A new STL model-based approach for tool path generation in CNC incremental forming

A new tool path generation method for sheet metal computer numerically controlled incremental forming was proposed based on the stereolithography model, considering the factors of sheet thickness variation, surface smoothness, and extruding direction. The new cutter contact surface modeling algorithm based on the non-equidistant offset was presented, which can be adapted to the sheet thickness variation so as to guarantee a reasonable gap between the forming tool and support. Moreover, a spiral tool path generation algorithm was introduced by considering the scallop height in both z-axis direction and circumferential rotation direction, so that a smoother surface can be obtained. In addition, the algorithm for keeping the tool direction perpendicular to the wall surface was also presented. Finally, the case study shows that the proposed method can automatically generate smooth and continuous spiral tool path with constant scallop height. The developed software system runs steadily and reliably.