Bob,
I am neither Ken nor a Technet guru, but I'll give your question a shot
anyway.
Temporary solder mask is applied by the board assembler (not the board
fabricator) to solderable areas (tin-lead coated areas, for example) of
boards going through the wave that you do not to solder at this particular
time. The solder mask is then removed after wave soldering to allow
subsequent operations on those areas. For example, we have a connector that
we hand solder in at a later stage (because it was easier due to other
process issues) so we apply temporary solder mask to those PTHs. We also
mask off SAT (select at test) resistor PTHs on that board, as well as a
strip where we bond a part subsequently.
I hope this clears things up.
-Steve
Steven K. Lustig
Process Engineer
EMS Technologies, Inc.
Norcross, GA
(770) 263-9200 x4714
[log in to unmask]
-----Original Message-----
From: Bob Vanech [mailto:[log in to unmask]]
Sent: Wednesday, October 06, 1999 7:22 AM
To: [log in to unmask]
Subject: Re: [TN] Temporary Solder Mask
Ken or any other Technet guru..
I am not a total novice in this business, but I
don't understand where you would use a temp.
soldermask. In all the application that I have been
involved in, I worry about soldermask adhesion. Soooo,
would someone explain so that I might become a little
smarter before this old mind starts to head toward
senility ??? Oh, am I already there?? Hey, thanks
in advance. Have a great day.
Regards,
Bob Vanech Bob
BVAN Enterprise
> We have an application where we need to apply temporary solder mask prior
> to a high temp bake in preperation for wave solder. These are polyimid
> boards and we bake them at 125C for 12 hours prior to wave solder. We try
> to wave solder them as soon as they cool to ambient so applying mask after
> bake is out of the question.
>
> We have two different masks we currently use that are water-soluble.
> Neither one comes off very well in the water wash and one of them leaves a
> residue/stain due to the high temp bake.
>
> Do any of you have a source for a temporary solder mask that can hold up
to
> this temp/time and still be removed easily without residue (preferably
with
> water)?
>
>
> Thank you,
>
> Ken Bloomquist
> Sr. Principal Process Engineer
> PRIMEX Aerospace Company
> P.O. Box 97009
> Redmond, WA 98073-9709
> http://www.primextech.com
>
> Ph: 425-885-5000
> FAX: 425-882-5786
> [log in to unmask]
>
> Northcon/2000, Chairman of the Board
> http://www.northcon.org
>
> Electronics Manufacturers Association (EMA), Vice President
> http://www.ema-wa.org
>
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