Investigation of spring-back using a discrete steel pad in multi-point forming

To verify the effectiveness of a discrete steel pad in suppressing the spring-back in multi-point forming (MPF), the spring-back states of three kinds of forming processes, namely, without a cushion, with a polyurethane elastic pad, and with a discrete steel pad, were studied by numerical simulation and test methods. The differences in the spring-back states of the three forming processes were discussed from the aspects of the thinning rate, section elongation, and curvature change. The results show that compared with the forming processes without a cushion and with a polyurethane elastic pad, an MPF process with a discrete steel pad can effectively improve the state of the stress and strain on the blanks, increase the degree of plastic deformation, and reduce spring-back.