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From what I've read, Sn63Pb37 solder melts between 182 and 183 degrees. Why can't you put something like that in a 3D printer instead of ABS, etc. ...Of course I'm asking because I'd like to know if I can draw/print a PCB

Depends, have you ever seen SN63Pb37 in 1.75mm diameter? 2 issues, first, the fumes would be EXTREMELY hazardous, second, I don't think solder would be stiff enough for the extruder to properly feed the material.

I've seen two different low-voltage conductive plastics hit the market in the past 6 months for 3D printers. The conductive plastic can be used as tracers within a print (dual extruder setups), it can also be used to print connection terminals for plugs, and most interesting, I've even heard it can be used as a capacitive touch interface. I haven't personally played with these filaments - but I think they are your best bet for now.

There have been attempts to print circuit boards using solder, the results were pretty rudimentary, it's apparently difficult to control the flow, at least one of the versions I saw used two heads, one to print plastic valleys, the second to fill it with solder.
There are certainly many easier ways to make a PCB.
On the conductive plastics, most of them should be called "resistive" plastics they tend to have very high resistance.

You probably couldn't just print a trace on something by replacing the filament. But I bet you could bridge the eyelets on a prototyping board like this one http://www.futurlec.com/Pictures/EXPBRD.jpg Solder likes to flow into things more than it likes to stick to itself.

I'm sure you could design an extruder (definitely not a bowden style), but the hard part would be making the solder flow start and stop. Solder doesn't have much of a plastic state (when it's gooey) like ABS and PLA do. It would be like printing with water, I think it would bead up and surface tension would clump it together. Maybe you'd need a chilled bed?

For prototyping, you could print plastic over the copper board and then photo or chemically etch it (using the 3d printed layer as a mask). Have you tried that?

You could use a syringe extruder and solder paste. Then just bake it to fuse everything when you're done... I wonder how that would work.

What about just printing the valleys then using a spackle blade to fill them with solder paste?

untitled86 wrote:What about just printing the valleys then using a spackle blade to fill them with solder paste?

A guy named Jerrill just posted a proof of concept for this technique. He makes his own nozzles down to 0.1mm, and recently made a little 555 chip PCB with valleys for traces. He then used a "circuit ink" pen and filled the valleys. For low-duty circuits this probably works okay, but for anything that you couldn't make in 1970 circuit technology is still a ways off.

[youtube]http://www.youtube.com/watch?v=jCzmQLZKNA8[/youtube]

how about the company camt? I think they started making it.

Polygonhell wrote: On the conductive plastics, most of them should be called "resistive" plastics they tend to have very high resistance.

Yeah, the one I saw on YouTube yesterday was 100 ohms per centimeter. They called it "conductive"

I think for printing solder you'd need a wax nozzle (featuring full flow shutoff) or a direct-mount extruder with really long retraction settings. That might work if you tuned it just right. I don't know how resistive solder is, though. Tin and lead so maybe not as good as copper. I just don't know how much worse. Might not matter at all. What I do know is that the existing "conductive" ABS filament is useless for most purposes.

I did see a guy using chemical wizardry to create a conductive ink using copper nanoparticles. The process is lengthy but it looks like you could do it for a reasonable price. The copper particles have to be sintered by hitting it with a xenon strobe a few times. I think the question is how much copper you can mix into filament before it stops wanting to extrude or remain cohesive. Might be better to just print a circuit onto paper or plastic film, sinter, and sandwich it into a 3D printed enclosure.

people have inkjetted solder bumps for C4 type chip bonding for 10+ years.
http://www.microfab.com/archive/about/p ... jmep98.htm
http://iopscience.iop.org/0960-1317/19/12/125021

This one is interesting: http://www.kickstarter.com/projects/ele ... -instantly

A conductive pen that doesn't require you to shake or squeeze the material out, also it only resists 20 ohms.

They say 50-100 milliohms of conductivity per square mil but I don't know how that turns into ohms of resistance at a given length and trace width. However it does look like I could just put it in a pen holder.