Assessing the performance of TiAlSiN coating on bandsaw tooth when cutting Ti-17 alloy

Cutting tool industries face an enormous challenge in finding the conditions that result in economically viable machining of titanium alloys such as Ti-17. The generation of high thermal and mechanical stresses in cutting tools during machining of titanium alloys accelerates tool wear and this significantly affects tool life, productivity and product quality. The application of advanced coatings on cutting tools has become an important way to improve the tool performance when machining titanium alloys. Recently, nano-structured TiAlSiN coatings have attracted increasing attention as an alternative to traditional TiN coatings, mainly due to its superior oxidation resistance at elevated temperatures and improved mechanical properties, which are ideal for machining titanium alloys. Very little attention has been given to the investigation of primary machining operations such as bandsawing. In this investigation, tungsten carbide-tipped bandsaw teeth were coated with TiAlSiN coating. The coating was characterized for structural, chemical and mechanical properties. Machining tests were carried out on Ti-17 alloy in a modified lathe using uncoated and TiAlSiN-coated bandsaw teeth. Forces were measured during the cutting tests and the specific cutting energy was calculated using the obtained force and material removal rate data. Wear modes and mechanisms in the bandsaw teeth were investigated using a scanning electron microscope and energy dispersive X-ray analysis. The results show that a TiAlSiN-coated bandsaw tooth performed better than an uncoated bandsaw tooth in terms of wear and specific cutting energy.