Simultaneous optimization of blank shape and variable blank holder force of front side member manufacturing by deep drawing

This paper presents a method to determine an optimal blank shape minimizing earing for a front side member. In addition, variable blank holder force, meaning that the blank holder force (BHF) varies through punch stroke, is adopted. Blank shape directly affects the material cost, and it is important to determine an optimal blank shape minimizing earing that is trimmed out. BHF also have an influence on the product quality. Large BHF leads to tearing, whereas small BHF results in wrinkling. Variable BHF (VBHF) approach is recognized as one of the advanced manufacturing technologies, but it is difficult to determine the optimal VBHF for successful sheet metal forming. To determine the optimal blank shape and VBHF simultaneously, design optimization is performed. Numerical simulation in sheet metal forming is so intensive that a response surface approach is valid. In particular, a sequential approximate optimization that the response surface is repeatedly constructed and optimized is used to determine the optimal blank shape and VBHF. Front side member provided from NUMISHEET 2011 (BM3) is used for the numerical simulation. It is found from the numerical result that the proposed approach can drastically reduce the earing. In addition, the maximum thinning is much improved, compared with other results reported in NUMISHEET 2011.