I¡¯ve tried milling on a mini mill (sieg x1) that I converted, but finally settled for laser.
bought a laser engraver off banggood. 3w laser diode i think.
clean the pcb with scotchbrite pad/ steelwool. Give it coat of black spray paint.?
I use Flatcam to generate the Isolation routing gcode.?
The laser engraver runs opensource software, requires reflashing. Cannot remember the name now.
after engraving, give it a rub with a sponge and drop in cupric chloride? ( hydrogen peroxide and HCL mix)
seems to come out fine, laser beam can be focussed to about 0.3mm?
