This is an old revision of the document!

Some additional notes on board design and fabrication:

  • Slots are hard in this process. Please consider using a single drill hit that’s wide enough if possible. If it’s unavoidable, the current recommended option is to use overlapping drill hits.
  • Plating is typically avoidable by making vias with a diameter of 40 mil (1 mm). A standard 0.1” header pin can then be pushed through and soldered on both the top and bottom.
  • Higher polygon isolation will reduce the chance of bridging to a plane during assembly (since we don’t really offer soldermask). However, it will also increase etch time.


  • Use the “ProtoLaser – ProtoMat – Double Sided – NoTHP” template
  • Orient all your boards *before* creating any fiducials.
  • 4 fiducials – always.
  • Do not forget to save before the toolpath!


  • Sometimes, when placing the board, the fiducials move in the opposite direction as the board. This is a known bug! You can either: try estimating the location of the fiducials and starting the process; start a new document; restart the software; or restart the hardware. (The latter two require a fresh 20 minute warmup for optimal performance.)


  • Clean with IPA and a TexWipe before beginning processing.
  • If you would like to adjust the plating time, ask a PI to put you in touch with an MPI.
  • Do not let your substrate sit in the bath (any bath) for very long after the timer runs out.
  • If the machine throws an error on startup, it’s likely a bath needs to be topped off. Get a PI to help.
  • After bath 3 (activator):
    • Swipe a “reasonable” amount off with squeegee (mostly just don’t want it dripping)
    • Dry for 20+ mins at 150F. (Higher than this can cause the ink to bake into the copper.)
    • When rinsing after drying (after “bath 4”), scrub the copper surface with a sponge to remove as much of the dried activator off the copper as possible.
  • Bath 5:
    • If the current drops to zero or is very low (<10A reverse):
    • First attempt to re-seat the PCB holder (i.e. take PCB holder out and put back onto pegs) and try again.
    • If that doesn’t work, you may need to sand down the PCB holder’s pegs that hold the substrate to the holder (i.e. remove the board, rinse it, and then sand down the holder before restarting the acid bath step).
    • Don’t forget to screw down the holder into place.
  • After final bath, dry for 20+ minutes in the oven. * Place a towel underneath the board to prevent reactions between the oven shelf and the copper layers *
  • pcb-tips.1610595345.txt.gz
  • Last modified: 2021/01/13 22:35
  • by benh