1.1 High cutting temperature
Because the thermal conductivity of
titanium alloy material is small (about 1/3 ~ 1/6 of steel), it is easy to produce high cutting temperature when processing titanium alloy. Under the same conditions, the cutting heat produced by machining titanium alloy is more than 1 times higher than that of the same steel, and the heat produced by machining is difficult to be released through the workpiece. Titanium alloy specific heat coefficient is small, the local temperature rises quickly during the processing, so easy to cause the tool instantaneous temperature is too high, so that the tip will wear sharply, so that the phenomenon of over-burning.
1.2 Strong cutting resistance
The cutting force of titanium alloy is basically the same as that of steel, so the energy consumed during the cutting process is the same or slightly lower than that of steel. But when cutting titanium alloy, the stress near the main cutting edge is very high. This may be due to the fact that when cutting titanium alloy, the contact area of the cutting chip on the front knife surface is usually very small (about 1/3 of the cutting steel under the same conditions), and the large cutting stress leads to the phenomenon of letting the knife occur during the machining process, and the workpiece size is not coordinated.
1.3 Tremor of weakly rigid structure
Vibration is an important problem to be overcome when machining titanium alloys with weak rigid structures, especially during finishing machining, the primary cause of vibration is the very low elastic modulus of titanium alloys. When subjected to cutting forces, titanium alloys deform twice as much as carbon steels. There is friction between the back cutter surface and the springback of the machined surface, which produces vibration and high cutting temperature.
