So you want to build a 3d printer? (A primer)
First thing I would tell you is think
very hard before you do, it's estimated that only around half of printers started from scratch actually get finished. Even then, it can take months and months to finish even then. It can also be a serious drain on your budget as things drag on and you find more things that you are unhappy with.
At this point, there are some really good kits that don't need a ton of work, as well as some ready to go printers (some at good prices if you can wait for a Kickstarter), however, you need to understand in car terms, we are not even at the Model T yet (though we may be close). Many companies and designers are just throwing anything at the wall and seeing what sticks, and it's buyer beware. The first car builders and owners were experimenters and tinkerers, they were not meant to be driven to work and back every day. So if you expect to buy, put together a kit, or build your own, and simply press a button and watch your object come out, you will be
sadly mistaken. I cannot reiterate this enough. This goes triple if you plan to build one yourself from scratch.
One thing to keep in mind, most kits and even pre-builds (turnkey/RTR/ Ready to run), often are, or are based, on open source plans, so while you may think a scratch built is better or worse it can sometimes come down to your skill and comfort level. Yes, some kits are a bit better, using injection molding can make batter parts, but on some types, injection molding actually has little to no benefit. Deltas don't really benefit from it, while Cartesians can (I'll explain these terms shortly).
Since kits and pre-builds usually (though not all) come with instructions or a guide (they at least come with a list of parts that work with it) and usually have a promotional website and such, I won't focus on those and instead, this will be a rough guide on building your own the way I did, from what amounts to a 5 minute explanation. Even if you are great at researching things, building from open source plans will stress even the best. This is just to help you avoid some pitfalls, some of which caught me, others are things I managed to avoid knew I dodged a bullet. I will try to update it as more things come to mind, or i simply learn something new.
First thing you need to do is decide on what type you want. Some people are working towards building a 3d printer that can build itself (Reprap), others just want a good printer. Keep in mind that most can turn out a decent print as they mostly use the same methods to actually put plastic down, some are just prettier, less hassle, more costly, or faster. Most printers are based on milling machines (Cartesian), x moves one way, y moves another and Z moves up and down.
BOOOORING. How about a design based on a robot? Yes(!), we have those too, they are called deltas, and they use 3 arms to move the print head. Cartesians are (WAY) better documented, deltas are are just neat as heck,
here is the first delta 3d printer (same model as mine) performing a test. While deltas can be (quite) a bit tougher to initially setup, they have the potential to be faster, use fewer parts, and their precision can be just as good, but at higher speeds. I will try to keep this a bit generic, but if you haven't figured it out, I really like (and know more about) deltas, and that is why I built one (a Rostock).
There is one other thing about deltas I like... On a cartesian, every axis is setup different, so there is a ton of bits and parts. A delta uses not only fewer parts, but several of each. So instead of one threaded rod x length, another y length, and another z length, I need 6 of the same length. Everything about a delta is repetition. You have 6 rods, 3 carriers, 6 linear rods, 6 linear bearings, 12 rod ends, etc, and all are identical. So I only need one spare of each, not a spare of each part. Plus, you make one, and you can use it as a pattern for the rest, making it easy to make everything the same. If there is a downside to deltas, it's that, as you can hear, they can be a bit noisy, plastic bearings (you can make them) do quiet them down, and with good bearings, mine is actually not that bad
while printing, I hear more motor than bearing screech. However when it moves fast, it can make quite a lot of noise.
You really should decide what you want first. Granted many parts, as I said, are generic, but a Delta only needs 4 motors, while a cartesian needs 5. A delta needs 3-6 guide rods, while a cartesian needs fewer. A delta will need belts or filament, while a cartesian needs belts and threaded rods...
CostsBefore you get gung ho and start planning too much, many kits will say $300 for hardware, even wikis on scratch built will say $500 for hardware... That may be true, however, it does not count electronics, and it doesn't account for mistakes. Electronics will run you an easy $300. Realistically, don't expect to build a 3d printer for under $700 unless you buy a complete kit for that much. Even then, expect more for upgrades, filament, broken parts and mistakes. Even the owners of good, respected kits find things they want to upgrade, and technology is marching on fast. The best print head today, could be junk 6 months from now.
After that, you still have consumables to buy, plastic, tape, hairspray (yes, hairspray). Plastic isn't so bad, until you start to realize that is per color. By the time you have a rainbow, you have several hundred dollars invested in plastic.
On the other hand, you can make
some money with them. Don't expect to get rich, in all honestly, buy the time you consider electrical costs, broken parts, and consumables, you might make enough for a lunch once in a while.
Here are some of the more common self built printersCartesian you have:
Darwin (the original home built)
Mendel (or Reprap)
Mendel 90 (larger Mendel)
Prusa
Huxley
And the list gets really long with tons of revisions of these. A new one seems to debut every other week it seem.s
Deltas you have:
Rostock (the original delta)
Rostock Mini (relatively easy to build)
Kossel (developped by the Rostock designer)
Kossel Mini (developped by the Rostock designer)
Cerberus (a very professional home built that needs a few specialized parts)
That's pretty much it for scratch built open source plans. The Rostock is only a bit over a year old, while cartesians have been under development for a few years with many people working on them.
