Andy,

The elongation at fracture for Sn40Pb is in excess of 50% at room temperature
(I am assuming by solder plate you don't mean as plated Sn Pb). Ref
P.A.Ainsworth "The formation and properties of soft soldered joints" ITRI
pub 440, Nov 1971.

David Whalley

>     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]
>
>
>