Geometry simulation and non-linear error analysis of free surfaces

Focused on error analysis in NC machining process of free surface,a generalized milling cutter model using parameter expression was proposed by analyzing the geometric characters of various milling cutters. On the basis of the generalized milling cutter model and with reference to the envelope machining theory of free surface,a geometry simulation algorithm for the point-contact envelope machining based on the basic engagement theorem was presented.The geometry simulation results were used for analyzing the normal error in machining of free surface.Because the algorithm converts the complicated simulating problem into the solving problem of non-linear equations,the simulating process gets simplified,which has an important significance for improving NC programming precision.In addition,the machining precision for free surface was analyzed and the algorithm was validated with taking the section envelope machining of free surface as an example.