'm thinking about building a wider (and shorter) delta printer. And stiffer. But I'm not in a hurry. Maybe in a year or so :)
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Sun, 15 December 2013, 16:37:44
I have spent the last two days trying to print a single part in ABS. What should take 20 minutes has kicked my butt for 2 days (of near constant printing!). After a ton of effort it occurred to me that I have never had this much problems printing ABS before, and that even smaller stuff was a problem. Turns out that Toybuilder's ABS has a rather high shrink rate. This was causing all sorts of cooling and curling issues. I tried hotter beds, cooler beds, higher hot end, lower hot end, more cooling. less cooling... If it looks halfway decent, the part would break apart when tapping it for threads. I like the Toybuilder ABS, it smells A LOT better when printing, and flows fine, but I can't print much with it under my current (and soon to be retired) setup.  Today, getting a fresh start I went back to the Ultimaker ABS and the first print was better than what I got from all of my attempts in the last two days.


I picked up some Toner Plastics PLA at Microcenter yesterday, I'll report how good that works. It looks like it's the same OEM as Ultimaker, and @ $40 before tax, and available (sort of) locally, this would be great for emergencies if nothing else, it's quite a drive but for a single roll, after tax and gas I save a buck compared to Ultimaker.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Sun, 15 December 2013, 16:48:06
Cool. I'm thinking about building a wider (and shorter) delta printer. And stiffer. But I'm not in a hurry. Maybe in a year or so :)

You have a Rostock right?
You could upgrade to something like what I am pretty easily and cheaply, about $200 to get an 18-20in build surface.
I designed it to use as many electronics and hardware from my Rostock as I could.

Other than the Wolfstock, nothing bigger than a Rostock has been documented, even then, none of them very well. Something I'm hoping to fix when I release mine into the wild.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Mon, 16 December 2013, 04:17:57
Interesting. Looks like filament can make a huge difference. I have it all from only re-seller (do not know the original producer) and it is doing fine so far.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Mon, 16 December 2013, 18:54:20
Toner Plastics is as far as I can tell, the same as Ultimachine (awsome!). I only tried the natural colored PLA, which I haven't used from Ultimaker, but it seems to work identical to the Ultimaker Black I have. I'll be using Toner Plastic black later tonight. Same spools, same tints, same temps...  It's cheaper, and while they have limited selection for colors, it's great to be able to buy locally.


And yes, filament does matter, more than I ever expected. 
We know there is only a few makers in China, and my experience has been that they each use a specific spool. I won't buy smooth sided spools again, I'm convinced the manufacturer has no QA of any form other than making sure it spools and gets loaded on a palette. One seller claims if it doesn't work for you, there's something wrong with your machine, lies, and that he uses it in his machines, more lies.  I know, because he asked me to do some prototype work for him. This was after he blew off my problems with his filament.

The ribbed spool like Ultimaker, Toner Plastics and Toybuilder/Prototype Supply, work great, barring the ABS shrink issues from the latter.
I don't think I have had a single jam with Ultimaker that I can blame on the filament. NONE. It was always an outside influence. So when someone tells me it's the machine that makes their filament jam my machine every 5 minutes, I have to take it with a grain of salt.

Nozzles matter, but in a much different way. When I had a .5 nozzle, I could run anything that fit through my Bowden. Now, no way. One thing I have also learned is that nozzle size is less crucial to good prints than I thought. A smaller nozzle allows tighter corners or thinner walls, but otherwise a smaller nozzle, just means more headaches and slower print times. Layer height will do more for quality than nozzle size. I've seen amazing stuff from .5's and junk from .35 all due to layer height. While I like .35 (I've had .5, .4 and .35), my next nozzles will probably be .4 again, as they seem quite a bit more forgiving without a large difference in size/quality. It seems like anything will block a .35 nozzle, while a .4 is just large enough to let things slip through. I also use a polishing pad from a Dremel as a filter. While I can't say it has stopped a jam for sure, I am pretty sure it has suspect it has, considering the junk it has pulled off the filament.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Mon, 16 December 2013, 22:13:39
ultimaker, toner plastics and toybuilder do not share a supplier.

there are far more than a few factories in china churning this stuff out right now. a whole bunch of molding factories are taking front-ends that were out of service, shoving a die on them and extruding crap. the commonality in the spool designs is because there are only so many pieces of spool tooling out there; i'd guess about 3 unique designs and maybe 4 copies of each design. further, even output from the same factory on different days can be wildly different, or output on the same day but with a different dye or master batch source; there are non-zero numbers of manufacturers who don't even buy from master batches but are extruding off the spot market, with little to no information source, chain of handling, or heat history.

bottom line: plastic is a very complicated beast. extruding plastic at home is even more so. with all things, my feeling on filament is to KISS. gravitate toward at most two suppliers for a single kind of material. taulman, obviously, for nylon is a no-brainer right now. toybuilder is a no-brainer for ABS and HIPs for me. I don't extrude PLA at all, but dcnewman is able to get some beautiful prints out of toybuilder PLA and a number of other people in the bot community swear by his PLA. i believe i've discussed the differences between his ABS and MBI ABS.
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Tue, 17 December 2013, 11:20:32
From what I hear there is less variance amonst the PLA than there is between the different ABS'es. PLA appears less sensitive to heat cycles, defects and changes in the supply chain or there just happens to be less shoddy manufacturers of it out there.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Tue, 17 December 2013, 21:02:19
abs is the most popular plastic for injection molding and there are about a zillion different formulations and suppliers. PLA is basically only used for biodegradable silverware and filament right now, so probably just batchmakers. that said, people also expect a lot less out of PLA in terms of material properties and stabilities. i mean, it's water soluble...

i was about to say that no one's printing guns with pla, but i have a guy who did just that. thankfully it broke before he could use it in any way.

eta: PLA is also way way easier to extrude and to mold because of its very very low shrinkage rate
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Tue, 17 December 2013, 22:20:23
COI full disclosure: i am now working in a consultant capacity for toybuilder labs.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Wed, 18 December 2013, 05:06:58
Interesting observation about belts:
https://groups.google.com/d/msg/arcol_hu/a_nj-AKpM4o/ecCT5wszkDQJ
https://groups.google.com/d/msg/arcol_hu/a_nj-AKpM4o/nNkTMAn826wJ
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Sun, 22 December 2013, 20:28:57
I started having problems with PLA warping as well and traced the problem to my heated bed's thermister. I'm getting MUCH better results from the TBL ABS now. TBL and TP may not be the same manufacturer as Ultimachine, but the plastic works the same (once I fixed the heated bed).

Yes, many companies over there can just slap on a die and produce filament, but how many actually are. This is still primarily a cottage industry.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Mon, 23 December 2013, 05:40:07
My first small enough and somewhat working extruder. Some parameters may need a bit more tweaking. It bents filament to an arc with radius of about 5 cm. This should not happen in ideal situation. The filament driving pulley needs to be cleaned after each slip. When filament slips the grit is packed between pulley teeth and that causes loss of traction. The pulley starts to grind the filament at about 8 cm/s (@ 230C, ABS). Maybe it is a filament problem too. May be the ABS is too soft or whatever. Otherwise I like it. Filament insertion is easy: just insert from the bottom and it will pull it itself properly. No need to fiddle with the idler clamp.
So the biggest problem is probably the filament drive pulley. To tell the truth it is not much better than my hobbed bolt version.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Wed, 25 December 2013, 02:01:21
Looks good.
Put a bit more clamping pressure or lower the amperage so the motor skips first. I think extruders are the biggest pain the neck on printers.


My monster is up and running, it's leveled to about .02mm across a 500mm (20inch) build surface. Still chasing bugs, but it's pretty neat. A bit quieter than then Rostock, however, it's shocking how much noise comes from the print head.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Fri, 27 December 2013, 05:20:03
Put a bit more clamping pressure or lower the amperage so the motor skips first. I think extruders are the biggest pain the neck on printers.
Good point. I should decrease the maximum stepper current. Skipping is better than filament grinding. The clamp is already as tight as it can be.
Or replace the filament driving pulley. Are you aware of anything with a big diameter (at least 15 mm) and bigger teeth spacing (so that the filament grit does not stick between teeth)?

The extruder is parametric (currently there are about 40 scalar parameters) so it is easy to use different filament diameters, driving pulleys, bolts, bearings, gear ratios etc. If anybody would like to try it, I can post it now. Otherwise I do it when it is more mature. Currently only two sets of parameters were really tested:

My monster is up and running, it's leveled to about .02mm across a 500mm (20inch) build surface. Still chasing bugs, but it's pretty neat. A bit quieter than then Rostock, however, it's shocking how much noise comes from the print head.
0.02 mm is very good. Did you use laser cut top and bottom plates?
What do you mean by noise from "print head"?
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Sun, 29 December 2013, 02:24:24
Good point. I should decrease the maximum stepper current. Skipping is better than filament grinding. The clamp is already as tight as it can be.
Or replace the filament driving pulley. Are you aware of anything with a big diameter (at least 15 mm) and bigger teeth spacing (so that the filament grit does not stick between teeth)?

Smaller pulleys are better for torque.
I like the Ultibots 1.75mm pulley, while most are made for 3mm and simply work on 1.75, Ultibots makes a pulley specifically for 1.75, and I've had better luck with it.

0.02 mm is very good. Did you use laser cut top and bottom plates?
What do you mean by noise from "print head"?
Depends on the print job and things, but on some printers you can hear the head rubbing ridges of the part you are printing. In my case, cheap pulleys were to blame, which I've since replaced. That significantly lowered the noise and made my layers much more uniform.

My new printer uses no wood or plates, it's a cross between a Kossel and Cerberus using aluminum channel.

Interestingly, I found my EZ-Struder extruder can handle .35 nozzle, with good filament and enough heat. However, the extra long wires on the large printer makes my thermister WAY, WAY off. By the time I see 175c at the nozzle with the infrared thermometer, Repetier is showing 250c. Only off a little, LOL.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Mon, 30 December 2013, 07:27:16
Smaller pulleys are better for torque.
My idea is to get bigger pulley so that there is more contact area with the filament. This should lead to grinding at higher forces. I can adjust torque easily by changing the gear ratio.

However, the extra long wires on the large printer makes my thermister WAY, WAY off. By the time I see 175c at the nozzle with the infrared thermometer, Repetier is showing 250c. Only off a little, LOL.
This does not sound right. If you use 100kΩ thermistor then resistance difference between 175C and 250C should be about 700Ω. Even long wires should have resistance of about 2Ω at most. That is too far from 700Ω. My guess is you have a bad connection somewhere (broken wire, bad solder joint) or you do not use 100kΩ thermistor, or something else is broken or improperly measured.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Mon, 30 December 2013, 14:00:14
IR thermometers measure total radiance emitted over a volumetric cone type thing and aren't useful for trying to measure point temps, but that's just one issue in that whole stack. there is also the thermistor. simple point thermistors are just not very accurate. RTD-style resistance thermometers are accurate, but expensive. for point measurement, you really should be using a thermocouple.

also, smaller pulleys are only better for torque at the pulley. however, you want to look at how the torque translates to force on the filament. to do so you need to utilize friction to apply downward force on the filament. friction depends on kinetic friction, since both the friction gear and the filament are moving relative to each other. hence, once has to consider the contact patch between the two objects. think tires and road
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Mon, 30 December 2013, 18:04:02
This does not sound right. If you use 100kΩ thermistor then resistance difference between 175C and 250C should be about 700Ω. Even long wires should have resistance of about 2Ω at most. That is too far from 700Ω. My guess is you have a bad connection somewhere (broken wire, bad solder joint) or you do not use 100kΩ thermistor, or something else is broken or improperly measured.

It wasn't right, I believe the Arduino was bad, though my reading is still way off. I'll have to test the wires and see what kind of resistance I'm getting.

IR thermometers measure total radiance emitted over a volumetric cone type thing and aren't useful for trying to measure point temps, but that's just one issue in that whole stack. there is also the thermistor. simple point thermistors are just not very accurate. RTD-style resistance thermometers are accurate, but expensive. for point measurement, you really should be using a thermocouple.

I'm not doing either just to expel plastic. If the plastic flows, it's good.
You are correct about the cone though, it's a hassle trying to focus it precise enough or close enough. Right or wrong, it allowed me to crank the temps without fear of a complete meltdown of the hot end.
Title: Re: The Living 3D Printing Thread
Post by: legodt on Mon, 06 January 2014, 12:50:34
Does anybody have a standard preferred STL for all keycap rows, mods, or standard spacebars?
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Mon, 06 January 2014, 18:09:33
I'd start with getting the tolerances right.

Depending on whether the operator chooses to print the parts with the roughness outside of the model, inside or with average height on the boundary, slightly different dimensions is required for ideal fitting between stem and cap. Because of this, different hardness of materials, different roughness of the gripping surfaces, printing orientation and such,  differences between machines and processes, it is a good idea to test the stem tolerances first.
(http://p3d.in/model_data/snapshot/hjjBG) (http://p3d.in/hjjBG)
Klick the image to view it or here to download an .stl (http://www.speedyshare.com/9zxU7/tolerance-test.stl)

The part above has stem fittings with the following dimensions, starting at the end with the extra chamfers:
0.95 x 1.15
1.00 x 1.20
1.05 x 1.25  <<< Measured stem size
1.10 x 1.30
1.15 x 1.35
1.20 x 1.40
1.25 x 1.45
1.30 x 1.50
(All dimensions in mm)

Edit: Below is an old image of a similar part I once made. It is just to give a better idea of what it might look like and how to use it:
(http://i.imgur.com/73pKJ.jpg)
Title: Re: The Living 3D Printing Thread
Post by: kmiller8 on Mon, 06 January 2014, 18:12:00
OHMYGOD I'M PRINTING ABS.

THIS IS SOME VOODOO WITCHCRAFT.

WILL REPORT WITH RESULTS LATER.

OMG IT CAME OUT LIKE ****, BUT IT WORKED

(http://i.imgur.com/d084w1Z.jpg)

(http://i.imgur.com/vBdHOCs.jpg)

ABS AND ME BESTEST FRIENDS.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Mon, 13 January 2014, 11:28:11
Does fan on print head help when printing ABS on a support?

The printed part is big enough so layer cooling as a whole is not a problem. There is no slowdown for a layer. But  the part of printed object which is being built on a support material looks terrible. Would fan help here? Does Cura (or some other slicer) even slow down and switch on a fan when printing the first layer on a support?

My point is that the first layer on support should use similar rules as when printing bridges. Other problem is that Cura does not built support well. It just does a sparse infill of a "support object". Which is wrong since a support is needed everywhere where the hotend changes direction while printing the first object layer on a support material. And also maybe something like each 8 mm under each straight line.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Mon, 13 January 2014, 21:47:51
A fan certainly helps definition, I get tighter turns.

However, with ABS, you can overdo it and cause delamination.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Tue, 14 January 2014, 04:05:26
Thanks Leslieann. I looked at Cura generated gcode and it does not look like it does anything special with fan for the first layers on support. I'm tempting to think I could achieve even more with an option to make the print speed for the first layer on support really slow. It should behave like bridges. But I do not see such an option in Cura, nor KISSlicer. Slic3r has a bridge speed option but I do not know whether it would be used for the first layer on a support material.

First layers on support do not look that bad when they are at least a bit sloped. Then only short pieces of extruded filament are on support. But if there is some area which is completely horizontal and resting on support then it is terrible. Cura tries to print it with normal printing speed (60 mm/s for me with 0.25 mm layers) and there is no chance the extruded filament staying continuous for the first (and often even the second (and sometimes the third)) layer on a support.

I'm almost tempted to fix Cura. Though I should try Slic3r and KISSlicer may be they are more intelligent even when options do not indicate so. No explicit options for the first layer on support.

I did only ABS, if I had used PLA I would have mounted some fan long time ago.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Tue, 14 January 2014, 04:09:24
kmiller8: Did you figure out why it did go wrong in the upper part?
Title: Re: The Living 3D Printing Thread
Post by: kmiller8 on Tue, 14 January 2014, 09:15:05
kmiller8: Did you figure out why it did go wrong in the upper part?

I'm thinking it's my retraction settings and ABS, I haven't tried messing with it since then however to confirm my suspicions.
Title: Re: The Living 3D Printing Thread
Post by: kmiller8 on Tue, 14 January 2014, 12:11:21
Upgraded my Z-rods (smooth)

(http://i.imgur.com/1trvJNg.jpg)
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Tue, 14 January 2014, 22:37:16
Thanks Leslieann. I looked at Cura generated gcode and it does not look like it does anything special with fan for the first layers on support. I'm tempting to think I could achieve even more with an option to make the print speed for the first layer on support really slow. It should behave like bridges. But I do not see such an option in Cura, nor KISSlicer. Slic3r has a bridge speed option but I do not know whether it would be used for the first layer on a support material.
The lack of fan tweaks and such is probably at least some of the reason Cura slices so fast.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Thu, 16 January 2014, 04:00:19
RFC about fan mounting.
Is it worth to add a fan duct to direct air more below the print head?
Or is fan without any air duct better?
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Sun, 19 January 2014, 03:48:04
RFC about fan mounting.
Is it worth to add a fan duct to direct air more below the print head?
Or is fan without any air duct better?
A duct shouldn't matter, the heater should be able to heat up plenty regardless.

Many deltas just stick a small fan blowing across everything and have no issues, this makes for a lighter moving assembly. I tend to go back and forth between effector mounted and just a loose fan, however I have yet to find a duct worth bothering with.
Title: Re: The Living 3D Printing Thread
Post by: Candyflip on Sun, 19 January 2014, 06:35:58
My friend printed Yoda the other day for me, the detail is amazing.  :p
I don't know a thing about 3D printing but I guess this belongs here.
[attachimg=1]
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sun, 19 January 2014, 10:57:41
Upgraded my Z-rods (smooth)

Show Image
(http://i.imgur.com/1trvJNg.jpg)

my god, where did you get the rod on the left from? that's a bit of a disaster right there

Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sun, 19 January 2014, 10:58:18
My friend printed Yoda the other day for me, the detail is amazing.  :p
I don't know a thing about 3D printing but I guess this belongs here.
(Attachment Link)
wow, that's fantastic. do you have any info on what printed that?

