Kevin

I to would be very suspect of this procedure. Before proceeding I would
ask the supplier for the details of the procedure, some data on it's
reliability and some samples. I would then run some reliability checks on
the samples. Of first order interest would be the composition and the
thickness (assuming that the new preservative is really silver). I imagine
the problem may be localized contamination on the copper land. If so, the
entire lot should be re-processed in the suppliers line.

Best regards

Lee

J. L. Parker Ph.D.
JLP Consultants LLC
(804) 779 3389



-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Kevin Glidden
Sent: Tuesday, November 11, 2008 10:47 PM
To: [log in to unmask]
Subject: [TN] Repair to ImAg plating?


Hi everyone,



We have an issue with loss of plating adhesion on some ImAg finished PCBs.
The affected area is small and consistent in location across the PCBs with
the defect.  All other areas seem to be ok when tested per a tape test.
The PCB supplier is proposing to visit and "repair" them here at our site.
I was not even aware plating could be repaired, let alone away from a PCB
fab shop without plating lines etc.  Is this even possible?  I am very
hesitant, as I very seriously doubt the control and/or quality of the
"repair" process.  At the very least, how would thickness be controlled?
We specify micro 5-12 inches in thickness per IPC-4553, and the overall
PCB is to meet IPC-6012 Class 3.



Anyway, they described the process as follows:



I will send you the solution by Fedex in a small bottle. Once you have
received it, I will come to your facility and repair the boards.  I will
need a hot plate and Pyrex container to heat-up the solution to 120 F. Do
you have these two items? Otherwise I will bring them with me. I will
clean and repair the boards locally.  Once it is done, I will do the tape
test to make sure the adhesion of the silver is adequate.



My little voice is screaming "NOOOOOOOOOOOOOOOOOOOOOOO!!"



Thanks in advance,

Kevin


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