... I'm outline-milling my PCB's, but did light-curing and laser-engraving etch-resistant coatings previously.
A good methode is buying PCB's with photo-resist and cure it with a BluRay-UV-diodelaser or UV-LED with a focussed spot fine enough (and/or attached optical fiber).
With higher powered diodelasers (>100mW) you can coat clean copper with black paint and engrave the coating - then you'll etch the freed areas, also inverted to the UV-curing methode ...
Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [
reprap.org] -- Deutsche Facebook-Gruppe - [
www.facebook.com]
Call for the project "garbage-free seas" - [
reprap.org]