WP-34S / 31S Key Caps?

[orcinus]

The main issue with nearly all consumer 3D printing technologies (yes, both FDM *and* SLA) is that the top surface will never ever be 100% smooth.

Which makes it unsuitable for this particular application.

You could print the keys upside down, but then you lose the ability to make anything but a completely flat profile (i.e. no slant at the bottom of the key). You could sand and polish them, but then you lose the whole point of *rapid* prototyping

Regarding multi-colored printing - it's currently fairly messy with the FDM printers and impossible with SLA printers. Certainly not applicable to printing keys. There are color-mixing extruder hotends on the horizon (e.g. https://www.youtube.com/watch?v=vmn7K1U06Wc) but i don't think those will be applicable nor convenient for this purpose (and, besides, they're still not here).

What can be done (and is a fairly common trick) is changing the filament midprint from one color to the other, with the top layers having a cutout so the other color shows through.

Bear in mind that even that will look fairly ugly, as the cutouts will be far from crisp and regular.