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October 2001

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Mon, 8 Oct 2001 08:03:42 -0400
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Neil,

I am curious about your reply because I am looking at v-score as a means to
panelize some boards. How were you separating the boards? I can see problems
if the boards were being broken apart by hand, but were you using a cab or
FKN type of separator amd getting failures?

Thanks.


Bob


Robert Barr
Manufacturing Engineering
Formation, Inc.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Neil Atkinson
Sent: Monday, October 08, 2001 4:24 AM
To: [log in to unmask]
Subject: Re: [TN] Leaky Capacitors


I have seen this in the past and you must be very careful during
de-panellising PCBs as well.

We banned 'v' scoring of FR4 surface mount PCBs because of the risk of
cracking surface mount capacitors. The time to failure can be anything from
hours to months depending on environment - temperature, moisture etc.

I have another question - has anybody out there seen chip capacitors fail
open circuit when operated in a circuit which runs quite hot?

Can the end caps become loose through temperature cycling causing the
capacitors to go open circuit at elevated temperatures?

Neil

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