Formability Improvement via Variable Binder Pressure - Numerical Models and Experiments

Robust operating window and subsequent quality of part is a major concern during sheet metal stamping. For a given part geometry, material, and lubrication conditions, the blankholder restraining force is the key parameter controlling metal flow, thus influencing formability and quality of the resulting part. Recent advances in press building provide capability of the blankholder force (BHF) variation during stamping stroke. In this study, a laboratory and numerical experiments were performed in an effort to better understand the effect of various BHF trajectories on stamping performance. The working numerical model using explicit LS-Dyna 3D code was successfully developed for time effective simulation of complex parts with variable binder force. Selected results of these numerical tests, showing strong influence and process design promise, are presented, compared to the experimental results, and discussed.