Research on dimple suppression in multi-point flexible stretch forming of parabolic spherical part

Abstract

Multi-point flexible stretch-forming process applies the idea of discretization to the die and clamp of stretch-forming, so that the die and clamp have high flexibility at the same time. Because the surface of the multi-point die is discontinuous, the sheet metal will produce the dimple during the forming process, which will affect the forming effect. To suppress the dimple, this paper takes parabolic spherical parts as the research object, and discusses the influence of swinging unit and discrete elastic cushion on the dimples of forming parts by numerical simulation. The results show that the strain and thickness distribution are more uniform and the dimples on the surface of the forming parts are obviously reduced when the swinging unit is used. The use of discrete elastic cushions on the fixed unit and the swinging unit can further suppress the dimples of the forming part and improve the forming accuracy. To verify the correctness of the numerical simulation, the multi-point die for swinging unit with discrete elastic cushion was used to carry out the flexible stretch-forming test of the parabolic spherical part. The test results are in agreement with the numerical simulation results, which shows that the methods are reliable and feasible.