Title: Re: The Living 3D Printing Thread
Post by: vvp on Sun, 19 January 2014, 11:25:05
A duct shouldn't matter, the heater should be able to heat up plenty regardless.
Many deltas just stick a small fan blowing across everything and have no issues, this makes for a lighter moving assembly. I tend to go back and forth between effector mounted and just a loose fan, however I have yet to find a duct worth bothering with.
If I would had known I would not start designing some duct.
Now, I do not know whether I should finish it :D

This is the reason I'm trying to improve printing on support.
[attachimg=1]
Title: Re: The Living 3D Printing Thread
Post by: Candyflip on Sun, 19 January 2014, 11:54:53
My friend printed Yoda the other day for me, the detail is amazing.  :p
I don't know a thing about 3D printing but I guess this belongs here.
(Attachment Link)
wow, that's fantastic. do you have any info on what printed that?
My friend told me its a cheap Chinese copy of Makerbot Replicator, it is printed with ABS plastic with 0.01 mm layer.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sun, 19 January 2014, 19:31:48
My friend printed Yoda the other day for me, the detail is amazing.  :p
I don't know a thing about 3D printing but I guess this belongs here.
(Attachment Link)
wow, that's fantastic. do you have any info on what printed that?
My friend told me its a cheap Chinese copy of Makerbot Replicator, it is printed with ABS plastic with 0.01 mm layer.
yes, i've seen these. they're sold as 'flashforge' and they've managed to second-shift the makerbot/ssys tooling to the point where their machines actually say makerbot all over them :P. they actually cost quite a bit considering, and use very well-made mbi revD controllers (from thingiverse) and all the other open source parts that MBI put up before they closed much of their design (and wasted tons of engineering time on posting images of your print to facebook :facepalm:).
Title: Re: The Living 3D Printing Thread
Post by: Candyflip on Sun, 19 January 2014, 19:51:49
My friend printed Yoda the other day for me, the detail is amazing.  :p
I don't know a thing about 3D printing but I guess this belongs here.
(Attachment Link)
wow, that's fantastic. do you have any info on what printed that?
My friend told me its a cheap Chinese copy of Makerbot Replicator, it is printed with ABS plastic with 0.01 mm layer.
yes, i've seen these. they're sold as 'flashforge' and they've managed to second-shift the makerbot/ssys tooling to the point where their machines actually say makerbot all over them :P. they actually cost quite a bit considering, and use very well-made mbi revD controllers (from thingiverse) and all the other open source parts that MBI put up before they closed much of their design (and wasted tons of engineering time on posting images of your print to facebook :facepalm:).
I don't even know what a mbi revd controller is and none of this 3D printing stuff. Just wanted to share this little Yoda I got   :p
I think my friend is noob in this field too.  :))
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 23 January 2014, 13:27:20
fun stuff! i started getting the worst air prints yesterday after pulling one of the heads off of my carriage to reduce backlash. for some reason, the exact same models at the exact same temperatures as before the head removal just stopped printing. at most i'd get a little bit of plastic out and then it would jam.

thankfully i have accurate thermocouples and kapton tape and a thermometers up the wazoo.

it turned out (and this is the cool part) what was happening was that the head temp was tracking with the mightyboard's TC up until about 200C with deviation at most like 5-10C. then suddenly at 200C, the deviation grew to 30C and actually kept growing up to like 40C. sat down and thought about this, and remembered that line CTE on aluminum is very non-trivial; it's like 25um/m/C. my theory on what was happening was that at 200C, the "kind-of-cold-end" nozzle retainer block of the rep2x would actually expand enough to start transferring a ton of heat into the carriage and the stepper motor and the heatsink etc. etc. basically everything near it, and then suddenly you have like 10x as much thermal mass, so temperatures actually drop; there's like a massive knee in the graph where these things connect.

food for thought, and a good reason to start making things out of magnesium instead. hah!
Title: Re: The Living 3D Printing Thread
Post by: vvp on Fri, 31 January 2014, 13:25:54
My first attempt to print a fan duct/holder. The print could be actually usable if I would not make a mistake a make it by about a millimetre smaller :-D

Anyway, I wanted to ask about your experience with printing slopes. The bottom part has a small piece which is almost horizontal (slope angle almost 0) but it turned out much better than the upper part. The upper part has the minimum slope of 20. You can see a burned plastic in the picture of the upper part and irregular surface. Pictures of both top and bottom part were taken from an angle which shows the part the worst print quality. The parts were already cleaned up a bit.

There was a difference in the way the parts were printed.
The bottom part was printed as a solid without infill and bottom/top surface. The bottom part model did not have the "hole", i.e. it was not isomorphic with toroid. It was done so because FreeCad/OpenCascade does not support "thickness" action on more complicated shapes yet.  It was kind of like spiralize mode.
The top part was printed as solid with 20% infill and both bottom and top surfaces. Well the 20% infill almost does not make sense since the printed solid is almost always very thin to allow for any infill.
All the printing was done with 0.1 mm layer height; material was ABS. There was a static external fan blowing a bit at the part. The fan is needed. It was too near in the case of the top part print. That led to delamination (thanks Leslieann for pointing that out) which was repaired with acetone. Repaired clumsily; I spilled it over bigger area of the printed part ... which is why it is so shiny sometimes.

What is your smallest slope angle you can print reliably and at what layer height, material? Assume at least 2 cm wide slope. Any tips how to print small slopes well?
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sat, 01 February 2014, 00:33:53
it looks like you have some polymer degradation there (the discoloring). that might explain why the upper part came out so sickly looking. have you measured your nozzle temps? i think what's happening here is that the nozzle is closer to the bulk of the upper part because of the low slope (it's just circling round and round for however long) and your nozzle is 'burning' the pla.

i went to a 3d printing "world expo" today. it was very depressing. i'm going to think about this a bit before i start drawing, but i suspect i will be trying to design an open source x86-based filament extrusion printer with specs suitable for geekhack-level production of parts. large build area, brute force will be the word of the day. this may start with some work on the ggppll such that it comes into being first.

thought will be applied before money, but there is quite a bit of talent on the board that is not NDA'd, and a standard commodity platform removes many of the dumb restrictions and adds a huge number of kernel options as well as a much faster bus than any of the embedded platforms i know of. i see this as a relatively long term project, but one that runs in stages. the first stage will be to move to the x86 platform (but i very likely will be powering the same motors and actual motion hardware). the second stage will be to design a new frame, then a new motive geometry, and so on and so forth.

i saw literally every trick in the book in the printers on the floor and none of them were enough to make something durable, reliable and consistent. one simply has to recognize the problems involved -- motion control, power control, mechanical repeatability w/rt material choices and previous, and apply basic principled engineering.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sun, 02 February 2014, 09:14:55
Yes, the low slope parts have thermally degraded plastic and also rough surface. The temperature should be ok. It was ABS. Does PLA work better for low slopes? It probably should since it does not have such a problem with contraction while it cools down.

I think that the problem is mostly in the slicer (I used Cura). It tried to print the 1.5mm thick wall of the low slope area by printing first the external and internal perimeters and then zing-zagging between the perimeters doing 100% infill. (The infill was set to only 25% but the wall is thick 1.5mm which is less than 2 times the shell thickness. Under 20 slope it looked like 4.3 mm wide area of 100% infill.) That does not look like a good strategy for sloped walls because:
Slicer should detect these situations and instead lay filament on these parts by extruding it only in parallel with the perimeters and with sufficient time for previous thread to cool before laying down the next one. The idea is to prevent having the whole top surface of the sloped wall melted at once and hence minimize curving of the outer perimeter which is not supported well from below).

The more I get involved into 3dPrinting the more I think the printer themselves are quite good (well, at least the old Rostock). That cannot be said about the slicers. They suck. All of them.

Looks like you want to do a new controller board too. Isn't SmoothieBoard quick enough? If not then BeagleBoard with some shield should do. Also there should not be a need for a lot of computing power on the controller board. Since a big part of the current 3dPritners are open loop (all the stepper control is open loop (temperature control is closed loop)) then you do not need to do much in the printer itself. They only need to know when to increment/decrement a stepper. Everything else can be done by the slicer which can run in a comfortable and powerful PC. Then you have a compression problem how to move the data from a slicer to a printer efficiently. We use G-codes currently. But maybe it would be better to use NURBS curves, or some other compression scheme.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sun, 02 February 2014, 19:10:09
the controller will almost certainly be fpga pcie based with high bit-width single-ended buses to the motor drivers. that's about as tight a coupling you can get, and your processor has extremely high compatibility with any kernel you can think of and is about a million times faster than any embedded board. if you're not size constrained, don't go embedded; it makes no sense.

the driver bits are a little bit of black magic because of the need for tight coupling and high power on any reasonable motor (i'm talking nema 24-26 here, with servos and brushless DC instead of steppers wherever possible). i've talked to a lot of people who like the gecko drivers, but there are a _ton_ of driver vendors out there because they are mostly analog current and/or voltage regulators, and there are as many recipes as there are particles in the universe. also, the big guys tend to farm out their driver boards because you need an analog design wizard to get a really good board that will hit your machine specs.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sun, 02 February 2014, 19:11:51
re: that part of yours vvp, it looks thin enough that you should able to tell cura to shell it with a high number of layers (like 4-5) with 0% infill.. that may keep it rotating quickly enough to not burn anything up. this may also point to an issue with your head thermocouples..

i will say that i've had issues like this with the makerbot slicer and i usually hack up some workaround like a sacrificial tower or something. the algorithms are pretty broken, but i will say that they're no more broken than any other gcode compiler i've seen.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Mon, 03 February 2014, 04:25:46
Good point! Slic3r can have shell count specified and that may be enough (or I can add support there).

Yes, if the idea is to go fully closed loop then computing power will be needed on the printer. It will give a lot of space for improvement and allow better modelling of the mechanical properties of the printer.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Mon, 03 February 2014, 11:28:03
yep yep. and decoupling the driving hardware from the control hardware will allow the use of serious motors given precise and noise-free power signals. i've talked to enough people who are using recipes like this and getting incredible results that i just think it's the way to go at this point for a serious printer.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sun, 09 February 2014, 08:56:08
The idea with multiple perimeters in slic3r did not work. It still printed it too quickly so it did not have enough time to cool. Increasing air flow did help a bit. The part is not very nice but it is usable.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sun, 09 February 2014, 13:11:45
this one looks a ton better.

can you not lower your nozzle temps at all? also, this is a little counterintuitive, but try making the walls thicker. more plastic to sink the heat and the head's going to run a little cooler since it's pushing more plastic through.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sun, 09 February 2014, 19:33:51
It is definitely better. Moreover picture of this one was not taken after "shaving" off the worst irregularities (contrary to the previous one). Everything the same as the old print. The only difference is higher air flow when the 20 slopes were printed and smaller air flow during everything else. I believe thicker walls would help but only a bit. The leading edge on the low slope will still have weak support. The trailing edge should look much better. But this one is usable as it is. So I leave it out as it is till I do not need to redo it because of something else.

Low slope areas need a lot of cooling otherwise they bend (since the support from bottom is weak), stick to the head more and burn. On the other side well supported areas can delaminate if they are cooled a lot. Varying cooling is not good though. It is visible on the walls which are vertical.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sun, 09 February 2014, 22:48:53
yah, you can see the shrinkage patterns.

had i been printing this, i very likely would have printed it in two pieces. the bottom section built straight up as kind of a cardioid originating on the plate and then the elliptical bit from the flat bit up. brush a bit of acetone on the sections and press together and abs will join quite cleanly with an adequately strong bond for most purposes; flanges would make it easier to join as well.

if i am trying to print hard edges i usually fillet or chamfer them pretty gently now. ironically, when the printer first showed up i thought that arcs would be the most difficult bit of printing. naively, i had completely discounted inertia. now i'm deathly afraid of edges, since ringing can completely destroy a print, and neither the bot or the slicer deal with it very well.

i feel like one of two things is going to happen as the hobbyist machines progress. either we'll have to start programming our gcode by hand like all the big boys do, or we're going to have to get a lot smarter about gauge checks and JIT with parallel simulation. one of the reasons the silly expo was so depressing was that everyone is trying to build a cheaper and/or flashier printer. fail. the hobbyist folks have yet to produce a printer that actually, dependably, works. that is the problem that needs to be attacked..
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Sun, 09 February 2014, 23:45:56
i feel like one of two things is going to happen as the hobbyist machines progress. either we'll have to start programming our gcode by hand like all the big boys do, or we're going to have to get a lot smarter about gauge checks and JIT with parallel simulation. one of the reasons the silly expo was so depressing was that everyone is trying to build a cheaper and/or flashier printer. fail. the hobbyist folks have yet to produce a printer that actually, dependably, works. that is the problem that needs to be attacked..
You've eclipsed what I would consider hobbyist at that point.
Even where we are now is stretching it for many hobbyists.

As for the race to the bottom... You may see it as a race to the bottom, but until we break the $200-$400 mark, with something reliable, and easy to use, regardless of quality (so long as it's similar to what we have), 3d printers are not going to invade the average geek's home, much less the average home. Companies are throwing a bunch of things at the wall hoping it sticks, looking for that golden ticket.  They know a lot of it's junk, but it funds their next attempt.

I think you just have unrealistic expectations for the technology as it stands. I do agree that the gcode the slicers generate could be better, but by hand, really? Many printers are hard enough to operate without having to hand code everything.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Mon, 10 February 2014, 04:59:39
mkava: The part is already in two pieces. The one shown lately is the top part only. But I could divide the top part to the duct section and fan holder section as you proposed for even better result. Good point. I believe this would help much more than thicker walls.

I have very good experience with connecting ABS parts with acetone too.

I also can confirm that part designer should try to avoid sharp corners. Especially then they should happen in the section of part which has low slopes. Sharp corners in the low slope area are unprintable with current slicers. Well if you re not willing to do everything very very slowly. I guess it could be printed if the corner itself is printed really very slowly.
I attached a picture of the failed bottom part of the duct which did have a sharp corner in the low slope area. Notice that the corner is collapsed. You can see the same part redesigned without the sharp corners in my old posts. After filleting the corners it turned out pretty well.

I think to get better results mathematical model of the FDM printer should be part of the slicers (for open loop) or the firmware (for closed loop). It is not like it is a new physics. It is just not a simple physics.

Btw I was asking somewhere in far history about belt young modulus. Here are some approximate data:
That indicates that for machines with long belts (e.g. deltas) the belt stretching can be significant part of corner errors at high printing speeds. Depends on the stepper motor rotor inertia in comparison to the inertia of the rest of the printer moving parts.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Mon, 10 February 2014, 08:51:30
mkava: The part is already in two pieces. The one shown lately is the top part only. But I could divide the top part to the duct section and fan holder section as you proposed for even better result. Good point. I believe this would help much more than thicker walls.

I have very good experience with connecting ABS parts with acetone too.

I also can confirm that part designer should try to avoid sharp corners. Especially then they should happen in the section of part which has low slopes. Sharp corners in the low slope area are unprintable with current slicers. Well if you re not willing to do everything very very slowly. I guess it could be printed if the corner itself is printed really very slowly.
I attached a picture of the failed bottom part of the duct which did have a sharp corner in the low slope area. Notice that the corner is collapsed. You can see the same part redesigned without the sharp corners in my old posts. After filleting the corners it turned out pretty well.

I think to get better results mathematical model of the FDM printer should be part of the slicers (for open loop) or the firmware (for closed loop). It is not like it is a new physics. It is just not a simple physics.

Btw I was asking somewhere in far history about belt young modulus. Here are some approximate data:
  • 6mm wide T2.5 belt with steel core - will stretch about 0.02 mm per 1m of length per 1N of force (from a rough measurement of a belt user)
  • 6mm wide GT2 belt with glass core - will stretch about 0.06 mm per 1m of length per 1N of force (from a provider data sheet http://www.bbman.com/assets/files/pdf-library/Engineering/Timing%20Belts/BeltTensileProperties.pdf ); notice the data sheet has incorrectly specified unit for their belt modulus; they specified it as lb/in but it should be only lb
That indicates that for machines with long belts (e.g. deltas) the belt stretching can be significant part of corner errors at high printing speeds. Depends on the stepper motor rotor inertia in comparison to the inertia of the rest of the printer moving parts.
yep, a huge part. and it gets worse when, like the makerbots, your idler pulleys can move.

re: leslieann

3d printing is just motion control with a filament extruder. motion control is a mature problem and the practical solution that people have come up with over the last 30 years is hand programming. sad but true. i personally think that's garbage and that all motion control can be done better faster etc. with smarter compilers; like vvp is saying, the physical parameters of the printer need to be given to the runtime and/or compiler. further, i would insist that a _lot_ more open loop feedback needs to happen.

as far as whether this technology can is beyond the scope of hobbyists, i really don't think so. hobbyist affinity really depends on whether technology is packaged up and black-boxable. it is less about total complexity and more about exposed complexity

that's my 0.02USD anyway.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Thu, 13 February 2014, 03:02:11
That indicates that for machines with long belts (e.g. deltas) the belt stretching can be significant part of corner errors at high printing speeds. Depends on the stepper motor rotor inertia in comparison to the inertia of the rest of the printer moving parts.
I see this on my large printer, I can't run the belts as tight, and with their length (2 meters each), and those long diagonals, it really can create issues. I have to dial down travel speeds, acceleration and deceleration quite a bit to keep it from causing problems, about 1/2 to 2/3rds the Rostock with it's 1.4m belts.

[re: leslieann

3d printing is just motion control with a filament extruder. motion control is a mature problem and the practical solution that people have come up with over the last 30 years is hand programming. sad but true. i personally think that's garbage and that all motion control can be done better faster etc. with smarter compilers; like vvp is saying, the physical parameters of the printer need to be given to the runtime and/or compiler. further, i would insist that a _lot_ more open loop feedback needs to happen.

as far as whether this technology can is beyond the scope of hobbyists, i really don't think so. hobbyist affinity really depends on whether technology is packaged up and black-boxable. it is less about total complexity and more about exposed complexity

that's my 0.02USD anyway.
I'm not saying the problem can't be solved, just not for the money most people are willing to spend on a printer. Particularly one with limited material.

These companies are focused on mass market appeal to regular consumers, which frankly, I think it's a stupid idea.  You can market these to geeks, tinkerers and makers, but to try pushing them into the average home is a complete joke.
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Thu, 13 February 2014, 08:26:59
Regarding the belts: I think the Z axis accuracy is far more important when it comes to reliability and failed builds. X and Y will cause less exact parts, but inaccuracy in Z will cause delamination, pressing the head into the part and general failures to a larger degree imo. This is why I suggest that FDM printers should strive for a large build surface but limited Z axis. This of course also means that the rods have to be able to withstand the weight and not drop too much over its length but strengthening them is fairly easy.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Fri, 14 February 2014, 04:41:15
I see this on my large printer, I can't run the belts as tight, and with their length (2 meters each), and those long diagonals, it really can create issues. I have to dial down travel speeds, acceleration and deceleration quite a bit to keep it from causing problems, about 1/2 to 2/3rds the Rostock with it's 1.4m belts.
Is it using GT2 belts you mentioned in the past? Do they have glass fibre core?

It looks like most GT2 belts sold use glass fibre core and most T2.5 belts use steel core.

GT2 belt producer claims GT2 should has more precise belt-pulley meshing compared to T2.5. And also GT2 (with glass core) should last longer too. I can agree with them about these too. They recommend it for precise positioning. That maybe be OK but only for short belts (if we are talking bout GT2 with glass core).

Glass core GT2 is not so good for deltas. From this point of view the reprap wiki page on belts is rather misleading by pushing GT2 heavily without even mentioning the problem of low modulus of glass core GT2.

Wolfram alpha claims these young's modulus values:
glass - 69GPa
kevlar - from 70 to 179 GPa (depends on type)
steel - 205 GPa

Looks like steel core is the way to go, maybe kevlar if the belts use the best one (DuPont Kevlar 149).
It would also help to use wider belts than the common 6 mm width.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Fri, 14 February 2014, 19:26:43
Regarding the belts: I think the Z axis accuracy is far more important when it comes to reliability and failed builds. X and Y will cause less exact parts, but inaccuracy in Z will cause delamination, pressing the head into the part and general failures to a larger degree imo. This is why I suggest that FDM printers should strive for a large build surface but limited Z axis. This of course also means that the rods have to be able to withstand the weight and not drop too much over its length but strengthening them is fairly easy.

Unfortunately, a large build surface on a Delta means a taller printer as well.

The problem is also exaggerated on a Delta because everything is tied together, with lose belts, or too much stretch, the head can dip or snag a lifted edge and throw off the entire print. On big high speed Deltas, it can be a razors edge between too tight and not tight enough and the only way to soften edge is to slow the printer down.

Is it using GT2 belts you mentioned in the past? Do they have glass fibre core?

It looks like most GT2 belts sold use glass fibre core and most T2.5 belts use steel core.

GT2 belt producer claims GT2 should has more precise belt-pulley meshing compared to T2.5. And also GT2 (with glass core) should last longer too. I can agree with them about these too. They recommend it for precise positioning. That maybe be OK but only for short belts (if we are talking bout GT2 with glass core).

Glass core GT2 is not so good for deltas. From this point of view the reprap wiki page on belts is rather misleading by pushing GT2 heavily without even mentioning the problem of low modulus of glass core GT2.

Wolfram alpha claims these young's modulus values:
glass - 69GPa
kevlar - from 70 to 179 GPa (depends on type)
steel - 205 GPa

Looks like steel core is the way to go, maybe kevlar if the belts use the best one (DuPont Kevlar 149).
It would also help to use wider belts than the common 6 mm width.

Yes, I'm using glass core GT2, cheap ones at that.

Steel core, or even better, Kevlar due to moving mass, would be nice, but going to a larger belt tooth may not be a good option either, as pulley selection and precision isn't as good. Wider would be an option, except that once again, pulley selection is a problem.

