Process simulation and feedrate selection for three-axis sculptured surface machining

Abstract

This research is focused on improving the efficiency of Computer Numerical Control (CNC) machining by enabling automatic feedrate selection. Model accuracy and utility are improved by a calibration process that uses spindle motor power and a wide variety of test cut geometries. A low-cost noninvasive spindle motor power sensor is combined with geometric and mechanistic models of the cutting process. Different constraints are set for rough, semi-finish and finish passes. A Numerical Control (NC) part program is processed one tool move at a time by the feedrate selection planner. For each tool move, a geometric model calculates the cut geometry. The selection algorithm then chooses the fastest possible feedrate, subject to constraints on part quality, tool health and machine tool capabilities. Experimental results for a sculptured surface bottle mould show the value of the method as an aid to process planning.