Prediction of cutting force in five-axis flat-end milling

Abstract

Milling force, closely related to machining efficiency and machining quality, is the most important technical parameter in computer numerical control machining. Aiming at five-axis flat-end milling, this paper proposes a milling force prediction model with arbitrary feed direction and cutter workpiece engagement (CWE). CWE, defining the interaction region between cutter and workpiece, is the basis for studying statics and dynamics of cutting. The efficiency of traditional solid modeling method is low and not suitable for large complex sculptured surface. Z-map method is also difficult to apply in five-axis flat-end milling. In response to this issue, analytic CWE model for five-axis flat-end milling of inclined plane is established by calculating the intersection of spatial surfaces; then, an algorithm is proposed to investigate the in-cut cutting edge. Different from the conventional slot cutting and half slot cutting processing, non-slot cutting processing with changing arbitrarily of cutter axis direction is used to calibrate the coefficients which are more suitable for five-axis machining. Combined with the instantaneous chip thickness considering cutter run-out, the cutting force coefficients which have quartic polynomial relationship with instantaneous chip thickness and the cutter run-out parameter identification model are established. The validity of this analytic model has been proved by experimental tests. The results also show that the measured milling force and predicted milling force are in good agreement in the aspect of the amplitude and trend in the different cutting depth, path interval, feed per tooth, and slope inclination angle, which verifies the efficiency of the coefficient identification model.