I may see about finding Kevlar GT2, that would be my preferred belt I think, otherwise, I'm going to try and track down some long Gates made GT2.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sun, 02 March 2014, 10:27:22
I did first 3 prints with a fan mounted on the platform:

This is all about ABS only. I did  not even try PLA yet.

So it looks like it was a good idea to mount the fan on. Even for ABS only.
Title: Re: The Living 3D Printing Thread
Post by: Insanto on Sun, 02 March 2014, 18:08:57
Hey, do you still need modelers for this stuff? I don't have any experience with 3D printing but 7+ years xp with hardsurface modeling so that should suffice with a little added intel on the constraints and whatnot. DO let me know.

[Edit]
Just for the hell of it i made a little KeyCap, unfortunately i didn't have any proper measurements so i winged it..
Details:
  KeyType: 
    Row #4 1x1

Measurements:
  w=18mm
  l=18mm
  h=11.4mm | 10.8mm

Stem:
  Cherry MX
  w=1.35mm
  l=1.15mm
  h=3.6mm

Wall thickness:
  1.4mm

Stem-wall thickness:
  1.0mm (should hold, even when self-printed; would however suggest additional struts to reInforce the marriage point)

Media:
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Mon, 03 March 2014, 10:10:48
nice! that should print nicely with solid HIPs support. i'm still too angry at my printer to bring it up :P

regardless, more cad drawings and drafters are always welcome here!!

in fact, the big thing i need right now is pieces of 3d printers  :cool: skunkworks!
Title: Re: The Living 3D Printing Thread
Post by: Insanto on Mon, 03 March 2014, 10:22:51
why would you be angry at your printer, and what'r HIPs?
i'm only at page 7 of this thread so far so not up to speed yet.

are these by chance printable pieces?
if you got some imagery and measurements.. ;)

btw what formats can you read / do you prefer your 3d dataSets in? what's the maximum floatingPoint precision you can handle?

btw i know that my design is flawed since the stem-wall is too thick to sink into the mx switch but i don't have anything to accurately measure, nor have i found all the data i'd need.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Mon, 03 March 2014, 10:37:17
HIPs is a support material that dissolves in pine-sol (d-limonene). you can actually print a solid block that consists of the HIPs material completely encapsulating an ABS part (for support of the abs part) and then dissolve the HIPs material completely so that very complex shapes can be made in the ABS without having to worry about "printing on air"; without support material, one has to set up prints very carefully so that every line of extruded abs has abs below it to support it mechanically.

STL files are the lowest common denominator for printing, but solidworks files or IGES/STEP files are quite welcome.

technically, none of our printers actually have floating point units :P, but the slicers/gcode compilers can take as much floating point precision as you can provide when making the integer gcode instructions.
Title: Re: The Living 3D Printing Thread
Post by: Insanto on Mon, 03 March 2014, 11:08:15
aah that stuff, good to know.. if you were to print using HIPs, would that have to be included in the 3d model as-well or could your compiler take care of that?

i know that the printers don't, i did mean your software :P

i revised the design somewhat and now it should actually work, in case anybody wants to give it a go, here's the file:
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Mon, 03 March 2014, 11:11:30
i've yet to play with the newer support renderer in makerware, but i think one can just make a solid block in solidworks and intersect it with the keycap model. the standard support functionality in the slicer tries to minimize the amount of support struts that are used, which provides less accuracy than just laying down a solid block.

this is something i have to play with to get you a solid answer though, for sure. i have some models in the backlog. once the printer is going again, i will have much more to say about supports and slicing. i've been trying to work out a long-term plan for printing and then production at medium scale based on the printed rapid prototypes, and things are still very much in limbo.
Title: Re: The Living 3D Printing Thread
Post by: Insanto on Mon, 03 March 2014, 11:49:33
ahh yeah i can make that (a support block) happen easily, only thing i'm a bit fuzzy about is the export and mesh separation, for these uses
solidworks can read fbx, dae, 3ds, obj file formats, yes?

should you need assistance with the digital pipeline/worflows i could try to assist in finding a way out of limbo

i'm not THAT altruistic, just bored :D
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Mon, 03 March 2014, 11:51:47
the trick with the support block is that you need two separate objects so that the slicer knows what to print in HIPs and what to print in ABS. otherwise that support block looks quite excellent.

also, boredom is just creativity waiting to happen!!
Title: Re: The Living 3D Printing Thread
Post by: Insanto on Mon, 03 March 2014, 12:10:52
so seperating them into 2 stl files (one for the support, one for the object) is fine?
Title: Re: The Living 3D Printing Thread
Post by: vvp on Mon, 03 March 2014, 12:18:56
As for as what is printable on dirt cheap single extruder reprap FDM printers. Mkawa's printer is dual extruder so this does not apply to it. Rotate, position or split your parts so that whatever you do is well printable. It is easy to glue a part together from more pieces.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Mon, 03 March 2014, 12:22:08
I'm curious whether that keycap stem will be strong enough to be useful. FDM printed parts more easily break (delaminate) across layer boundaries. Makwa, let us know if you try to print it.
Title: Re: The Living 3D Printing Thread
Post by: Insanto on Mon, 03 March 2014, 12:47:43
yes the strength using single material printing would be a problem, with a support material one can rotate it 90 and increase it that way.

thx for the info vvp,
based on it i modified and reOriented the cap a little to make it printable with your printer aswell.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Mon, 03 March 2014, 13:06:35
if it's packed at 100mic layers, it will be significantly stronger than a rough print, but you do kind of have to choose between shear and tensile strength along dimensions with FDM parts. ideally, you would print a clean positive and then mold the individual caps as most of the capmakers on the board have been doing.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Fri, 14 March 2014, 05:47:32
This is something Leslieann knows well. Thanks for the warning.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sat, 22 March 2014, 20:30:27
Regarding the belts: I think the Z axis accuracy is far more important when it comes to reliability and failed builds. X and Y will cause less exact parts, but inaccuracy in Z will cause delamination, pressing the head into the part and general failures to a larger degree imo. This is why I suggest that FDM printers should strive for a large build surface but limited Z axis. This of course also means that the rods have to be able to withstand the weight and not drop too much over its length but strengthening them is fairly easy.
yes, a huge number of the printer designs i've seen just use rods that are too small everywhere. this includes the makerbot. and then they don't spec them to high straightness tolerance or high strength material. and then rod diameter is generally difficult to change without redesigning everything, so i've had to go to exotic materials for pretty much everything in the bot. everything is either 440 or case hardened steel at this point, with straightness to < 1 mil and surface hardness at C65 or better. further, bearings obviously play a huge part in error components along the linear actuation, so i've had to go exotic on those too. everything is either extremely high precision (mostly misumi) ball bearing or rulon lined sleeves when there is more surface area and less duty cycle.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Mon, 24 March 2014, 13:38:14
a huge number of the printer designs i've seen just use rods that are too small everywhere. this includes the makerbot.
And the original Rostock. It uses Φ 8 mm rods and linear bearings. I'm surprised Johann did not go for Φ 12 mm rods. Based on a local supplier here the rods would be 35% more expensive and linear bearings would be 10% more expensive. Rod error specified as at most +0μm -8μm. Bearings specified as at most +8μm -0μm. It is the same for both 8 and 12 mm versions. 12 mm versions look worth it. Especially when some people put linear guides on their Kossels which are much more expensive than rods and linear bearings.

Still, I did not compute the dynamic forces. But I can do high bound estimation quickly for the Rostock here: 0.25 kg * 4 m/s = 1 N. Seems enough to bent 0.8m long Φ 8mm rod a bit. My rough experiment with a scale indicates about 0.25 mm displacement. Not good. Looks like this may be a problem.

Edit: I computed how much the rod should bend with some simplifications which should make the result worse than in reality (simple Euler-Bernoulli bending considering two half rods instead of one rod loaded in the middle). I got the result of about 0.4 0.2 mm. That is in congruence with my experimental result - the measurement "by eye" (about 0.25 mm). Since we would like better precision than 0.1 mm, then this really may be a problem.

Edit2: And bending resistance depends on 4th power of radius so switching to 12mm rods from 8mm rods may be just enough (about 5 times stronger (from bending point of view)).

Edit3: in italic and strikethrough.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Mon, 24 March 2014, 14:36:22
don't forget torsional forces on the delta design.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Mon, 24 March 2014, 15:00:57
Well, those should be compensated by frame. I just assumed the frame is completely rigid. I do not have enough mental commitment to do a good model. Just some "on the napkin" estimates to get an idea how significant it may be.

That is what I should to next, stiffen the frame so that it is not twisting. Some metal beams and a stick welder is in the garage ... I just need not to be lazy to do some manual work :D

I actually made an error while integrating, the theoretical value for maximal rod bending should have been 0.2 mm and not 0.4. I'll fix it there too. Still looks about right when compared to my "by eye" experiment.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Mon, 24 March 2014, 15:18:58
LOL, looks like our el-cheapo 3dPrinters are designed so they just barely work. And if one wants higher quality either he needs to print really slowly or just replace almost all the parts :)
Makes sense.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 26 March 2014, 22:20:36
LOL, looks like our el-cheapo 3dPrinters are designed so they just barely work. And if one wants higher quality either he needs to print really slowly or just replace almost all the parts :)
Makes sense.
i can't believe you actually sat down and calculated to determine this. it's pretty obvious if you just look at it. a) well, it seems to print something b) what the hell? how could this possibly work?

c) it must be designed to the absolute limits.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Thu, 27 March 2014, 06:03:37
And the original Rostock. It uses Φ 8 mm rods and linear bearings. I'm surprised Johann did not go for Φ 12 mm rods. Based on a local supplier here the rods would be 35% more expensive and linear bearings would be 10% more expensive. Rod error specified as at most +0μm -8μm. Bearings specified as at most +8μm -0μm. It is the same for both 8 and 12 mm versions. 12 mm versions look worth it. Especially when some people put linear guides on their Kossels which are much more expensive than rods and linear bearings.


I agree though about them using too small of rods and seeming to be common in the Reprap community. I've seen many different printers and almost all are too flimsy in my opinion, sometimes shockingly so. Most is likely done for cost reasons, but combined with some questionable design methods, like threaded rod and jam nuts, it makes for a bad printer.


As far as Deltas go,
The Rostock was an exercise to even see if the idea would work. In the case of the Kossel Mini, my understanding was that Johann was trying to use a system like the Cerberus, which used bearings and rollers on the Misumi (see the first Kossel design). It worked sub par and while looking for alternatives, another person gave him the sliders, it worked well and others just started copying that.  There are some other issues I have with that particular design as well, but I won't go into that here. I have to respect the guy though, we wouldn't have Deltas without him.


This was all part of why I did my own. As Mkawa found, trying to re-engineer something often just creates more and more problems. I tried scaling other designs and they just didn't work well, each part change required other parts to change.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Thu, 27 March 2014, 10:48:52
i can't believe you actually sat down and calculated to determine this
Yes, the conclusion is fairly obvious :)
I did it for three reasons:

I do not think that the model I used for rod bending is much good though. If I put higher forces in it then the results do not conform to experimental measurements.

OK, back to the belt stretching of the delta here (classical rostock with 6mm wide T2.5 belts with steel core). It is still true to the original except the diagonal rods were changed to carbon rods with MP-Jet ball joints. So it should be about the same for other classical rostocks. The data for stepper motors were taken from internet (I'm not sure especially about stepper motor rotor moment of inertia - I did not have it for the exact type I use so I took it from something which look the same).

The maximum belt stretching error is in the range of 0.21 mm to 0.55 mm. What I mean is: The real printer use will lead to some dynamic (temporary) belt stretching. And the maximum of that belt stretching is in the given range. I ignored pulley, idler and belt weight but I doubt they would change it in any significant way.

Btw, the maximum usable acceleration of a carriage is about 8g. At 15g, the stepper would definitely skip steps instead of moving a carriage :-) At 8g, the side force on the smooth rod is about 15N and that can bent it about 0.8 mm. Just to get you some idea what the very worst situation can be.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Thu, 27 March 2014, 14:31:37
This was all part of why I did my own. As Mkawa found, trying to re-engineer something often just creates more and more problems. I tried scaling other designs and they just didn't work well, each part change required other parts to change.
_everything_ causes problems, as we all know. we have all had our share of incredible frustration. now that i have a more global view of the FDM printer market, i can laugh about it (even 60 grand printers are incredibly frustrating), but my response to this is to sit down and engineer stuff. after working in research for so long, i don't really expect anything to work, ever. ;)

Quote
I do not think that the model I used for rod bending is much good though. If I put higher forces in it then the results do not conform to experimental measurements.
you cannot rely on material specs on the web for steel. if the part is using chinese steel formulations that goes doubly so. even if you have completely traceable material sourcing, the way that the part is formed and machined is just so stochastic. even the "expensive" rods i source are not aerospace or space part quality at all. and all space parts, aerospace parts and structural parts are tested per batch for compliance by the engineering firm to ensure that QC was performed and that the material will generally have the specified characteristics. we would be hard pressed to actually accurately determine young's modulus for anything we have on hand, so at some point we just have to put the parts in and see what happens.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Fri, 28 March 2014, 06:15:15
OK, back to the belt stretching of the delta here (classical rostock with 6mm wide T2.5 belts with steel core). It is still true to the original except the diagonal rods were changed to carbon rods with MP-Jet ball joints.

{cut}
Btw, the maximum usable acceleration of a carriage is about 8g. At 15g, the stepper would definitely skip steps instead of moving a carriage :-) At 8g, the side force on the smooth rod is about 15N and that can bent it about 0.8 mm. Just to get you some idea what the very worst situation can be.
While I haven't looked for steel core, most Rostocks and Kossels are using fiberglass core GT2 belts (not steel or T2.5). I found a chart showing stretch, but I would have to dig it up. I looked at Kevlar, but it's expensive. T2.5, especially steel would be MUCH stronger than common GT2.

As for your speed calculations...
I don't know what G's equate into mm per second, firmware lists it a bit strange and weights vary from one printer to another, but I do know there is a LOT of people claiming some insanely high speeds on their deltas. I have even heard some recent claims of 500mm per second and I can pretty much tell you they are 100% B.S. partly for exactly what you just found. You can only yank a belt and stepper so fast before it skips, stretches, or whatever.

It's pretty obvious when your printer takes a second and a half to cross a 170mm print bed that you aren't hitting 500mm per second. Even if you account for some acceleration, it shouldn't take that long. One clue many miss is when your slicer says it will take 3 minutes to print and then you start to print and now it says 9 minutes.

Don't even get me started on those claiming 300mm per second on a Kossel Mini with magnetic ball joints. The ball bearings add a LOT of weight to the moving assembly, probably doubling it. I barely trusted them at 150mm per second on my Rostock.


_everything_ causes problems, as we all know. we have all had our share of incredible frustration. now that i have a more global view of the FDM printer market, i can laugh about it (even 60 grand printers are incredibly frustrating), but my response to this is to sit down and engineer stuff. after working in research for so long, i don't really expect anything to work, ever. ;)
Tell me about it. LOL
I would hate to do design for a living, not that I need worry, I would be fired for taking too long and far too many mistakes.  :))

Revision #350.... Oops... Revision #351... Oh darn...
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 28 March 2014, 14:40:37
so one of the nice things about putting your stepper on top of your extruder is that you can use much less extrusion pressure because you don't have large losses in filament flex and weird off-axes stuff going on. one HUGE downside to that is that your low pressure extruder will happily build up the most insane clogs full of degraded plastic that you can possibly imagine and just try to fight through them. of course, when you fail to push through, nothing blows up, it just air prints. however, constant air printing is a HUGE PITA.

so kids, that's why you give your nozzles a serious acetone bath every now and again, and then _get the resin that's sitting around clogging things_ out. chances are that you're going to have moments where that's a bit too much backpressure, or you're below or above process temp and this stuff will build up over time no matter what you do. however, if you wait too long, you will have to spend 4 hours with a drill, bottle of acetone, music wire, and every single probe you own cleaning that crap out. don't be me. don't wait too long :(
Title: Re: The Living 3D Printing Thread
Post by: vvp on Fri, 28 March 2014, 16:45:59
What I have written down are absolute physicaly possible maximums for my machine (if I would allow it to run in SW to the very limits) ... and I'm not sure even they are achievable with my 24V power source (but they would be achievable with 48V power source). The reason I'm not sure here is because of the static moment charts for my steppers are missing or incomplete for 24V power source. I considered only 1/3 of the maximum static torque of my steppers but may be it should have been 1/5.

The point is when you actually want a high acceleration to lead to some error you must be able to sustain the acceleration long enough to actually move the carriages for a distance bigger than the error they should lead to and that means you must be able to run steppers at high enough speed with some torque still available. With high acceleration speed ramps up really quickly. The motor torque goes down with the speed because of wiring inductance. But to sustain the acceleration printer needs the torque.

Anyway I rerun my notebook with only 1/5 of the maximum torque and got maximum acceleration of 5.6g and maximum belt elongation of 0.3mm and maximum radial force on carriage of about 10N (and that should lead to rod bend of about 0.4mm - this is just "by eye" measurement - I'm lazy to pull the rods out of the printer and do it precisely).  For these to be achievable the maximum printer speed limit can stay at probably common 0.3 m/s
but the maximum acceleration would need to be set to uncommon 56000 mm/s (most people probably use only 10000 mm/s or 9000 mm/s, which was (and probably is) the Marlin default) or it can be somewhat smaller but then jerk must be non-zero.

Most people probably use the default acceleration limit which is about 10e3 mm/s = 10 m/s^2 ≅ 1g. But they also will probably have non-zero jerk (probably about 20 mm/s).
If they would use also zero jerk (which probably nobody has set to 0 but lets assume it for a while) then that would mean that their maximum belt stretch error for T2.5 steel core belts is about 0.07 mm. 20 mm/s jerk will probably increase it only by about 0.005 mm (just an educated guess).

So really, if people run at low acceleration limits  of about 1g and low jerk (at most few tens mm/s) then they can assume their belt stretch just below 0.1 mm. That is if they use steel core T2.5 belts. If they use glass core GT2 belts then the maximum error is about 3 times worse (i.e. 0.3mm). The rod bend error will be around 0.1 mm.

For these numbers to be valid speed limit may stay rather low at about 300 mm/s. If they use some insane high jerk (but which still does not lead to stepper motor skipping) then that may increase their maximum error by at most half step (i.e. about 0.1 mm). This all assumes their frame is rigid and no resonance happens.

Now, do I typically hit these errors. Hah, not at all because most of the time:
So if I would improve the printer then the order of improvements should be:

As for as people claiming some insane speeds. Well maybe they citied their slicer limit and forgot about lower limit in firmware :-)
Title: Re: The Living 3D Printing Thread
Post by: vvp on Fri, 28 March 2014, 16:58:12
so kids, that's why you give your nozzles a serious acetone bath every now and again, and then _get the resin that's sitting around clogging things_ out. chances are that you're going to have moments where that's a bit too much backpressure, or you're below or above process temp and this stuff will build up over time no matter what you do.

Interesting. Isn't it enough to pull it out with filament? Well, probably does not work with degraded plastics but this is what I did when I experienced a piece of broken pneumatic fitting in the nozzle:
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 28 March 2014, 17:33:03
your stepper moment depends on the driver and motor, as the driver does not pass off vcc to the stepper. the driver is buck charging down to a lower voltage and high current. if you buy matched drivers and steppers, the driver datasheet will give you the holding torques, but the vcc voltage of the driver doesn't really matter, since it's buck charging whatever it gets down to the stepper voltage. the advantage of giving a driver higher voltage is generally that the power supply will run more efficiently, as it doesn't have to push out nearly as much current.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 28 March 2014, 17:35:19
graded plastic doesn't really hold together well. it's kind of burnt and all coked up. i actually think this cold end is just done for. i cannot for the life of me get it to pass filament without clogging every few minutes.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Fri, 28 March 2014, 17:48:01
It's pretty obvious when your printer takes a second and a half to cross a 170mm print bed that you aren't hitting 500mm per second. Even if you account for some acceleration, it shouldn't take that long.
500 mm/s is hight speed. If they use the common 1g acceleration then (even with 0 jerk) crossing 170 mm bed should take 0.34 s. That is really quick. Although 1g (10000 mm/s) or 0.9g (9000 mm/s) is the default acceleration in Marlin. It is rather high. E.g. it takes only 12.5 mm (and 0.05 s) to get to 500 mm/s with 1g.
If they use non-zero jerk then it should be even quicker.

