I believe IPC has a weight loss (or weight gain) test method to check the
volatile of the PWB during qualification... If the material is fully cured
or low moisture, it should easily pass the test...If your vendor is
qualified as IPC class 3, you should be able to ask about the test results
provided by the vendor (until you feel it is no longer a problem).  Both
un-cured UV or moisture problem PWB normally would fail the test...(can't
remember the IPC-T number...sorry)..I don't think your vendor would (or
should) charge you for the standard IPC test.
                             jk
At 10:14 AM 8/31/99 +1000, you wrote:
>Apart from all thinks suggested (humidity ; large copper grounds, etc.) ;
>what gave us the worst on this line was undercured (UV) LIQUID PHOTO .
>Apparently speeding the process or underpowered lamps can leave top dry and
>on copper contact not so .
>Than reflow measled it all . No idea if baking does influence this scenario
>(never bothered) :
>Did as Bev did afterwards . Not that you would have this luxurious options ,
>as I remember when I've had a sub shop ; you take what you get, say yes sir
>and do (not look) your best.
>This Nortel fellows bake on sunshine comforts forgetting mere mortals
>sometimes .
>
>Paul Klasek 
>ResMed
>
>-----Original Message-----
>From: Stephen R. Gregory [mailto:[log in to unmask]]
>Sent: Tuesday, 31 August 1999 6:37
>To: [log in to unmask]
>Subject: [TN] Delamination and Blisters after Wave, a follow-up...
>
>
>Hi ya'll!
>
>Well, I waved a dozen more of the boards that blistered on me Saturday. This
>
>time I "baby-sat" the boards from baking to wave. I baked them at 125º C.
>for 
>3-hours, and waved them within 2-hours after baking...no blisters this time.
>
>They were the same datecode as the ones that blistered on Saturday (9915)
>and 
>even a few of them had a 9831 datecode...but nada blisters. I used the exact
>
>same profile I used Saturday when I waved em' too...
>
>Hmmmmmm...
>
>I've got a digital camera and if anyone wants to see the blisters I got on 
>Saturday, I can send ya' a picture.
>
>>From the responses I got from a number of people and from a lot of the 
>messages I read in the archives on this subject, if I were a betting man, I 
>woulda bet that the boards would have blistered on me today...but they 
>didn't...
>
>-Steve "Guess I'll bake more often now..." Gregory-
>
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