Titanium alloy is difficult to process, from the hardness on the one hand, there are alloy metal elements and so on. In the manufacturing of titanium alloy for many years, the four major reasons for the difficult processing of titanium alloy are that titanium alloy has high strength, high hardness and low density material characteristics, such as titanium alloy Ti-6AI-4V(referred to as Ti-6-4) tensile strength of 900MPa, hardness of 250 ~375HB, density of 4.42g /cm3, making titanium.

The generated temperature can be as high as 1000 ° C or more, so that the cutting edge of the tool is rapidly worn, cracked and generated chip tumors, the blade is rapidly worn, and the cutting area generates more heat, further shortening the life of the tool.
The high temperature generated during the cutting process also destroys the surface integrity of the titanium alloy parts, leading to the reduction of the geometric accuracy of the parts and the work hardening phenomenon that seriously reduces their fatigue strength.
The elasticity of titanium alloy may be beneficial to the performance of parts, but in the cutting process, the elastic deformation of the workpiece is an important cause of vibration. The cutting pressure causes the "elastic" workpiece to leave the tool and rebound, so that the friction between the tool and the workpiece is greater than the cutting action. The friction process also generates heat, which aggravates the thermal conductivity of titanium alloys.
This problem is even more serious when processing thin-walled or torus and other easily deformed parts, and it is not an easy task to process thin-walled titanium alloy parts to the expected dimensional accuracy. Because when the workpiece material is pushed away by the tool, the local deformation of the thin wall has exceeded the elastic range and produced plastic deformation, and the strength and hardness of the material at the cutting point have increased significantly. At this time, machining at the previously determined cutting speed becomes too high, further leading to sharp tool wear.