For the problem of springback affecting size and assembly performance in the bending process of window lift plate for automobile caused by the existence of elasticity and residual stress of sheet metal, the forming process and the springback prediction were carried out by the Dynaform software. Then, nine sets of different process parameters were designed with four influence factors as the sheet thickness A, the stamping speed B, the friction coefficient C and the mold gap D, and the springback results were obtained by the orthogonal test and repeated orthogonal test (the number of repetitions S=3 ). Furthermore, the primary and secondary sorting of influence factors and the process optimization were carried out by the range analysis (Option 1) and variance analysis (Option 2). The results of Option 1 and Option 2 were as follows: A>B>D>C, A2B2D3C2 and B>D>C>A, B2D3C2A1 respectively. After comparing and verifying the two groups of process parameters, the optimum process parameters were determined as follows: sheet thickness A is 0.9 mm, punching speed B is 5000 mm·s-1, friction coefficient C is 0.125, and die gap D is 1.15. The trial production was manufactured, and the thickness of dangerous rounded corner for parts is 0.70 mm and the thinning rate is less than 25%. Finally, the trial assembly shows that the part produced by the optimized process parameters can meet size and assembly requirements under their working conditions.
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