[coderjames]

For the 2D version, you might not need very much custom. Use a regular pen plotter and use a pen with conductive ink. These both exist today, though personally as a hobbyist PCB designer, I can get 2-layer and 4-layer boards cheap enough from JLCPCB or Oshpark or PCB Unlimited that I don't bother trying to make them myself.

[jrmg]

I always thought conductive ink had too high a resistance to use to make PCBs. That’s not the case?

How do you attach the components to it?

[coderjames]

I haven't tried it myself so you might be right, but I was thinking of the silver conductive pens from Chemtronics with a conductivity of 0.02-0.05 ohms/sq/mil.

For attachment, I'd evaluate their conductive epoxy or maybe glue down the underside of the component and then smother the lead with the silver conductive ink. But again, just hypothetical since I have a quickturn shop make cheap prototype PCBs for me and either hand solder or use a stencil, paste, and a hot air gun for my hobbyist projects.

https://www.chemtronics.com/circuitworks-conductive-pen

https://www.chemtronics.com/circuitworks-conductive-epoxy-2

[dsign]

Yes, conductive ink has too high resistance; at least the one that works on a basis of carbon; a "trace" can easily have kilo-Ohms, and the metal ink interface makes things worse.

I remember reading some "Sputnik" magazines from the 1970s where Russian scientists were searching for the holy grail of a good conductor resin. I didn't understand at the time why they found the (concept of the) thing so valuable; but now I've got an inkling...