The Correct Use Of PCBN Tool

The sharpening of diamond cutting tools has not been small. But still, based on experience, it is still a subject to be solved. The geometric parameters of diamond cutting tools may inadequate. So it remains to be explored. Generally, the rake angle is 0°, the back angle is 5-6°, and there are two kinds of ends. One is an arc and the other is a straight line. The latter is sometimes called a wiper, and the length is selected according to the material to process. The adjustment of the circular turning tool during the cutting process is relatively simple. And the adjustment of the flat blade is relatively time-consuming. If applied in high-precision surface machining, the arc grinding requirements are very strict, and the accuracy of its precision will copy on the surface.

The cutting process of the PCBN tool

During the cutting process, the thermal conductivity of the diamond is superior to heat dissipation. But the cutting heat should not higher than 700 °C. Otherwise, graphitization will occur and the tool will wear out quickly. Because diamond reacts with W, Ta, Ti, Zr, Fe, Ni, Co, Mn, Cr, Pt, etc. at high temperatures. In the current ultra-precision machining, diamond grinding wheel natural single-crystal diamond cutting tools are essential. It achieves a very sharp cutting edge with a radius of the edge of the cutting edge that is not detectable by scanning electron microscopy (SEM).

Characteristics of PCBN tool

PCBN is a sintered CBN particle with a binder. It is resistant to high temperatures and has a hardness second only to diamond and has no affinity with ferrous metals. Many new materials need to process with PCBN. For example, the gears of the automobile gearbox adopt the PCBN gear hob, which not only achieves high productivity, but also significantly improves the quality, and the machined surface becomes a mirror surface. According to the data, the surface of the PCBN roll-cut gear is also hardened due to the infiltration of boron. This was confirmed by the experiment of the Harbin Institute of Technology. Due to the high-temperature resistance of PCBN, there is no change and stability under 900 °C in the atmosphere and water vapor. Even at 1300 °C, there is almost no reaction with Fe, Ni, Co, etc., and it does not wear sharply like a diamond. It still maintains the hardness of cemented carbide, so it can not only cut hardened steel parts or chilled cast iron but also can widely used in high-speed or ultra-high-speed cutting work. However, PCBN is not suitable for cutting general steel parts, therefore. Care must be taken when selecting tools to take into account their concentration and particle size.

The specificity of PCBN tool

The geometry of the PCBN is also special. Generally, the cutting edge needs to be chamfered into -30° or arc to protect the tip from damage. There are many manufacturers of PCBN. The major foreign companies include GE in the United States, Sumitomo Electric Co., Ltd., DIJET (Deluxe), and DeBeers in the UK. The main tools are the Chengdu Tool Research Institute, Guizhou No.6 Grinding Wheel Factory, and Guilin. Institute of Geology, etc. Superhard material tools still have many shortcomings in our country. Many further improvements and improvements are needed to achieve more and more precise technical requirements for grinding and cutting, so as to be more widely used in processing and use.