Numerical simulation of orthogonal machining process using multilayer and single-layer coated tools

Abstract

In this study, numerical simulation was carried out to determine the effect of coating type on the cutting forces, tool stresses, and temperatures. The Lagrangian thermo-viscoplastic cutting simulation of AISI 4340 steel was conducted using two different coating types (TiCN + Al2O3 + TiN and Al2O3) and uncoated carbide tool having same geometry. Johnson–Cook work material model is used for plastic deformations. The predicted cutting forces for the coated and uncoated tools were compared with the experimental results. The variation of tool stress and temperature with coating type and number of coating layer were investigated. The predicted results indicated that the tool coated with Al2O3 showed minimum tool temperature value due to its decreasing thermal conductivity with increasing temperature. Maximum tool temperature occurs at the rake surface of the cutting tools (coated and uncoated) and decreases rapidly with depth in the coated tools. On the other hand, the tool stress within the coating increases along the thickness with increasing cutting speed and feed rate. Minimum shear angle is observed in uncoated carbide tool whereas maximum shear angle occurs for Al2O3-coated tool. This result also confirms the results obtained from cutting tests.