I don't have help for you in finding sources for design guides, but after designing/procuring highly stressed (in terms of bend radius) flex designs over the past 10 years, I can tell you that it would be a very rare fabricator who knows how to tell the grain direction of the RA foil:  Out of 18 orders of flex, 9 have come in with the grain in the wrong direction!  After I educated those fabricators, they MAY now be able to identify it, but I never trust them.  If you need to push things at or beyond standard limits, count on learning to read the grain and on the extra time required to have a fabricator remake boards.  One fabricator I used last year made the initial delivery in May.  By the time they agreed the grain was wrong and they re-made the boards, it was October!  They had purchased the material from DuPont.  DuPont also did not know how to read grain.  DuPont then went to their foil supplier.  I have my doubts on whether any of the "education" stuck!

Wayne Thayer

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Robert Coburn
Sent: Monday, January 28, 2013 7:45 AM
To: [log in to unmask]
Subject: [TN] Flex design guidelines / assembly guidelines

T-netter's;
Can anyone provide direction regarding design and assembly guidelines for flexible PCB's / PCA's?
Thanks in advance for your responses.
Rob Coburn 		 	   		  

______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________

______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask] 
______________________________________________________________________