多点成形中压痕的形成与控制方法

Dimple formation and its elimination in multi-point forming for sheet metal

对多点成形中压痕缺陷的形成及影响因素进行了力学分析,指出弹性垫技术可以明显地消除压痕缺陷。采用多点压机及多道多点成形技术改变了约束方式及变形路径,因而有效地抑制了成形缺陷的产生,提高板材的成形极限并实现了大变形量成形。通过典型的数值模拟及成形实验说明了弹性垫技术及多道成形技术消除压痕缺陷的有效性。

The formation of the defective dimple and its influencing factors in multi-point forming(MPF) process of sheet metal were analysed mechanically and it was indicated that dimpling defect could be eliminated evidently with elastic cushion.In the forming processes of MPF press and multi-step MPF,the restraint condition and deformation path of sheet metal were changed,and the forming defects were subdued,then the forming limitation was improved and large deformation could be achieved.Numerical results and forming tests of typical specimens demonstrate that dimples are eliminated effectively by means of elastic cushion and multi-step MPF.