preface:
Dongguan CNC processing plant titanium alloy has the characteristics of small specific gravity, high thermal strength, good thermal stability and corrosion resistance, which is widely used in aviation, aerospace, atomic energy and chemical industry. However, it is difficult to cut the material, which has been solving the technical problems of low efficiency and poor surface quality of titanium alloy. In the continuous exploration, with the advanced manufacturing technology more and more widely used in the manufacturing industry, the ultra-high speed cutting technology applied to the cutting of titanium alloy shows obvious advantages.
1) The main factors that affect the machinability of materials are the difficult machinability of titanium alloy processed by Dongguan CNC processing plant. Generally, the main reasons for the poor machinability of difficult materials are as follows:
① The material contains particles with high hardness. ② High hardness or high temperature hardness.
③ Work hardening is large. ④ Poor thermal conductivity and high cutting temperature.
⑤ The material has high strength, especially at high temperature. ⑥ Easy to bond with cutting tool. ⑦ It has high chemical activity.
The machinability of the processed material may be poor due to one or more of the above factors.
2) Machinability of titanium alloy
a. Relative machinability of titanium alloy
The machinability of materials in Dongguan CNC plant is usually measured by the allowable cutting speed for cutting a certain material under a certain tool life. Generally, when t = 60min, VT is written as V60. If V60 of cemented carbide turning tool when cutting carbon steel is taken as the benchmark and the allowable cutting speed when cutting other materials is V60 ", the ratio of V60" to V60 is called relative machinability of the material and relative machinability of titanium alloy
b. Machinability analysis of titanium alloy
It can be seen that the main reasons for the poor machinability of titanium alloy are the great chemical affinity and poor thermal conductivity of titanium alloy
①
     Titanium alloy with high affinity is easy to "affinity" with tool material at high temperature above 300 ℃. When cutting, some elements in tool material are either dissolved in titanium or chemically interact with titanium.
② The thermal conductivity of titanium alloy is poor, the thermal diffusivity is very small, and the cutting temperature is very high. The average thermal conductivity of titanium alloy is half of that of industrial pure titanium, and the thermal conductivity is 1 / 5 ~ 1 / 7 of that of 45 steel. Therefore, under the same cutting conditions, the cutting temperature of titanium alloy is more than one time higher than that of 45 steel.
③ Although the cutting force of titanium alloy is small, about 75% of that of carbon steel, the contact length between the chip and the tool rake face is much smaller than that of carbon steel, about half of that of carbon steel. Therefore, the stress on the tool tip when cutting titanium alloy is about 1.5 times of that when cutting carbon steel.
④ The work hardening phenomenon of titanium alloy is not very serious, which is about the same as that of low carbon steel.
The results show that the greater the strength of titanium alloy, the worse the machinability; The higher the content of Al, Sn, Zr, Fe, Mo and Cr, the higher the strength and the worse the machinability of the alloy; The impurity oxygen, nitrogen, carbon and hydrogen in titanium produce interstitial solid solution, which makes the alloy stronger in strengthening and has greater influence on machinability.
Ultra high speed machining of 2 titanium alloy
Due to the high chemical affinity, poor thermal conductivity and high strength of titanium alloy in Dongguan CNC plant, the cutting temperature is greatly increased and the tool wear is intensified, so it is difficult to process titanium alloy with traditional processing methods.
For a long time, the way to improve the machinability of titanium alloy has been exploring. Reasonable selection of tool materials and tool geometric parameters, reasonable formulation of cutting parameters, and appropriate cutting fluid in Dongguan CNC plant can improve the machinability of difficult to machine materials to varying degrees. So far, there have been some methods, such as using special heat treatment, heating cutting, introducing ultrasonic and vibration into the cutting area, etc., but these methods generally have the disadvantages of low efficiency, high cost and difficult to guarantee the processing quality.