RepRap: Blog

With a lot of work going on on putting pen-plotters in RepRaps for PCBs (and other things), it seemed to me that we might re-visit an old idea.

That idea was using oil to assist separation of support material. Now that the Java host software does full overhang support calculations, it seemed that we might combine the two: a pen plotter with an oil-filled felt pen would run over the top layer of the support after it had been laid down to make it easier to break away when the part was finished.

Above is a brief experiment I did by hand. The L shape was built 'the wrong way up' forcing it to need support. Both the part and it's support were PLA. I paused the build at the last layer of the support deposition, and wiped corn oil over the support with a Q-tip. Then I resumed the build. The support material did indeed separate much more easily than it does without the oil.

If a support layer was simply plotted twice when it was the last support layer under the part, once with the polymer, and then once with an oil-filled felt tip, this would give the same ease of separation. The same pen plotter could be used with an etch-resist pen to make PCBs, such as these designed to make reprappable electronics simple. Two birds; one stone.

Labels: pcb, support

Acting on a suggestion from Vik, I have found that PLA can be extruded onto copper clad board and, if it is hot enough, it sticks very well. I have to flex the board to remove it. 55°C is too cold but 130°C works well. I haven't tried anything in between yet.

Assuming PLA will resist PCB etchant, this could be a way of making PCB's without a laser printer, albeit quite low resolution. With 0.3mm filament squashed to 0.24mm a single line would be 0.36mm wide, which is 14 thou.

It also seems like a good bed material for making PLA objects on.



More details here: hydraraptor.blogspot.com/2010/04/cu-pla

Labels: copper, heated bed, pcb, pla

I've got the assembly instructions done for the Universal PCB V1.2 board you can get from the RRRF. Now available here for public comment and ridicule:




I'm part way through the extruder board instructions, so cut me some slack on that one!

Vik :v)

Labels: controller, instructions, pcb, universal

Yesterday I bought a piece of copper-clad board and tried sticking it under Zaphod. The idea being to deposit a trail of CAPA on the copper and then etch the exposed copper. Unfortunately, it looks like copper makes a nigh on perfect non-stick surface for CAPA extrusions. Even after cleaning with contact cleaner and cranking up the heat, I couldn't get any CAPA at all to stick to the copper.

Looks like time for plan B; the etch resist pen.

Vik :v)

Labels: board, capa, circuit, etch, pcb, polymorph, track

We've updated the design on the Power and Communications board. The parts are all the same, but now its a one sided board, and much easier to fabricate. All the files have been added to subversion, and the wiki entry will be updated with new pictures later this week once I actually make one.

In the meantime, here is a shot of the schematic from Kicad:

Changes

• single sided. makes it much easier to fabricate, and cheaper too. (no more alignment issues)
• fatter tracks on power circuits
• component silkscreen included for easier reference.

Labels: electronics, pcb, powercomms