Study on Segmented Variable Blank Holder Force method of Rectangular Box Drawing

The form of blank holder and the manner of blank holder force (BHF) on the complicated parts forming are very important. The blank holder of rectangle box forming was divided long straight segments, short straight segments and corners. The forming process simulation of rectangular box was conducted by FEM based on explicit algorithm, including single-piece blank holder with constant BHF, single-piece blank holder with variable BHF, segmented blank holder with constant BHF, segmented blank holder with variable BHF. The results were analyzed according to the thinnest level of the parts. The displacement in the Z direction of blank holder in the simulation was considered, and the method of determining segmented variable blank holder force (VBHF) was proposed. Finally rectangular box was obtained by rectangular box drawing system of segmented variable BHF on the basis of the simulation result.