Process modeling of controlled forming with time variant blank holder force using RSM method

In this paper, a process model of the controlled forming process was proposed based on Response Surface Methodology (RSM). The forming process was controlled through adjusting the blank holder force (BHF) varied with the time and other process parameters. Due to the wide application and the high efficiency of the Finite Element Method (FEM), this is the chief tool used instead of experiments to carry out the controlled forming process. Deep drawing processes of material SPCC were simulated, and the simulation results were verified by the experiments. The forming processes with several types of time variant BHF were simulated and compared to find a suitable one to achieve our desired product shape. The comparison implied that the staircase-shaped time variant BHF can direct the strain path to the desired place to acquire a targeted product.Then the process model was built up using RSM to the forming process with time variant BHF and friction coefficient. The equations explored the relationship between the principal strain of fracture risk elements and the working parameters, including BHF. Three–dimensional (3D) principal strain surfaces of the element were drawn, which visualised the relationship between the principal strain and the working parameters, especially BHF. Using the model, it is feasible to acquire a fracture-free product through regulating the BHF profile.