Rigid plastic

[iandoug]

hi all

I need to make another keyboard... another sandwich style.

The first one had an aluminium plate with perspex for the other layers. I had to have them laser cut in two places... and their kerfs were different and so things didn't quite line up. And the switch holes ware fractionally too small, I had to file them bigger with mixed results.

So I was thinking if it would be viable to also have a plastic plate ... but which material is rigid enough? Is their a suitable laser-friendly perspex/polycarbonate/whatever?

I actually bought a brass plate years ago, but would need to sort out the kerfing issues. I did ask the vendor about their kerf settings but he strangely didn't understand what I was on about ....

Thanks, Ian

[nevin]

polycarb plates (usually half plates) are popular. polycarb is softer and much more pliable than acrylic. some have machined cases from large blocks of polycarbonate.
acrylic (perspex) is probably the most popular stacked/layered style case.
- check out qlavier for inspiration, they do beautiful layered cases
FR4 make good plates and most are semi transparent (will diffuse light) depending on the finishing of the top & bottom surfaces
- you can do a really cheap spaced FR4 case. FR4 plate, pcb, FR4 bottom plate all held together with standoffs
another option would be to 3d print. or even better, 3d resin print

as far as vendors... check
http://builder.swillkb.com/    https://lasergist.com/ (stainless steel)
https://www.ponoko.com/ (all kinds of materials)
see what other vendors are suggested, these are the couple that i know of, may depend on your location as well.

[dusan]

You already know the true kerf, right?

For shaft, actual kerf = sketch size - actual size
For hole, actual kerf = actual size - sketch size

So why not use your preferred material - aluminum and perspex?