Piers Goodhew <
piers@...> writes:
> I recall DJ Delorie makes a "pocket" out of the 2 sides of artwork, aligned
> by holding the sides up to a strong light, securing them together, and then
> inserts the PCB. It wouldn't be milli-inch-accurate, but it's top of my
> "I'll try that if I ever need a 2-sided board" list.
A light box helps with that, too. I suspect if you passed the taped
edge through the laminator first, it would automatically center the
"fold" on the pcb, which would help.
My current method uses UV, which is done on transparent films anyway. I
print a mask on plain paper, tape it to the pcb, and drill the
registration holes, before cleaning the copper and laminating the film.
Each design has 3 special land patterns outside the outline, which when
printed on the inkjet (in negative), result in a fine black crosshair.
I can line these crosshairs up with the 13 mil drilled hole fairly
accurately, so I just do each side independently, lining each up with
the registration holes.
While this technique would work with TT if you pre-punch holes in the TT
paper, the trick is keeping the paper from moving between that step and
the lamination step.
You could also pre-punch holes (accurately, since you can see the toner)
in the printed TT paper, to use for aligning two sheets for taping.
Another of my methods is to print each side separately on thin SS
boards, and use double-sided tape to tape the two boards together.
Again, pre-drill two registration holes (they can be holes you'd drill
anyway) on each board and use some wire to keep the boards lined up as
you tape them.
Side note: putting the PCB in a folded or taped pocked like this, makes
the laminator pull the pcb in fairly reliably. With a paper carrier,
laminating 63 mil boards works like a charm, something that's hard to do
if you're feeding only the pcb itself in.