reprap

Multi-use platform

One thing I think I will definitely want to try once I get the 3D printer working is to use a sharpie in place of the extruder and try using it for making PCB prototypes.
Note to self though, don't try to use IC pads as vias, if you use sockets it's impossible to solder the damned things. Maybe machined pins broken out the strip would work, you could solder both sides. I should buy some machined pins off eBay and try that with last year's prototype.

EDIT: actually, building an X-Y-Z platform for pens and routers is probably a better idea than trying to get the extruder on and off a RepRap. There are plenty of videos up on YouTube of people patching together such platforms out of random junk, and most of them are using RepRap electronics since that allows control using g-code so a normal software chain can be used.

  • Todd Johnson - I've used machined pin strips with good success on non-plated-thru boards.

    Hey, how about just using the extruder to deposit a single layer of plastic onto the copper as resist? I never had very good luck with markers myself.
  • John Ridley - Yeah, I went ahead and ordered a bag of machined pins off eBay, $7 got me 400 pins (in 4 pin groups). My last year's prototype barely held together and isn't useable now, I'll try these on it when they come in (from NJ, should be this week), I'd like to have the prototype working for demoing the process, and the designs I'm thinking of for future blinkies will need durable prototyping to even be testable.

    Hm, that's a thought about using plastic for the resist. Definitely worth a try. It could be a challenge getting the plastic back off again when done. It apparently sticks really well to roughed up surfaces and PCBs need to be scrubbed pretty good before laying down resist and etching.

    I hear that acetone dissolves the stuff, that's what people soak their hot ends in when they get clogged up, so after etching an acetone bath may clean things up if the stuff doesn't just come right off.
  • Todd Johnson - I suspect if you chilled the board, the plastic might just pop off due to differential contraction.
  • John Ridley - http://reprap.org/wiki/Automated_Circuitry_Making
    See: Thermoplast resist. They say the acetone removal process will probably take a while regardless of how thin the layer is made.
    It is a good point though that if drilling is done before plastic removal, it would make a nice drilling guide.
  • John Ridley - I suspect it'd need a lot of chilling. There's not likely to be that much dimensional stretch across a 50 mil line. You might get some cracking longitudinally, but you might have to use dry ice and I'd be nervous that the copper might bond to the plastic better than to the fiberglass board.

    I bet it could be taken down quite a bit with a razor window scraper (used by painters) then acetone could go fast. This is prototyping so it doesn't have to be all that efficient.

    The bonus here is that it's a potentially very accurate way to line up resist on both sides of a 2-sided board. That's always a pain in the rear.
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