Investigation of springback behavior and process control for stamping of ring-shaped workpiece

Due to the elastic deformation of metal stamping, springback is a serious problem to cause shape deviation and thus reduce precision. The springback behavior of ring-shaped workpiece is investigated in this paper and an auxiliary boss device is proposed to control the springback deformation. A finite element model is developed. The characteristic parameters including boss height, boss angle and boss gap are discussed systematically. It can be concluded that the gap has a positive linear correlation with springback percentage, and the boss angle has an optimal interval of 30 ◦ —60 ◦ to reduce springback. When the boss height increases, the springback decreases, but the effect weakens when the boss height is larger than 1.0 mm. Then, a response surface analysis is conducted with Design Expert 8.0.5 software and an optimal parameter process window (i.e., boss height from 2.1 to 3.0mm, boss angle from 53◦ to 60◦ and the gap from 0 to 1.2mm) is obtained. Finally, a set of molds are fabricated and the stamping experiments are conducted. The springback behavior is well controlled. The springback percentage can be decreased from 33% to 6% by using the auxiliary boss device of ring-shaped workpiece.