3D printing DSA ALPS keycaps

[DefProc]

I've been doing an Ergodox build with Matias keys, and soon found that DSA keycaps don't easily come with ALPS compatible stems, so I started down the path of 2D printing keycaps.

I have access to a couple of FDM printers as I work out of a makerspace, and I was able to validate the model sizes and fit, but the layers and fillament lines on the prints weren't quite right. You can feel the shape on the keys, and they pick up dirt in the printing pattern.

Rather than spend lots of time finishing each key individually, I've tried going to a finer print method: SLA printing, with much better results. I've got some samples from shapeways that prove the method, so I've just put in an order for a larger set to furnish my whole keyboard with a *less pricey* manufacturer.


https://twitter.com/DefProc/status/756527533558996992

They will still need finishing (as the prints are still porous from the printer) but they have been polished in a rock tumbler, so the surface finish is very similar to cast keys. I'm looking at options for legends too.

I did put the keys on a shapeways shop with model downloads, but I normally work open source, so the STL files are online, along with the source CAD models.

[TheVengeance]

Nice project, strange that your printer did the top in radial as opposed to lines, something you specified?

What slicer?

[MajorKoos]

The keys have a concave top.
What you're seeing there is the slicer converting the curve into layers.

I can tell from the gaps between the parallel lines that the short belts on the printer are too loose - backlash.

[DefProc]

That's right, these are DSA caps, so there's a spherical sweep to give the dome indent on the top. When you get to the centre, that shows as complete circular layers.

The white has been a little tricky to print with, as it's a PLA mix, rather than pure. The temperature is a little off, and even the sides haven't flowed quite as nicely. Plus it doesn't help that I've got some dirt in the gaps from handling, which shows up the top fill pattern.

I should point out that the smoother, shapeways printed cap has been made on it's side (which you can do with powder printing, as the powder fully supports any overhanging volume). There are some small steps that are slightly visible on the side, but the top surface has no visible marks that give away it being printed. For the fused fiber print, any overhang needs support adding (and you want to do that on the inside so it doesn't mark where you break it off) so printing vertically is the best option, even though it highlights the top profile from the size of the layers.

[MajorKoos]

The red and gold are PLA, and the green and purple are NGen - mostly printed with a .25mm Nozzle in 0.1mm layers at 30 mm/s on an Ultimaker 2+.  The G and bat are printed at 0.06mm if I recall.

The NGen prints really well - probably my favorite filament so far.