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     Simple question, but we can't seem to find the answer:

     What is the % elongation to failure for solder plate?



     We have an application where a single sided flex circuit is being
     folded back on itself at .0005" radius (not recommended). The outer
     surface is solder plated.

     The copper (RA) is experiencing 11.9% max. strain and the solder plate
     sees 17.4%. Both the copper trace and the solder plate are cracked.
     It's not clear if the crack started in just one of the metals, and
     progressed into the other.

     We'd like to suggest opening up the bend radius to provide a reduced
     strain, but we need to know the max % elongation of the solder plate
     to know how far.

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