Notice that if I lower the acceleration to only 0.5g (almost everybody has it at this or higher value) then the time to cross the bed increases only to 0.44 s. Still significantly less than a second.

If they cross 0.17m bed in 1.5 s then that would mean that their acceleration is limited to 0.03g (300 mm/s) and the maximum speed they would reach while trying to cross it would be only 225 mm/s (far from 500 mm/s). Assuming 0 jerk. I doubt anybody uses so low acceleration.

Don't even get me started on those claiming 300mm per second on a Kossel Mini with magnetic ball joints. The ball bearings add a LOT of weight to the moving assembly, probably doubling it. I barely trusted them at 150mm per second on my Rostock.
They probably do not really know what speed they are actually running. I'm very satisfied with my ball joints. No way I would switch them for magnetic joints (especially after what you reported about them). One ball joint weights only 5g (even with the associated screw/nut to platform/carriage and the screw to the carbon rod). One finished rod with two ball joints and the nuts to connect them to platform/carriages weights only 15 g. It is stiff, strong and does not have any play I can notice. No way I could achieve this with magnetic joints.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Fri, 28 March 2014, 18:08:19
your stepper moment depends on the driver and motor, as the driver does not pass off vcc to the stepper. the driver is buck charging down to a lower voltage and high current. if you buy matched drivers and steppers, the driver datasheet will give you the holding torques, but the vcc voltage of the driver doesn't really matter, since it's buck charging whatever it gets down to the stepper voltage. the advantage of giving a driver higher voltage is generally that the power supply will run more efficiently, as it doesn't have to push out nearly as much current.
OK, I'm not that good with stepper drivers. Do at least some of them even multiply voltage internally to ramp up current quickly? Because if they do not, then it takes some time to raise the current (because of stepper winding inductance). And if this time is significant part of the whole time the coil is driven (which is shorter with higher rotor speeds) then it lowers the available torque.
I believe I needed to raise the driving voltage to achieve bigger extruder stepper speeds because my stepper drivers cannot multiply voltage internally to speed up the current rise in a motor coil. The result is (with my stepper drivers) I need higher driving voltage to achieve higher speeds.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 28 March 2014, 22:51:46
here's a pretty detailed treatise from STM: http://www.st.com/st-web-ui/static/active/jp/resource/technical/document/application_note/CD00003774.pdf

start at page 8. the basic idea is torque is _only_ a function of stator topology and current. you're better off buck charging, even from a 0 step frequency. buck charging using BJTs or IGBTs is basically a V/I operation, so a higher voltage will be more efficient, especially, as you said, when the stators are starting from 0 spm and there's no inertia to lower coil resistance.

to make things more concrete, here are some of applied motion's torque curves for their matched driver/motor pairs:

here's a very small motor with Vcc at different voltages http://www.applied-motion.com/sites/default/files/5014-842_STR2.jpg

here's a very large motor with Vcc at different voltages http://www.applied-motion.com/sites/default/files/HT23-601_STR2.jpg

you see repeatedly that higher voltages give you better low frequency behavior, when the resistance of the windings is high, but that as rotational velocity increases, you're just kind of freewheeling and it doesn't really matter how much voltage you give the driver.

if the STM document doesn't have any schematics, it's easier to just visualize it. a stepper motor, like pretty much any other rotary motor, is just a bunch of coils that you need to energize in some sequence in order to move a magnet. so you put a bunch of BJTs in front of the coils and you switch them according to the sequence you need to fire. these BJTs are going to have to split either current or voltage, and your goal is lots of current, so you have them split voltage. that's pretty much it. there are a lot of tricks to minimize noise and weird resonances, but that's the basic idea.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sat, 29 March 2014, 11:50:40
mkawa, thanks for references. It does not contradict what I know about it. The only misunderstanding may be that what you consider "low frequency" I consider to be "high speed". In that region torque depends quite a bit on the driving voltage. Based on the speed-torque chart of my motors* it is just the region where Rostock is when it runs at speeds of 200 - 400 mm/s. Which are common high speeds for Rostock ... hence my reference to it as a "high speed" region.

* They are with different stepper drivers but they look like a H-bridge with chopping drive plus some more high level features added to it (like internal memory, ascii control protocol, and boring stuff like that).

The only way to avoid this initial torque drop off would be to use some kind of internal voltage multiplier and some form of bilevel (or better multilevel) current driving. I do not know about any driver doing this.

Interesting that the rps - torque charts you provided are levelling so well after the initial drop. 20000 steps/rev also looks like some kind of a geared stepper or they use word "step" but mean "microstep". OK, based on google search, HTR23-601 motor has 1.8 step angle. So they must mean microstep but use word "step".
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sat, 29 March 2014, 12:25:27
yah, they mean microstep. the str units work in units of microsteps. they interpolate when given larger steps. to get the full step graph though you just make it a straight line

hah!

as far as avoiding the initial torque drop, afaic, change the motor, not the driver. lower impedance windings are really key. this is one reason why servos are much preferred to steppers whenever possible. in motion control, without a LOT of smarts on the control side, it's almost impossible to use servos, but that's the ideal.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sun, 13 April 2014, 11:29:28
IS THIS INSANITY??!?!?!

NO, THIS IS DOMO
Title: Re: The Living 3D Printing Thread
Post by: vvp on Fri, 18 April 2014, 14:41:20
Well, it looks like DOMO cannot accept a Cherry MX switch into that nice middle hole. If so what it is good for?
This is what I would like to print ... eventually. It can accept 40 switches. Not only one, not only after the teeth are filed away :D
[attach=1]
On the other side, DOMO has a decisive advantage. It can be printed now. My part is far from ready to be loaded to a slicer.
Title: Re: The Living 3D Printing Thread
Post by: zorglups on Wed, 07 May 2014, 15:17:22
I'm sorry because I did not take the time to read the 600+ messages of this thread and I'm afraid my question may be off topic...

A friend did print my Ergodox case using SLS 3D printing with white polyamide powder.

The case is really nice. The only point is the granularity/porosity of the surface which will make it get dirty quite quickly and impossible to clean up.

I got told to spray the case with Sikkens Spotprimer then spray with any color I want.

I built the Ergodox because:
- I found the project really nice
- I'm not 100% satisfied by my TEK
- I'm a geek (at least this is what the other say)
- I'm willing to reduce some elbow/shoulder pain

I would like to avoid exchanging elbow RSI with some finger skin allergy due to the "any color I want" I would have sprayed on my everyday keyboard.

Any suggestion about which color or kind/type of color I should select for that usage ?

Thanks.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 07 May 2014, 15:35:45
I'm sorry because I did not take the time to read the 600+ messages of this thread and I'm afraid my question may be off topic...

A friend did print my Ergodox case using SLS 3D printing with white polyamide powder.

The case is really nice. The only point is the granularity/porosity of the surface which will make it get dirty quite quickly and impossible to clean up.

I got told to spray the case with Sikkens Spotprimer then spray with any color I want.

I built the Ergodox because:
- I found the project really nice
- I'm not 100% satisfied by my TEK
- I'm a geek (at least this is what the other say)
- I'm willing to reduce some elbow/shoulder pain

I would like to avoid exchanging elbow RSI with some finger skin allergy due to the "any color I want" I would have sprayed on my everyday keyboard.

Any suggestion about which color or kind/type of color I should select for that usage ?

Thanks.
for a porous surface i'd start with a layer of white artist's gesso. it's a very white acrylic primer that can be bought from any art store for almost nothing and loves porous surfaces. just brush it on.

once the gesso is on, you can go crazy with any kind of paint you want. seal with a layer of acrylic clearcoat. i use a golden glossy UVLS clearcoat (uv protection layer) because it's water based and yet very hydrophobic once it dries. it is also made to allow even oil paints to dry underneath it. however, once it's on, it's on. you can't paint over this clearcoat.

Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 07 May 2014, 15:36:08
Well, it looks like DOMO cannot accept a Cherry MX switch into that nice middle hole. If so what it is good for?
This is what I would like to print ... eventually. It can accept 40 switches. Not only one, not only after the teeth are filed away :D
(Attachment Link)
On the other side, DOMO has a decisive advantage. It can be printed now. My part is far from ready to be loaded to a slicer.

the domo keychains can in fact accept MX keyswitches in their mouths.
Title: Re: The Living 3D Printing Thread
Post by: zorglups on Wed, 07 May 2014, 16:17:14

for a porous surface i'd start with a layer of white artist's gesso. it's a very white acrylic primer that can be bought from any art store for almost nothing and loves porous surfaces. just brush it on.

once the gesso is on, you can go crazy with any kind of paint you want. seal with a layer of acrylic clearcoat. i use a golden glossy UVLS clearcoat (uv protection layer) because it's water based and yet very hydrophobic once it dries. it is also made to allow even oil paints to dry underneath it. however, once it's on, it's on. you can't paint over this clearcoat.

Thanks
Title: Re: The Living 3D Printing Thread
Post by: vvp on Wed, 07 May 2014, 17:24:11
the domo keychains can in fact accept MX keyswitches in their mouths.
Nice, I'm p0wned.
Title: Re: The Living 3D Printing Thread
Post by: oystein.krog on Sun, 11 May 2014, 05:20:03
Hi guys,

I'm considering building a 3d-printer, my primary motivation is vvp's keywell prototype:p
I want to 3d print custom keyboards, like the ergodox but with curved keywells.
I'm aware that building a 3d printer takes a lot of work, that's OK, I like building stuff and have some experience with other kinds of DIY projects.

What kind of kit would you recommend?
I'm currently looking at various prusa i3 models, e.g. the i3v, i3xl or the omega.
What kind of material would you recommend for my purpose?
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sun, 11 May 2014, 11:44:06
the prusa i3 has an 8x8" bed, which isn't really large enough for vvp's design.

at this pointl, for a plug and play solution, i would actually recommend one of the flashforge makerbot clones. i've seen them in action and they're a pretty darn good value. the price on the basic unit recently dropped to a thousand dollars even, and unless most prusa kits it comes fully assembled and ready to print.
Title: Re: The Living 3D Printing Thread
Post by: oystein.krog on Sun, 11 May 2014, 11:58:03
Yes, the 8x8" bed on the standard i3 is why I was looking at the derivative models.
Massdrop has the i3xl (9x12x7) up currently: https://www.massdrop.com/buy/diy-tech-shop-prusa-i3xl-3d-printer-hardware
Here is the omega model (9x12x7): https://shop.diytechshop.com/index.php?route=product/product&product_id=54

What size do you think is needed?

The flashforge models do look pretty good, but the ones I can find seem to be a smaller print size?
Is this what you are referring to?:
http://www.ebay.com/itm/Flashforge3D-printer-extruder-3d-printing-machine-nozzle-double-extruder-creator-/190877628239?pt=COMP_Printers&hash=item2c7131774f

Having a ready-to-go solution is tempting, but on the other hand I do like to build stuff, and the reprap concept is very nice.
I guess the flashforge is less customizable?
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sun, 11 May 2014, 12:12:01
the issue i have with most prusa kits is pretty much summarize by the following: printed load-based and positionally important components. glass build plate.

glass build plates are very suboptimal for a couple of reasons. the obvious one is that they break. they break a lot, and the bigger the plate the more likely it is to break. imagine putting a piece of window glass into your oven at 260F and taking it out every 30 minutes for a couple months. the internal warpage in the glass alone will cause it to break. add the prying of completed prints off and you're going to be going through a lot of glass plates. these plates are also not flat to any tolerance. prusas can clam 100 micron precision, but if you have 1mm of warpage in your plate, you're not going to get 100mic precision. the final nail in the coffin is that glass is a thermal insulator. it's going to take forever to heat up that plate, and then the temperature is going to heavily fluctuate over the course of the build, doubly so because of the lack of a chamber to keep environment temps consistent.

i have internal sources that claim that the basic flashforge creator is going to drop in price fairly soon, something which should be obvious from the current pricing at http://www.flashforge-usa.com/ who is the US distributor of flashforge product and provides warranty support on flashforge products distributed through them and their resellers.
Title: Re: The Living 3D Printing Thread
Post by: oystein.krog on Sun, 11 May 2014, 12:24:36
So it's better to use a mirror or alu plate?
Is it really so bad to switch out the plate if it breaks?

Flashforge looks nice, but I want to be able to upgrade/tweak and I think the build volume is too small.
Even the basic prusa i3 has a larger build volume?

Your point about printed components is a really good one, I guess it will cause lots of problems.
However it seems very nice to be able to print spare parts/replacements.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sun, 11 May 2014, 12:55:08
I can comment about rostock: http://reprap.org/wiki/Rostock
It is the only printer I ever used so far so I do not have experience with cartesian printers. But people recommend to start with a cartesian pritner so prusa looks like a good choice. I cannot comment on prusa more. Definitely get a kit or a finished printer.

I print everything with ABS. The main reason is that it was cheaper when the material was bought. The prices seem about the same now. ABS is probably better for a keyboard case too. It is more flexible than PLA (but stiff enough). It is harder to print with (requires higher temperature and the parts are more prone to bending while they are printed).

As for as whether to get a 3d printer or use a 3d printing service. I do not really know. Lets assume a situation at my location. There is no local 3d printing service. One half of the keyboard case uses about 200g of filament (25% infill, shell thickness 1mm). That is about 5.6 for the material. Shapeways asks about 27 for some small 9g sample part. But most of that is probably shipping. Anyway my guess is they would ask somewhere around 60-100 for it. Can somebody provide a better estimate? 4 prototypes were done and all of them were tossed to garbage. But the shape is stabilized now. Looks like buying a 3d printer only for this does not make sense. A rostock kit is about 800 and it would "save" somewhere around 450 in a project like this.
That all assumes one does not count the time spent building and calibrating a 3d printer. Here it depends whether it will interest you. People even pay to do what they like to do in free time. Look e.g. at the glider pilots, they pay quite a lot for their hobby :)
If you spent only free time after work building it then it will be done after about 2 months. As somebody on the internet indicated: "It is a full time hobby".
Title: Re: The Living 3D Printing Thread
Post by: oystein.krog on Sun, 11 May 2014, 12:59:49
vvp: ah, thanks for the good info there.
Regarding the cost efficiency of building a printer just for the keywell; I am well aware it does not make sense:p
However I want to be able to print lots of stuff, and I want to prototype my own keyboard.
I think your keywell looks really good, but it seems like people have quite different hands, and I really like the idea of being able to print/prototype my very own design:)

Another printer that is prebuilt and has really nice specs/price:
http://www.robo3dprinter.com/collections/3d-printers/products/robo-3d-abs-model-fully-assembled
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sun, 11 May 2014, 13:17:48
the prusa i3 has an 8x8" bed, which isn't really large enough for vvp's design.
The plan is to print one half of the keyboard in 4 pieces. Two pieces will be acetone-glued to the top part and the other two to the bottom part. So it comfortably fits to a 20x20 cm heat bed. I do not yet know how well the gluing will work but I believe it can be done well enough. So far my experience with acetone (and ABS-glue) is good. We shell see how it turns out.

Anyway if the gluing will turn out to be a problem then it just fits 19cm x 17cm square. And it fits 23cm diameter circle so it should be printable even in one piece with a standard rostock. The reason why it is divided is to save on support material ... and of course printing small things is easier. I'm curious how well will this turn out. Anyway, some work needs to be done on the electronics now so that positions of mounting holes of PCBs is know. If there will be any PCB at all (an option to do only a "bird nest" is still there)).
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sun, 11 May 2014, 14:03:39
So it's better to use a mirror or alu plate?
Is it really so bad to switch out the plate if it breaks?
The rostock here uses a mirror. There was no problem with flatness. Actually there was one. But it was not because of glass. The problem was that too much insulation was below the PCB heater and that caused the PCB to bent. When the mirror was clipped to the PCB it did bent accordingly. Putting smaller amount of insulation under PCB heater fixed the problem.

I do not have any measurements how flat mirrors typically are. The one here seems to be ok. It did not break yet because of thermal stress but only a 110W PCB heater was used. A lot of people use borosilicate glass to mitigate problem of breaking because of thermal stress.

Glass being a thermal insulator is a problem. It takes 11 min to heat it up from 25C to 105C. Maybe it can be done more quickly with more powerful heater but the problems with glass breaking due to thermal stress may start to appear then. I do not know at which wattage it would start to break. But glass is super cheap and I doubt you will have problem with it breaking if you use only 110W PCB heater. As for as replacing it on a rostock. It takes negligible amount of time. But replacing the kapton tape on it takes about 20 minutes. It must be laid down carefully without bubbles and overlaps.

As for as aluminium plate. Does not MakerBot recommend replacing them after some use because aluminium will bent after repeated thermal stress? As far as I know there is no good and cheap material for heat bed. Glass is a thermal insulator and aluminium will bent over time.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sun, 11 May 2014, 14:09:09
As for as questions how good specific cartesian printers are, you may try to post also on reprap forums http://forums.reprap.org/list.php?151
Unfortunately I do not know much about cartesian printers. I know quite a lot about linear delta printers (e.g. rostock) and especially how to calibrate them well (which is not so easy).
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sun, 11 May 2014, 14:18:58
yah, the aluminum plate wings out like crazy. i have been through three, but on MBI's part, i just have to demonstrate that they're out of tolerance and they send me a new one.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Sun, 11 May 2014, 18:58:32
Any glass bed is likely to be more accurate than a cheap aluminum plate, and better than a used aluminum plate. That is part of why so many use a glass plate. It's easy enough to change regardless.

I have had a bunch of glass beds...
Soda glass - (also called soda lime or green glass), this lasted me 9 months. It broke when I had a cooling fan positioned wrong and it cooled one half and not the other. It flexed, but never broke. I had a head crash take a chunk out and it survived. Accuracy on it was described as "good".  I have no idea what that means. lol  Large chunks when it breaks.

Cheap window glass - I used it for 4 months before I replaced the printer. I have heard people say it lasts quite a while, and at $5 or so a plate, who cares. Beware head crashes though. Expect large chunks when it breaks.

Borosilicate - (a.k.a. oven glass, or corning ware) I had one plate for 3 months, a head crash (minimal damage) and too tight of a bed clamp eventually cracked it in half.  Seems it doesn't like impacts or stress, this is partly due to thickness (3mm).  It's hard to find thicker pieces and it's not cheap as cheap as plate glass. Accuracy on it is considered the same as tempered. Expect very large chunks when it breaks.

On any thin glass, what it is clamped to will have a more dramatic effect on flatness than the glass itself.

The thick tempered glass on my big printer...
While there is no industry standard, the industry generally considers tempered to have an accuracy of .0005in (.01mm) tolerance across the surface. This glass is thick and heavy, but I have yet to have an issue with it. In fact, I prefer it to every other bed I have worked with. Head crash, it's more likely to break the printer. It's nice because it feels solid, as opposed to the flimsy glass on my other printers. When this breaks, it breaks into thousands of tiny pieces, however, it's stronger than other glass by a lot. Mine is heavy enough to break a foot if it falls on you. The weight actually adds stability to the printer and there is no way to warp it.


As for heat times and insulation...
My small printer has a kapton heater on it, it takes about 4 minutes to heat. When I added the double thick borosilicate, heat times only went up 25% and my temps held better ones heated.

Regarding even bed temps, it's a joke, no matter what you put for a heater, your temps will vary. I found Kapton heaters and pcb heaters to vary 15 degrees from one spot to another as they heated up. An aluminum plate with glass will heat the most evenly, however once that warps, it's worse than the rest. Personally, I like to use a Kapton heater, and give it time to settle. The very edges will still be cooler, but that's true on any surface. Because it holds the heat, it should remain more stable than others across the surface once heated.  The bad side is that if the glass breaks, your heater is stuck to it, this is a mixed blessing, as while it offers no strength, it will hold the glass together when it breaks, giving an added level of safety.

