Effect of arc-deposited diamond-like carbon (DLC) coating thickness on friction and size effects in high-speed micromilling of Ti6Al4V

Diamond-like carbon (DLC) can be considered one of the frontline coating materials for high-speed cutting tools owing to both abrasion resistance and solid lubricant properties. However, coating thickness increases the edge radius of the micro tools, which may result in adverse rubbing and plowing that need to be investigated. In this work, DLC coatings of 440, 640, and 1160 nm thicknesses with a similar to 250 nm Cr interlayer are deposited on WC micro-end mills using a cathodic-arc system. DLC-coated surfaces exhibited enhanced tribological and me-chanical properties compared to uncoated surfaces. Among the DLC-coated micro-end mills, the DLC-640 nm coated tool outperformed, manifesting the best machining performance by reducing friction and size effects together.