So you have an idea of what printer, what do you need to start.
What you need...This isn't going to be a buy this and that, it's more of a what to be on the lookout for. These tips can save you a ton of money, frustration and heartbreak.
Obviously plastic parts... This can be cheap or costly.
Know someone with a 3d printer? Ask them how much to make you some. Otherwise, do what I did and shop around. I found a kit of printed plastic parts on Ebay for $70. It looks like someone started to build it, put two parts together and realized they were in over their head, so, I got a deal. Typically, if you have someone do it for you, you can get the plastics anywhere from free, to $40 for a roll of filament. Filament to people with 3d printers is like bribing your guy buddies with beer. What do I mean by that? Well, ever notice how you can offer to pay someone to do something for say $40 and they keep thinking and thinking, but you throw out a 12pack, which is way less than the $40, and suddenly they say “OKAY”. That is how 3d printer owners are about filament. $20 of filament is worth $60 in cash. It's stupid, but it works. Isn't bribery great. Anyhow, if you have to pay, expect anywhere from about $80 up to $200 depending on the model and how many parts it needs.
Next, I HIGHLY, HIGHLY recommend a “Vitamin” or “Minerals kit”. (hereby referred to as a mineral kit).
These are kits with all of the metal parts you need, if you can, pick a printer that has one. Why? First off, many of the wikis and list of materials tell you things like “Fasteners: Stainless steel, mostly M3 (some M4 and M8). “ Seriously, that's what it says. In other words, you won't find a complete hardware list on some of them. A Minerals kit solves this for you. Second, you can buy one kit, or you can order fasteners from 50 places, find you need something else, and have to make another order. Another problem with this is that some of these plans are metric, others are S.A.E., while you think it may not matter, when you order your parts and miss a screw, and can't find it locally, it's a pain. Mineral kits solve all of that. Just make sure what all it comes with, some come with bearings, others do not.
A note on bearings,
For ball bearings, who cares, buy them wherever. Linear bearings and linear guide rails, do NOT skimp on them. Some people use drill rod instead of linear rods, don't do it. Cheap rods and bearings wear fast and are not accurate. You will be replacing both quite fast and while you may save a buck now, it will cost you even more very shortly. Personally, there is only two places I have seen recommended for linear rods and bearings and those are McMaster-Carr and VXB. VXB is a good way to go if you buy a mineral kit. If you decide to do without a minerals kit and do it yourself, McMaster may be a better option, as McMaster is expensive for low volume, when you buy lots, they can be worthwhile.
Electronics:
You will need endstops, some sort of Arduino/Ramps combo (or compatible), and of course motors.
The Arduino and Ramps setup needs a mention. These are open source, so quality can vary but also, there are not only alternatives, and variance, if you decide to use a delta, make sure it's compatible. Not all are. Be sure you know what you are getting. My board was a V1.4 and the only way to tell was by one extra row of easily missed pins. The same applies to the firmware that runs the system. Personally, I have found Repetier to be a whole lot easier to deal with, but it;s not compatible with everything and less well documented.
You will probably also want a heated bed as it allows easier printing. On heated beds, some use a metal plate, some use glass, some just put tape over the bed and print on that. I highly recommend a glass plate and heated bed, forget the tape. Kapton tape is big money, and even blue painters tape adds up over time. With glass, you spray it with Aqua Net hairspray and plastic sticks like glue. It's cheap, and universal, instead of this tape for that plastic, the other tape for that plastic. Be carefull with metal plates, they tend to warp over time. Also, some are teflon coated, scratch it, and you will be taping it for prints. Glass is cheap and solves all of that. You want either borosilicate glass or green window glass., there is also an Ikea mirror some people use safely. Other glass breaks from the heat. Green Window glass is cheap. I clamp my glass to the heater using clamp style paper clips, it's cheap and works well.
Personally, I bought a “kit” on Ebay, it came with Arduino, Ramps, endstops, some belts, some pulleys, a heated bed, and a lot of the necessary wiring for about the cost of the Arduino and Ramps.
For motors (usually Nema 17), you can buy them pretty cheap on Ebay, look around, you can often do $10-$15 each. Nema 17's are a standard motor size, it is not a product name. This means they are all relatively the same, however shaft length, and torque can differ. For the most part, the only time it matters is your extruder, where high torque is needed for any nozzle size smaller than .5, This is even more important on a bowden tube system (remote extruder). For your main motors, just look for at least 15mm shaft, and I would encourage you to get them with flat spots (though you can add these with a Dremel later if you want). On the extruder motor, if you use a bowden, or plan on a smaller nozzle size (leave the smaller nozzle for after you get things running right) you may want to consider a gear reduction system, either an geared extruder or a gear reduction equipped motor.
Hot Ends
This is one of the more personal decisions.
