Efficient, Accurate Geometric Modeling For Three-Axis Sculptured Surfaces Milling

Efficient, accurate geometric modeling for three-axis sculptured surfaces milling is quite challenging due to complexity of workpiece geometry change during machining. This paper presents an efficient, accurate approach to extracting the cutter/workpiece engagement (CWE) geometry and applying this geometry to an existing mechanistic force model in order to predict instantaneous cutting force, torque and power. In our research, a basic geometric modeling of chip removal in three-axis milling is investigated, and an effective model is proposed to represent the cutter swept profile. Computationally efficient, closed-form formulations are derived for general APT (Automatically Programmed Tools) cutter geometry. A Z-level B-Rep model is adopted to represent the in-process workpiece model, and an innovative geometric approach is used to extract the CWE geometry. Then, a mechanistic cutting force model is integrated to predict the cutting forces. As a result, a milling process simulation system is developed for three-axis virtual milling of sculptured surfaces. The developed system is experimentally verified by comparing the simulation results with actual forces measured from machining a test surface.