My guess is that the set-up of the pressing operation was not done correctly
and the operator used too much force when inserting the PEM spacer. I guess
what I am looking for is criteria to make an accept or reject decision on
the product that exhibits this condition.
Thoughts? Are there test methods, examples, or is this purely a judgement
decision?
Thanks for your help everyone.
Rich
-----Original Message-----
From: Boldt, Mike (msd) USX [mailto:[log in to unmask]]
Sent: Thursday, November 09, 2000 9:40 AM
To: [log in to unmask]
Subject: Re: [TN] Stress Cracks on PCB
Hi Rich,
We routinely use press-in hardware and I'm not aware that we've ever had a
PWB cracking problem. Have you double checked your hole size, both
specification and actual, to make certain they're correct?
Mike
Michael E. Boldt
Electronic Packaging Engineer
Moog Inc., Motion Systems Division
-----Original Message-----
From: Rich Lasko [SMTP:[log in to unmask]]
Sent: Thursday, November 09, 2000 9:40 AM
To: [log in to unmask]
Subject: [TN] Stress Cracks on PCB
Good morning everyone.
I need some input from you guys. We have a product (pcb assembly) in which
we needed to "press in" a PEM spacer. Unfortunately when we pressed in the
spacer, it has caused stress cracks in the pcb. I have looked in the
IPC-A-610 to find out acceptable and rejectable criteria for stress cracks,
however, I have not been able to find any. The closest I can come is
crazing. However, the defect appears to be more of a stress crack then
crazing.
Need help. Is there any other accept/reject criteria or anyone else
experience with stress cracks from pressing in hardware.
Please advise.
Rich
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