Tool path generation for the point-pressing-based 5-axis CNC incremental forming

Abstract

Considering the residual height of the sheet metal part surface formed by the point-pressing incremental forming method and the efficiency of the forming process, the candidate terminal cutter location points based on the latitudinal/longitudinal residual height were calculated firstly, and then adjusts the candidate terminal cutter location points that are beyond the maximum residual height. Finally, all the terminal cutter location points are obtained. Thus, while satisfying the maximum residual height, the pressing points are sparse as much as possible, which improves the forming efficiency. In addition, for the problem that the ordinary 3-axis CNC incremental forming cannot press the sheet in the different directions according to the surface features, a method for determining the spatial posture of the 5-axis pressing tool by adjusting the front angle and side dip angle was proposed so that the sheet metal can be pressed in different extrusion directions. According to the proposed 5-axis point-pressing incremental forming tool path generation method, the actual forming experiment was carried out, and the sheet metal part was successfully formed, which meets the residual height requirements and shows that the methods for the tool path generation and the spatial posture determination of the forming tool are feasible. In addition, a comparative experiment was conducted with the 5-axis consecutive incremental forming tool path under the same residual height conditions. Through the measurement and analysis of the experimental parts, it is concluded that the profiles of the sheet metal parts obtained under the two forming methods have a good geometrical agreement with the designed parts. However, the profile of the sheet metal part formed by the 5-axis point-pressing incremental forming tool path is closer to the designed part as a whole, and the thickness in the forming region is also slightly higher than that of the sheet metal part formed by the 5-axis consecutive incremental forming tool path.