I don't dare heat the big one, while the glass was tempered to 1000 degrees and I have had quotes for a heater ($30), but it would take an insane amount of heat. It would use almost as much power as my air conditioner while running. Which would also need to run.

I use hairspray on my heated bed, and blue tape on the big printer. Works for me.



Delta printers are great, they are fast, but can be fickle, and have less documentation. The calibration issues can be solved using a few new parts that are out which allow it to auto calibrate. It takes a few extra parts, but makes the delta easier to calibrate than a cartesian. Documentation is a big problem for deltas still, so you may want to try a cartesian first. If it was me, I would build a delta or H-bot (core-XY), but then, I like a challenge.

They all print similar quality, remember, they almost all use the same basic components. I have seen everything from a Printrbot Simple, to Ultimaker 2, to 1meter tall deltas make nearly equal prints, the difference was how they did it, how fast and for how long. The best consistent quality I have seen was from a well tuned Ultimaker and the fastest was a Griffin delta, which was running at well over 300mm per second (which was crippled by the extruder).  My thoughts on printers have changed a bit after having interacted with both of them.  Want good, consistent prints, buy/build a stiff, solid printer, something almost every other printer lacks. The Griffin and Ultimakers are the only ones I have seen that could really handle being moved and not require a lot of maintenance (I have seen both turned upside down while printing).

Printers I have experience with:
Ultimaker, looks older and sort of like a homemade kit, but in the right hands, it's an amazing printer.
Ultimaker 2, very nice looking, and the impression I got was that in the right hands, would be a really nice printer. I helped with some early tuning on one.
Griffin delta, personally, best delta I have seen. It's fast, as big as you want, solid and cheap too. Documentation is coming along, auto-calibration is in the works. Kits are rumored to be in development.
Lulzbot Taz, it's a nice printer, but the nozzle is fickle and the bed is easily knocked out of alignment if moved.
Rostock, they work, but lose calibration pretty easy. Switch to rod ends and make an actual frame. (May as well just make a 3DR)
Kossel Mini, nice, but entirely too flimsy, and not the cheapest delta. Without auto level it would be as troublesome as the Rostock. Maybe more.
Rostock Max, change the diagonals, it's a decent machine. I haven't seen how the new ones are, but the old ones were a nightmare. Not one of my favorite machines, if only because of the excessive use of wood and junk diagonals.
PrintRbot original, it's an old design, and we have come a long way.
PrintRbot Simple, keeping it's cost in mind, it's an amazing deal. It's high maintenance though and over time the accuracy will drop off.  Would I buy one? yes, then make a different printer and cannibalize it for the parts. LOL
Prusa, just no. Like the Printerbot original, it's an old design that requires constant tuning.  The I3 is supposed to be miles better, but I just can't get excited by it. Probably because it's not something the average person can build without buying the main assembly (it uses laser or waterjet cut aluminum plate), while other designs can be done with common tools. This is a big departure from Reprap ideology.

I have yet to see a Makerbot in person, which is about all I will say about them.
Title: Re: The Living 3D Printing Thread
Post by: oystein.krog on Mon, 12 May 2014, 14:36:12
Wow, lots of info there, thanks leslieann!
The Griffin looks nice, but it seems a bit early, does the design have any major differences/improvements over the 3DR?
I don't like that there is next to no information/open development on it.

I am tempted by the delta style in general, but I think maybe a cheap cartesian starter kit with lots of users is best for me as a noob:P
Once I master a simple cartesian I can always build a delta later.

You say "just no" on the prusa, is there a relatively cheap cartesian kit you can recommend?
I like the ultimaker-style with plate up/down movement, since it seems it would be easier to enclose (for ABS).

Another thing I've realized is that chasing support for a very large build area may be bad, as it seems like ABS is tricky to print for large models.
If I am to build a keyboard plate/well and case I should probably build it in multiple pieces instead.

vvp: from just looking at my ergodox it seems like the keywell itself most certainly does not require 8", have you tried to split the keywell from the rest of the model and print the wristrest etc as a separate piece?
What has your experience been with regards to cherry mx switch mounting in the printed material?
Title: Re: The Living 3D Printing Thread
Post by: vvp on Mon, 12 May 2014, 18:45:25
vvp: from just looking at my ergodox it seems like the keywell itself most certainly does not require 8", have you tried to split the keywell from the rest of the model and print the wristrest etc as a separate piece?
What has your experience been with regards to cherry mx switch mounting in the printed material?
The standard ergodox probably does not fit 20cm x 20cm heat bed. My contoured version easily fits since: I still intend to print the palm support part separately to avoid need for support material.

Some switches hold well in the slots. Others do not (you can pull them out when pulling out a keycap). I plan to solve this by using a bit of glue from a hot pistol (or maybe even a regular glue) on all switches. I do not expect this to be a problem.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Mon, 12 May 2014, 19:46:40
use tack spray or starch based glue. acetone and other solvents will cause the key chassis to permanently bond with the keywell print :P
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Mon, 12 May 2014, 19:59:20
i have heard that the better prusa kits are quite nice. the evolution of the prusa design is the parameterizable Mendel 90 design. the key is really getting accurate rods, rod ends, precision cut gantry and not skimping out on stuff like the two vertical leadscrews and gantry gate itself.

the other thing is to use appropriately thick rods. it's not just rod joints that cause slop issues (eg, the many rostock tie rod ends) but the bending of rods themselves. the x-rod on a gantry design needs to be appropriately thick. you have two steppers to provide lift and still torque, so don't be afraid to put some weight up there.

last bit of optimization is stepper driving. most of the single-chip drivers that people are using (including me) are insufficient for precision on high duty cycle axes. it doesn't matter what microstep precision your steppers and drivers claim if they can't microstep accurately due to lack of current control.

finally, the build plate. glass isn't particularly flat, and it's even less flat when you hold it down wtih binder clips. standard soda glass is also very weak and brittle. note that this really only matters after you've sufficiently reduced tolerances in the rest of the machine. it matters a bit more in a cantilevered Z design like the replicators and flashforges, but it's always going to be the end all if one assumed that motion control on the rest of the machine is perfect. anyway, for optimality, there are really only a couple of material on earth that can survive the kinds of hits that 3d printer plates take, and not break or warp. one of them is sapphire. the other one is diamond.

:|

so it's a tradeoff thing. thin borosilicate will bend, but not break for much longer than soda glass, and thin boros isn't nearly as bad of an insulator than thick (4+mm) boros that will basically never break unless you smash it with a hammer. that's basically the story with glass.

for metals, you're basically looking at fairly exotic alloys. martensitic (400 series) stainless steel, has good thermal expansion properties, but is heavy as crap. 7075 aluminum isn't nearly as horrible as 3-6000 series, and is light, but it's also nearly unobtainium.

there's one more readily available metal left. i'll let you guess what it is ;)
Title: Re: The Living 3D Printing Thread
Post by: Pacifist on Mon, 12 May 2014, 20:01:11
How would you rate the printrbot metal simple?

Also I screwed up the printer somehow with the z axis...how do I recalibrate it?
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Mon, 12 May 2014, 20:06:26
the major weakness of the printrbot simple seems to be inertia on the y-axis. assuming the machining and large rods keep that axis square, you're still moving a lot of mass back and forth on that axis. the plate could be a large inertial source of error, but it depends on the current stability into the stepper, the quality of motion planning algorithms, and what material the plate is made out of. i assume it's a PLA printer, and given that the specific heat of metal tends to be pretty high, you might get a plate slightly under room temp, which could cause some warpage even with pla.

it's a fairly inexpensive and sturdy looking tool though.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Tue, 13 May 2014, 01:55:52
You're welcome.
The Griffin is new and was only recently made available to the public, it had a long development phase, the creator didn't want to release it as a beta.
I understand that at the local hackerspace (Arch Reactor), there are tons under construction and seems to be becoming the most popular printer there. There hasn't been a lot of development due to being new, and it working well from the start, but I would expect a lot soon as it is picking up interest. I started with a delta, I hand built then designed my own, if you can handle Linux and some tools, you can probably do it.

I only have experience with the cartesians I mentioned. I would either build/design my own or buy an Ultimaker. I considered a Mendel 90 but went delta instead. It was cheaper and more interesting.

For large models, in ABS, you are correct, you will want a heated chamber, a heated bed doesn't cut it. There are no kits you can simply enclose and heat. This is partly because the electronics are usually inside, but also, the company who bought Makerbot had a patent on windows on a printer (I believe it recently expired), which is why almost none are enclosed.

Switches mount just fine in plastic if done right, they did in the few I tried, but I only did 3 as a test.
Title: Re: The Living 3D Printing Thread
Post by: oystein.krog on Tue, 13 May 2014, 14:22:25
You say a heated chamber... I've yet to find any info on what kind of temperatures are recommended, do you know?
Werner Berry had a interesting test with a moving "containment chamber":
I've seen several deltas with a heated bed + side panels, which I guess helps a bit?
Title: Re: The Living 3D Printing Thread
Post by: vvp on Tue, 13 May 2014, 16:50:01
Moving "containment chamber" may help but it also limits printing speed significantly.
You do not need it for such a small part as Werner was printing. It is easier to add "printing pads" to the part. Or often it is enough to enable brim in slicer. If it is still not helping then it may be possible to modify the part by adding holes to it (so that it does not tend to warp that much).
Enclosing is completely is better than adding "moving chamber":

Edit: The changer temperature should be below the glass transition temperature. ABS glass transition temperature is about 105C so I would try it at about 70 - 80 C. If it is too low it will not help that much. If it is too high then the part will not cool (it will be sagging).
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Tue, 13 May 2014, 17:41:58
some people are trying to get their chambers up to 80C, which is Tg for most ABS formulations. personally i think this is overkill. my chamber usually sits around 40-50C. you just want the abs to cool down very slowly. you don't need to keep the entire print at Tg for the entirety of the print process.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Tue, 13 May 2014, 19:23:09
If it is rubbery at 80C then 50C for chamber sounds about OK. The good difference would depend on ABS thermal expansion.

Any idea about how ABS dynamic viscosity changes from 80C to 230C? It is probably quite non-linear when at Tg=80C it should be about 10 Pa.s, at 110C (heat bed temperature) it should be still in the range of 10⁹ Pa.s, and at 230C it is probably in the tens of Pa.s. Actually may fit exponential drop, which sounds plausible.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Tue, 13 May 2014, 19:41:43
it totally depends on the formulation. what we call ABS is a huge number of different copolymers with all kinds of different additives. the rule of thumb is that Tg is around 80C, but it can be anywhere from 70C to 100C or so. viscosity and tensile/yield/elongation/shrinkage/adhesion etc. etc. etc. all depend on the exact formulation. another thing that i hadn't even thought about until it was pointed out by an expert on the polymer spot market is that heat history can significantly change the internal properties of the bulk material. if your extruded filament is processed at too high a temp or is a reprocessed polymer formulation you could end up with a formulation that is mostly degraded monomers even.

the impression i got from folks i've talked to who are experts in the field and practitioners who are experts on the markets is that ABS is the wild west. you only get consistent behavior if you use the exact same supplier with the exact same processing, formulation and batch maker every single time.

PLA on the other hand is a much more stable market. before the advent of biodegradable utensils there was very little demand for polylactic acid. even now there aren't a huge number of batch makers, so you're more likely to find consistency with PLA than with ABS.
Title: Re: The Living 3D Printing Thread
Post by: Leslieann on Thu, 15 May 2014, 02:32:49
As Mkawa said, you don't want the temp too high because things will remain soft and will slowly start to collapse as you add more structure on top of it.

I didn't really agree with Mr. Berry's system, but as he said, it was only an experiment. I've used books, paper, plexiglass and more to just shore up the sides of mine, blocking air flow and getting good results. Your chamber doesn't need to be 100% sealed, you are just trying to control the cooling is all.

As for actual temps and such, it's all experimentation really.
Title: Re: The Living 3D Printing Thread
Post by: physicsmajor on Fri, 16 May 2014, 18:46:08
Backed the Robox from CEL on Kickstarter a while back. They got delayed a bit, but production is moving forward again. Anticipating when I can contribute to this thread!
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sat, 17 May 2014, 09:11:58
The idea with coarse and fine nozzle in one head looks interesting. I'm curious whether the micro valves will not jam. Let us know how it will perform.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sat, 17 May 2014, 12:34:04
yep, always great to hear about new printer designs
Title: Re: The Living 3D Printing Thread
Post by: microsoft windows on Mon, 23 June 2014, 13:32:16
ANYBODY EVER USED 3-D PRINTING TO MAKE KEY CAPS YET?
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Mon, 23 June 2014, 16:44:04
ANYBODY EVER USED 3-D PRINTING TO MAKE KEY CAPS YET?

Ehum, probably at least ten people in this very forum have.
Title: Re: The Living 3D Printing Thread
Post by: legodt on Sun, 29 June 2014, 03:36:58
ANYBODY EVER USED 3-D PRINTING TO MAKE KEY CAPS YET?
Yeah but the stem was the wrong size. Quality off of a FD bed though was pretty damn good when sliced with a decent infill
Title: Re: The Living 3D Printing Thread
Post by: vvp on Tue, 01 July 2014, 13:17:49
Since we discussed a heated chamber for ABS.
Per Stratasys patents, it should be around 70C-90C depending on the ABS.
https://groups.google.com/d/msg/deltabot/eobq16FVPTA/mWyDbluf0dAJ
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Wed, 02 July 2014, 00:44:24
yes, same temperature as a heated bed would be. there are more than a few issues with this though. the biggest is that a chamber sitting at 90C with lots of aluminum and ABS parts in it is going to have a bad time. the second is that the power involved in doing this is equivalent to running a convection oven for however long your print is. the third is that running a high airflow convection oven is going to cause too much systematic airflow that will screw with tolerances, so you have to carefully apply IR heat and use a low-airflow circulation method.

i am generally of the opinion that heated chambers for hobbyist printing are silly things that people only a few people on google groups talk about, but no one is particularly willing to engineer or build properly. if you're not willing to engineer a proper heated bed, then a sauna is pretty much out of the question.

anyway, the current migration among manufacturers is to unheated PLA FFM with printer parts that stay in tolerance for about 5 prints (which is probably the attention span of most people who buy small printers). other than the whole disposable world thing, i don't think this is that bad, but i do think it's possible to make much better tweener printers, and it's very sad that people aren't really trying to do so. it's still a very new set of markets though, and speaking as an engineer who needs money, the money has to come together to fund the engineering, so once the market becomes clearer, i do expect that there will be a push to design good tweeners.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Wed, 02 July 2014, 02:50:15
i do think it's possible to make much better tweener printers, and it's very sad that people aren't really trying to do so.
I'm trying. I stiffened the frame with a metal beam :)
Though I still did not improve the extruder.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Fri, 11 July 2014, 05:15:38
So, I did some test of printing on support. Mostly I was interested whether it really helps to print the first layer on support slowly and with fan.
There are 2 parts on the picture. One just next to another. They are spearated by a plastic piece which was printed directly on bed (so it is nice and smooth). The left side (without switch) was printed at 9cm/s, 30% fan. The right side (just the rim around the switch) was printed at 3cm/s, 100% fan. The left side is terrible, The right side is kind of OK, not nice but will do. Considering that this will be inside the case (and therefore typically invisible), it is good enough. Material was ABS, 230C, 0.2 mm layer height.
[attachimg=1]
Now only if I would have a slicer which allows tweaking fan and speed when printing on support so that I do not need to slow down the whole print. Slic3r will not use its bridge options for printing on support so it is not helping. Moreover it does not slice as well as cura. KISSlicer was a bit of better with the layers directly on support (I suspect this is mostly because it has quite good support pattern) but some of its top layers are terrible (top skin is not closed/tight sometimes). I think we need separate print/fan speed for first layer on support in cura. The same should be used for bridges.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sun, 13 July 2014, 13:35:42
Very dirty hack to cura and here is the difference:
* top - 30% fan, 9 cm/s, 0.2 mm layer
* bottom - 50% fan, 2.5 cm/s, 0.2mm layer (other layers are 9 cm/s, only the first one on support is 2.5 mc/s)
[attachimg=1]

But still sometimes the first layer on support does not catch well (it may still have holes). I see two options to try. Over extrude the first layer or slow down even the second layer on support (so that it can catch better if the first one fails). Any ideas? Over extrusion is probably better, but some video of printing bridges did first low extrusion and then thick one on it  :-\
Title: Re: The Living 3D Printing Thread
Post by: keypro on Thu, 17 July 2014, 12:22:46
Hi guys, what is the best 3D printer for making a keycap? I'm interested to get one but I need to learn more about 3D printer. I have seen a potato keycap from massdrop. As link provided, the spec is 3D Printed Beige. So If any 3D printer can do the same thing as that keycap, I will be so excited to get one!  :eek: :p
https://www.massdrop.com/buy/potato-keycap?s=keycap
Title: Re: The Living 3D Printing Thread
Post by: vvp on Thu, 17 July 2014, 13:06:58
The common dirt cheap FDM printers will not produce a keycap of good enough quality by themselves. If I would want to do a keycap I would use take some generic low profile Cherry MX keycap and I would cut sides of it away (leaving only the stem and the flat top of the keycap). I would 3dPrint the keycap shape I want without the stem and then I would glue it with the stem.

Even with an well calibrated FDM printer, you can get quite nice detailed prints with small nozzle (e.g. 0.3 mm), small layer height (e.g. 0.1 mm) and really low print speed (e.g. 3 cm/s). The only thing I would be afraid about is the strength of the stem (if you would 3dPrint it too).
See e.g. this as an example how small prints can look like:  http://www.tridimake.com/2013/05/3d-printing-with-smaller-nozzle-diameter.html
If you would add some acetone treatment to it then it would look even better (if you do not mind shiny).

Otherwise some SLA (stereolithography) printer can probably do it strong enough even with stem. But that is also much more expensive.
Title: Re: The Living 3D Printing Thread
Post by: keypro on Thu, 17 July 2014, 13:43:23
The common dirt cheap FDM printers will not produce a keycap of good enough quality by themselves. If I would want to do a keycap I would use take some generic low profile Cherry MX keycap and I would cut sides of it away (leaving only the stem and the flat top of the keycap). I would 3dPrint the keycap shape I want without the stem and then I would glue it with the stem.

Even with an well calibrated FDM printer, you can get quite nice detailed prints with small nozzle (e.g. 0.3 mm), small layer height (e.g. 0.1 mm) and really low print speed (e.g. 3 cm/s). The only thing I would be afraid about is the strength of the stem (if you would 3dPrint it too).
See e.g. this as an example how small prints can look like:  http://www.tridimake.com/2013/05/3d-printing-with-smaller-nozzle-diameter.html
If you would add some acetone treatment to it then it would look even better (if you do not mind shiny).

Otherwise some SLA (stereolithography) printer can probably do it strong enough even with stem. But that is also much more expensive.

Many thanks for your input. Do you own a 3Dprinter? Which brand? And have you ever pirnted a keycap yourself? Thanks! :p
Title: Re: The Living 3D Printing Thread
Post by: vvp on Thu, 17 July 2014, 16:45:10
I have an access to a somewhat improved Rostock (better diagonal rods, stiffer frame, geared extruder, integrated fan).
http://reprap.org/wiki/Rostock
I did not try to print any keycap. I would like to print a custom keyboard case first. Then maybe a keycap. I'm just not that interested in strangely shaped keycaps.
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Fri, 18 July 2014, 01:51:34
Hi guys, what is the best 3D printer for making a keycap? I'm interested to get one but I need to learn more about 3D printer. I have seen a potato keycap from massdrop. As link provided, the spec is 3D Printed Beige. So If any 3D printer can do the same thing as that keycap, I will be so excited to get one!  :eek: :p
https://www.massdrop.com/buy/potato-keycap?s=keycap

As long as you make sure to adapt your cap a bit to the technology there are plenty of printers capable of making decent key caps. None of them are very cheap though, and as mentioned, FDM is probably a bad idea for this. Examples:

(http://i.imgur.com/PJZLkfn.jpg)(http://i.imgur.com/GYPvxGH.jpg)
(http://i.imgur.com/e0CMtrY.jpg)(http://i.imgur.com/MyKdfWZ.jpg)

The last image shows some compromises which I recommend you to do to make the stem far easier to print.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Fri, 18 July 2014, 02:24:43
Some of them look like metal. So that would be SLS. Are the plastic ones done with SLS too?

