AN INVESTIGATION INTO THE INFLUENCE OF BLANKHOLDER FORCE ON SPRINGBACK IN U-BENDING

Springback is the main defect in U-channel forming process. Applying the blankholder force is one of the ways of solving the problem. On the other hand the value of the blankholder force should be chosen carefully. In this paper the relation of the blank-holder force and final springback, taking a benchmark of NUMISHEET'93 2-D draw bending and using a commercial FEM code has been studied. The simulations are pre-formed for AA5754-O and DP-Steel. In order to probe the relation, five different values are utilized in simulations. It is found that springback increases for the middle values of the blankholder force where the stretching and bending have equal effects on the blank. The maximum required punch loads are compared for the different values of blankholder force.