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Forum: Reliability & Maintainability Questions and Answers

Topic: Reliability & Maintainability Questions and Answers

Topic Posted by: Reliability & Maintainability Forum (src_forum@alionscience.com )
Organization: System Reliability Center
Date Posted: Mon Aug 31 12:47:36 US/Eastern 1998

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Original Message:

Posted by: Quek Puay Keng (qpuayken@dso.org.sg )
Organization:DSO National Laboratories
Date posted: Mon Jan 31 21:44:40 US/Eastern 2000
Subject: Reliability of Flexible PCB
Message:
Thermal shock test was performed on a batch of flexible PCBs. After the test, waviness was observed at the PCB edges and at areas where there is no copper. Circuit continuity was maintained. However, will the waviness pose a long term reliability problem? Is it a sign of delamination? Appreciate advice/comments. Thank you and regards.


Reply:

Subject: Flexible PCB
Reply Posted by: Bruce Dudley (bdudley@alionscience.com )
Organization: Reliability Analysis Center
Date Posted: Mon Feb 7 10:37:35 US/Eastern 2000
Message:
I searched the RAC library for references on possible delamination problems that you have observed with temperature shock testing. Most of the design guides seem to expect delamination after repeated flex cycles or thousands of thermal and humidity cycling but not shock test. Some references are: "Flexible Circuit Design Guidelines" by Darren Hitchcock and "Printed Circuit Handbook", Chapter 39, by Sheldahl Technical Staff.


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