The Mechanism of Surface Low Defect in Sheet Metal Stamping

Abstract

In this paper, the mechanism of surface low defect in sheet metal stamping is studied. Firstly, we simulate the forming procedure of a stamping component by Finite Element Method (FEM) to observe the growth of surface low defect. And then, we establish an analytical model and deduce the critical stress for local buckling. Finally, we take advantage of the critical stress to detect local buckling areas in the component. The FE simulation result shows that during springback the non-uniform displacement in the thickness direction forms surface low. Moreover, the detected local buckling area agrees with the experimental surface low area. This indicates that the essence of surface low phenomenon is panel’s local buckling under the residual compressive stress during springback.