A Multiple-Tool Approach to Rough Machining of Sculptured Surfaces

This paper proposes a methodology by which machining instructions can be generated directly from the 3D point data derived from either contact or non-contact measuring devices. Starting with the creation of a B-spline surface model from the 3D point data, several algorithms are developed to automate the generation of process plans, which contain detailed information needed for NC machining processes. In particular, the following issues are considered: 1. Use of ordered data points to fit a smooth surface. 2. Automatic selection of multiple cutting tools. 3. Generation of cutter-paths for rough machining. A cubic non-uniform B-spline (NUB) mathematical model is used for fitting measured data points into a smooth surface. For process planning based on the surface model, the selection and optimisation of cutting tools are based upon the criteria of maximum material removal and minimum tool change, while the generated NC cutter path ensures fast machining and the required surface quality.