The grinding surface is finished by applying or pressing the abrasive particles embedded in the grinding tool through the relative movement of the grinding tool and the workpiece under certain pressure.Grinding can be used to process various kinds of metal and non-metal materials,the surface shapes of machining have plane,inner and outer cylindrical and conical surface,convex and concave spherical surface,thread,tooth surface and other types.The machining accuracy can reach IT5~IT1,and the surface roughness can reach Ra0.63~0.01 micron.

　　Polishing is the processing method that uses mechanical,chemical or electrochemical efforts to reduce the surface roughness of the workpiece to obtain a bright,smooth surface.

　　The main difference between the two is that the surface finish achieved by polishing is higher than that of grinding,and chemical or electrochemical methods can be used,while the grinding is basically only mechanical,and the abrasive grain size used is thicker than that used for polishing.That is,the grain size is large.

　　Physical polishing is the most commonly used polishing technology before the 1980s,but the rapid development of the electronic industry puts forward increasingly stringent requirements on the size and flatness of material devices.When a millimeter-thick substrate needs to be made into hundreds of thousands of layers of integrated circuits,the traditional old polishing process has been far from the requirements.

　　Today's level of optoelectronic information industry,the parallelism of sapphire,monocrystalline silicon,diamond and other materials as optoelectronic substrate materials is becoming more and more precise,and has reached the nanometer level.This means that the polishing process has also entered the nano-scale ultra-precision.How important is the ultra-precision polishing process in modern manufacturing,and its field of application can directly explain the problem:integrated circuit manufacturing,medical equipment,auto parts,digital parts,precision molds,aerospace.

　　The core component of the polisher is the"grinding disc".Ultra-precision polishing is almost demanding on the material composition and technical requirements of the grinding disc in the polishing machine.This steel disc synthesized by special materials not only needs to meet the nano-scale precision of automatic operation,but also has a precise coefficient of thermal expansion.At present,the top polishing process is only available in a few countries such as the USA and Japan.

　　The polishing process needs to meet the requirements of current electronics manufacturing,and can be summarized as ultra-precision and large size.With the top polishing materials only the foundation,based on this,China needs to take two steps,first to solve the problem of grinding disc,and secondly to enlarge polishing area.