Modeling of cutting forces in orthogonal turn-milling with round insert cutters

Accurate prediction of cutting force plays an important role in simulation and application of orthogonal turn-milling operation. However, the existing cutting force models for this operation are limited to the case with flat-end cutters, which is not enough in practice. The objective of this paper is to extend the simulation of cutting forces in orthogonal turn-milling into the case with round insert cutters. To achieve this goal, the basic kinematic relationship between the tool and the part is discussed firstly in detail. Then, the approaches to determine two vital factors, namely undeformed chip thickness and the tool-part engagement region are presented. With the real swept surface of the cutting edge replaced by the geometry envelop of the tool, the analytical formulation of the undeformed chip thickness is derived. The engagement region is determined by judging the positions of discretized cutting edge elements and the in-process workpiece surface, which is described by the mapped grids. Using the cutting coefficients calibrated through experiments, cutting forces are calculated. Validation experiments under different conditions were conducted on a turn-mill machine tool with rotating cutting force dynamometer used. The results prove that the proposed model is capable of predicting cutting forces accurately both in shape and magnitude.