Properties and tool performance of ta-C films deposited by double-bend filtered cathodic vacuum arc for micro drilling applications

This paper describes the results of the application of ta-C films to micro drilling operation for deep and small machining boreholes. Tetrahedral amorphous carbon (ta-C) films were successfully deposited on WC-Co substrates by a double-bend filtered cathodic vacuum arc (FCVA) system. The structure, mechanical and tribological properties of both pure ta-C and ta-C incorporated argon gas (ta-C:Ar-flow) films were systematically investigated. And then, high-speed through-hole drilling tests were performed on the PCB (printed circuit board) workpiece to investigate the machining performance of ta-C coated micro drills. The experimental results show that the ta-C:Ar-flow (2 sccm) coated micro drill has excellent microstructure, microhardness, and friction coefficient properties and represents the optimal coatings for micro drilling applications.