The difficulty of cutting titanium alloy structural parts

1. High cutting temperature
Because the thermal conductivity of titanium alloy material is small (about 1/3 to 1/6 of steel), it is easy to produce high cutting temperature when processing titanium alloy. Under the same conditions, the cutting heat generated by processing titanium alloy is more than 1 times higher than that of the same steel, and the heat generated by processing is difficult to release through the workpiece. The specific heat coefficient of titanium alloy is small, and the local temperature rises quickly during processing, so it is easy to cause the instantaneous temperature of the tool to be too high, which makes the tip of the tool wear sharply, so that over-burning occurs.

2. Large cutting resistance
The cutting force when cutting titanium alloy is basically equivalent to the cutting force when cutting steel, so the energy consumed in the cutting process is the same or slightly lower than that of steel. However, when cutting titanium alloys, the stress near the main cutting edge is very high. This may be due to the fact that when cutting titanium alloy, the tool chip contact area on the front tool face is usually very small (about 1/3 of the cutting steel under the same conditions), the larger cutting stress leads to the phenomenon of the workpiece in the processing of the knife, and the size of the workpiece processed is not coordinated.

3. Tremor of weakly rigid structure
Tremor is an important problem to be overcome when machining titanium alloy weakly rigid structural parts, especially in the finishing, titanium alloy very low elastic modulus is the primary cause of vibration in the cutting process. When subjected to cutting forces, titanium alloys deform twice as much as carbon steel. The friction between the back tool surface and the surface to be machined produces vibration, and also produces a high cutting temperature. The high dynamic cutting force when cutting titanium alloy is part of the cause of tremor, and its value can reach more than 30% of the static force, which is caused by the plastic shear process during the formation of titanium alloy chips. Due to the influence of cutting tremors, the surface quality of the milled workpiece is difficult to meet the accuracy requirements.