--- In
Homebrew_PCBs@yahoogroups.com, DJ Delorie <dj@...> wrote:
>
>
> Anyone see these extra bits of photomask after developing?
>
> http://www.delorie.com/pcb/inkjet/mask-bits.jpg
Yup, I have seen a bit of this. I am no longer doing boards myself,
the commercial shops are SO cheap, although I might do one every few
years. But, I am using my system for making solder stencils out of
.003" brass shim stock, just like a double-sided PCB. And, the
geometries are getting VERY small. The edges of your resist look VERY
jagged. What is your master artwork? If the edge of the master
artwork is not very sharp and crisp, it can cause the edges of the
pattern to be jagged or thin, which I believe I can see in your
micrograph.
I have a laser photoplotter that runs at 1000 DPI in both directions,
and it prints a sharp-edged image on litho film. I definitely get a
sharper resist pattern developed on the PCB/brass, without that
scalloped edge look.
One thing I have been doing is to scrub the board/brass with either
steel wool or fine (600 to 1500 grit) sandpaper, wash well and drip
dry, before laminating. This greatly helps the resist adhere to the
laminate.
Jon