Investigation into bulging-pressing compound forming for sheet metal parts with very small radii

A newly proposed method for the manufacturing of sheet metal parts with very small radii is the bulging-pressing compound-forming process (Wang et al. Chin J Eng 39:1077–1086, 2017). The principle of this method is introduced, and the key process parameters such as the hydraulic pressure loading path, punch velocity, and initial punch position are optimized by establishing a new optimization strategy. The optimum setting was obtained in order to achieve minimum possible radius with the highest process robustness. Meanwhile, the influences of the punch velocity and friction on the stress state and deformation situation of the rounded corner region are analyzed by FE simulation. Finally, the proposed method is applied for the actual manufacturing of an aluminum alloy sheet metal part. The result showed that the part has high forming quality, and the feasibility of the method was proven.