Bruce,
Do you have any customer requirements that state the board must be free from
all cosmetic defects? If not, and the board is not functionally affected by
the "smears", I don't see what the hang-up is besides a good "touchy-feely"
sense that the product looks good.
I have run into this many times with my own inspectors wanting to "make the
product look good". And, I have to say, I fall on that side of the argument
from my desire to give the customer the best product possible. But, there
are constraints on everything we do - based on cost, time and labor expended
- plus the standards we build product to, both industry and customer
specified. If you find nothing in either of them that makes you fail the
product, then you have a good product.
Warning: Some customers do expect a clean "no smears" product, regardless of
the standard which you have been told to use to build them. I have had to
push back at times in that regard so that their expectations meet the
specifications given to us to build the product. Of course, I always leave
the door open for a change in requirements if they deem that necessary (with
a potential change in unit cost if more labor or other resources are
necessary to make that happen). Be careful with the customer's expectations.
This is a tricky mine field, so tread carefully.
Good luck in resolving this,
Dale Ritzen, CQA
Quality Manager
Austin Manufacturing Services
-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Bruce D Stilmack
Sent: Friday, December 12, 2003 7:56 AM
To: [log in to unmask]
Subject: [TN] Foreign material on top of the conformal coating
Hey guys,
I have be hit recently on a couple of occasions by the quality folks
over "foreign material" that is present on CCA's after conformal coating.
On quite a few boards we install heat sinks after CC and usually use an
epoxy to aid in heat transfer as well as loctite on the mounting screws. I
have been gigged for the residuals (just smears really) whether it is on
the solder pads or not. I know that we all are concerned with material
left over directly on the solder connections, but I am having trouble with
this one from a logical standpoint. I mean lets face it, you definitely
can't test for the presence of ionic contaminants or anything, but I know
the general impression is the boards should be clean.
I know the simple answer here is to clean up all the residuals (and
everyone is instructed to do that), but there are times when stuff just
happens.
Your thoughts
Bruce Stilmack
GDLS-TO Manufacturing Engineer
(850) 574-4773
[log in to unmask]
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