Enhancing Cutting Tool Performance through ta-C:Ta Coating for CFRP Dry Machining: Investigation of Wear Resistance and Cutting Forces

Currently, in the machining of CFRP, the mainstream tools are CVD diamond-coated tools known for their high wear resistance. However, a challenge arises from the thick coating, leading to blade dulling and increased occurrence of burrs. Therefore, DLC, which can be thinly coated and exhibits high wear resistance, is gaining attention. In this study, a Ta-containing DLC (ta-C:Ta) coating, reported to have a lower friction coefficient than conventional DLC in atmospheric friction tests, was applied to CFRP machining drills, and its effects were investigated. The ta-C:Ta with various Ta contents were deposited by a system that combines FAD and UBMS. The coating characteristics were analyzed through nanoindentation, Raman, and XPS analyses, revealing a trade-off relationship among Ta content, hardness, and the ID/IG ratio. In CFRP cutting tests, drills with higher Ta concentrations coating exhibited initial reductions in thrust forces, suggesting a potential for lowering cutting resistance. However, the observation of chipping and delamination in the coating indicated the importance of improving adhesion strength.