FE analysis on the association between tool edge radius and thermal-mechanical load in machining Inconel 718

The cutting edge geometry has a significant influence on thermal-mechanical loads and the quality of machined surface in machining operations. In this study, a joint numerical and experimental investigation was conducted to study the effects of tool edge radius on process variables (tool temperatures, force components, stresses) and process dynamics in orthogonal machining Inconel 718. The numerical model was implemented based on Coupled Eulerian-Lagrangian (CEL) formulation, in which the tool is regarded as elastic, making it possible to realise the fluctuation of the tool tip. The results show that the temperature at the tool tip is more sensitive to the change of edge radius than the maximum temperature at the tool-chip interface. The force components acting on rake face and flank face increase with increasing edge radius due to more negative effective rake angle and increasing ploughing depth respectively. Besides, the generated chip tends to be more segmented with increase of edge radius, causing severer fluctuation of forces and tool tip displacement. It was also found that a larger edge radius leads to a smaller uncut chip thickness and a poor surface roughness.