3D Printed Caps?

[jchan94]

Can anyone tell me about their experience with 3d printers & keycaps?

I'm looking into making some custom caps, and have access to industrial 3D printers (I just need to make a few calls).

Let me know! thanks.

[xondat]

Can anyone tell me about their experience with 3d printers & keycaps?

I'm looking into making some custom caps, and have access to industrial 3D printers (I just need to make a few calls).

Let me know! thanks.

Lower quality/accuracy than resin/CNC but cheaper and easier to create most designs.

[See Spot Solder]

Lower quality/accuracy than resin/CNC but cheaper and easier to create most designs.

Do you know how a set of 3D printed, normal keycaps would fair/feel?

[Leslieann]

Durability and precision is an issue at the size you need.

Can you make one, yes, will it break as soon as you put it on the stem, quite possibly. Keycaps are injection molded at high pressure, creating a very dense plastic, 3d printers lay the plastic layer upon layer, not only is it not dense, but there are micro fractures between the layers. Resin is better in this aspect to a degree, however the resin has less strength than the ABS and PLA typical printers use. You could use casting resin and some molds and get much stronger parts than 3d printed parts.

If you really want 3d printed caps, your best bet is to have them done in metal by a company like Shapeways, since, even less dense metal is stronger than layered plastic. Keep in mind, one teeny mistake, forgot something, or just figuring out tolerances (which are very important here!), all cost money. You may be thinking you can afford one, but it may take 5 or more tries before you get it all figured out. What you could do is have them do one in plastic(about $4 ea), get it worked and then switch to metal ($20-$30 per cap), however, the tolerances change from metal to plastic and in 3d printing it can cause some very strange effects. Worse, with the type of machine Shapeways uses, you may not be able to account for it, because of the style printer, the direction of warp or distortion may be different each time you order.


Just because you CAN 3d print something, doesn't mean you should.
So why and how do people do it? Because they can. It's cheap fun, and a challenge, things like this help you understand your printer and helps with other projects, think of them more as a constructive/engineering exercise than making practical key caps.

[KitWasHere]

3D printers go by another name, rapid prototyping machines. Keyword there is prototype. They're great for getting a model from CAD into your hands, but the part itself is not very durable. 3D prints are relatively weak, especially along the Z axis if using an FDM printer.

I have printed a basic keycap and it worked after messing with the scale a bit, and for this use case it probably would hold up for a decent amount of time but the cap was sort of ugly

[widdlekitty]

I've used 3d printers as a means of testing a design before getting something CNC'd. It's a great tool for prototyping, but I've been unable to get my desired final results from one. There's specific compounds that can be used to touch up 3d prints to make them cleaner, but I haven't attempted to use them. This is the one that comes to mind: http://www.smooth-on.com/Epoxy-Coatings-XTC/c1397_1429/index.html.

As others have mentioned, durability is going to be a factor to consider, too.

Don't let this put you off! Definitely experiment, and see if you can get what you want from them.

[vvp]

If you print with ABS and do not require a perfect surface then simple paining with acetone helps quite a bit. And it is very quick. It dries in about 3 minutes.
https://geekhack.org/index.php?topic=43362.msg2058345#msg2058345

[Leslieann]

While the general public tends to over-estimate what they can do, people with them greatly under estimate them.

Yes, they are great for rapid prototyping (rapid only in the sense that it's faster than sending it out and waiting months), but you can get actual products from them, but it depends on the final product. It may require finishing, or simply be a part that doesn't need a lot of strength.  Not everything needs to be polished to perfection or have a ton of strength. Even then, done right, printers can make strong parts, they just need to be pretty solid, which a keycap is not.

We use them for products we sell, would they be stronger injection molded, yes, but the ability to alter our supply chain at a moments notice is a great asset that saved us tons of money already. One injection mold we checked on would have cost us $80k, we can make that part for $1 on our printer line, at current sales rates, that would take us 20 years to turn a profit, the part will be outdated in less than 5. Which by the way, we already had to alter that part once. So it can work, it just depends on the part.


The other issue I have is people thinking what comes off the printer is all you can do with it. You can make negative molds, to make your positives. We've done this for chocolate and resin casts. You can also use the printers to make molds for lost wax castings or even cast right from PLA since it burns clean. You can buy a mini foundry for $1000 and do home metal casting right in your yard using the printer to make the molds.

We experimented with using the printers to make molds for our parts and then cast them, it worked well, but at the time was too much of a hassle and we were inexperienced in mold making. It did result in nicer parts, we just need to experiment more.

Acetone doesn't fix the microcracks or strength, it just gives it a shiny surface.

[vvp]

Acetone doesn't fix the microcracks or strength, it just gives it a shiny surface.

It does not fix microcracks but makes them less serious. Acetone wets ABS very well and it will get into cracks thanks to the capillary forces. It will dissolve the ABS surfaces and the solutions from the adjacent surfaces will mix. Then it dries. The microcracks on the surfaces will stay filled with low density ABS (instead of air pockets as they were before). Of course, the low density ABS is much weaker than high density injection molded part.
I know quite well since I managed to break the red marked almost straight 1.6 mm thick vertical wall many times by accident.

I never broke it by accident after it was acetone painted.

[sinusoid]

I believe that you can't answer that question without answering this first:

What technology do you plan on using?

There are technologies out there that will give you awesome, durable, production-ready keycaps. FFF is not one of them, unless you are willing to put a lot of time into post processing, or use a really high grade machine on a really well thought-out model that's fit for the technology you're using.
Polyjet should be fine on most things.
Powder should do OK if you use appropriate material, but they will look a little rough on the surface.
UV cured resin is nice, durable and can be transparent.

Most of those technologies are painfully slow to use in production. Though that's kinda relative - you can upscale the output by getting more machines