An investigation of cutting forces and cutting temperatures during laser-assisted machining of the Ti-6Cr-5Mo-5V-4Al beta titanium alloy

Beta titanium alloys are increasingly attractive because of their superior combination of properties such as high strength and fracture toughness. These alloys are finding potential applications in the manufacture of aircraft components such as landing gear, springs and nacelles. Innovative machining solutions are required to reduce the cost of production of beta titanium components and improve cycle time. Previous research has reported that these alloys have poor machinability compared to the more common Ti-6Al-4V titanium alloy. This paper aims to investigate the behaviour of the Ti-6Cr-5Mo-5V-4Al beta titanium alloy using laser assisted machining (LAM). The LAM technique utilises a laser beam which is applied onto the workpiece surface locally in front of the cutting tool in order to provide external heat to significantly reduce the yield strength of the material. This reduces the cutting forces required to machine the workpiece and increases metal removal rates. In this study, the effect of the laser beam on the cutting forces and cutting temperature is critically analysed over a wide range of feed rates and cutting speeds and is compared to the results obtained from conventional (un-assisted) machining of this beta titanium alloy. This investigation has shown that LAM significantly reduces cutting forces within a certain range of cutting parameters. Maximum benefit was achieved at feed rates between 0.15 and 0.25 mm/rev and cutting speeds between 25 and 100 m/min at a laser power of 1200 W during LAM of the Ti-6Cr-5Mo-5V-4Al beta titanium alloy