Influence of cutting edge radius of coated tool in orthogonal cutting of alloy steel

This paper investigates the effects of edge radius of a round-edge PVD coated tool upon chip formation, cutting forces, and tool stresses in orthogonal cutting of an alloy steel 42CrMo4 (AISI 4142H). A comprehensive experimental approach based on end turning of thin-walled tubes is conducted using advanced coated tools with well-defined cutting edge radii ranging from 9 to 28 microns. In parallel, 2-D finite element cutting simulations based on Lagrangian thermo-viscoplastic formulation are used to analyze cutting temperature and tool stress distributions within the coating layer and tool substrate. The results obtained from this study provide a fundamental understanding of the cutting mechanics for the coated tool used and can assist in the optimization of tool edge design for more complex geometries such as chamfered edge. Particularly, the results obtained from the experiments and simulations of this study have underlined that there exists an optimum cutting edge radius that minimizes tool stresses, especially within the coating layer, and prolongs the tool life.