I am spending lot's of time trying to find the best way of heating
and pressing.
There appears to be a distinct correlation b/w tempreture and
pressure (paper being a given for the ezperiment). I won't mention
humidity either. The other problem I have is that my boards are
larger than an iron footprint. Iguess if my idea was to make a small
board with heavy traces it would be trivial. With small board and SMD
it would be also relatively easy. The problem starts with size. Just
yesterday I tried moving from one end to the other end of the large
board with fine traces and I made stops with iron every inch and
stayed there for a minute and half, wool setting. Some places came up
perfect, next to it pads were flattened (pressure issue?) and
lsewhere I obviously did not laminate long enough. The good news is
that where the ink stuck it did stuck like enamel. The links you are
including and are fascinationg how he did it.
One more thing: lamiantors require 12 to 15 passes... I want a better
laminator. Just went thru an excercise with the heat press- worse
than iron. Is there anybody knowledgeable to suggest how to control
heat and pressure on large size PCBs. Oh, I even had my boards
preheated. I use dmax pressure but probably not evenly.
Mike
--- In
Homebrew_PCBs@yahoogroups.com, "wheedal99" <wheedal@h...>
wrote:
> --- 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.htm
> http://myweb.cableone.net/wheedal/pcbconstruct/cpu3_7b.jpg
> is 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.