Iterative, simulation-based shape modification by free-form deformation of the NC programs

In production engineering, there are several applications where the geometry of a designed workpiece has to be modified, e.g., optimization of forming tools during springback compensation in sheet metal forming. In general, the modified shape of the workpiece is given as a mesh and has to be converted to a parametric representation by surface reconstruction before manufacturing. In this paper, a new approach for obtaining small shape modifications by direct deformation of the NC programs is presented. In an iterative process, the CAM data is modified by a free-form deformation and is verified by a milling simulation so that the modified workpiece can be manufactured directly on the basis of the original CAD/CAM data without surface reconstruction.

► We present a new approach for shape modification without surface reconstruction.
► The NC programs for a workpiece are modified directly using a free-form deformation.
► A milling simulation is used for the generation of the workpiece surface.
► We have shown that the shape accuracy can be increased using an iterative approach.