Hi Arif
Once we've came across this subject the problem was cheap ( step in
process missing ) solder mask = fabrication .
I'd reject it all , especially if you go with it over solder pot , the
cracks do seep the solder underneath , peeling the mask in the process .
Otherwise it corrodes in time , and breaks down further still .
Definitely not the boards you want in medical devices ( class 2?) .

Paul Klasek
ResMed , process eng.

>----------
>From:  Arif[SMTP:[log in to unmask]]
>Sent:  Tuesday, 27 January 1998 10:29
>To:    [log in to unmask]
>Subject:       [TN] IPC question
>
>Hi there,
>We are a medial device manufacturer and we're getting our finished PCB
>assemblies via a local vendor.
>We are getting many rejects as we try to implement IPC-A-610. Our trouble is
>in 7.2.3 solder mask coating
>breakdown.
>
>MY QUESTION:
>
>We are getting a small areas of exposed copper. Stuff you can't see with the
>naked eye. This is due to
>either PCB fabrication or assembly process.  IS THERE AN ACCEPTABLE EXPOSED
>AREA THAT
>CANNOT BE EXCEEDED OR SHOULD ANY EXPOSED COOPER NO MATTER HOW SMALL
>IT IS BE REJECTED.
>
>Thank you for your time and I look forward to getting an answer soon.
>
>Arif Quronfleh
>Sr. Project engineer
>NeuroCare Group
>
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