Wednesday, November 19, 2014

PCB prototyping research...

over the last month we spend an ungodly amount of time trying to figure out how to make double sided PCB's in a decent speed at home...


1. CNC
  • works great for through hole soldering
  • not so good for small SMD connectors and it was just to much hit and miss
  • 2 working boards out of 30 attempted are not acceptable, 0805 and SOT-23 package size mostly with some JST-PH 6 connectors
  • breaking to many mill bit's
Toner Transfer Method:

1. H2O2 + CH3COOH etching
  • 1h in the tank -> 2 bubbles
  • 24h later, still not done
  • problem are these 3% H2O2 solutions you can get locally
2. HCL + H2O2
  • about 3 hours a board, but this causes some serious under cutting and a lot of destroyed traces.
  • again 16.5% HCL is the strongest I can locally get
  • again 3% H2O2 is the main culprit for super slow etching speed
  • lot's of nasty fumes, causing rust on stuff around it, not good in a machine shop
  • but might be the only way right now
3. FeCL2
  • not tested yet, since rather messy and expensive
Combination of Toner Transfer and Milling

The really big advantage of the CNC is right now that it will drill all our VIAS and mounting holes for sockets, etc. Which makes it lot easier and it's rather fast. I do wish that I could find a decent free G-CODE optimizer