i have a good friend looking for a UV laser for etching PCBs. this is going to break his little heart.
405nm is very close to UV though - Most PCB photoresists will be very well exposed by 405nm. I do wonder though if it's going to be enough to simply target the laser in that case without masking off the rest of the board - any splash, beam artifacts or reflections and the rest of the photoresist may get partially exposed.