FORMING PROPERTIES AND SPRINGBACK EVALUATION OF COPPER BERYLLIUM SHEETS

Copper beryllium (CuBe) alloys possess excellent strength and conducti vity. They have become the most important materials used for producing high reliability connectors and interconnections for electrical and e lectronic applications. As demand for high connection density in elect rical and electronic products grows, springback behaviors become incre asingly critical in fabricating these miniaturized contact components from sheet base materials. In the present article, a study of the spri ngback behavior of CuBe sheets under different heat treatments is pres ented, with the goal of providing reliable information needed for fabr icating more intricate connection parts. Both experimental and analyti cal techniques were adopted. The tensile tester was first used to stud y the springback related tensile properties. The governing tensile par ameters on springback were identified, and their variations for sheets with different heat treatments were studied. It was found that a bili near constitutive relationship can best characterize the stress strain behavior of the CuBe alloy. A closed form solution based on this bili near relationship was formulated to predict the springback for the CuB e sheets at bending conditions. A V-shaped bend tester having an inter changeable punch to accommodate multiple radii was designed and built to evaluate the springback properties of CuBe sheets. A good correlati on was found between the analytical predictions and experimental data. A parametric study, as an example, was also performed to provide the springback information needed for designing complicated connectors.