Abstract: Sculpting pattern onto free-form surfaces in five-axis CNC machine tools is a potential method for many applications such as jewelry, glass blow-molding, injection molding, even automatically spray painting on the surfaces, etc. Since traditional methods map the pattern placed in parameter domain onto the part surface by using the surface equation, this may not be feasible for multiple trimmed surfaces, mesh surfaces and cloud of point surfaces. An angle-based flattening (ABF) based method for pattern sculpting on free-form surfaces is developed. 2D pattern is converted into discrete data points for tool path generation from digital image using image boundary processing technique. To map the discrete pattern onto the part surface, ABF is introduced, which is used for flattening the part surface onto 2D plane. Using this mapping of the part surface to 2D region, a linear mapping method is proposed to inversely map the pattern onto the part surface. On basis of this, according to the selected cutter parameters and the depth of cut, tool path for pattern sculpting is generated. Simulation and real machining is implemented on several sample surfaces and experimental results demonstrate the validity of the proposed method.

Key words: Free-form surface, Pattern sculpting, Tool path generation