Tribology of Coated Tools in High-Speed Machining: A Tool Wear and “Equivalent Toolface” Geometry Based Study

Predicting tool-wear (and thereby, tool-life) and selecting proper coated tools along with appropriate tool geometry still remains a major concern for industries trying to achieve increased productivity using automated machining processes. This study is focused upon aggressive high-speed rough turning of AISI 1045 steel. The wear patterns in different coated tools (one mono-layer PVD and two multi-layer CVD coatings) are correlated to changes in nominal tool geometry. This study focuses on the role of tooling geometry (inclination and rake angles) and their importance in dictating the behavior, performance, and wear of coated tools. Using an ‘equivalent toolface’ (ET) model, this study correlates the nominal tool geometry to an equivalent geometry, thereby introducing a new methodology for characterizing the complex effects of multilayer coatings in terms of simple effective tool geometry. The ET approach provides a new angle for understanding the tribological effects of coatings in machining.