My advice, DON'T SKIMP and research, research research. One of the most common is the J-Head. There is tons of them, and since they are open source, many companies also make them. This means you can get a good one, or a junk one. The hot trend now is towards all metal hot ends, this will be one of my next upgrades. If you want 1.75mm I have seen a lot of good reviews of the E3d all metal hot end. For 3mm, the Trinity head is rumored to be great. In both 3mm and 1.75mm, J-Heads are always a favorite, however, try and get it from a reputable seller, Hotends.com is actually the designers of the J-head if I remember right and you are encouraged to buy from them. I got mine from Ultibot(?), as everywhere else in the country was sold out, it works well.
Misc notes:
You still need a bunch of misc stuff, like belts, pulleys, probably some framework, wood, metal extrusions, plexiglass, etc.. One benefit of building the Rostock Mini is there are two places selling pre-cut and pre-drilled upper and lower plates for a decent price. Whereas most others you will need to be doing the cutting and drilling yourself. Another company is now doing Rostock plates, however they are QUITE expensive ((several hundred dollars!).
A note about Bowden tubes
On deltas, the design idea is to have as little mass being moved as possible, for this, they use a bowden tube, which allows your extruder to be remote mounted. The bowden tube is just a teflon tube running from your extruder to your head/hot end. If you use a bowden tube system, which most Deltas do, pneumatic fittings are very handy, I really recommend getting some, however, I wouldn't buy them again if they have metal teeth in them. The ones from SeeMeCNC work great, but I overpowered them, and broke out all of the metal teeth. These teeth ended up in my bowden tube, fittings, and even my nozzle. Needless to say, they really made a mess of things. This was due to me overpowering them, it's not a fault of the fittings, but after that mess, I want to avoid that again. Not that the plastic ones are better, I ripped the tube out of them as well, but they didn't put metal in the system when they did. Many really loath bowden tubes because it's a ballet between putting enough pressure to push filament through, and blowing out the fittings.
Pulleys...
When I got my kit from eBay, it came with two pulleys and some belts, but they weren't long enough, and not enough. I later found that if you contact sellers doing this, they will properly equip the kit. I didn't and bought another kit with longer belts and 3 pulleys, however, I quickly learned another lesson here... Not all pulleys are created equal. The first two I got were nice, they had a good steel shank on them, the second set was very thin, had terrible set screws, and were soft as butter. Combined with no flat spots, I never even got them tight before they stripped. Make sure your pulleys have a thick shaft. Oh, smaller pulleys, offer higher accuracy, and while it can be said they slow down your prints, in actuality, your motors will move faster than you can print regardless.
Delta Arms.
On deltas, there are two things that determine print quality, the first is the head, the second is the arms. The printed arm/u-joint systems that they usually come with, are complete garbage and can even take a ton of effort to get them even that good. On mine, I never even finished assembling them. What most do is they buy Traxxas rc car tie rod ends and some sort of rod. Several companies sell these for about $30-40. The rod ends are cheap, it's the rods costs a lot. I found a cheap method, I used the rod ends, for rods I used 3/8in oak round rod, to connect the two, I cut the heads and re-threaded some screws. Total cost was $12, and they work better than stock. The hot thing though and what I'm making now, is magnetic rods, instead of a tie rod, or u-joint, a magnet holds a steel ball against a cup, using a magnet. This offers no slop at all, however it will run you about $50 and need access to a printer to make the new carriers, rod ends and effector (what holds your head).
On my red ends, I removed even more slop by adding 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.
Filament..
Don't buy cheap filament. I have some PLA that only works in a 1-2 degree window before I either jam the head, or it won't melt enough. Some of this is due to not having gear reduction, some is just the PLA, but 2 degrees is not a very big window. PLA is what busted my bowden fittings, overheated my extruder motor, made me change my print head, and just drive me batty in general. My cheap ABS on the other hand, I have 2 pounds of it, while it should be 1.75mm, 1 pound of it is nearly 2mm and will not go through the bowden tube. Get recommendations and be prepared to pay for it. As a general rule, if it's under $20 per pound, it's going to be garbage. My cheap filament probably cost me two weeks of diagnostic time, a set of bowden fittings, and possibly a head I didn't need. I have heard good things about Ultimachine and I just got some form them today, but I have yet to test it.
The Living Printer Thread will probably get some good recommendations as we learn more.
Belts...
Okay, I lied, there is a third thing that effects delta print quality and that is belt tensionm which also effects cartesians, too. The belt should actually sound like an upright bass guitar when you pluck it. Seriously! It took me a while to figure out how tight they actually needed to be. I use three of
these, they make tensioning the belts much easier.
These are probably a bit better but will add mass to the system (not good on a delta).
Taps
I also highly recommend a set of taps, but they aren't necessary IF you are careful. Drill things out and take it slow, you can get away with it, but don't be surprised if you break something.
Support
For cartesians,
Reprap.org is probably one of your best bets. There is a treasure trove there. For deltas, things are spread all over, however two good places for support are
SeeMeeCnc's Rostock Max support forum. There is lots of good info there, but it's meant for their delta kit, so don't go asking about your home built delta there. The other place is the
Delta Robot 3d Printer Google Group, the big movers and shakers (I.E. the designers) in delta bots all hang there. If you can't find what you are looking for elsewhere, that's the place to go for Deltas.
