Cutter location interpolation methods and error analysis for prosthetics socket machining

Based on the analysis of NC machining features for the prosthetics socket, three typical interpolation methods, i.e., the direct method, the fall back cutter method and the vector method, were discussed in the application of the socket mold machining with the 3-axis NC milling machine. The error sources and the error distribution were analyzed, and the calculation method of approximation error and cutter compensation error were discussed specifically. The validity of three methods and the correctness of the error calculation were proved in the machining experiments. The experimental results has shown that the direct method is simple with the high machining error which makes it only suitable for the rough machining; the fall back cutter method is complex and the high machining error which makes it unsuitable for the socket machining system; the vector method is complex with the low machining error which makes it suitable for the system.