I’ve been building multirotor copters for quite a few years now. One of the frustrating things about the build is the need to create a wiring harness to supply power from the battery to all the speed controls. I decided to try and build the power distribution into the bottom plate. The first one I built I used my CNC router to take the copper off the PCB. I didn’t like this method as it also took a little bit of the PCB material away as well. I decided to try a different method.
I used the CNC router to drill all the holes and cut the board out from the copper clad PCB stock material.
Then I spray painted both sides of the PCB with this flat black spray paint.
While I let the paint dry for about 20 to 30 min I imported the dxf vectors into the laser engraver software. I am using a 50W laser engraver I bought from an ebay vendor. the software is actually quite good. I’ll post more about it later. I setup the software to do a “scan” engrave of the areas I wanted copper removed from. I did 2 passes with the laser. The first pass was 200mm/s at 100% power and took about 25 min. The second pass was set to 450mm/s with power level of 100% and took about 12 min. The second pass helps to clean up the residue left from the first pass but might be able to skip it in the future.
Even with the second pass there is still some residue on the board.
I used some alcohol on a cloth to remove the residue. Be careful not to remove the paint. The board is now ready for etching with ferric chloride.
Here is the board after etching.
I removed the left over paint from both sides with acetone to expose the copper. It came off very easily rubbing it with a cloth.
Next I masked off the solder pads with electrical tape.
Now for the insulation coat I sprayed both sides a couple of times with black truck bed liner in a can. I lightly sanded both sides with 1500grit paper before painting. This bed liner paint provides a really hard coat. In this picture I have already removed the electrical tape to expose the solder pads.
Here is a shot of the quad copter being assembled after the esc’s and battery connector were soldered on. I used a liquid mask insulator to cover all the joints on the PCB.
In summary I’d say this was a complete success and I’ll be doing future boards using the same process.
I built a hexacopter using the same method Folding Hexacopter
Here is a video of a flight of the folding hexacopter with the PCB power distribution made with the above method.