--- In
Homebrew_PCBs@yahoogroups.com > Hello, I noticed that laminators are being used for pcb's, but how
> reliable are they when it comes to doing double sided images? I was
> thinking if using two heating plates and "sandwiching" the copper
> clad with the images would be better? There should be less mis-
> alignment because there is no movement. Any ideas? Thanks, Genaro M.
Nearly all my boards are 2 sided. Alignment isn't nearly as
difficult as it may seem. If you put some alignment marks on your
carrier paper and can see them with bright backlight, you can get the
pads to line up. I use a glue marker to fasten one edge of
the "sandwich" and put the pcb in between. Insert the bound edge
into the laminator first. Even on my Royal Sovereign NR900, the
toner "tacks" down on the first pass. They don't move and missalign
in the additional passes. I normally use 40-20 mil vias pads and
they line up pretty well over 95% of the time. The only problem I've
had is if I got carried away with the glue. One time I got some glue
on the outside of my sandwich and stuck the paper to the laminator
roller. Even the small skew possible by the board thickness (paper
might be pulled slightly to the top or the bottom) turns out to be a
non-event. The paper/pcb tends to align get centered when initially
put into the laminator rollers.
http://myweb.cableone.net/wheedal/pcb.htmhttp://myweb.cableone.net/wheedal/pcbconstruct/cpu3_7b.jpgis a 2 sided cpu board with a lot of @$&%∗#!! drilled vias.
As far as pressure plates, that should work in theory. I think in
practice it may be difficult to get even pressure.