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Date: | Thu, 15 Jun 95 11:04:11 |
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Good day!
This is a request for any input to an increasing problem we're having
with our wave solder process. We are a contract assembler and have starting
using wave solder fixtures more often now than in the past, and for a
different reason too.
In the past, wave solder fixtures were primarily used when an assembly
either did not have an acceptable shape to adapt to the conveyer of the
wave solder machine, when there were components or items on the assembly
that needed to be fixtured to meet a positional requirement that could only
be acheived with fixturing, and when the board size needed additional
support in preventing warp and twist.
Recently, there has been another motivation to use fixtures...and that
is for masking. We, as many other companies I'm sure, are cleaning our
boards using aqueous methods and utilize a closed-loop water treatment
system. This means NO WATER SOLUABLE MASKS! So we use a liquid latex mask,
and just like everyone else has probably found out, this sure does add a
lot of time to the process! The time it takes for the mask to cure, and
then the time required to remove each peice of mask prior to wash eats a
bunch of time as well. So that's why we use fixtures....it sure does make a
difference in overall process time!
But now a problem with our profiles is starting to show-up. It is becoming
difficult to create decent profiles with the added mass of the fixtures
thrown in to the equation. We use G-10 as the material for our fixtures,
and we have Electrovert Econopac and Ultrapac wave solder machines.
My questions are:
* Is there a better material to be using? Something maybe a little more
thermally transparent? ....that doesn't cost an arm and a leg?
* Any tips on the design of the fixtures? (The fixtures need to be fairly
robust...we do a lot of boards)
* Any suggestions regarding profile creation?
My thanks in advance! I know if ya'll can't help nobody can!
Steve Gregory
Pragmatech Inc.
101 Nicholson Lane
San Jose, California 95134
Phone: (408) 943-1151
Fax: (408) 943-1461
Email: [log in to unmask]
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