AN ‘EFFECTIVE CUTTING TOOL THERMAL CONDUCTIVITY’ BASED MODEL FOR TOOL–CHIP CONTACT IN MACHINING WITH MULTI-LAYER COATED CUTTING TOOLS

Abstract

This paper presents a new modeling approach, based on Oxley's predictive model, for predicting the tool–chip contact in 2-D machining of plain carbon steels with advanced, multi-layer coated cutting tools. Oxley's original predictive model is capable of predicting machining parameters for a wide variety of plain carbon steels, however, the tool material properties and their effects are neglected in the analysis. In the present work, the effect of the tool material, more particularly, the effect of multiple coating layers and the individual coating thicknesses on the tool–chip contact length in orthogonal machining is incorporated. The results from the model predict the tool–chip contact length with respect to major cutting parameters such as feed and rake angle, work material parameters such as the carbon content in the steel, and varying thicknesses and combinations of coating layers. This model enables more precise cutting tool selection by predicting the relative tribological impact (in terms of tool–chip contact length) for a variety of multi-layer coated tools.

Keywords:

• Cutting tool thermal conductivity
• Tool-chip contact length
• Multi-layer tool cutting

ACKNOWLEDGMENTS

The authors gratefully acknowledge the vision and accomplishments of late Professor P.L.B. Oxley (University of New South Wales), without whom, the results from this study would not be possible. The first author (A.K. Balaji) also gratefully acknowledges the guidance of Professor I.S. Jawahir (University of Kentucky). Finally, the first author also acknowledges the initial discussions with Dr. Ranajit Ghosh (Air Products and Chemicals, Inc.) on characterization of multi-layer coating properties.