Enhanced wear resistance of TiCN/AlCrN coated tools in internal micro turning of titanium dental implants

Titanium is a key material for dental implants due to its biocompatibility and corrosion resistance, but its machining remains a challenge because of low thermal conductivity and high chemical reactivity, which accelerate tool wear and compromise implant precision. This paper compares the performance of uncoated, AlCrN-coated, and TiCN/AlCrN multilayer-coated carbide tools during internal micro turning of ASTM F67 Grade 4 titanium, a critical operation in implant manufacturing. Tool wear was evaluated by optical microscopy and energy-dispersive X-ray spectroscopy (EDS). Compared with uncoated tools, AlCrN reduced the maximum flank wear (VBmax) by 40% at 1,000 m. The TiCN/AlCrN multilayer exhibited superior behavior: no visible wear was detected after 1,000 m of cutting length, and although EDS revealed tribochemical interactions, the multilayer preserved edge geometry and ensured stable machining. These findings highlight the effectiveness of TiCN/AlCrN multilayers in titanium machining. By extending tool life and minimizing geometric degradation, this coating strategy offers direct benefits for the reliable and cost-effective production of dental implants, with implications for improved surface quality and long-term clinical performance.