Re: [ATM] holographic null test on round robin mirror C

["matt" <mariusrf@bellsouth.net>]

-----Original Message-----
From: mconsidine@netreach.net <mconsidine@netreach.net>
To: atm@atmlist.net <atm@atmlist.net>
Date: Saturday, February 05, 2005 9:19 AM
Subject: Re: [ATM] holographic null test on round robin mirror C


>Okay, time for a dopey question from the guy in the back
>row, in regards to making these masks ...
>
>Why not use the process that is used to make your own
>printed circuit boards to get the mask made?  In other
>words, print out the mask on a laser printer and use a Radio
>Shack-type kit to etch the holes into a sheet of copper (or
>some other material)?
>
>Matt Considine

I might be biased by a lifetime of fumbling around with electronic projects,
since I'm an electronics engineer.

I wouldn't rely on home style etching to have the required precision . The
result would have jagged edges, pinholes and other artifacts. Unless someone
can calculate their effect and guarantee it's negligible, I wouldn't
venture.

Another consideration is cost. The materials for such a mask while cheap are
not free. One botched attempts and costs would ramp up.

Third is there are professional ways to get the same thing done . Sign
cutting companies are everywhere and are using more precise cutting tools
than you could achieve at home. All you need is get them the computer file.
Another option is sailmaker lofts , which can do large precision cuts with
similar computer controlled cutters.
A third option is photoplotting companies that are making films for circuit
board fabricators. These guys are routinely making thin sheet metal stencils
for circuit board making, silkscreening and other applications. To have a
20" x20" very thin stainless steel sheet laser cut stencil with arbitrary
holes and paterns cut in it typically costs only a couple hundred dollars.
Instead of risking a few bucks and a few days of work, I'd rather have it
done professionally and complete other partsof the project in the time I'd
be saving.
As they say, YMMV , that's only my opinion, etc.

best regards,
matt tudor

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