Harvey White <
madyn@...> writes:
> My problems in photoetch are not the developer, nor the exposure (made
> a vacuum frame and use an enlarger timer), but the density of the
> positive.
I use an Epson R280 (Claria Inks) with Jetstar and my own printing
software, and I'm able to span 8 steps on the 21 step gauge, which is
pretty good (toner is only 2-3 steps). Regular print drivers will not
work correctly for UV films! They try to avoid putting down too much
ink and do not know about the special UV films.
For Jetstar Premium, I can put down a full coat of ink (smallest drop
size, 2880 DPI) without smearing. For Standard, I dither 50% except for
a few pixels at the edges that are 100%.
> Not unless I invest in trying to put my own film resist on.
I figured out to put film resist on very reliably. Summary:
cut the film 1-2 inches extra on one edge, tape this edge to a piece of
carrier paper as the "top" edge (the edge that goes into the laminator
first). Put your pcb under it. Cut two "tabs" of paper - about 0.5 x 2
inches. Tape these to the two "bottom" edges at a 45 degree angle.
Now, when you laminate, once the paper is caught, use the tabs to lift
the film OFF the pcb. Pull UP and BACK gently just to keep it flat.
Once the leading edge of the film is caught, pull harder, and up more,
to make sure the film won't touch the pcb until it's in the rollers.
This pretty much eliminates air bubbles.
You can also combine Adam's squeegie method with a laminator if you can
reduce the laminator temperature to less than 212 F (100 C) or the
steam from the boiling water causes bubbles in the film.