Cartesian machining versus parametric machining: a comparative study

The 'de facto' standard methods of machining sculptured surfaces are by sweeping either the parametric space or the physical space of the workpiece. This paper presents the computational aspects of generating toolpaths for both methods and then compares their performance. For given chord error and scallop height tolerances, the CPU time, the toolpath length, either in cutting or fast moving modes, and the number of cutter retreats are compared for representative surfaces. This comparative study demonstrates the subjective aspects of selecting either machining approaches. It has been found that the only clear difference in performance is in the CPU time, hence the necessity of offering the user the possibility of quantitatively comparing the performance of each approach in order to select the most appropriate.