I would say that if you have done your homework during the initial
qualification stages of the vendor then you should be OK.  It should not be
necessary to qualify on a part by part basis, unless the part you are
speaking of has some out of the ordinary design/performance characteristics
or is poorly designed for manufacturability and has a rocky history.  I can
think if a number of occasions over the years where a vendor change to a
stable product has opened some old wounds.  

- Design changes made by a vendor for DFM or design issues which were
communicated (or even requested) by the owner but where the original design
files were not updated.  When a vendor change is made you are right back to
square one.

- A particularly challenging part which has a rocky history with vendor(s)
to either obtain the owners performance or quality expectations (not talking
about your average part here but a part which has design features typically
avoided in a "good" design).  The existing vendor has, over time, engineered
a solid manufacturing process for the part and you, as the customer are
happy with the results.  Based solely of cost I would suggest that a vendor
change be considered vary carefully.

Good Luck

John
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Jack Olson
Sent: Friday, February 22, 2008 7:00 AM
To: [log in to unmask]
Subject: [TN] FAB Vendor Verification? Validation?

FAB: Vendor Verification? Validation?

It seems like I have leaned on Technet too often lately,
and I hope I'm not wearing out my welcome....

...but I am having to address this question:
"If you switch bare board manufacturers, what should you
do to verify that the new boards are just as good or better
than the old ones were?"

I can say a lot about how to CHOOSE a bare board vendor
and how to SPECIFY minimum levels of acceptability, but
from a technical point of view, is there more that should be
done than typical visual inspection, dimensional checks and
cross sections of the boards themselves?

Do any of you periodically monitor your bare board vendor
by asking for process control reports and stuff like that?

Have any of you ever been asked to re-validate a product
(reliability testing) on products just for changing the bare
board vendor?

Maybe I have just had a fortunate career by always getting
good boards, but lately I've been stung a few times in this
brave new world.

have a good day,
Jack

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