Wear of CBN in Hard Turning

Hard turning is a developing technology that offers many potential benefits compared to grinding, which remains the standard finishing process for critical hardened steel surfaces. To increase the implementation of this technology, questions about the ability of this process to produce surfaces that meet surface finish and integrity requirements must be answered. Additionally, the economics of the process must be justified, which requires a better understanding of tool wear patterns and life predictions. An ongoing comparative study of wear rates and tool lives under varying cutting parameters is presented here. To date, the study has consisted of seventeen different machining conditions with four different cutting tool materials. Tool life results agree with previous research in this area, indicating that polycrystalline cubic boron nitride CBN tools with low CBN content have improved lives resulting from the benefits of the ceramic binders compared to the cobalt binder typically used for higher CBN content tools. More interesting is a resulting trend in flank wear patterns that could currently help to predict tool life under certain cutting conditions. Further work is being done to understand the wear process in an attempt to model this relationship for a larger range of conditions.

Ty G. Dawson and Dr. Thomas R. Kurfess
The George Woodruff School of Mechanical Engineering,
Georgia Institute of Technology,
Atlanta, Georgia, USA 30332-0450