Cutting edge wear in high-speed stainless steel end milling

Wear of cutting tools has a major impact on production cost, quality, and efficiency of the machining processes. Tool wear depends on many parameters including cutting parameters and conditions, tool geometry and materials (coating and base materials), and the workpiece material. This study examines and compares the performance of three state-of-the-art milling tools for high-speed end milling while cutting the same material, stainless steel. The tools have the same base material (tungsten carbide — WC-Co), with different geometrical parameters and coatings (TiAlN and AlCrN). Systematic microscopic analysis and finite element (FE) simulations are used to study mechanisms of damage at the cutting edge. Microscopic analyses show that the flank wear is the most critical damage mechanism at the cutting edge. Having the highest material removal rate, the MT-1 tool experiences cutting edge wear faster among the studied tools with a maximum wear size of 420 μm. This tool ran with a radial depth of cut (ae) equal to 0.96 mm and feed per tooth (fz) of 0.15 mm/tooth, which are maximum values among all the tools. The maximum tool stresses from the FE simulations are obtained equal to 1267, 920, and 1145 MPa for MT-1 (ae of 0.96 mm and fz of 0.15), MT-2 (ae of 0.48 mm and fz of 0.12), and MT-3 (ae of 0.6 mm and fz of 0.15) tools, respectively. This indicates that the radial depth of cut and feed per tooth are the key parameters dictating stresses and degree of wear at the cutting edge.