Author Topic: The Living 3D Printing Thread  (Read 132759 times)

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Offline mkawa

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Re: The Living 3D Printing Thread
« Reply #650 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.

to all the brilliant friends who have left us, and all the students who climb on their shoulders.

Offline oystein.krog

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Re: The Living 3D Printing Thread
« Reply #651 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.

Online vvp

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Re: The Living 3D Printing Thread
« Reply #652 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".

Offline oystein.krog

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Re: The Living 3D Printing Thread
« Reply #653 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
« Last Edit: Sun, 11 May 2014, 13:02:50 by oystein.krog »

Online vvp

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Re: The Living 3D Printing Thread
« Reply #654 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)).

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Re: The Living 3D Printing Thread
« Reply #655 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.

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Re: The Living 3D Printing Thread
« Reply #656 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).

Offline mkawa

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Re: The Living 3D Printing Thread
« Reply #657 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.

to all the brilliant friends who have left us, and all the students who climb on their shoulders.

Online Leslieann

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Re: The Living 3D Printing Thread
« Reply #658 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.
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Offline oystein.krog

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Re: The Living 3D Printing Thread
« Reply #659 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?
« Last Edit: Mon, 12 May 2014, 14:38:28 by oystein.krog »

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Re: The Living 3D Printing Thread
« Reply #660 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:
  • there is no additional case rims around the keys at the top/left/right sides,
  • my thumb cluster is a bit nearer to the keywell,
  • outer little finger columns use standard 1x1 keys,
  • the palm rest size is about the same as on kinesis contoured (not sure how big it is on ergodox).
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.

Offline mkawa

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Re: The Living 3D Printing Thread
« Reply #661 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

to all the brilliant friends who have left us, and all the students who climb on their shoulders.

Offline mkawa

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Re: The Living 3D Printing Thread
« Reply #662 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 ;)

to all the brilliant friends who have left us, and all the students who climb on their shoulders.

Offline Pacifist

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Re: The Living 3D Printing Thread
« Reply #663 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?

Offline mkawa

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Re: The Living 3D Printing Thread
« Reply #664 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.

to all the brilliant friends who have left us, and all the students who climb on their shoulders.

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Re: The Living 3D Printing Thread
« Reply #665 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.
« Last Edit: Tue, 13 May 2014, 01:57:30 by Leslieann »
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Offline oystein.krog

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Re: The Living 3D Printing Thread
« Reply #666 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?

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Re: The Living 3D Printing Thread
« Reply #667 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).
« Last Edit: Tue, 13 May 2014, 16:56:13 by vvp »

Offline mkawa

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Re: The Living 3D Printing Thread
« Reply #668 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.

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Re: The Living 3D Printing Thread
« Reply #669 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.

Offline mkawa

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Re: The Living 3D Printing Thread
« Reply #670 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.

to all the brilliant friends who have left us, and all the students who climb on their shoulders.

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Re: The Living 3D Printing Thread
« Reply #671 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.
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Offline physicsmajor

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Re: The Living 3D Printing Thread
« Reply #672 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!

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Re: The Living 3D Printing Thread
« Reply #673 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.

Offline mkawa

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Re: The Living 3D Printing Thread
« Reply #674 on: Sat, 17 May 2014, 12:34:04 »
yep, always great to hear about new printer designs

to all the brilliant friends who have left us, and all the students who climb on their shoulders.

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Re: The Living 3D Printing Thread
« Reply #675 on: Mon, 23 June 2014, 13:32:16 »
ANYBODY EVER USED 3-D PRINTING TO MAKE KEY CAPS YET?
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Offline damorgue

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Re: The Living 3D Printing Thread
« Reply #676 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.

Offline legodt

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Re: The Living 3D Printing Thread
« Reply #677 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

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Re: The Living 3D Printing Thread
« Reply #678 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

Offline mkawa

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Re: The Living 3D Printing Thread
« Reply #679 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.

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Re: The Living 3D Printing Thread
« Reply #680 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.

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Re: The Living 3D Printing Thread
« Reply #681 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.

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.

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Re: The Living 3D Printing Thread
« Reply #682 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)


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  :-\

Offline keypro

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Re: The Living 3D Printing Thread
« Reply #683 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

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Re: The Living 3D Printing Thread
« Reply #684 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.

Offline keypro

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Re: The Living 3D Printing Thread
« Reply #685 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

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Re: The Living 3D Printing Thread
« Reply #686 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.

Offline damorgue

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Re: The Living 3D Printing Thread
« Reply #687 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:




The last image shows some compromises which I recommend you to do to make the stem far easier to print.

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Re: The Living 3D Printing Thread
« Reply #688 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.

Offline damorgue

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Re: The Living 3D Printing Thread
« Reply #689 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.

Offline keypro

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Re: The Living 3D Printing Thread
« Reply #690 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
Show Image

Show Image
Show Image


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

Offline damorgue

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Re: The Living 3D Printing Thread
« Reply #691 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
Show Image

Show Image
Show Image


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.

Offline keypro

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Re: The Living 3D Printing Thread
« Reply #692 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
Show Image

Show Image
Show Image


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:

Offline damorgue

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Re: The Living 3D Printing Thread
« Reply #693 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
Titan 1
Pegasus

Offline keypro

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Re: The Living 3D Printing Thread
« Reply #694 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
Titan 1
Pegasus


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.

Offline mkawa

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Re: The Living 3D Printing Thread
« Reply #695 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

to all the brilliant friends who have left us, and all the students who climb on their shoulders.

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Re: The Living 3D Printing Thread
« Reply #696 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

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Re: The Living 3D Printing Thread
« Reply #697 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.

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Re: The Living 3D Printing Thread
« Reply #698 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.

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Re: The Living 3D Printing Thread
« Reply #699 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.

to all the brilliant friends who have left us, and all the students who climb on their shoulders.