It appears to me that UV resin, used for SLA printers should be quite convenient for making PCBs with a laser etcher. You can spread a thin layer of resin on the board and quickly expose it using a laser engraver. It should be most convenient for silkscreen layers that are otherwise difficult to apply.
I think the common method of applying UV mask and spreading it using a piece of plastic sheet is messy and I can never guess how much resin to apply. It’s always too much or too little and it’s always unevenly spread. And then the UV light exposure is another guessing game.
I have a 500mw 405nm laser module attached to my 3D printer and could easily ‘print’ some PCB layouts on a thin layer of SLA resin.
Does anyone have experience with this?
For my use case fidelity is no problem at all. My spot size is minimally about 0.1mm and I’ve increased it to 0.5mm to increase speed.
For photosensitive dry film you don’t need much power so you don’t need max focus. In fact you’re likely to burn through the film with the smallest spot size.
Toner transfer has been messy and unpredictable for me. Also alignment with double-sided PCBs is more difficult this way.