Numerical assessment of tool geometry for improving productivity in milling stainless steel 316 L

Abstract Improving the material removal rate (MRR) can significantly enhance the efficiency of the milling operations during machining. However, increasing MRR develops a larger degree of stress and eventual wear at the cutting edge, reducing the tool’s lifetime, in particular for hard metals like stainless steel. Therefore, it is important to optimize the tool geometry to enhance the stress-carrying capacity under extreme cutting conditions. Considering a four-fluted tungsten carbide milling tool for cutting stainless steel, we propose in this study a procedure for reducing tool stresses by modifying the tool geometry. Using a systematic set of finite element simulations, we showed that the degree of stresses on the cutting edge can be reduced by optimizing three geometrical parameters, i.e., helix angle, rake angle, and cutting edge radius. To validate the simulation results, we manufactured 18 four-fluted milling tools with varying geometries and tested them by milling stainless steel 316 L under identical cutting conditions. The performance of each tool was ranked based on microscopic inspections of their cutting edges, showing a close agreement with the numerical simulation predictions. This study presents a procedure for modifying milling tool geometry to enhance performance under extreme machining conditions.