Trial fabrication and cutting performance of c-BN-coated taps

In this study, the possibility of using a c-BN-coated tap for cutting a beta-type titanium alloy which has been known as one of the most difficult to cut materials was investigated. The beta-type titanium alloy is known to strongly adhere to the tools during the operation. The authors considered that the c-BN coating film, which is known to have good tribological characteristics, could be effective in preventing this adhesion for cutting operations of the beta-type titanium alloy. We fabricated c-BN-coated taps by means of a magnetically enhanced ion plating method and carried out tapping experiments to evaluate the performance of the tap. As seen from the results, the c-BN-coated taps proved to be effective in the cutting of beta-titanium alloys with improvement in the accuracy, tapping resistance and tool life over those in the case of commercially available conventional-coated taps.