Flexural resistance, fatigue behavior and ductility determination of flex circuits on Kapton.

With the fatigue ductility of metallic foils and flexible metal foil/dielectric laminates can be determined. Ductility together with the tensile strength this allows prediction of the fatigue behavior of flexible printed wiring (FPW) in both the low-cycle/high- strain (ductility dependent) and the high-cycle/low-strain (strength dependent) ranges. However, for laminates and FPW with Kapton as the dielectric the standard fatigue ductility test method does not produce the expected results and flex life predictions deviate from experimental results.