When the deformation of the workpiece exceeds permission of one step, the wrinkling defect will be produced, the multi-steps forming can resolve the problem.

• 当工件要求的变形程度超过一次变形的允许值时,一次成形会使工件产生起皱等成形缺陷,而采用多道次成形则可以解决这样的问题。