Ultra-precision Cutting of Titanium Alloys by Using Coated Carbide Bite

This paper deals with the experimental investigation for the ultra-precision cutting of titanium alloys. Titanium alloys, which are well-known as difficult-to-cut materials, have excellent mechanical and chemical properties. In order to produce the value-added high quality components of titanium alloys, the productive cutting technique of high dimension accuracy with high smoothness surface has been strongly required. The cutting technique, however, has not progressed well because the surface roughness and product accuracy become over the necessary finished values in the extremely short cutting length due to rapid cutting tool wear. The research aims to develop the practical ultra-precision cutting technique of titanium alloys. In the experiments, the β titanium alloy and α-β titanium alloy are face-turned by various kinds of commercial cutting bites such as a single crystal diamond bite, carbide bite, cermet bite and coated carbide bite. From the experimental results, a coated carbide bite is found available for ultra-precision cutting of titanium alloys. Over the cutting length of 2, 000m which is enough length to produce some high quality components of β titanium alloy, the cutting tool wear is little and the finished surface roughness, which includes the step over 100 nm between the crystal grain boundarys, is keep smoother than 200nm(P-V). The best finished surface roughness obtained by using TiCN coated carbide bite is about 60nm(P-V) for a-β titanium alloy.