Study on hydroforming process and springback control of large sheet with weak rigidity

The control of instability and springback about large sheet with weak rigidity is difficult in the process. The hydroforming process of aluminum alloy engine cover, springback prediction and compensation were analyzed, and the manufacturing method of parts with high precision was obtained. In this paper, the effect of drawbead, pressure versus punch stroke, and blank holder force on the thinning rate of the plate was analyzed, and the phenomenon of wrinkling and fracture was judged according to the forming limit diagram. And springback is predicted through the method of the finite element and the surface of die was compensated by the iterative method. The results show that the quality of large aluminum alloy plate with weak rigidity is improved, the cost of the mould is reduced by the compensation, and the period of mold repair and commissioning is reduced by the sheet hydroforming, which is the flexible manufacturing process. Springback of large aluminum alloy sheet with weak stiffness is within 10mm through process optimization, and the surface of die was compensated in local region. The springback not only has been effectively controlled, but the accuracy of dimensional also is more than 90% of ± 0.5 mm.