Hi Ken - My suggestion is to plot your monthly solder pot analysis results
and couple that with the amount/number of components that goes through your
solder pot. You should be able to "predict" where the impurity levels are
going to be and can use this data to support "why" you haven't jeopardized
the overall process reliability.  Many shops just dump their solder pot
(dump = recycle) monthly rather than incur the cost of testing and doing
the predictions. As for the amount of gold that you can live with, take a
look at section 5.4 in the J-STD-001 Handbook - it does a nice job of
covering the details of gold removal and why! Good Luck.

Dave Hillman
Rockwell Collins
[log in to unmask]





Kenny Bloomquist <[log in to unmask]> on 05/14/98 09:58:37 AM

Please respond to "TechNet E-Mail Forum." <[log in to unmask]>; Please respond
      to Kenny Bloomquist <[log in to unmask]>

To:   [log in to unmask]
cc:    (bcc: David D Hillman/CedarRapids/Collins/Rockwell)
Subject:  [TN] Gold Solder Pot




Fellow TechNeters,

We manufacture hardware for DOD per ANSI J-STD-001 and I have a couple of
questions regarding solder pots for removing gold from components prior to
tinning and soldering.

We send out solder samples for testing from our tinning and gold stripping
solder pots every thirty days.  To answer the question of "what do you do
with parts that were tinned while the solder pot is being tested (and the
test fails)" we shut the pot down until the test results come back.  The
problem is we only have one gold pot and don't want to shut it down during
testing.  How does your companies address this issue?  Is it fair to assume
that since there is a secondary tinning operation that the small amount of
gold that may remain on the parts will not be a problem?  Do you dump the
pot every thirty days?

My second question is, what is the maximum amount of gold that can be
plated
on a terminal and still be soldered into an assembly with only tinning and
not cleaning?  Is there a specification that allows this?

Thanks in advance for all responses.
Ken Bloomquist
Sr. Principal Process Eng.
PRIMEX Aerospace Company
[log in to unmask]
(425) 881-8990 ext. 6645

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