- high speed, high efficiency, high precision, low cost of grinding technology CBN (Cubic Boron Nitride) is after the advent of synthetic diamond, in 1957, by the American GE first synthesis of another kind of superhard materials. In China in 1966 developed successfully CBN, has a history of nearly 40 years. CBN just below the hardness of diamond, but is better than diamond excellent heat resistance and chemical inertness of iron family of metal materials. Use it these excellent properties for research materials made of CBN abrasive grinding, especially suitable for all kinds of iron metal materials grinding. It and diamond is mainly used for machining hard and brittle materials supplement each other, make superhard materials greatly broaden the application scope of. Compared with ordinary abrasive abrasive, CBN abrasive with high speed, high efficiency, high quality, long life, and the characteristics of low cost, can be used as the CNC grinding machine efficiency and high precision grinding tools of choice. In automobile, machine tools, tools, bearings and other industrial fields is widely used.

1, the nature of the CBN

Reigned in the CBN abrasive materials use, we mainly study the hardness, wear resistance, strength, and thermal conductivity properties.

Should CBN hardness is much higher than other ordinary abrasive. Hardness means cutting ability stronger, more sharp;

Should CBN have high wear resistance, means that it is much more difficult than ordinary abrasive wear. The ability to keep grinding grain shape is CBN as a high performance one of the main characteristics of abrasive; Should the compressive strength of CBN is very high, this means that in harsh conditions when using it can preserve the integrity of the granules and not easily broken.

Should CBN has good thermal conductivity, when grinding cold cutting can be realized.

Because of the difference of certain properties of diamond and CBN, their range of materials is different also. CBN is suitable for processing the materials for the tool steel, bearing steel, alloy steel, super alloy and cast iron. Diamond is suitable for processing the materials for cemented carbide, glass, ceramics, metal ceramics, cast iron.

2, CBN grinding system

CBN abrasive is made of different types of bond CBN abrasive bonding together and made into a certain shape of a tool. It is only through the reasonable grinding process, rely on the performance of grinding machine, in order to maximize its role. In the research and application of CBN grinding technology, must be the CBN abrasive, grinding machine, the workpiece, shaping, cooling and grinding process factors into a system to optimize, can get the best technical and economic effect.

CBN grinding technology of several important factors to consider are as follows.

2-1 CBN abrasive

In abrasive manufacture and choose main consideration when its shape, size, CBN abrasive grain size, concentration, the type of binder, and the use of parameters such as speed.

Should CBN abrasive the shape, size, and marked according to the GB/T6409.2-1996 and the standard of GB/T6409.1-1994 regulations;

Should in four bond of CBN abrasive (resin, metal, ceramics, electroplating), with ceramic binder fastest growing. This is due to ceramic CBN abrasive grinding efficiency, shape good stable, high durability, easy dressing, grinding wheel service life is long, and make the first selection of high efficiency, high precision grinding abrasive.

Should grinding concentration expressed during grinding working plane grinding wheel in the grinding mill grain number of how many. High concentrations can bring high grinding ratio and low surface roughness of workpiece. Such as 200% concentration than 100% concentration of grinding wheel 4-5 times longer service life.

Should abrasive hardness level representation of pyrophyllite on abrasive the size of the control force. Grinding wheel hardness uniformity and stable and hardness of the reasonable selection of high and low is an important prerequisite to ensure the quality of grinding.

2-2 grinding machine

Grinding machine is the center of the grinding system, the performance of the grinding machine for grinding effect is the most important thing, especially for CBN grinding.

Should improve the work of the grinding wheel velocity, can obviously improve the efficiency of grinding, grinding ratio and the surface quality. The use of 80 ~ 125 m/s speed has become the current domestic imports of CBN for camshaft grinding machine one of the basic features. As far as possible the use of high speed CBN grinding is to improve the technical and economical efficiency of the important premise.

Should the characteristics of high speed grinding and CBN wheel grinding, requirements of spindle and overall have high rigidity and good vibration resistance, this is the basic requirements of the CBN grinding machine in high speed grinding technology. Don't have such requirement, in the use of CBN grinding wheel, if you want to get a higher amount of metal removal, the geometric accuracy and surface quality of workpiece will become poor. The surface of the ripple is common quality defects, it is generated by the vibration. Can cause vibration machine tool is the cause of the low rigidity, vibration resistance or grinding parameter design is not reasonable cause excessive force.

2-3 trim

Use diamond wheel dressing, not only can improve grinding efficiency, more important is can get a better grinding wheel topography. Dressing device into higher precision, every time feed should be able to reach microns. Excessive amounts of dressing is affecting grinding quality and will greatly reduce the service life of the grinding wheel.

2-4 cooling

Correct selection of cooling fluid types and cooling process parameters, often can receive the twice the result with half the effort effect.

2-5 grinding process parameters optimization

Fully optimize the grinding parameters can make the grinding quality and grinding efficiency, cost and other technical and economic indexes on a higher level of balance.

3, the application of CBN abrasive

3-1 technology development situation at home and abroad

With the progress of industrial technology, high speed, high efficiency and high precision grinding has become the mainstream of the development of grinding technology today. CBN grinding, as a kind of advanced processing technology on the steep. CBN abrasive manufacture and application technology development has the following features:

(1) application field expands unceasingly, has set up a file from the tool industry for grinding hard metal material processing, to the bearings, automobile, machine tools, compressors, and other industries of ordinary black metal materials processing, grinding way also from the general tools and inner circle grinding, development to slow, high-precision grinding feed, high speed and CAM grinding, grinding crankshaft, replace the corundum grinding.

(2) high speed, high efficiency, high quality and low cost is its main characteristics. Use speed is 80 ~ 125 m/s; Big surplus crude fine grinding a complete; By grinding the surface state of compressive stress can make to improve the working life 20 ~ 30%; Comprehensive grinding cost can be reduced more than 10%.

(3) domestic and imported complete set of CBN grinding technology showed the trend of rapid growth.

(4) the manufacture and application of domestic CBN abrasive technology into a high level and the new stage of rapid development, and has set up a file in the mainstream market car manufacturing. Part of CBN abrasive performance close to the level of similar products abroad, can substitute the imports.

(5) of domestic high speed CNC special CBN grinding machine has been developed.