Effect of Cutting Fluid on Surface Roughness Formed by Ultra-precision cutting of Titanium Metal

In the previous report, we have found that the TiCN PVD-coated carbide tool is useful for ultra-precision cutting of titanium metal. This report aims to clear the effect of cutting fluid on surface roughness formed by ultra-precision cutting of titanium metal with the coated carbide tool. Cutting fluids used are kerosene for general ultra-precision cutting of soft metals, and three kinds of water-immiscible cutting fluids, which consist of fats and oils, fats and oils with special additives, fats and oils with extreme additives of sulfur type, respectively. The surface roughness formed using the water-immiscible cutting fluids is better than kerosene. The additives contained in the water-immiscible cutting fluid have the great influence on the surface roughness. The mist fluid supply method in which the fluid is supplied together with compressed air to the cutting point, is superior in getting the smooth surface roughness to the spray fluid supply method. The finished best surface roughness obtained using the best water-immiscible cutting fluid, which consists of fats and oils with special additives is about 60nm(P-V) for α-β titanium alloy.