Lead stiffness Measurements and Calculations.

Mechanical testing and finite element modeling have been used to determine the z-direction stiffness of the AT&T straight and dimpled J leads on 68 I/O PLCCs. Mechanical testing measurements confirm R. W. Kotlowitz's (54582) finding that the dimpled J is stiffer than the straight J in the z-direction. Lead displacement plots show that the lead deformations arising under a compression load are accompanied by lateral bending toward the package, which is achieved more easily with a straight J than with a dimpled J, thus making the dimpled J stiffer in the z-direction. The good correlation between measured and calculated values gives support to the use of simple beam finite element models for in-plane stiffness calculations.