1: There has 3 general types binder for PCBN Inserts

  • Metal binder; it is composite of Al, Ti, Co, Ni, etc.
  • Ceramic binder; mainly have Nitrides, carbides, borides, etc.
  • Cermets binder; it is made up of ceramic and metal or metal alloy based on certain ratio.

The metal binder PCBN usually with high content, good toughness and the thermal conductivity is better than ceramic

binder PCBN. However, the metal usually softens at a temperature of 700-800°C, which will cause the PCBN wear

resistance decrease. There has huge difference of the linear expansion coefficient between metal and PCBN and the

high temperature can lead to the changes in PCBN structure, so that the read hardness decreased. The ceramic binder

has a relatively high melting point, doesn’t produce the softening effect at high temperature, and ceramic binder

PCBN with better high temperature wear resistance and strong chemical abrasion resistance. However, the

thermal conductivity of ceramics at high temperature is poor, the cutting temperature is concentrated on the

processed material, made it soften. Cermets binder combines the advantages of both metal and ceramic binder.

2 :The CBN content of CBN inserts

The higher content of CBN, the harder of PCBN hardness. Usually, the PCBN hardness is HV3000~HV 5000.

The content of CBN is between 40%~95%, when over 95%, the sintering performance is worse, and the wear

resistance is greatly reduced.

3: The grain size of CBN

The size of the CBN grain has a great influence on the wear resistance and the breaking resistance of the PCBN.

In general, when the CBN grain is smaller, the wear resistance of PCBN is better and the compressive strength

is higher, but the fine CBN grain is not easy to be sintered. The larger the particle size, the PCBN mechanical

wear resistance is stronger; the weaker wear resistance will lead to the worse sharpness of the PCBN cutting

edges.

 

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