Hi Dave and all,

1)The rigid flex would be assembled

2) I have read all of the multitude reports on kapton and airplanes and the problems. In my opinion the problems where associated with kapton wiring (wire wrapped with kapton) - never seen any major problems with a flexible printed circuit board anymore than a standard rigid board. Build it right like the people at Rockwell for example expect and it will last a long, long time.

So I go back to my question is polyimide rigid better in long term storage conditions than a high end FR-4. The operative word is storage - a finished assembly never used sitting in some bunker in the desert or Arctic  that 20 years from now has to turn on.



Regards Steve Kelly





From: [log in to unmask] [mailto:[log in to unmask]]
Sent: July-14-09 3:30 PM
To: TechNet E-Mail Forum; Steve Kelly
Cc: [log in to unmask]
Subject: Re: [TN] Storage life for rigid flex




Hi Steve - Wow, if you really are going to sit around for 20 years, I would make the pwb surface finish bare copper and apply an OSP treatment right before assembly. A good tin/lead finish might make 20 years self life but you are really on the edge. Good Luck.

Dave Hillman
Rockwell Collins
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Steve Kelly <[log in to unmask]>
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07/14/2009 02:11 PM

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[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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