The binder is the material that binds the abrasive particles to make various grinding wheels. The type and properties of the bond determine the strength, hardness, heat resistance and corrosion resistance of the grinding wheel. In addition, the binder also has a certain influence on the surface roughness and grinding temperature.
The binder is mainly based on its own properties. There are many types of binders, and the most commonly used binders are the following:
1. Ceramic Binder v(old standard code A)
Ceramic binder is a kind of inorganic binder, which is widely used. Ceramic bonding abrasives are generally used for rough grinding, semi-fine grinding, molding grinding with large contact area, grinding of superhard abrasive sintered body, etc. Grinding wheels of various particle size, hardness, structure, shape and size can be made by using ceramic bond. Its main advantages are: low price, stable performance, not affected by dry and wet weather, temperature changes and storage time; Good heat resistance, sharp cutting, high grinding efficiency, grinding process is not easy to heat and clogging, small thermal expansion; Good corrosion resistance; The adhesion between the ceramic bond and the abrasive particle is large, the grinding wheel wear is small, and the contour of the grinding wheel can be maintained better, and the processing accuracy can be easily controlled. The grinding wheel made of ceramic combined with thorn can not only dry grinding, but also adapt to grinding with various coolant.
However, due to the brittleness of the ceramic bond is large and the elasticity is poor, it can not withstand the large side twisting force and impact force, so it can not be used to manufacture thin wafer grinding wheels with thin thickness. In addition, due to the friction and heat generated by the ceramic bond during grinding, when the grinding wheel or grinding amount is not selected, it is easy to cause workpiece burns and cracks.
2. Resin Binder B (old standard code S)
Resin bond is an organic bond. The resin bond itself has good elasticity, impact resistance and polishing effect. The grinding wheel made of resin bond has high strength and can produce high-speed grinding wheels with grinding speeds higher than 52m/s and very thin grinding wheels. In addition, the resin abrasive has good self-sharpening performance and is not easy to plug; After a dressing rarely dressing, grinding efficiency is high, grinding roughness is low, grinding temperature is low. Because of this series of superior properties of resin bonded abrasives, they are widely used in superhard abrasives. Resin diamond abrasives are used for semi-fine grinding and fine grinding of cemented carbide and steel-bonded cemented carbide workpieces and some non-metallic materials. Resin cubic desalination boron grinding tool is mainly used for high vanadium high speed steel grinding, tool steel, die steel stainless steel, heat resistant alloy steel workpiece semi-fine grinding, fine grinding.
Due to the poor bond between the binder and the abrasive particle, the grinding wheel wears fast, it is not easy to maintain the contour, and the binder is easy to burn at high temperature. The corrosion resistance of the resin bond is also poor, the performance is not stable enough, and it is easy to be eroded by alkali, so the alkali content in the coolant must be reduced by 1.5% when wet grinding. Too humid environment will also affect the strength of resin grinding wheel, so pay attention to the storage of resin grinding wheel, storage time can not be too long (up to one year).
3. Rubber binder R(old standard code X)
Rubber binder is an abrasive tool made of synthetic rubber or natural rubber as the main raw material, mixed with a certain proportion of sulfur, zinc oxide and other minerals and abrasives, vulcanized at 150℃ ~ 200℃.
The elasticity of rubber bond is greater than that of resin bond, and the strength is also high, which can make very thin grinding wheels. Under the action of high temperature in the grinding area, the bond on the surface of the grinding wheel gradually ages and becomes brittle, and the dull abrasive particles are easy to fall off, so that new sharp abrasive particles are often maintained on the working surface of the grinding wheel, thus reducing the possibility of workpiece burns. At the same time, the grinding wheel has a strong polishing performance and can obtain a low surface roughness. However, the grinding wheel of the rubber bond has tight organization, small porosity, and can not grind away a lot of processing allowance, so it is generally not suitable for roughing; The grinding wheel of rubber bond has poor oil resistance, so oil can not be used as coolant during grinding.
4. Metal Bond (M)
Metal binders are divided into bronze binders and electroplating binders. Bronze binder has good cut, high strength, good wear resistance, long service life, good shape retention, and can withstand large loads. But its self-sharpness is poor, easy to plug and heat, difficult to repair. Diamond abrasives are mainly used for rough, fine grinding and cutting of metal materials such as glass, ceramics, stone, concrete, semiconductor materials and superhard materials, and a small amount is used for rough grinding and shape grinding of cemented carbide and honing of various materials.
5. Magnesite binder (Mg)
Magnesia and iron oxide are used to prepare magnesia and iron oxide. It can be hardened at room temperature without roasting process, and it needs to be protected by water paint when using.
6. Complex binder
In order to improve the performance of the above single binders, several binders can be mixed to become composite binders, such as rubber resin binders, ceramic metal binders, etc.
