Research On Cutting Performance And Mechanism Of Superhard Tools In Cutting Titanium Alloy

The Titanium Alloys have been widely used in industry due to their excellent corrosion resistance and high ratio-strength, but they are expensive and difficult to machine. Therefore, it is necessary to pay more attention to the cutting mechanism of Titanium alloys and the way to improve its processing efficiency. The PCD/PCBN tools have irreplaceable advantages in processing Titanium alloys with high quality and efficient, relative to carbide tools. But few involve in the using comparison between PCD and PCBN tools. Aiming to fill the gap, this paper focuses on the contrast between PCD/PCBN tools in tool wear and surface quality when cutting Ti6-A14-V. Meanwhile, the cutting mechanism and the phenomenon of chip side flow will be investigated based on the chip morphology of Ti6-A14-V. This paper is of great significance in industrial processing of Titanium alloys.Firstly, the paper analyzed wear amount, wear form and wear mechanism of PCD and PCBN tools according to wear test. The result shows that the wear amount of PCD tools are less than that of PCBN tools in low speed and feed, while higher in high speed and feed. The dominant wear form of PCD tools are micro-chipping and flank wear. The dominant wear mechanisms of PCD tools are diffusion and adhesion. However, the micro-chipping, spalling, flank wear and groove wear are PCBN tools’wear form. Adhesion, diffusion and oxidation are found to be the main wear mechanisms of PCBN tools. The study shows that thermal effect is the main reason of PCD tools’wear. But for the wear of PCBN tools, it is the result of interaction of thermal effect and chemical effect.Secondly, the paper analyzed the surface roughness of two tools in different cutting parameters. The result shows that compared with PCD tools, the surface roughness when using PCBN tools are better. For both of the two tools, the cutting feed has large influence on surface roughness, and the cutting speed has lest influences. Surface roughness will keep low in high speed, low depth and feed, but it will rise when cutting depth is less than0.05mm.Finally, the paper analyzed the cutting mechanism and the phenomenon of chip side flow of Ti6-A14-V based on orthogonal cutting experiment. The result shows that the chip begins to be serrated chip when cutting feed exceeds0.08mm/r or cutting speed is higher than40m/min. The tooth spacing and the degree of sawtooth are positively correlated with cutting speed or cutting feed, while the band orientation is negatively correlated with speed or feed. The phenomenon of chip side flow is obvious when increasing cutting feed or decreasing cutting speed, and it is more sensitive to speed.