A comparison of solid model and three-orthogonal dexelfield methods for cutter-workpiece engagement calculations in three- and five-axis virtual milling

Abstract

Virtual simulation of three- and five-axis milling processes has started to become more important in recent years in various industries such as aerospace, die-mold, and biomedical industries in order to improve productivity. In order to obtain desired surface quality and productivity, process parameters such as feedrate, spindle speed, and axial and radial depths of cut have to be selected appropriately by using an accurate process model of milling. Accurate process modeling requires instantaneous calculation of cutter-workpiece engagement (CWE) geometry. Cutter-workpiece engagement basically maps the cutting flute entry/exit locations as a function of height, and it is one of the most important requirements for prediction of cutting forces. The CWE calculation is a challenging and hard problem when the geometry of the workpiece is changing arbitrarily in the case of five-axis milling. In this study, two different methods of obtaining CWE maps for three- and five-axis flat and ball-end milling are developed. The first method is a discrete model which uses three-orthogonal dexelfield, and the second method is a solid modeler-based model using Parasolid boundary representation kernel. Both CWE calculation methods are compared in terms of speed, accuracy, and performance for three- and five-axis milling of ball-end and flat-end mill tools. It is shown that the solid modeling-based method is faster and more accurate. The proposed methods are experimentally and computationally verified in simulating milling of complex three-axis and five-axis examples as well as predicting cutting forces.