Cutting forces prediction in generalized pocket machining

Abstract

Cutting force prediction is important for the planning and optimization of machining process. This paper presents an approach to predict the cutting forces for the whole finishing process of generalized pocket machining. The equivalent feedrate is introduced to quantify the actual speed of cutting cross-section in prediction of cutting force for curved surface milling. For convenience, to analyze the process with varying feed direction and cutter engagement, the milling process for generalized pocket is discretized into a series of small processes. Each of the small processes is transformed into a steady-state machining, using a new approximation method. The cutting geometries of each discrete process, i.e., feed direction, equivalent feedrate per tooth, entry angle, and exit angle are calculated based on the information refined from NC code. An improved cutting force model which involves the effect of feed direction on cutting forces prediction is also presented. A machining example of a freeform pocket is performed, and the measured cutting forces are compared with the predictions. The results show that the proposed approach can effectively predict the variation of cutting forces in generalized pocket machining.