DJ Delorie wrote:
> I've found that ink blocks UV better than toner (8 steps vs 3 for
> toner). I've heard that "photo" inks have an extra UV inhibitor in
> them, but I haven't tried mine to see if they work better than black.
> Inkjet is the way to go.
What do you mean by "steps"?
> I have a special target footprint I use on my boards - four square
> pads with a 1 mil gap between them. Since I use negative prints, this
> results in a big sqare hole in the ink with a thin crosshair in it. I
> pre-drill registration holes in the pcb, and line up both sides' films
> using the targets.
I've pretty much decided on Microtrak after spending most of the evening
digging through MSDSes and datasheets. That's a positive-acting resist (i.e.
on the transparency, black = copper, clear = blank FR4) which is developed in
metasilicate.
I did get a reply from Mega, basically the difference is mainly down to
Microtrak being an "inherited" product. Fotoboard is roller-coated, Microtrak
is dip-coated. Other than that, the FR4 laminate is basically identical. The
shelf life is a guaranteed minimum, not an absolute, so theoretically
pre-coated MT should last a while, but will get harder to expose and develop
as it ages.
This should be a fun week. :)
--
Phil.
ygroups@...http://www.philpem.me.uk/