Printed Circuit Boards

I have great hopes for reprap'd circuits. Particularly in the deposited conductor form. Currently, the best chance appears to be conductive polymers. Conductive epoxy is too expensive to be practical and requires mixing. If we can deposit the polymer well enough, we should be able to build 3D circuits--Massive applciations.

I had wondered about sintered copper powder, but that looks like it requires too much pressure.

I've been trying to find info on thick-film paste, but I haven't gotten anything useful yet.

I'm in contact with a couple Chem Ph.D's and an engineer who I'm hoping will help out with this project. If I get info from them, I'll post it here.

My goals are .1mm traces, .1mm spacing to allow connection to modern BGAs. "solder" would be conductive epoxy or direct application of wet conductive polymer.

Boards would be assembled by repraping a frame that holds all the components upside-down then fabing the PCB on top of the components. They naturally get bonded to the conductive polymer as part of the fabing process.

Etch resist is not an elegant solution.

Hi Annirak,

AFAIK copper-dust isn't suitable because of massive oxidisation of the particles.

Most conductive pastes i know use silver-flakes in polyimide and are heat-cured.

What's possible too are silver-flakes in acetone or another easy evaporating solvent, but then you haven't a solid/rigid material, so this would only work with embedded trays or vias only ...

Viktor

Hmmm... there is another option. Carbon impregnated PLA is a weak conductor, but it is conductive enough for electroplating.

Do you think it's viable to print then plate? It would mean that the fabbing process would have to be stopped for each layer of circuit, which adds the requirement of an alignment system which, AFAIK, reprap does not have.

Attachment methods for components would be either low-temperature solder or conductive epoxy.

... look here: [forums.reprap.org] for another methode.

Viktor

The current recommendation for Mendel uses low-melt metal. The channel size is something that I was trying to get away from due to the limitations that it causes.

See here for the work done on Mendel at U of Bath
[staff.bath.ac.uk]

... thanks for the info, should be interesting for some other problems i actually have too ...

Viktor