Multiresolution offsetting and loose convex hull clipping for 2.5D NC machining

A complex curve can be decomposed using wavelet-based multiresolution analysis into lower resolution curves. In this paper B-spline wavelet theory is applied to NC machining of contoured 2D objects. High-resolution curves are used close to the object boundary, while lower resolution curves are used farther away from the object boundary. This reduces tool path length and sharp corners are smoothed out thereby reducing uncut areas. The wavelet curves are clipped against a loose convex hull of the 2D object contour to further improve the efficiency of the generated tool paths. Simulation results indicate that the wavelet based tool paths and clipping improves machining efficiency.