Abstract
Recently, a titanium alloy has been as biomaterials that have stable mechanical property and superior biocompatibility. But the titanium alloy generally has higher young’s modulus in comparison with cortical bone, then bone resorption was occurred by stress shielding. For this reason β-type titanium alloy exhibiting super-elasticity and super-plasticity was developed. However, tool life is getting shorten, because this alloy have low thermal conductivity and high welding ability at cutting. In previous study, the coated tool is valid to extend tool life and AlCrSiN coating is the most effective in tool life. However, a large amount of water-soluble cutting fluid is required, and not only the impact on workers and the environment, but also the burden of oil solution management and waste liquid treatment becomes large. Therefore, it is indispensable to study the cutting environment even when cutting difficult-to-cut materials such as this alloy. In this research, the effect of different cutting environments using dry, wet, dry ice powder supply method and minimum quantity lubrication (MQL) supply method on tool wear was investigated by milling of super elastic-plastic β-type titanium alloy using a small ball end mill. As for changing the cutting environment, it is clarified that the MQL supply method is effective in prolonging the tool life and suppressing the adhesions on the finished surface. When the cutting speed is increased in the MQL environment, flaking occurs at the lower end of the flank wear, which is the cause of the increased flank wear width.
