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September 2006

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TechNet E-Mail Forum <[log in to unmask]>, li na <[log in to unmask]>
Date:
Thu, 7 Sep 2006 08:18:21 -0400
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Guy Ramsey <[log in to unmask]>
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I have seen thermal cycling data from two different sources that suggest
high aspect ratio PTH >9:1 fail more quickly than an 0805 chip resistor
solder connections.

What is the aspect ratio of the PTH?

-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of li na
Sent: Thursday, September 07, 2006 2:40 AM
To: [log in to unmask]
Subject: [TN] PTH barrel crack


Hello All,

We recently met one problem when we were doing 1000 cycles thermal cycle
test(-40C to +125C) on daisy chain boards.  The resistance change after
1000 cycles is less than 10%, however we see complete barrel crack on PTH
hole walls. Should I accept or reject this test result?  Have you ever met
this kind of problem before?  What did you do on it?

Your advice are highly appreciated.

Best regards,
Lina

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