**Abstract**

Green technology is one of the major aspects in order to reduce the global pollution content from manufacturing industries. There is a need to investigate the different available tools for high-speed micromilling process of advanced alloys to achieve desired surface finish without traditional coolants. In this chapter, tool wear investigation of uncoated and PVD-coated AlTiN, TiAlN tungsten carbide end mills in high-speed micro-end milling of alpha + beta Ti-6Al-4V ELI titanium alloy (Grade 23) under dry cutting conditions was presented. A comparison for machining performance with the three tools is reported. Cutting force analysis was done under the considered machining input parameters for evaluating the tool condition. Tool wear observation was done by SEM analysis. EDX analysis was performed to know the material constituents and wear mechanisms on the cutting tool tip. It is found that diffusion, oxidation, adhesive and abrasive wear mechanisms were the major phenomena taking place on the cutting edge of micro end mills. From the comparison of cutting tools for machining Grade 23 titanium alloy, it was found that TiAlN tools performed better than AlTiN and uncoated tungsten carbide tools.

**Keywords:** green technology, micro-end milling, PVD-coated AlTiN and TiAlN tungsten carbide end mills, tool wear, titanium alloys, and uncoated tungsten carbide end mills
