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Tue, 14 Jul 2009 21:40:11 +0200 |
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Steve,
I would (with great caution) aquestion if polyimide would be the ideal
material for such extrem handling. Polyimide (Kapton) has some properties
that most people avoid to talk about. Many years ago, I warned my collegues
to blindly use this material for our fighters (we make military aircrafts).
The reason is that I got the result from the investigation of a deadly
flight close to Nova Scotia. Without going into details, polyimide simply
can change its mechanical/electrical characteristics when exposed to harsh
environment a longer time. There are many PI makers, so there ought to be
some difference. If PI still got the said disadvantage, I can't tell you. As
I said, one needs to be very careful with what to say in this forum. The
conclusion is that FR-4 might be as good as polyimide. You must not use my
comment for any decision, but do your own research. As I said, the crash
investigation was done many years ago. I feel a little uncomfortable
announcing this, but your choice may be important.
/Inge
http://www.usatoday.com/money/biztravel/wiring/w002.htm
----- Original Message -----
From: "Steve Kelly" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, July 14, 2009 9:11 PM
Subject: [TN] Storage life for rigid flex
Good Afternoon,
We have a program for some reasonably simple rigid flex (4-8 layer) where
the requirement is a 20 year life in storage conditions from -40C to +125C.
Is there any evidence that polyimide rigid material and pre-pregs would be
better than a good FR-4 (170C) for long term reliability. Thanks. Steve
Kelly
Steve Kelly (PLEASE NOTE NEW E-MAIL ADDRESS)
(416) 750-8433 (work)
(416) 750-0016 (fax)
(416) 577-8433 (cell)
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