Numerical and experimental investigation of tool geometry effect on residual stresses in orthogonal machining of Inconel 718

Residual stress has become more important than ever with the increasing performance requirement of components especially for those applied in safety-critical areas. As the machining process is fundamentally correlated with the acquired component properties, it is essential to fully understand the formation mechanism of residual stresses in the cutting process and its influence on the performance of the component. This paper presents results based on numerical and experimental analysis on the effect of tool geometry on thermal-mechanical load and residual stresses in orthogonal machining Inconel718 alloy. The Coupled Eulerian-Lagrangian (CEL) method is used to simulate the effect of tool geometry on temperatures, forces, equivalent plastic strains, and residual stresses. The local normal/tangential stress is introduced to determine the degree of the tensile plastic deformation induced by the tool. It is observed that a negative rake angle and a sharp edge radius tool tend to generate more compressive stress on the machined surface than the ones generated with positive rake angle tools and/or lager edge radius. Besides, an increase in flank wear produces less magnitude of compressive stress in subsurface due to a decreased local normal stress caused by increased flank contact length.