Wavelet-based Multiresolution Representation of a Geometric Model for Free-form Surface Machining

In a 3D free-form CAM system, a series of intermediate shape models for machining are required as the references of NC programming. The safety and efficiency of the machining greatly depend on the geometric relation between these intermediate shape models. However current CAM systems lack the function of automatic generation of the appropriate series of these shape models. In this paper, a new wavelet-based multiresolution representation (MRR) of a series of intermediate shape models for machining is proposed. The proposed MRR enables very compact data representation for these models. In this MRR, geometric relations between each resolution model can be controlled so as to avoid overcut and to level the cutting loads. Two new control methods for MRR based on the lifting scheme and wavelet coefficient modification are proposed to support the contour line and scan line milling. The effectiveness of the MRR was verified through simulation.