Influence of different technology modes on spring-back in multi-point forming

Finite element method was used to numerically simulate spring-back in multi-point forming (MPF). By contrasting two forming modes of multi-point die (MPD) and multi-point press (MPP), the influence of different forming modes on spring-back was analyzed. Firstly figuration was simulated by explicit method, and then implicit method was imported to calculate the spring-back of the spherical parts of 1 mm and 2 mm in thickness. The results indicate that when forming a figuration piece of 400 mm in curvature and 1 mm in thickness by the MPD forming mode of 10×10 array without hold blank, its spring-back value is 1.22 mm up to the most. But under the same condition, the spring-back value only is 0.24 mm by MPP. Namely the spring-back value of a metal sheet by MPP is 1/5 that by MPD. Moreover the spring back value is approximately 0 when forming a spherical part of 2 mm in thickness by MPP. It is concluded that MPP is better for MPF than MPD, and spring back value is sharply reduced.