Research on the CNC incremental forming method of the special-shaped sheet metal part with the 3D top edge lines

Aiming at the problem that the special-shaped sheet metal part with 3D top edge lines is difficult to form directly, this paper proposed a method of transforming the 3D top edge lines into the planar top edge lines by filling the surface to realize its CNC incremental forming. Firstly, the optimal datum plane for the surface filling was determined by using the multi-objective decision making method according to the formability, forming depth, filling area, and other factors. Then, the vacant area between the datum plane and the sheet part was filled. Finally, the forming toolpath for the forming process was generated using the filled model. The forming quality of the formed sheet part was analyzed by using the numerical simulation, and the sheet metal parts was formed by the forming experiment. The results show that the maximum and minimum deviation in the Z-axis direction between the experimental part contour and the designed model contour in the Z-axis direction are 0.4672 mm and 0.0096 mm, respectively. While the maximum and minimum thickness are 0.698 mm and 0.533 mm, respectively.