Cemented carbide is tungsten carbide, titanium carbide and other metal carbide as hard phase, with cobalt and other metal as adhesive, made by powder metallurgy method, has a high hardness (up to HRA89-93, Microhardness of 1300-1800N/mm2), low thermal conductivity (16.75-79.55W/m·K), low bending strength (3.0-4.5gpa) and large elastic wear (540-650gpa). It is a hard brittle material at room temperature, showing different grinding requirements from steel and other materials. Used to using green silicon carbide grinding wheel for grinding carbide, but because of the high silicon carbide abrasive hardness is not enough (microhardness n/was 32000-34000), when grinding carbide abrasive wear passivation easily, cause the increase of grinding force, grinding temperature is exorbitant, leads to the formation of a cutting tool surface crack defects, such as silicon carbide grinding wheel threshing too fast at the same time, Grinding wheel shape is not easy to maintain, resulting in tool size instability.

  Because it is often restricted by the diameter of the inner hole of the workpiece, the diameter of the inner circle processing is usually low, the speed is often affected by the speed of the inner spindle of the equipment, and the circumferential speed of the ceramic diamond grinding wheel is often lower than 30-35 m/s.  Therefore, vitrified diamond grinding wheels are usually more efficient in machining roughness and cylindrical grinding  

As a major part of rail transit, it is in direct contact with the wheel of the train, and its quality directly affects the safety and stability of the train. Under the influence of the dynamic action of the train, the natural environment and the quality of the track itself, the track will often be damaged, such as cracks, wear and other phenomena. In addition, the enormous pressure of millions of tons of trains moving across the track every year can easily cause the track to buckle and distort the contact surface with the wheels. And improper wheel-rail contact surface may bring negative effects on driving, such as fuel consumption, vibration noise, wheel wear, maintenance workload and cost increase, serious and even may lead to the destruction of the track and vehicle and the occurrence of driving accidents.
Special shape CBN grinding wheel, grinding efficiency increased 15 times, greatly save manpower, improve the grinding efficiency.

The combination of resin and metal bond to abrasive is generally considered to be the mechanical inlaying force, but due to little or no pores, the grinding wheel has a high strength (although there is a saying: "Strong carbide forming elements can generate carbide and diamond reaction, the formation of chemical combination", but it's only a theory, not a strong experimental observation to the existence of the carbide), ceramic bond can form and abrasive chemical combination, but due to the brittle ceramic bond, high impact load, the abrasive loss is more serious.
The choice of bond, on the one hand, is the choice of bond type. Due to the progress of product technology, many processing areas, resin bond grinding wheel can be processed, ceramic bond grinding wheel can be processed, or metal bond grinding wheel can be processed, and how to optimize the grinding scheme, this is the industry to consider. On the other hand, is the choice of bond system. For example, there are many systems or types of each bond, and it is also very difficult to choose or prepare the bond according to the specific grinding requirements.

Silicon wafer back grinding is generally divided into two steps: rough grinding and fine grinding.
In the rough grinding stage, the diamond wheel with grit 46 # ~ 500 # , the axial feed speed is 100 ~ 500mm/min, and the grinding depth is generally 0.5 ~ 1mm.
The aim is to quickly remove most of the excess material (90% of the processing allowance) from the back of the silicon wafer.
In the process of fine grinding, the machining allowance is from several microns to more than ten microns. The diamond grinding wheel with grit 2000 # ~ 4000 #, and the axial feeding speed is 0.5 ~ 10mm/min.
It is mainly to eliminate the damage layer formed during rough grinding to reach the required thickness. In the fine grinding stage, the material is removed by ductility domain mode, and the surface damage of silicon wafer is significantly reduced.

PCD tool must ensure good cutting edge before machining workpiece. Diamond grinding wheel is the most widely used method. The higher the quality of the cutting edge, the finer the tool mark left at the junction of the geometric reflection region of the workpiece surface, and the higher the surface finish of the workpiece. Because cutting edge collapse or expansion easily cause tool wear or damage, reduce tool life. Edge collapse is a key index of edge quality of diamond tools.