jcarlosmor wrote:
>
>
> If you refer to the green soldermask in the video, that is real
> soldermask for industrial PCB making. However, the last shot on the
> finished PCB shows very poor finish, because is almost for sure that the
> datasheet for that soldermask states that it must be baked in an
> air-forced oven before imaging with UV. Also, it must be applied by
> screen printing, not manually with a card. If the user follows all the
> steps according to the manufacturer you end with a professional board,
> since the soldermask in the video is "the real thing" used in industry.
I've recently been playing with Liquid Photoimageable Solder Mask
(LPISM). Your right, it needs a proper bake before exposure or it gets
damaged in the developer.
∗ LPISM part A and B are mixed on a metal spatula (typ. 1 gram)
∗ screen printed (polyester mesh 125 thread/inch)
∗ baked 80C 20min,
∗ UV exposed (2 minutes from 4 x 8W UV BL tubes)
∗ developed (10g/l Na2CO3 @ 35C, manual paint brush agitation)
∗ baked 150C 20min.
notes:
∗ All equipment is readily cleaned in the developer tray.
∗ It goes a long way, 1 gram of LPISM does your typical 10 x 10cm PCB.
∗ A PCB holding jig is required for double sided printing.
∗ working in a artificial lighting area seems safe.
The link below is of a board I did recently. I know its quite ugly, but
I'm only just learning about this solder mask stuff.
http://members.optusnet.com.au/eseychell/revH_photo.jpgI'd like to know what experience people have with dry film soldermasks.
Might be lot more practical for hobbyist.