Development of Press Forming Load Prediction Technology by FEM and Press Forming Load Reduction Technology by Optimization of Die Rigidity

The application of ultra-high strength sheet steels is expanding in the auto industry, in order to reduce the weight and to improve the collision safety of auto bodies. The increased strength, however, leads to a higher load in press forming. Making the capacity of the existing press equipment insufficient, the increased load hinders the application of the ultra-high strength sheet steels. Therefore, it is required to develop a cold press forming method that can reduce its press load. In this study, a technique for press forming load prediction was developed by forming analysis in which the die was modelled with elastic shell elements to take not only the die surface shape but also the inside structure of the die into account. A new die with appropriate rigidity was designed by the application of the developed technique.