I do not know whether there is any SLS printer which can be home made. There are some SLA home made printers.

Do you have any idea how is SLS expensive compared to SLA? As for as home made FDM, that is dirt cheap. Mostly the price of filament, which is somewhere around 25 per 1kg (for a good quality). Leslieann mentioned that resin for SLA is about 10 times more than filament for FDM.
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Fri, 18 July 2014, 10:12:36
Some of them look like metal. So that would be SLS. Are the plastic ones done with SLS too?

I do not know whether there is any SLS printer which can be home made. There are some SLA home made printers.

Do you have any idea how is SLS expensive compared to SLA? As for as home made FDM, that is dirt cheap. Mostly the price of filament, which is somewhere around 25€ per 1kg (for a good quality). Leslieann mentioned that resin for SLA is about 10 times more than filament for FDM.

Not only are there EBM, SLS, SLA and FDM, you can also sinter a very porous part which is later brazed together or a bonding agent added. You can also sinter either a positive or negative mold, and cast in it or use it to create another mold. Some machines are capable of performing several such stages.

Regarding the comparison of the cost between SLA and SLS:
The material is cheaper in SLS. It is powdered thermoplastic. The requirement is that it should be binned with a narrow enough spectrum of grain size with little contamination. SLA as a liquid has to have the right viscosity, react to UV or a particular wavelength, not react to oxygen or general light and is generally a more expensive thermoset. On the other hand, I'd say that SLS machines are larger, more expensive and not as suited to have in a home. Both materials can be nasty to have in a home as the tiny particles can cause respiratory issues and the liquids can give off fumes and be fairly carcinogenic too.

So yes, FDM is the only one I'd recommend at home, but I find them all to be quite bad. Especially when it comes to smaller things. They scale up better than some other technologies though.Speaking of FDM and homes, they are FDM printing houses these days. (http://vimeo.com/90333642)
Title: Re: The Living 3D Printing Thread
Post by: keypro on Sat, 19 July 2014, 04:42:48
Hi guys, what is the best 3D printer for making a keycap? I'm interested to get one but I need to learn more about 3D printer. I have seen a potato keycap from massdrop. As link provided, the spec is 3D Printed Beige. So If any 3D printer can do the same thing as that keycap, I will be so excited to get one!  :eek: :p
https://www.massdrop.com/buy/potato-keycap?s=keycap

As long as you make sure to adapt your cap a bit to the technology there are plenty of printers capable of making decent key caps. None of them are very cheap though, and as mentioned, FDM is probably a bad idea for this. Examples:

Show Image
(http://i.imgur.com/PJZLkfn.jpg)
Show Image
(http://i.imgur.com/GYPvxGH.jpg)

Show Image
(http://i.imgur.com/e0CMtrY.jpg)
Show Image
(http://i.imgur.com/MyKdfWZ.jpg)


The last image shows some compromises which I recommend you to do to make the stem far easier to print.

Those look nice! I want to make my own keycap but I don't know which printers suit me well. Thanks though
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Sat, 19 July 2014, 05:28:51
Hi guys, what is the best 3D printer for making a keycap? I'm interested to get one but I need to learn more about 3D printer. I have seen a potato keycap from massdrop. As link provided, the spec is 3D Printed Beige. So If any 3D printer can do the same thing as that keycap, I will be so excited to get one!  :eek: :p
https://www.massdrop.com/buy/potato-keycap?s=keycap

As long as you make sure to adapt your cap a bit to the technology there are plenty of printers capable of making decent key caps. None of them are very cheap though, and as mentioned, FDM is probably a bad idea for this. Examples:

Show Image
(http://i.imgur.com/PJZLkfn.jpg)
Show Image
(http://i.imgur.com/GYPvxGH.jpg)

Show Image
(http://i.imgur.com/e0CMtrY.jpg)
Show Image
(http://i.imgur.com/MyKdfWZ.jpg)


The last image shows some compromises which I recommend you to do to make the stem far easier to print.

Those look nice! I want to make my own keycap but I don't know which printers suit me well. Thanks though

For tiny plastic objects, I'd say SLA is the way to go.
Title: Re: The Living 3D Printing Thread
Post by: keypro on Sat, 19 July 2014, 22:12:11
Hi guys, what is the best 3D printer for making a keycap? I'm interested to get one but I need to learn more about 3D printer. I have seen a potato keycap from massdrop. As link provided, the spec is 3D Printed Beige. So If any 3D printer can do the same thing as that keycap, I will be so excited to get one!  :eek: :p
https://www.massdrop.com/buy/potato-keycap?s=keycap

As long as you make sure to adapt your cap a bit to the technology there are plenty of printers capable of making decent key caps. None of them are very cheap though, and as mentioned, FDM is probably a bad idea for this. Examples:

Show Image
(http://i.imgur.com/PJZLkfn.jpg)
Show Image
(http://i.imgur.com/GYPvxGH.jpg)

Show Image
(http://i.imgur.com/e0CMtrY.jpg)
Show Image
(http://i.imgur.com/MyKdfWZ.jpg)


The last image shows some compromises which I recommend you to do to make the stem far easier to print.

Those look nice! I want to make my own keycap but I don't know which printers suit me well. Thanks though

For tiny plastic objects, I'd say SLA is the way to go.

Where could I get it? any links would be appreciated! I think it's not available in Thailand. For making keycaps by using 3D printer, any basic knowledge of programming (design) needed? Thanks.  :thumb:
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Sun, 20 July 2014, 15:41:31
For tiny plastic objects, I'd say SLA is the way to go.
Where could I get it? any links would be appreciated! I think it's not available in Thailand. For making keycaps by using 3D printer, any basic knowledge of programming (design) needed? Thanks.  :thumb:
SLA is a type of additive manufacturing, not a brand. Here are a few machines which sort of target the home market:
Form 1 (https://www.kickstarter.com/projects/formlabs/form-1-an-affordable-professional-3d-printer)
Titan 1 (https://www.kickstarter.com/projects/kudo3d/titan-1-fastest-tallest-print-high-res-sla-3d-prin)
Pegasus (https://www.kickstarter.com/projects/fsl/pegasus-touch-laser-sla-3d-printer-low-cost-high-q)
Title: Re: The Living 3D Printing Thread
Post by: keypro on Sun, 27 July 2014, 13:10:48
For tiny plastic objects, I'd say SLA is the way to go.
Where could I get it? any links would be appreciated! I think it's not available in Thailand. For making keycaps by using 3D printer, any basic knowledge of programming (design) needed? Thanks.  :thumb:
SLA is a type of additive manufacturing, not a brand. Here are a few machines which sort of target the home market:
Form 1 (https://www.kickstarter.com/projects/formlabs/form-1-an-affordable-professional-3d-printer)
Titan 1 (https://www.kickstarter.com/projects/kudo3d/titan-1-fastest-tallest-print-high-res-sla-3d-prin)
Pegasus (https://www.kickstarter.com/projects/fsl/pegasus-touch-laser-sla-3d-printer-low-cost-high-q)


Thanks! I just realized that a 3D printer costs a lot of money and since I'm just a beginner about this. So, I have decided to play around with a company that offers 3d print service.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Fri, 01 August 2014, 21:55:10
my buddy dan pointed me at a new mechanical design for x-y carriages that i really really like. it's an extremely intelligent use of analog error cancellation (positive biased noise + negative biased noise often approaches zero): http://www.corexy.com
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sat, 02 August 2014, 05:31:55
Can you expand on how the noise cancellation works? This could be an advantage to delta.

I heard about core-xy before. The only thing I noticed is that one stepper does not need to be moved with the carriage. So there is a potential for it to be faster than the standard cartesian printers. It is actually the only thing I considered beside delta as a candidate for me. But I favoured delta because it does not need to move a stepper around too and I did not mind the bigger height. I just put it on the ground and it serves as a small table too  :cool:

One disadvantage for delta is that the precision and maximum speed depends on X/Y position.

There were times when delta was harder to precisely calibrate but now it is easy: just set the proper steps per mm(*) and probe the bed z-height and feed it to a program which tells you how to update the calibration parameters.

* which is easy since it depends only on belts, pulleys, steppers, and micro-stepping
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sun, 03 August 2014, 08:25:20
the error cancellation works by virtue of the belts pull on one another. belt and stepper noise on each side of the crossover bar, if we assume it to be gaussian, will tend toward the negation of the matching belt and stepper system on the other side of the gantry. very smart design out of MIT

it would be very difficult to implement this system on a delta design and achieve low error results. the problem with the delta design has to do with the number of joints/links between armature pieces more than the belts.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sun, 03 August 2014, 10:23:30
To tell the truth I do not understand what you are saying. If it is about vibrations from steppers then (since the equations are ∆x = (∆a+∆b)/2 and ∆y = (∆a-∆b)/2), clearly, if the vibrations get cancelled in the x direction then they are amplified in the y direction and vice versa.

But I found a nice article explaining how corexy eliminates unwanted moments on the carriage (which were introduced in hbot (which eliminated stepper on the carriage before corexy)):
http://joshuavasquez.com/docs/jVasquez/Projects/coreXY.html
The absence of moments will lead to longer life of the bushings/rods. That is clearly good.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sun, 03 August 2014, 10:33:23
it's about belts have an inherent inaccuracy due to the gear/stepper drive w/rt manufacturing tolerances on both gear and belt. assume this error is a gaussian, and give it a polarity depending on which surface of the belt you're pulling or pushing on. then, both gears pull on the far face of their belts, which results in positive tolerance on both sides. the overall tolerance of the system, which has positive tolerance towards the left on the left side and toward the right on the right side, will result in a system tolerance is the difference between each side's tolerance in expectation. is we assume that variance and mean are the same on each side, the system tolerance will approach zero in expectation.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sun, 03 August 2014, 14:50:25
system, which has positive tolerance towards the left on the left side and toward the right on the right side
This is the part which I do not see how it could apply to corexy.
It is not like the two corexy steppers work like the opposite sides of an anti-backslash nut. The steppers do not somehow apply a pretension on the belt forcing the belt to be always aligned to one side of the pulley teeth.

The two steppers are independent. Really (from the point of view of carriage movement and belt alignment to pulley errors) corexy looks only like a mechanism which transforms the coordinate system. In corexy it is rotated by 45 compared to a traditional cartesian. If you would not mind that the build area is diamond shaped (and not square shaped) then you can drive corexy just like a traditional cartesian. In corexy, driving only one stepper just moves carriage along a diagonal and changing direction of this one stepper (the second one still standing) will experience backslash just like in a traditional cartesian. The only difference is that the backslash will be along diagonal.

If corexy would somehow eliminate pulley to belt alignment error (the backslash) then you probably can also claim that traditional cartesian can eliminate this error too when it moves only diagonally (drives both steppers at the same time).
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sun, 03 August 2014, 20:00:50
system, which has positive tolerance towards the left on the left side and toward the right on the right side
This is the part which I do not see how it could apply to corexy.
It is not like the two corexy steppers work like the opposite sides of an anti-backslash nut. The steppers do not somehow apply a pretension on the belt forcing the belt to be always aligned to one side of the pulley teeth.

The two steppers are independent. Really (from the point of view of carriage movement and belt alignment to pulley errors) corexy looks only like a mechanism which transforms the coordinate system. In corexy it is rotated by 45 compared to a traditional cartesian. If you would not mind that the build area is diamond shaped (and not square shaped) then you can drive corexy just like a traditional cartesian. In corexy, driving only one stepper just moves carriage along a diagonal and changing direction of this one stepper (the second one still standing) will experience backslash just like in a traditional cartesian. The only difference is that the backslash will be along diagonal.

If corexy would somehow eliminate pulley to belt alignment error (the backslash) then you probably can also claim that traditional cartesian can eliminate this error too when it moves only diagonally (drives both steppers at the same time).
let's forget about bias and polarity of forces on the carriage here for a second. assuming iid error on the A and B steppers and respective belts, dY = c(dA - dB). error cancellation.

you may be right about the dX motion. i may have been over/underthinking myself on that one.
Title: Re: The Living 3D Printing Thread
Post by: gcb on Fri, 08 August 2014, 06:04:09
If anyone want to have a go on my just designed arcade buttons that use cherry MX (how come nobody thought of that before?!) here you go:

print one of these http://www.thingiverse.com/thing:421598

and one of these http://www.thingiverse.com/thing:417509

just pay attention to the 2 paragraph instructions on each "thing" and you should be fine.

I don't have a printer yet. And i'm dying to know if the plastic "plate" will survive one match of street fighter :D
Title: Re: The Living 3D Printing Thread
Post by: vvp on Fri, 08 August 2014, 16:52:18
assuming iid error on the A and B steppers and respective belts, dY = c(dA - dB). error cancellation.

I thought about it but the only result is that that I more believe that corexy does not have any built-in error cancellation for stepper pulley / belt meshing errors. That equation is just a mechanical coordinate transformation thing.
Here is the picture:
[attachimg=1]
Lets assume the carriage is moving up first. Both steppers are moving the red/blue arrow directions, i.e. red (left) stepper counter clockwise, blue (right) stepper clockwise.
There you go. There is full play even in the Y direction. No cancellation.

CoreXY is cool. If I would built a cartesian bot it would be corexy. But I do not think it has any error cancellation features related to the play between pulleys and belts.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Fri, 08 August 2014, 17:08:11
If anyone want to have a go on my just designed arcade buttons that use cherry MX (how come nobody thought of that before?!) here you go:

print one of these http://www.thingiverse.com/thing:421598

and one of these http://www.thingiverse.com/thing:417509

just pay attention to the 2 paragraph instructions on each "thing" and you should be fine.

I don't have a printer yet. And i'm dying to know if the plastic "plate" will survive one match of street fighter :D

What printer are you planing to get? As you designed it, it will be very hard to print with an FDM printer.
The problems to fix if you want to use FDM:

The button itself should be printable as you have it but the stem may not be strong enough.
Title: Re: The Living 3D Printing Thread
Post by: gcb on Fri, 08 August 2014, 17:46:48
If anyone want to have a go on my just designed arcade buttons that use cherry MX (how come nobody thought of that before?!) here you go:

print one of these http://www.thingiverse.com/thing:421598

and one of these http://www.thingiverse.com/thing:417509

just pay attention to the 2 paragraph instructions on each "thing" and you should be fine.

I don't have a printer yet. And i'm dying to know if the plastic "plate" will survive one match of street fighter :D

What printer are you planing to get? As you designed it, it will be very hard to print with an FDM printer.
The problems to fix if you want to use FDM:
  • Remove the top rim of the housing so that the cylinder wall ends at the top suface of the Cherry MX mounting plate.
  • Align the tops of the clips to the top of the mounting plate.
  • You may need to make clips thicker so that they are stronger.
  • Turn the whole thing upside down.
  • If the inner overhang is wider than nozzle diameter then make it smaller.
  • Print with support touching build plate enabled in slicer so that the outer overhang does not sag.

The button itself should be printable as you have it but the stem may not be strong enough.

to be honest, i was thinking about visiting a hackerspace and was going to print the threaded version of the housing split in two... so that i'd sandwich the switch and hold everything thogheter with a nut :)  so i'd be printing 2 tunnels.... but yeah, i gave up that idea when i start to consider metal printing on shapeways...

but i think i can improve it for FDM with your suggestions...

1. i was planning on adding a few trapezoids on the side so the switch could take a heavier beating... but yeah, without the support i think i should do that. (that is actually the bottom :) (which cover your number 4... i still have to get used to the community preference for inverted Z)

2. the part is parametric and people will probably adapt it to several sizes. made it that way to fit it with most 80's cabinet panel wood depth. but i will adapt it to sanwa spec when i get my switches in the mail. then i will probably fine tune it more.

3. what do you suggest? the part actually has one variable wall_thickness that control the desired minimal wall of the whole part. it is currently 1 or 2mm...

4. have to get used to everyone's upside down world :)

5. are you talking about the button plunger (keycap) hole vs the main cylinder body size? yeah, that is a mistake that i will fix if not, no clue :)

6. i understood no word from this one.



Title: Re: The Living 3D Printing Thread
Post by: vvp on Fri, 08 August 2014, 18:12:30
If you are going to print it in metal using SLS or EBM then it is good just as it is.

add 1,2) Removing of the rim at the top was intended so that if you flip it upside down then the whole MX switch mounting plate will be touching the build plate. No support needed there and it will stick well to the build plate. The alignment of the tops of the clip id done for the same reason.

add 3) Thin short walls (like in the clips) are not very strong when they come from an FDM printer. FDM printed plastics will split (de-laminate) along layer boundaries more easily. The short vertical walls start to be usable at about 2 * nozzleSize. If you need to print thing cuboids then it is good you if you can orient them in such a way so that filament is laid down along the longest dimension of the cuboid. This is not possible in the case of your button housing so other option is to make the wall thicker.

add 5) Yes. If the overhang should not be there than even better.

add 6) You will when you will actually print and play with slicers for FDM printing. The point is that outer overhang (that is the overhang opposite of the inner one you are going to remove) cannot be printed in air. It is too big for that. It would sag down. It must have some support from the bottom. Slicers can generate such a support automatically. I was telling you that you should ask slicer to "generate support touching build plate" automatically.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sat, 09 August 2014, 13:55:55
assuming iid error on the A and B steppers and respective belts, dY = c(dA - dB). error cancellation.

I thought about it but the only result is that that I more believe that corexy does not have any built-in error cancellation for stepper pulley / belt meshing errors. That equation is just a mechanical coordinate transformation thing.
Here is the picture:
(Attachment Link)
Lets assume the carriage is moving up first. Both steppers are moving the red/blue arrow directions, i.e. red (left) stepper counter clockwise, blue (right) stepper clockwise.
  • The bottom teeth of the red stepper pulley will be aligned to the left side of the belt teeth.
  • The bottom teeth of the blue stepper pulley will be aligned to the right side of the belt teeth.
  • Now we change the direction of both motors so that the carriage is moving down.
  • First both steppers move a little bit without moving the belts/carriage.
  • Then finally the red stepper pulley will engage the right side of the belt teeth and move the red belt.
  • At about the same time the blue stepper pulley will engage the left side of the belt teeth and move the blue belt.
There you go. There is full play even in the Y direction. No cancellation.

CoreXY is cool. If I would built a cartesian bot it would be corexy. But I do not think it has any error cancellation features related to the play between pulleys and belts.
what you're saying is true regardless of which direction the steppers move. however, look at the next pulley. in each system. we're looking at the error _at the carriage head_. in y-motion, the force of the two belts oppose each other. that's where the error would otherwise be coming from. you have to calculate ultimate positioning error due to red and blue forces.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sat, 09 August 2014, 14:23:32
what you're saying is true regardless of which direction the steppers move. however, look at the next pulley. in each system. we're looking at the error _at the carriage head_. in y-motion, the force of the two belts oppose each other. that's where the error would otherwise be coming from. you have to calculate ultimate positioning error due to red and blue forces.
If you mean there are no moments of force on the big carriage (and therefore it should not twist a bit while it is changing direction) then I agree. That is the advantage against hbot.

If you mean that the forces will not move the small carriage because they compensate each other then they better should. If they would not then it would be worse than a simple cartesian because what was intended only a Y motion would cause a small X motions too.

