Rigid-Flex boards need to be dry during any thermal excursions, and
     the temperatures need to be limited to the lowest practical levels.
     The flex materials readily absorb and hold moisture. The inability of
     the moisture to quickly escape from these boards creates forces at
     solder temperatures that can tear apart the structure. Prebaking is
     critical, and controlling hand/rework operations is always a
     challenge.


     Andy Magee - Applications Engineer
     Rogers - Circuit Materials Unit
     Tel: (602) 917-5237
     Fax: (602) 917-5256
     E-Mail: [log in to unmask]


______________________________ Reply Separator _________________________________
Subject: Rigid/Flex: Open Circuits
Author:  GeoFranc (GeoFranck)
{NAME:GeoFranck|EMS:INTERNET|MBX:[log in to unmask] at MCIMAIL
Date:    9/14/95 9:10 PM


Problem:
We experience an unacceptable failure rate with open in rigid flex boards
AFTER assemby and thermal cycling.

Question:
I feel there is a good chance the problem is in the assembly process.  What
kind of things should I look for?  The boards are mixed surface mount and
thru-hole, with much hand soldering and rework.

Thanks
George Franck