I can't see why not use the same technique used in PCB shops;
Punch registration holes in the board based on registration marks on the
drawing, so you can align both sides (drawings) to the board at the same
time.  Nothing that a piece of scotch tape to hold the film/toner-paper on
place will not solve.

In the PCB shops, all the holes are punched, then fiber corrosion (holes)
and metalization is done (you will not do it at home), then it is UV marked
and only then corroded.

By doing this, it is practical impossible loose double layer alignment.

Registration holes should be in a square triangular geometry, as far as
possible one to another.

Wagner.


Dwayne Reid wrote:
> At 09:51 PM 1/22/03 -0600, Josh Koffman wrote:
>
>> I cut my boards on a paper cutter/shear, so my boards aren't cut to
>> an exact measurement, so I can't just key off the edge of the board.
>> I was thinking about putting a couple of registration holes around
>> the edge of the board
>
> My technique of using a scrap of PCB material cut into a large "L"
> shape should still work well for you.  I usually make mine with about
> 4" & 5" arms about 1" wide.  In other words, it looks kind of like a
> carpenter's square, except smaller and made of un-etched PCB material.
>
> Tape on piece of printed toner paper, toner side down.  Tape to both
> legs of the "L".  Now flip the whole thing over and carefully line up
> the other piece of toner paper.  Once you are sure of the
> registration, tape to both legs of the "L".  Kapton tape might the
> best bet for tape - it is very thin and can take the heat.
>
> Now, just slip the cleaned PCB into the pocket formed by the toner
> sheets and the "L".  Do the heat and pressure thingy.  If you are
> feeding into a powered laminator, feed the "L" material first.
>
> Do note - I've only used this technique for exposing boards with my
> photo process.  But I'd think that it would work almost as well for
> toner transfer paper.
>
> dwayne
>
>
> --
> Dwayne Reid   <dwayner@planet.eon.net>
> Trinity Electronics Systems Ltd    Edmonton, AB, CANADA
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