Effects of Punch and Die Parameter on Spring-back at Bending Process of Thick Sheet A5083

Abstract

Bent sheet metals are now used widely because their welded part that can cause the debasement of product strength can be reduced by a bending process. Bent plates are contained in many products, and their use is rapidly increasing. However, such plates tend to undergo stronger defective deformation than thin sheet metals, and thin and thick sheet metals differ in accuracy and shape of their products in the bending process. As for the accuracy of bending process and defective deformation, we need to rely on the interpretation by technicians to determine the operational conditions. Therefore, it is necessary to clarify defective deformation phenomena in the bending process of a thick plate. In this study, the effects of the sizes of the punch and die on spring-back angle were examined. By reducing die open width it is possible to control spring-back angle however it is also necessary to consider the crack of the plate. Meanwhile, punch radius hardly affects spring-back angle. Note that it is necessary to consider that damage remains on the inside surface of the plate as caused by the punch and the shape of the plate on central portion in the longitudinal direction. As a result, an optimum die open width is proposed for the suppression of defective deformation in the thick plate bending process of A5083.