Custom Circuitry

I read on the versions page that making our own circuit boards could be a possibility. I wanted to know how the progress has been in that department because that really interests me

Hi Mythprogrammer,

... some folks tried with copper-filled epoxies and some comercial available conducting paste, what was used in a syringe-extruder (as in the f@h-printer) and seems to work fine ...

I'm on laser-sintering a pure-gold-paste to solid gold, what went good too, but is a bit to expensive for 'ordinary' circuitry

Others used graphite-filled polymers, what's limited by max current, but is usable for signal-feeding and is optimal when needed elasticity.

So it's possible, but you have to design which way yo go.

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For the interest (and RepRap-philosophy) i'm trying with extruding conducting trays, but with my CNC-repstrap and a mill-head it's much easier to route PCB's or apply a wire-wrapp-tool ...

Viktor

ah gravy then nice to know people are on it reprap ftw

I'm stalled on a project for church, (next warm weekend, I'm mixing some etchant, until then...)
As a consequence, I've been thinking about something mentioned before. Etching PCB's with the McMaster.
The originator of the design, if my memory and understanding of what I read is accurate, did some routering of circuit boards, but found that a small error in alignment caused him to cut the boards too deep. Someone else suggested using extra thick boards, grinding grooves in the board, then etching the whole thing down, until the grooves dissolved out completely.

I had another idea.
Coat the whole board in wax, then use a tool sufficient to cut the wax, but not the copper, to cut your traces.
Alternately, you might coat the thing in ink, for instance, and use a motorized eraser, (think of a hollow dremel with a long eraser running down the middle, used to be popular with draftsmen,) to erase those areas you want the etchant to reach.

In either case, use a tool that won't do anything significant to the copper, will remove whatever etch resist material you settle on, and won't rapidly dull going repeatedly over the copper surface.

Hi Sean,

some years ago i tried with painting the copper-sheet with black paint and burn the trays with a 3W-CO2-Laser, what went fine ...

Actually you can salvage 220mW-Diodelasers from fast DVD-RW-drives or even higher powers from DPSS-laserpointers.

At home i have a pigtailed 1W-diodelaser and will try with burning trays when my CNC is working again.

Copper is a very good mirror for laser-radiation, so you need only a etchresistant but laser-absorbing coating of some sort - black paint or ink, wax or similar.

It's not so good with plastic-coating, as the plastic melts and curls away on the borders, so it could delaminate and the etching would go fuzzy - but it could be a try laminating with thin black paper-sheets ...

Viktor

I cant help to still think my idea is pretty cool, its a modification/refinement of an instructable (http://www.instructables.com/id/The-Saltwater-etch-process/)

how about having a CNC-needle plumsing about in a pool of saltwater containing the pcb covered with some color or plastic coating.

The needle would need some kind of feathering to it so it can compensate for uneven pcb's

If you want to disconnect two areas, A and B, you first drag the needle to scrap away the paint along the track A-B.

Then you hit the needle down hard on either A or B and attach the current (several amps)

Now continue with the next "island" you want to create.

First of all, however I should verify myself that the saltwater etching method really works...


Of course this is not really additive manufacturing but the material removed can be limited to very thin lines!

perhaps also a second syringe could extrude saltwater while the current is running, getting rid of the tray altogether and making it a "dry" process.

one could also add another needle just to probe if the two "islands" are really disconnected!

Someone who went to my uni was developing the idea of printing circuits onto paper with ink loaded with powdered silver & then using epoxy loaded with silver to attach components to the paper. From what I recall, he got a radio working on a sheet of A4.. I'm also pretty sure that the uni nabbed the rights off him, so this technique does have I.P. issues, but it might be fun to experiment with.