--- In
Homebrew_PCBs@yahoogroups.com, "joshdewinter"
> Now I have another question...just as I was about to submit my
> circuits to a board house...I need a method to align my top and
> bottom sides. Is there anything anyone does that works especially
> well? I have looked through the messages from the group and have
> heard of people taping both top and bottom on, and running them
> through at the same time. That sounds like it would work, but how
do
> you align them accurately?
I use the TT method and a laminator; although I haven't had the heat
problems you had with my stock laminator. It might have to do with
the type of toner you are using. I know a guy accross town that has
been doing 1 sided boards OK with the same laminator (w/o modifying
the heat element btw). What kind of clad are you using? He does .5 -
1 oz 1/16" stock in his --although the rigid roller transport does
make a bit of noise doing so.
Most of the homebrew boards I do are double sided. I print the top
and bottom, (top mirrored) onto magazine paper making a few alignment
crosses outside of the board boundary lines. Under a bright desk
lamp I align the crosses of the two pages with the toner sides in. I
use a glue stick and bind one of the edges to create an envelope.
Sandwich the board into the envelope and insert the bound edge side
in first into the laminator. Make 2-3 passes in the same direction
until the toner "tacks". After that you can clip off the bound edge
and rotate and flip the board for a few passes until the toner has
fastened to the copper clad.
The sandwich works pretty well on some pretty tight via pitches. The
possiblity of the skew from the bound edge justifying to the top or
bottom turns out to be a non-event. The rollers tend to align the
binding with the center of the board when initially fed --as long as
you insert the bound edge in first and fairly perpendicular to the
board edge.
I have a write up on this in case you missed it in the TT links
section...
http://myweb.cableone.net/wheedal/pcb.htm -Dal
(Pocatello, ID)