Research on the multi-stage CNC incremental forming of unequal height sheet metal part with large forming angle

In order to realize CNC incremental forming of unequal height sheet metal parts with large forming angles on both sides of the sheet metal part, a three-stage incremental forming method is proposed. In this method, the sheet metal parts are inclined to the required angle during the forming process, and in order to ensure reasonable material flow during the forming process, the forming toolpath adopts the inclined forming toolpath, the contour line forming toolpath, and the equal interval parallel downward forming toolpath, and the algorithms for constructing the forming model and forming toolpath for each stage are also given. The case studies of the algorithm show that the proposed algorithms can generate the required forming model and forming toolpath. And three different forming methods of numerical simulation and forming experiments had been conducted; the results show that the forming method proposed in this paper is compared to the traditional two-stage and three-stage forming methods, the minimum thickness is large about 0.119 mm and 0.125 mm, the difference between the thickness is reduced by about 0.101 mm and 0.114 mm, the average profile deviation is reduced by 0.077 mm and 0.131 mm, and no bulging phenomenon occurs, which indicates that the profile dimensional accuracy of the sheet metal parts obtained by the forming method proposed in this paper is better, the minimum thickness is larger and uniformly distributed, and the forming quality is better.