deskthority

Almost finished designing a Model F front and back plate for a future project but I am now facing the prospect of either paying hundreds to get hold of Model F buckling spring assemblies or having to recreate a buckling spring's barrel and flipper assembly to 3d print. Before I try to do this I wanted to quickly check if there is already 3d designs of buckling springs out in the wild. There is one on shapeways but I am unable to contact the designer or get hold of the 3d file and aside from that I cannot find any other examples online.

I am hoping to have a completely homemade F107 sometime near the end of the new year and while it would be easier to just buy the barrels and flippers I want to be able to make the project open source once completed. As always thank you all in advance!

This sounds a sterling project. Good luck!

The flippers will need to be conductive for capsense to work. Is that something you can do with the print material itself?

Muirium wrote: 28 Dec 2022, 16:03 This sounds a sterling project. Good luck!

The flippers will need to be conductive for capsense to work. Is that something you can do with the print material itself?

Thanks! As far as I am aware you can get conductive filament for FDM printers, even metal filament that you can heat treat and polish. However I have recently scored a SLA 3d printer due to its bargain price and will have to work with resin filaments which, as far as I am aware, are not available as a conductive material.

But if my understanding is correct with capacitive sensors the flipper does not nessasairly have to be a solid conductive material. I could add a copper lining to the bottom of each flipper to get them to operate.

Correct. Only the bottom of the flipper, directly above the PCB, really matters for capsense. The downside I can think of with a thin conductive layer is wearing off with use. Capsense controllers are fairly forgiving—every key is effectively analog, as Pandrew’s signal meter shows—but if a thin conductive layer disintegrates with time, it will eventually disable the key until opened and replaced.

These are moving parts so there is always wear. IBM put a layer of resistant solder mask (?) on top of their sense pads on the PCB, which I gather give them some protection from wear and tear from the flipper above. The OG flippers are of course conductive throughout so no need to worry about a thin outer surface.