If you mean something else than I do not understand.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sat, 09 August 2014, 14:46:20
There may be something wrong with Makerbot Gen 5 machines:
http://www.hacknorway.com/project.php?id=28
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Sat, 09 August 2014, 15:29:06
There may be something wrong with Makerbot Gen 5 machines:
http://www.hacknorway.com/project.php?id=28

Can't help but be a little happy that Stratasys seems to fail at everything they try.
Title: Re: The Living 3D Printing Thread
Post by: salcan on Sat, 09 August 2014, 17:54:13
There may be something wrong with Makerbot Gen 5 machines:
http://www.hacknorway.com/project.php?id=28

Can't help but be a little happy that Stratasys seems to fail at everything they try.

Hm, kinda interesting. I don't have a z18, but we have a replicator 2x at work and it won't even get close to printing a passable keycap.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sat, 09 August 2014, 21:29:40
ssys is headed downhill quickly.

unfortunately i seemed to have acquired a lot of insider baseball on the company and the future does not look particularly good for them.

other than AHEM someone's ridiculously incredible single product company, i don't really know much about the rest of the industrial market, but i do know that all the consumer efforts seem to be failing on top of that.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sat, 09 August 2014, 21:32:16
what you're saying is true regardless of which direction the steppers move. however, look at the next pulley. in each system. we're looking at the error _at the carriage head_. in y-motion, the force of the two belts oppose each other. that's where the error would otherwise be coming from. you have to calculate ultimate positioning error due to red and blue forces.
If you mean there are no moments of force on the big carriage (and therefore it should not twist a bit while it is changing direction) then I agree. That is the advantage against hbot.

If you mean that the forces will not move the small carriage because they compensate each other then they better should. If they would not then it would be worse than a simple cartesian because what was intended only a Y motion would cause a small X motions too.

If you mean something else than I do not understand.
yes, i'm talking about the former, specifically twist and ringing. obviously during a steady state feed, the thing is just moving and that's about that.

Title: Re: The Living 3D Printing Thread
Post by: damorgue on Sun, 10 August 2014, 05:41:12
The consumer SLA machines which are reaching the market appear good. They cost a bit more than the FDM ones, and the material is a bit more special and expensive. On the other hand though, with a more unique and better controlled material comes the advantage of higher consistency among batches and manufacturers. The technique itself is less prone to problems too. There is no chance of clogging, over/under heating or damaging other combonents and it has less mechanical moving parts. I think it can provide the reliability and consistent prints which the consumer market is lacking. SLA also allows for finer detail than FDM so the added price can be somewhat justified by that too.

The only thing which needs to happen is a decrease in price and I think it could grow big. Hopefully people's initial expectations on cheaper FDM doesn't throw them off the idea of at-home additive manufacturing all together.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Mon, 11 August 2014, 12:48:00
i haven't been following SLA. i do know that the FFM machine market is starting to become dominated by inexpensive chinese clone designs whose prices are inexpensive enough to match their utility (not all that high). a lot of the early home SLA efforts that raised initial funds on kickstarter, etc. don't look all that promising, but the market is pretty much wide open, so i'm quite interested to hear if someone with competent manufacturing and engineering resources has come out with something nice.

imo, nothing driven by an 8-bit micro is competent, so just toss all of those out immediately :P
Title: Re: The Living 3D Printing Thread
Post by: gcb on Wed, 13 August 2014, 16:28:19
Do you guys know a good reference for designing for FDM? i can't find anything.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Thu, 14 August 2014, 06:03:43
If you search my posts in this thread I was giving some recommendations.
I do not know about some better design guide for FDM. Googling seems to return only some guides for commercial 3d printing which may be applicable if you have an excellent slicer but home made reprap machines seem to have more limits than what is mentioned. It probably depends a lot whether you have a separate dissolveable support material.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Sat, 16 August 2014, 14:29:17
Do you guys know a good reference for designing for FDM? i can't find anything.
if you're doing true FDM and not filament fusing, you can use the shapeways references. they're pretty good for the majority of machines. they have specific wall tolerances to their machines, but generally you want to stay much larger than those anyway.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sun, 17 August 2014, 06:02:04
Based on wiki there FFF (fused filament fabrication) is just another name for FDM. The difference is that Stratasys has a trademark on FDM.
So the question probably is whether it is going to be  printed on a commercial machine or a reprap. The process is the same. The differences are in firmwares and slicers and whether you have a separate nozzle for support material.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Mon, 18 August 2014, 00:06:43
i can't really say much more, but FDM doesn't even require thermoplastics to be used. the stratasys patent is limited, but there are a large number of techniques that are considered FDM.

we're mincing terms at this point though. it's kind of like how AHEM arcam calls their process Electron Beam Melting (EBM) instead of Selective Laser Sintering (SLS), because their laser is so thin and there are specific proprietary magics going on inside the vacuum chamber that constitute their IP protected process.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Mon, 18 August 2014, 03:08:14
OK, so the process is not the same (or the names FDM/FFF are not specific enough). Thanks.
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Sun, 31 August 2014, 16:45:35
I honestly see little future for FDM. They aren't being developed fast enough and struggle a bit as it stands. Their biggest advantage is that they are less limited in how big they can get, something which isn't a concern to the hobbyists. The example I posted earlier where it is used to build enormous building components is an interesting example which SLA or SLS would have had a hard time accomplishing.

There are machines which use the better technologies for additive manufacturing which and approaching consumer level pricing. Here is a new cheap-ish SLS printer:
https://www.kickstarter.com/projects/1812935123/ice1-and-ice9-the-first-low-budget-sls-3d-printers?ref=card

I recon the first wave of "at-home-3d-printers" has hit and passed leaving many wanting more, and that FDM didn't turn out as good as many people had hoped. I think it will soon be the time for better 3D printers to find their way to hobbyists.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sun, 31 August 2014, 17:37:10
Hopefully they can deliver. I would buy an SLS printer for 5k if the material price would be comparable to what we have for FDM. If they would want 10 more for material (as leslieann mentioned it is with SLA) then I'll pass.
Title: Re: The Living 3D Printing Thread
Post by: damorgue on Mon, 01 September 2014, 02:21:42
Don't forget to  account for less material use. Instead of using more filament to build a support structure and waste more material the part is suspended in reusable powder which supports it instead, and you will likely have less failed parts which will have to be reprinted. Material prices depend a lot on bulk volume and I think they can be decreased somewhat for low volume hobbyists if this thing takes of more stores dedicated towards hobbyists begin to offer it.
Title: Re: The Living 3D Printing Thread
Post by: mkawa on Tue, 02 September 2014, 01:33:36
i think one thing that people forget when thinking about printing in general is how freaking hard it is in any number of dimensions. a HUGE number of extremely hard engineering problems had to be solved to turn computable objects in 2-space into pieces of paper and even though some devices are basically commoditized now, there are many that aren't: very high resolution, solid inks, very soft and very hard printed mediums, perceived color correspondence between source and output, extremely large format, extremely small format, etc. etc. etc.

butler lampson is one of the smartest people to have lived in the last 30 years, and he spent like 5 good years trying to make graphite fusing laser printing on paper happen. that crap was hard!

although i hate to say it, because i think it's kind of silly, FFM will almost certainly settle into life as a commodity where the printed medium is a starchy polymer, the machine designs will differentiate based only on whether the bed moves horizontally or vertically, and the support is just more water soluble than the print. there's absolutely nothing wrong with this, as long as the machines reach commodity pricing. see: idealab's new mod-t printer. longevity of this machine will be about the same as a typical 30$ inkjet printer, but frankly, that's enough for the vast majority of users. ie, they'll get it to make one or two objects either to demonstrate a point or to replicate a neat design they saw, but their interest will mostly end there.

zzzz.... more later.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Tue, 02 September 2014, 04:39:05
makwa: 3dPrinting does not sound hard to me. How it could be hard when people build printers themselves at home and they actually work quite well. There is a lot of work to make them better (especially better firmwares and slicers) but it is just a simple implementation. Medium level code monkeys can do it. Strengthening printer structure is not hard either. No new research is needed.

damorgue: Material wasted in FFF printers on support and failed prints is about 30% at most. That is my experience. You cannot claim much savings there. You can claim better savings in time when designing parts (less constrains for SLS/SLA) and post processing (when support is not soluble). And of course, some things are well doable in SLS/SLA but not practically doable in FFF.
Title: Re: The Living 3D Printing Thread
Post by: gcb on Fri, 17 October 2014, 23:00:49
so the cheap filament printer i will find in the nearby hackerspace is not exactly an FDM?  what keyword should i look for when researching design guides?


PS: it is freaky as hell having fred mercury staring at you while you read the nice informative posts about 3d printing.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sat, 18 October 2014, 03:48:18
It is probably FDM. FFF is just a different name for FDM.
http://en.wikipedia.org/wiki/Fused_deposition_modeling
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sat, 18 October 2014, 04:31:31
I was talked into trying to print a keycap (including the stem).
Doing it the way an original stem looks like is not possible with 0.5 mm nozzle.
So this is out of the question:
[attach=1]
But after removing a small sprue on the switch stem it is possible to make the keycap stem bigger and then it is printable. Quite a bit of clean up is needed around the stem. I painted it with acetone to make sure the fibres fuse better. It is seems to be strong enough.
[attach=2]
The top view. There is some error in the layer alignment on the keycap sides. Not sure why that happens. The common reasons are fluctuating hotend or bed temperature or uneven extrusion. But that is probably not my case. I would blame it on slicer :-)
[attach=3]
It fits OK.
[attach=4]

So I need to correct my original opinion. It is possible to print a keycap with a strong enough stem using FFF. It is just a lot of work.
Title: Re: The Living 3D Printing Thread
Post by: NeedAFix on Sat, 18 October 2014, 04:38:54
This is proof of concept though, now all that musts needs be done is Improvement, Dramatic improvements!

Innovation FTW.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sun, 19 October 2014, 14:03:42
Version 2. The good about it is that only post processing needed was to cut away the remains of the brim. And I painted it with acetone. It may not be needed. But it is quick, makes surface smoother, and helps layer adhesion.
I changed the stem dimensions slightly. Before I needed to "scrub"  the inside of the stem too. Now it fits Cherry MX like a butt on a chamber-pot  :))
[attachimg=1]
Ok, this is only for fun. People here clamour for double shot PBT keycap magic so FFF printed ABS will not do. But still, it was fun to try it.
Title: Re: The Living 3D Printing Thread
Post by: gcb on Mon, 27 October 2014, 16:13:14
now you got me wondering... why not print the whole thing? all the way down!

imagine printing the cap, steam (not sure about naming. the brown/blue/black/red/etc thing that pushes the contacts.)

would also have to cut one side of the switch cove to slide everything in.

maybe it will be harder because that lower part requires even less clearance on the end...  but should be interesting.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Tue, 28 October 2014, 08:27:22
I do not think it makes sense to try to print the switch itself using a reprap:
* you cannot print the metal parts anyway (so one would need to buy a switch for the metal parts)
* ABS/PLA have low glass transition temperature - the switch housing would soften and deform when soldering the switch
* its lifetime would be low since ABS/PLA are less abrasion resistant compared to delrin
* some parts of the switch are too thin (notice how I needed to increase the size of the keycap stem compared to the original to make it printable)
Title: Re: The Living 3D Printing Thread
Post by: vvp on Tue, 28 October 2014, 11:29:26
As for as the research and 3dPrinters, this was recommended for people who want to improve delta printers.
http://books.google.sk/books/about/Parallel_Robots.html?id=78DHjrzNt9oC
Title: Re: The Living 3D Printing Thread
Post by: Krogenar on Wed, 19 November 2014, 07:45:38
I was going to put this in 'Great Finds' but figured this might be the more appropriate place.
A company called USCutter (http://www.uscutter.com) that is located in Redmond, Washington is having an Open House on December 12th. Why is that important? They sell a 3d printer and various vinyl cutting machines - and they're giving away a 3d printer and a vinyl cutter as door prizes. I received an email with this test:

Redmond Washington Open House on 12/12!

Quote
If you live in or will be visiting the Northwest December 12, consider this your invitation to come see us at our big Open House at our USCutter location in Redmond, WA. There will be food and drinks galore. Were giving tours of our warehouse and showrooms. And well be showing off the latest new Mimaki, our full line of 3D printers from Leapfrog, Phoenix, and other equipment that can help make your 2015 more prosperous. Well also be giving away a Mimaki 28 CG-SRIII and a Phoenix 3D Printer as door prizes and other goodies as well.
The fun starts at 12 Noon and well be open until 7PM. Mark your calendars now and plan to attend. We'd love to see you there!

Now, I'm in New York - but I know a lot of Geekhackers live in the California area, so if I were you guys --- ROAD TRIP! Get as many people together as possible, and work the numbers on the door prize. The Phoenix 3d printer is here: http://www.uscutter.com/Phoenix-3D-Printer-EZ3D

Hope this maybe helps someone get into their first 3D printer.

EDIT: Ok, I realize now that California is actually VERY FAR from Seattle.  ;D
Title: Re: The Living 3D Printing Thread
Post by: Asininity on Wed, 04 February 2015, 23:31:39
I was inspired by others and tried 3D printing a keycap. I didn't use my own design but from someone on Thingivesrse The results were mediocre (not due to the file but the 3D printer.)

(http://i.imgur.com/o3B4NE0.jpg)

(http://i.imgur.com/7I6av4M.jpg)
The greatest difficulty was the Stem. With a little work I was able to clean it out.

(http://i.imgur.com/oIvaVZk.jpg)
I'm hoping to solve these issues by using a uPrint that's available to me. It uses a proprietary cartridge and costs $1 per gram, which is a lot. However, the keycaps I made (using a different 3D printer) weighed only 1g.



Title: Re: The Living 3D Printing Thread
Post by: KHAANNN on Sat, 21 February 2015, 06:13:26
I was just thinking of printing/designing a simple keycap, upside-down printed so there are no supports, therefore having a flat surface (as a down-side)
(and consider using 3d printed keycaps from now on : )

PLA comes easy to me, but I'm not sure how it will act as a keycap, yet I'm sure the texture from the 3d printing will make the cap feel great

Any inspiration / existing designs? (I checked the very few thingiverse designs, yet they all concentrate on design/accuracy rather than printability)

I guess it's not a very good idea, better buy dsa/pbt blanks instead :)
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sat, 21 February 2015, 06:35:54
You do not need to print it upside down. FFF printers are good enough at bridging to print a keycap. Just design the bottom side of keycap top to be horizontal and it will print just fine without support. See here:
https://geekhack.org/index.php?topic=43362.msg1507680#msg1507680
Title: Re: The Living 3D Printing Thread
Post by: KHAANNN on Sat, 21 February 2015, 07:42:37
You do not need to print it upside down. FFF printers are good enough at bridging to print a keycap. Just design the bottom side of keycap top to be horizontal and it will print just fine without support. See here:
https://geekhack.org/index.php?topic=43362.msg1507680#msg1507680

Theoretically yes, but practically it's much easier, robust to print without bridges and supports, also the end results is usually much more pleasing
Title: Re: The Living 3D Printing Thread
Post by: tp4tissue on Wed, 25 February 2015, 14:35:56
Hey guys..  I'm about to pull the trigger on a Form 1+  ..  any other recs that I should look at  @ this price range?
Title: Re: The Living 3D Printing Thread
Post by: BlueNalgene on Fri, 17 April 2015, 23:21:47
Hey guys.  I made a thing.  I originally posted the .stl files in the CAD thread, but I figured I should cross post it here in case anyone finds it useful.

I'm teaching myself Fusion 360 so I have some experience with CAD which is based on a GUI rather than scripting.  My practice item is a Row 3 spherical keycap.  This should be similar to the SA keycap dimensions but not quite the same.

(http://i.imgur.com/VSZQ1Vg.png)

(http://i.imgur.com/gN5zWHE.png)

I've sent off to have Sculpteo print a copy of it off, so I can see how it looks in the real world.  My first time using Sculpteo over i.Materialise, so I am interested to see how their stuff looks in comparison.

If you want the .stl file, I attached it to this post (https://geekhack.org/index.php?topic=47744.msg1710259#msg1710259).  If somebody wants a different format, let me know, and I will try to hook you up.

I got the real world version in today.  My 3D printed cap. 
(http://i.imgur.com/f69hiKG.jpg)

The height is somewhere between Signature Plastic's DSA and SA row 3 profiles

(http://i.imgur.com/eUjFSm0.jpg)

I'm glad I did this test run.  The stem shrank in a way I didn't expect, and the cruciform is a bit too big.  It slips on and off the stems too easily.  This is an easily fixable problem.

(http://i.imgur.com/i6mCA9D.jpg)
Title: Re: The Living 3D Printing Thread
Post by: CPTBadAss on Sat, 18 April 2015, 00:21:38
Nice cap bluenalgene
Title: Re: The Living 3D Printing Thread
Post by: MOZ on Sat, 18 April 2015, 05:03:14
Nice design.
Title: Re: The Living 3D Printing Thread
Post by: TheJonas on Wed, 10 February 2016, 02:08:56
Don't mean to bump a dead thread, but didn't wanna make my own if it's already there. I've got access to one of those Cube 3D printers and a MakerBot Replicator 2. I've tried printing a cherry R2 keycap and it turned out alright, needs a bit of filing, but I recently found out I can change the filament to be much thinner. I've also tried printing a topre keycap, but had no support and the edges turned into spaghetti. I don't have much time to tinker around with 3D files at the moment, but once I do I would want to make MX compatible sliders next. Anyone have any experience with these?
Title: Re: The Living 3D Printing Thread
Post by: sinusoid on Wed, 10 February 2016, 13:31:10
Don't mean to bump a dead thread, but didn't wanna make my own if it's already there. I've got access to one of those Cube 3D printers and a MakerBot Replicator 2. I've tried printing a cherry R2 keycap and it turned out alright, needs a bit of filing, but I recently found out I can change the filament to be much thinner. I've also tried printing a topre keycap, but had no support and the edges turned into spaghetti. I don't have much time to tinker around with 3D files at the moment, but once I do I would want to make MX compatible sliders next. Anyone have any experience with these?

This thread shouldn't be dead imvho :P

Makerbot Replicators 2 are solid machines.

What do you mean by changing the filament to much thinner? This shouldn't affect your prints. What you want to change is the print head diameter, preferably to something like 0.2.

If you want to avoid spaghetti, cut the models into two parts that will print nicely and glue them together, then file.
You can also use Replicator's two heads to print support from a dissolvable plastic. for PLA use PVA, for ABS use HIPS.
PVA dissolves in water, HIPS in Limonene.
That's overkill in most cases, though.

As for 3d printing keycaps: you need calipers, some 3d software, patience and time. Print, make amends to the model, print again. FFF printers tend to mess up the dimensions on a submilimeter scale, there are several factors that stack up on each other:
- calibration
- imperfections in the filament
- plastic properties (flow, shrinkage)
- approximations in the slicer software
- oscillation from mechanical parts
etc.

