The relationship between the cutting-edge, tool wear, and chip formation during Inconel 718 dry cutting

Abstract

This study comprehensively addresses the machining of nickel alloys, focusing its attention on crucial aspects related to chip formation and tool wear. Detailed characterization of the morphology and the chip formation process was performed by analyzing parameters such as chip segmentation ratio and variables such as shear band thickness and strain rate. Additionally, a numerical model was used to quantify stresses and temperatures at the tool/chip interface and to evaluate damage, thus contributing to the understanding of the development of chip formation. A transition in chip shapes as the toothing increases is highlighted, evidenced by segmentation ratio values below 0.5, indicative of the presence of discontinuous chips. The increase in cutting-edge radius is associated with a gradual increase in the compression ratio, indicating a higher plastic energy requirement in chip formation. Numerical simulations support this theory of failure. A significant correlation of 80% was identified between flank wear and the increase in shear force oscillation amplitude, indicating that flank wear contributes to system vibration. It is also noted that the adiabatic shear bands (ASB) are narrow, revealing a marked plastic deformation in the primary shear zone. Consequently, the remarkable incidence of wear with cutting parameters on chip formation is demonstrated, affecting the cutting force amplitude and, hence, the workpiece topography.