c-64 keyboard reboot

matt3o · 04 Oct 2014, 16:23

Findecanor wrote: ↑What kind of layout do you want to support? I suppose that the keycaps are intended to be completely new also, I.e. no support for vintage keycaps with adapters like the MeC64 keyboard.

the layout would be a 60%+arrow cluster+F-row on the left (2x5 1u probably). It should fit well the C64 look and feel. The keycaps would be brand new, SA profile.

I'm trying to find a way to build the case, that is the main problem

hoggy · 05 Oct 2014, 22:24

Never had a Commodore, but I used a Pet for my computing GCSE in 1990. Kinda interested in how this turns out.

matt3o · 05 Oct 2014, 23:35

I can't find an inexpensive way to have the case done. Tomorrow I'll try to work on the final 3d file. Wondering if the plate should part of the case itself (ala HHKB)

Muirium · 06 Oct 2014, 00:17

A plastic plate MX? Interesting! I'd like to see, and hear, how that turns out if you try it.

Findecanor · 06 Oct 2014, 14:19

matt3o wrote: ↑I can't find an inexpensive way to have the case done. Tomorrow I'll try to work on the final 3d file. Wondering if the plate should part of the case itself (ala HHKB)

I wonder if it would be feasible to have a vacuuformed case CNC-milled to get the grooves. You would first reinforce some parts on the inside with plastic using plastic cement to allow the mill to go deep enough.
You would have to cut the holes for the keys anyway, so you could kill two birds with one stone by doing both in the milling step. Drawbacks are that edges are soft and you won't always get a perfect result, so getting matching top and bottom halves could be difficult.

A 3D-printed case won't have a nice texture. If you do a plate in ABS as part of the 3D-print then you should reinforce it around the switches, or do it thicker overall like the milled plastic plate you made.
Kinesis and Maltron have plastic "plates". Kinesis' key wells are injection-moulded, Maltron is vacuuformed.

Another option could be casting in room-temperature resin, most likely polyurethane. Resin is also more brittle and crumbly, not as bendy and tough as ABS plastic. To make hollow resin objects you would typically spin it while the resin sets ("rotocasting") in a special machine (could be manually powered) but it is very difficult to control the thickness, so an integrated mounting plate would not be feasible. There would be a whole lot of extra work required to saw it into two halves and clean it up. Inner corners also tend to get very thin with rotocasting.

matt3o · 06 Oct 2014, 15:46

I'm not sure resin casting would work, or at least there would be really a lot of work.

with 3D printing, I would seal it with a filler/primer and than paint. That would be quite easy.

matt3o · 06 Oct 2014, 17:37

I did a semi-final 3d model of the keyboard case. Shapeway says €75 which is more or less how much I estimated. That just for the top, the bottom could be laser-cut maybe. To have the bottom as well it would be almost x2.

I could try to make a mold out of the 3D model. So 3d model in the cheapest material, then filler + lots of sanding. Then silicone mold. Not sure how resin casting would work though. If that works the cost per case could be in the €30-40 range depending on the number of cases we make. To that you have to add the plate.

vvp · 07 Oct 2014, 18:30

Interesting, can you post how much is for work, material, and printer volume?
Also what are the dimensions of the printed part?
Does the printed part also contain mounting plate or is it laser cut?
Maybe it is so expensive for my keyboard because the mounting plate is printed. Maybe they include also model complexity somehow in "printer volume".

matt3o · 07 Oct 2014, 18:49

vvp wrote: ↑Interesting, can you post how much is for work, material, and printer volume?
Also what are the dimensions of the printed part?
Does the printed part also contain mounting plate or is it laser cut?
Maybe it is so expensive for my keyboard because the mounting plate is printed. Maybe they include also model complexity somehow in "printer volume".

the case doesn't include the plate. the plate will be laser cut in steel or aluminum. that removes a lot of complexity from the model. The keyboard is approx 36x26cm. I'll double check later, I have removed the model from my designs on shapeways.