Research the CNC incremental forming of straight-wall parts based on a virtual auxiliary body

Abstract In order to realize the CNC incremental forming of straight-wall part, a CNC incremental forming method for multi-directional adjustment of sheet postures based on the virtual auxiliary body was proposed. In the method, the sheet posture was adjusted based on the virtual auxiliary body which was set inside the straight-wall part to establish a gently inclined surface, thereby the forming angle was reduced to successfully form the straight-wall part. To ensure the non-rupture forming of the straight-wall part, a generation algorithm of the virtual auxiliary body based on the desired forming angle determined by the user and the forming limit angle was presented. And, in order to achieve the forming of the straight-wall part with uniform thickness as much as possible, a forming toolpath generation algorithm that could realize the sheet postures adjustment and the sheet parallel downward movement was given. The case studies show that the proposed algorithm can generate the required virtual auxiliary body and the forming toolpath, and achieve the multi-directional adjustment of the sheet postures. The results of the numerical simulation and the forming experiments show that the proposed method is applicable and can be used to form the straight-wall part that cannot be formed by the conventional CNC incremental forming.