On the Mechanism of Multi-process Compound Spinning for Thin-walled Deep Cup Shaped Parts

To solve the problems of long forming process, low efficiency, and difficult quality control in the traditional machining methods for thin-walled deep cup-shaped parts, a deep drawing-flow multi-process compound spinning method, which can realize the precise preparation of such parts with high efficiency, was proposed in this paper. Based on software Abaqus, a finite element model of Compound Spinning for the deep cup-shaped part of SPHC steel was established. It was used to study the strain and stress distribution and the flow of the material in the compound spinning process of deep cup shaped parts, and reveal the forming mechanism of compound spinning. Combining with the compound spinning forming experiments, the correctness of the finite element model was verified. The results show that the multi-process compound spinning process can obtain the thin-walled deep cup-shaped parts with good forming quality in single spinning process. According to the deformation of materials, multi process compound spinning can be divided into drawing spinning stage, flow spinning initial stage and compound spinning stable stage. In the initial stage of flow spinning, the maximum equivalent strain rises sharply with the progress of spinning. In the stable spinning stage, the maximum equivalent strain appears in the formed region, and its deformation state is axial and tangential tension and radial compression, while the transition region is axial tension, radial and tangential compression. In the initial stage of flow spinning, the axial flow of the material in the die area to the mouth increases with the increase of the axial offset between the rollers for deep drawing and flow spinning. In the stable stage of compound spinning, the outer area of the blank in contact with the roller for deep drawing spinning is subject to three-dimensional compressive stress, while the inner area is subject to three-dimensional tensile stress,and the contact area between the blank and the roller for flow spinning is subject to three-dimensional compressive stress. To ensure the spinning forming quality, the axial offset between the roller for spinning drawing and the roller for flow spinning should be greater than 5.3 mm.