Effect of Cutting Conditions on Tool Performance in CBN Hard Turning

Cubic boron nitride (CBN) cutting tools are commonly used for single-point turning of hardened materials. Their performance is of importance for hard turning to be a viable technology in view of the high cost of CBN cutting tools and the cost of downtime for tool change. Based on the calibrated tool wear model in finish turning hardened 52100 bearing steel, tool performance is evaluated as a function of cutting conditions based on the flank wear criterion. A satisfactory match has been reached when comparing model predictions and experimental measurements. Further, an analysis of variance was carried out to investigate statistical significance among cutting conditions, and it shows that cutting speed plays a dominant role in determining the tool performance in terms of tool life, followed by feed and depth of cut, and overall tendencies agree with predictions from the general Taylor tool life equation as well as experimental observations. The proposed methodology in evaluating the tool performance can help to optimize the hard turning process and, eventually, help hard turning to be a viable technology.