From my experience slicers mess up the most, both commercial and opensource. Stick to one slicer, get to know it, you'll do fine.
Title: Re: The Living 3D Printing Thread
Post by: TheJonas on Sun, 14 February 2016, 00:18:42
Thanks for the reply and excellent advice. I indeed didn't mean change the filament but instead the printing head. Cutting the molds in half is a great idea, but I'd rather not do that. Getting to know one printer and make adjustments based on your prints is probably what I'll be doing now.
Title: Re: The Living 3D Printing Thread
Post by: KHAANNN on Sun, 14 February 2016, 01:38:40
Anyone else get a new spool for every new project? :)

Just got a spool of Colorfabb's PLA/PHA in black, can't wait to try it out - to print a keyboard plate

I'm just hoping it's more matte then regular black PLA, because that turns out pretty glossy
Title: Re: The Living 3D Printing Thread
Post by: TheJonas on Sun, 14 February 2016, 02:15:52
1 spool per project would drive up the costs, then yet again, running out halfway could be worse. Show us some pics of your 3D print once it's done :)
Title: Re: The Living 3D Printing Thread
Post by: KHAANNN on Sun, 14 February 2016, 03:20:57
1 spool per project would drive up the costs, then yet again, running out halfway could be worse. Show us some pics of your 3D print once it's done :)

For me it's a seldom hobby or occupation, so spools costs aren't much of a worry, haven't ran out of a spool yet :) - tho my current chinese black pla is about to be done

Here is my initial prototype
[attachimg=1]

I was going to use this case with colorfabb bronzefill, yet exotic filaments are too risky, and I'm not sure how it would turn out, so decided to stick to black PLA instead, as the keycaps are Dolch, and gray + black + Dolch would probably go well

Here is a prototype bronze plate:
[attachimg=2]

After clogging my initial hotend with bronzefill, then dislodging the replacement E3D with XT-CF20, sticking to PLA seems like the better choice, tho I have a hunch the E3D should handle bronzefill well, but can't risk it
Title: Re: The Living 3D Printing Thread
Post by: TheJonas on Sun, 14 February 2016, 03:27:06
Looks like a snug fit. Any idea as to why it clogged up? It seems to have less of a mesh texture, or is that just because it's small?
Title: Re: The Living 3D Printing Thread
Post by: KHAANNN on Sun, 14 February 2016, 03:39:07
while pla is more like a gel in optimal circumstances, bronzefill felt a lot like clay, so my guess is only a pristine and clean nozzle should handle it well, my nozzle at the time was a year old (hexagon), clogged really bad, I could only unclog it by repeatedly penetrating it with a thin wire, it took days, then I realized I bent the hotend anyway, and got an E3D

If the temp/speed dynamics aren't optimal with bronzefill, it should irreversibly clog the nozzle fast, once a build up occurs in the nozzle, it's really hard to get decent performance afterwards
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sun, 14 February 2016, 13:35:58
Anyone else get a new spool for every new project? :)
Not me. But do you know that you can pause a print, replace the spool/filament and continue later? The filament will not be perfectly primed so you will be able to notice it on the printed part but it mostly does not matter.

Edit: The best place to do it is during infill.
Title: Re: The Living 3D Printing Thread
Post by: KHAANNN on Sun, 14 February 2016, 13:43:15
Anyone else get a new spool for every new project? :)
Not me. But do you know that you can pause a print, replace the spool/filament and continue later? The filament will not be perfectly primed so you will be able to notice it on the printed part but it mostly does not matter.

Edit: The best place to do it is during infill.

yeah :D

used to do it a lot, not for replacement but mainly for fun, mixing different colors

last time I paused a print tho, during a power outage, things went to hell, for some reason the print didn't continue as expected, it turns out if I waited 2-3 minutes the power would come back and the ups would last - after that event I didn't risk another pause yet, let alone a spool change :)

In hindsight, I'm guessing it was a Simplify 3D bug
Title: Re: The Living 3D Printing Thread
Post by: vvp on Sun, 14 February 2016, 13:46:25
If the printer controller board lost power then the internal state was lost too. I'm not surprised resume did not work.
Title: Re: The Living 3D Printing Thread
Post by: alexjd99 on Sun, 14 February 2016, 14:02:54
1 spool per project would drive up the costs, then yet again, running out halfway could be worse. Show us some pics of your 3D print once it's done :)


Here is a prototype bronze plate:
(Attachment Link)

After clogging my initial hotend with bronzefill, then dislodging the replacement E3D with XT-CF20, sticking to PLA seems like the better choice, tho I have a hunch the E3D should handle bronzefill well, but can't risk it

Bronzefill plate is giving me so many ideas.
Ninjaflex plate here I come  ;)
Title: Re: The Living 3D Printing Thread
Post by: sinusoid on Sun, 14 February 2016, 15:12:44
I use Orbitech black or neutral ABS for my stuff, rather avoiding PLA.

The reason is mechanical properties - PLA is impossible to sand, cut or machine. Any attempt at postprocessing it is a gate to a world of pain. Since I print stuff to tight tolerances, I often remove imperfections from the prints mechanically, and ABS has the right feels for that. Plus - you can easily glue it with acetone or ABS juice.

PLA is very good for polyester resin pouring, if you want to make molds out of it. Peels off without any mold separator or anything. You can heat it up a little, that helps to get it off the model.
ABS is totally crap at it.

I'm curious about metal powder mix filaments, because they might have better heat conductivity and lower shrinkage rate, especially when ABS is used as base. Haven't used them yet, though.

Ninjaflex is totally nuts, one of the most awesome materials I've printed with. Takes some time to get used to it, but then it's simply awesome.
Use PVA or PLA as support on a dual-extruder machine.

If anyone knows what solvent works for Ninjaflex, please tell!
Title: Re: The Living 3D Printing Thread
Post by: TheJonas on Mon, 15 February 2016, 01:15:28
Anyone else get a new spool for every new project? :)
Not me. But do you know that you can pause a print, replace the spool/filament and continue later? The filament will not be perfectly primed so you will be able to notice it on the printed part but it mostly does not matter.

Edit: The best place to do it is during infill.

yeah :D

used to do it a lot, not for replacement but mainly for fun, mixing different colors

last time I paused a print tho, during a power outage, things went to hell, for some reason the print didn't continue as expected, it turns out if I waited 2-3 minutes the power would come back and the ups would last - after that event I didn't risk another pause yet, let alone a spool change :)

In hindsight, I'm guessing it was a Simplify 3D bug

If you lose power the memory probably got cleared, best to start over again in this case. Don't hold yourself back and mix those colors :D
Title: Re: The Living 3D Printing Thread
Post by: KHAANNN on Mon, 15 February 2016, 04:39:58
My previous assumption was the print to be stateless, so the printer could execute the g-code at hand, and after the resume, continue executing the remaining g-code simplify3d sends, I also recall asking at robo3d forums about this scenario, remember getting a positive reply, however since the printer auto-levels at the firmware level, obviously at a power loss that information would be lost too, so the non-continuity is obvious in this case :D - I should've probably let the printer board stay powered

Don't know why but I always have a strong desire to try exotic materials for keyboards, I briefly considered a fully bronze keyboard after posting the prototype, however the size challenge is keeping me back

The keyboard would need to be printed in 2-3 pieces, and those 2-3 pieces never align perfectly, the alignment flaws are almost always noticeable from the keycaps

It's probably a good idea to
1) Print the case in 2 pieces, the top plate would be a part of the case
2) Print the lower plate in 3 pieces, so the intertwined parts could correct the alignment
Result) Making the keyboard a hand-wired one with a 5mm plate

But still, a small impact could bend the keyboard easily, so some sort of glue would need to be used, one that is strong, yet doesn't take up space between the parts

Even if it turns out perfect, 3d printed parts are awful to touch :D
Title: Re: The Living 3D Printing Thread
Post by: vvp on Mon, 15 February 2016, 06:24:53
This works well with ABS:
Title: Re: The Living 3D Printing Thread
Post by: TheJonas on Mon, 15 February 2016, 06:46:13
I prefer laser cutting some acrylic for a plate (don't ban me from this thread). But as vvp mentioned; leaving a gap between the plates and then filling it up should work. However, vvp, the reason for printing it in three pieces is because a one-piece 60% plate is impossible to print for some people, as the dimensions can be larger than the build plate. So it would not be possible to print a planar piece the size of a whole plate with cuboids for aligning. Unless you also print this in pieces; but this will probably cause more problems.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Mon, 15 February 2016, 13:00:50
The size of the printed part is limited not only by the build plate but also by warping (especially when you do not have heat chamber).
My problem with laser cutting is that I cannot laser cut a contoured plate like this: https://deskthority.net/post247068.html#p247068
The top part of the case is printed in 2 pieces (keywell and palm part). Then they are glued using the technique I described. Works pretty well.
Title: Re: The Living 3D Printing Thread
Post by: KHAANNN on Mon, 15 February 2016, 13:25:18
The size of the printed part is limited not only by the build plate but also by warping (especially when you do not have heat chamber).
My problem with laser cutting is that I cannot laser cut a contoured plate like this: https://deskthority.net/post247068.html#p247068
The top part of the case is printed in 2 pieces (keywell and palm part). Then they are glued using the technique I described. Works pretty well.

Off topic, those keycaps are just "mmm"

Another challenge with multi-part printing is the sub-1mm imperfections, when you put 2 pieces side by side, the 3d printing imperfection is pretty obvious even if it's 0.1mm
Title: Re: The Living 3D Printing Thread
Post by: TheJonas on Tue, 16 February 2016, 00:37:54
Good point vvp, I was mainly thinking of 60%s, forgot about those ergonomic contoured split boards. And I completely agree with KHAANNN, a small gap looks enormous. I made a sandwich case (stacked laser cut plates) and the misalignment bothers me so much even though it's 0.1mm or less.
Title: Re: The Living 3D Printing Thread
Post by: vvp on Tue, 16 February 2016, 03:31:42
Off topic, those keycaps are just "mmm"
Nothing special. The black ones are OEM DCS salvaged from an old keyboard.
The blue ones are SP DSA. The rest is SP DCS.
Some legends do not correspond to the actual layout I use.

Another challenge with multi-part printing is the sub-1mm imperfections, when you put 2 pieces side by side, the 3d printing imperfection is pretty obvious even if it's 0.1mm
Yes that is the problem. That is also the reason to leave 0.3 mm gap at the places where parts are going to be glued together. 0.1 mm from each side for surface imperfection and 0.1 mm in the middle for the glue.

One probably can do better than 0.1 mm surface precision if printing really slowly and with 0.1 mm layer height ... or even smaller. But I prefer to have it printed quickly  so I typicality print at 12 cm/s and 0.2 mm layer height.

Here is an example of a part printed at 0.1 mm layer height and 2 cm/s. Very low speed to allow for cooling. It is acetone painted ABS. Wall precision is about 0.05 mm except the obvious locations where it is much worse. The locations are:The thread size is M16. So it is a small part. If you want very precise wall then extruder calibration gets very important ... and also filament diameter stability. I just settle at 0.1 mm precision which is rather easily achievable.
Title: Re: The Living 3D Printing Thread
Post by: sinusoid on Tue, 16 February 2016, 13:16:33
Leave 0.3 mm gap between the pieces.

Ha! 0.3mm seems to be a magic number for FFF machines :P For XY axes, at least.

Mirrors my experiences for tolerances on small parts. I tested this several times, and always ended up with 0.3mm for parts that have to match each other, or an external element.

My previous assumption was the print to be stateless, so the printer could execute the g-code at hand, and after the resume, continue executing the remaining g-code simplify3d sends

[...]

Even if it turns out perfect, 3d printed parts are awful to touch :D

That's actually a pretty fine idea! If the printer runs off Gcode, you could set the firmware to remove parts of it that were already executed, allowing the whole thing to get up after a power failure.

Firmware homing is not present on certain printers, mine fortunately doesn't have it, relies on Gcode from slicer to do that. If that's the case, you can try to trim the gcode manually to the line where the print failed, and run it like a usual Gcode.
For machines that run off compiled Gcode like Makerbot, you have to run it through GMX plugin (Simplify bundles it, also - free on github afair) to make it readable.

A good UPS is a safer bet, though.

re:awful to touch, that depends. 0.1mm layer with soft ABS isn't all that terrible. 0.05 takes looooong but is very smooth. I prefer to post-process parts instead.



Btw, if you don't like the feel, Skeinforge has an option to subdivide the external part of the model to fractions of the main layer, so you can get a 0.3mm layer on the insides, and 0.3/4=0.075 everywhere else :)
Title: Re: The Living 3D Printing Thread
Post by: TheJonas on Wed, 17 February 2016, 01:37:32
About being smooth to the touch; I can imagine 0.05 being smooth, but some people could still notice the imperfections. Post-processing is indeed the best way to smooth it out, but you have to be very methodical while doing it.
Title: Re: The Living 3D Printing Thread
Post by: KHAANNN on Wed, 17 February 2016, 09:32:57
It's more of a metallurgical thing actually, metal >> plastic, I tend to grip the keyboard from the sides, aluminium always stays clean, it kind of reduces sweating significantly, while with plastic the situation is opposite - that's why even If I work through all the challenges, a plastic keyboard doesn't appeal to me too much

By the way, as a small piece of information, PLA absorbs spray paints, so no matter what color PLA you use, you can spray paint it, and even if it gets scratched, the original color doesn't reveal itself easily - haven't tested the same thing with ABS

The problem with spray painting is always having the need to coat it, as the paint itself chips etc. - but with PLA, it's a joy, no need for coatings
Title: Re: The Living 3D Printing Thread
Post by: sinusoid on Wed, 17 February 2016, 15:23:48
@KHAANNN, you can spray coat both PLA and ABS with ABS juice using a spray paint gun. Doesn't chip, sticks like cyanoacrylate to eyelids, and smooths out the print nicely :)
Title: Re: The Living 3D Printing Thread
Post by: KHAANNN on Mon, 14 March 2016, 03:57:05
PLA/PHA Experience

It's awesome, not much different than regular PLA, yet shines slightly less, has a better color, the occasional warping is gone (I print PLA into the build plate, which prevents warping, with PLA/PHA, the resulting bottom layer can be thinner, closer to the actual dimensions, with no warping)

My only remaining issue is shining sections (a different shining) of the parts, I don't know why they shine, it might be vegetable oil from my oiler (that I didn't re-fill) - or it might be from the PLA/PHA material, but somehow parts of the resulting print shines, and when I spray paint it with a matte paint, the shiny parts shine under the paint too, it's pretty disturbing :D - probably oil

I tried sanding the part a bit, hoping the dust would absorb the oil, it indeed did tone down the shiny sections significantly
Title: Re: The Living 3D Printing Thread
Post by: MajorKoos on Thu, 12 May 2016, 17:56:41
After building a couple of kits I decided to take the plunge and 3d print as much of as Ergodox as possible.
So far the case is done and I'm working through printing all the keys - I've included some shots of my WIP.

Because I'm using a FDM machine and want to avoid supports as much as possible I've based the case around Lister's acrylic case.
For my printer I had to make the switch plate 1.3mm thick for the clasps on the switches to properly engage, but that was the hardest part.

The keys themselves can be tricky on a FDM style printer, but I've found something workable @ 60 microns and 30 mm/s
The stems were particularly tricky to get "just right" so they don't grind anywhere.

FWIW material costs are insanely low - the case cost perhaps $10 to print (including failed attempts) and the keys are 5-10 cents a pop. :thumb:
The a circuit board, switches and teensy from MK set me back another $100 or so.
For my next attempt I'm going to see if I can use ninjaflex to mask the traces on some copper clad board and etch it myself  :))

Title: Re: The Living 3D Printing Thread
Post by: KHAANNN on Thu, 12 May 2016, 22:50:45
After building a couple of kits I decided to take the plunge and 3d print as much of as Ergodox as possible.
So far the case is done and I'm working through printing all the keys - I've included some shots of my WIP.

Because I'm using a FDM machine and want to avoid supports as much as possible I've based the case around Lister's acrylic case.
For my printer I had to make the switch plate 1.3mm thick for the clasps on the switches to properly engage, but that was the hardest part.

The keys themselves can be tricky on a FDM style printer, but I've found something workable @ 60 microns and 30 mm/s
The stems were particularly tricky to get "just right" so they don't grind anywhere.

FWIW material costs are insanely low - the case cost perhaps $10 to print (including failed attempts) and the keys are 5-10 cents a pop. :thumb:
The a circuit board, switches and teensy from MK set me back another $100 or so.
For my next attempt I'm going to see if I can use ninjaflex to mask the traces on some copper clad board and etch it myself  :))

Wow, I love the keycaps, how did you pull the gaps off? (the texts) - it must be a detailed printer

A while ago, I tried manually drilling the texts and filling them with stuff, sort of like a double-shot, yet gave up easily
Title: Re: The Living 3D Printing Thread
Post by: vvp on Fri, 13 May 2016, 03:36:06
Yeah, pretty good result.
Title: Re: The Living 3D Printing Thread
Post by: MajorKoos on Fri, 13 May 2016, 07:52:44
I printed out my top row numbers overnight - not too shabby

I'm using a Ultimaker 2 for the work.
- 0.25mm nozzle
- 0.06mm layer height
- 30mm/s

I used the 3D builder app in Windows 10 to add the embossed lettering to the keys.

I'll keep the STLs here and update as I go:
https://github.com/MajorKoos/KBDParts

Title: Re: The Living 3D Printing Thread
Post by: vvp on Fri, 13 May 2016, 11:58:02
If it is ABS you can try to paint them with acetone.
If it is PLA you can try paint them with tetrahydrofuran (THF).

Acetone works fine. I did not try THF yet but it is claimed to dull colors.
Title: Re: The Living 3D Printing Thread
Post by: sinusoid on Sun, 15 May 2016, 17:11:15
Isn't that stuff carcinogenous?

You can paint PLA over with acetone/ABS slurry, it bonds to PLA VERY well.
You can add a bit of a powder dye to it as well, to make the colors better.


Actually, ever since I got into that 3d printing thing, ABS/acetone slurry started to cover most of my gluing needs, replacing cyanoacrylates and epoxies in most cases. Stuff's fast drying, sturdy, has great elasticity, and shrinks when drying, clinging mechanically to elements it can't make a chemical bond with. And you can easily dilute or concentrate it.
Title: Re: The Living 3D Printing Thread
Post by: MajorKoos on Sun, 15 May 2016, 21:27:04
I've been testing ColorFabb XT for making switch plates and cases - pics attached.

The JD40 is looking pretty sweet - I'm thinking of making it a Bluetooth number considering how small and portable it is.
Because it's translucent I'll add some internal LEDs for some pimp lighting

Title: Re: The Living 3D Printing Thread
Post by: vvp on Mon, 16 May 2016, 05:39:23
Wiki claims THD is about as poisonous as acetone but it is suspected of causing cancer.
Styrenes (released when printing with ABS or sublimating from polystyrene) may be linked to cancer too.
Wording about PLA was "probably not causing cancer". So it is not completely safe either.

I guess only few substances nowadays are not suspected of being linked to cancer.
Title: Re: The Living 3D Printing Thread
Post by: BlueNalgene on Tue, 17 May 2016, 12:32:32
Isn't that stuff carcinogenous?

You can paint PLA over with acetone/ABS slurry, it bonds to PLA VERY well.
You can add a bit of a powder dye to it as well, to make the colors better.


Actually, ever since I got into that 3d printing thing, ABS/acetone slurry started to cover most of my gluing needs, replacing cyanoacrylates and epoxies in most cases. Stuff's fast drying, sturdy, has great elasticity, and shrinks when drying, clinging mechanically to elements it can't make a chemical bond with. And you can easily dilute or concentrate it.

Wiki claims THD is about as poisonous as acetone but it is suspected of causing cancer.
Styrenes (released when printing with ABS or sublimating from polystyrene) may be linked to cancer too.
Wording about PLA was "probably not causing cancer". So it is not completely safe either.

I guess only few substances nowadays are not suspected of being linked to cancer.

Chemist here.  THF can be a bit nastier than acetone.  But for both, I recommend the same precautions:

1) do it outside or well ventilated
2) Goggles and gloves(nitrile) for PPE
3) Don't huff it like a dumbass.

If you follow those rules, you should be fine.  If you are doing something every day, then you should worry more about chronic exposure.  But if you are just doing some crafting every once in a while, I wouldn't worry about it too much if you use proper safety precautions.
Title: Re: The Living 3D Printing Thread
Post by: THX1138b on Wed, 25 October 2017, 09:42:12
Hey are you aware of this SCAD project to produce many keys (with engraved or embossed legends) at the same time?

https://www.thingiverse.com/thing:468651/#files

https://github.com/rsheldiii/openSCAD-projects

(https://imgur.com/vSlFWyD.png)

Title: Re: The Living 3D Printing Thread
Post by: Ailment on Tue, 09 January 2018, 11:55:15
Putting my 2 cents in.  Finished a case prototype for my TADA/SABER.  Sketchy height for the size, definitely had a clog half way up but it cleared itself.  Need to slow down but happy that everything lined up correctly for the screw holes etc.  Now to work on looks and a wrist wrest.

Little album
https://imgur.com/gallery/YkKsB