Grinding characteristics of diamond sanding belt

The hardness of high-hardness thermal spray coatings such as superalloys and special ceramics is generally above 1000HV0.2, the coating thickness is mostly between 0.1mm and 0.5mm, and the thermal spray coating is hard and thin. In the grinding process, due to the high hardness of the thermal spray coating, diamond grinding tools are often used. However, due to the use of diamond consolidation grinding - grinding wheel grinding not only has high power consumption, high grinding temperature, easy to burn the workpiece, affecting the surface and internal quality of the workpiece. Moreover, the grinding wheel needs to be trimmed frequently, which is labor-consuming. However, the use of ordinary abrasive grinding wheels and abrasive belts for grinding has lower cutting efficiency or difficulty in grinding due to its low hardness (see Table 1, Mohs hardness table of various substances for details).

Diamond Mohs hardness is 10, the hardest material ever found. It is especially suitable for machining hard-to-machine non-metal and non-ferrous metals with high hardness and brittleness. The diamond abrasive belt made by electroplating process has high bonding strength between diamond and base cloth, and adopts the arrangement of grinding units with gaps (see Figure 1, the arrangement of several diamond abrasive belt surface grinding units). It has better chip removal and lower grinding temperature, which can not only ensure the surface quality of the workpiece, but also the internal quality of the workpiece, thereby improving the fatigue strength of the parts, prolonging the service life and improving production efficiency. The grinding process of diamond abrasive belt also has the characteristics of less dust, low noise and low energy consumption, which is in line with my country's policy of energy conservation and environmental protection.

The surface quality of diamond abrasive belt grinding workpiece is high, which is mainly manifested in small surface roughness value, good residual stress state, and no microscopic cracks or changes in metallographic structure on the surface. From the surface roughness point of view, abrasive belt grinding can reach Ra0.01mm at present, achieving the effect of mirror grinding, and for the case where the roughness value is above Ra0.1mm, it is very easy to achieve. The test shows that under certain other conditions, when the linear speed of the abrasive belt increases from 35m/s to 100m/s, the grinding surface roughness decreases from Ra2.0µm to Ra1.5µm, and the precision reaches the effect that ordinary abrasive tools cannot achieve. . Therefore, diamond abrasive belts and their derivatives are the best products for grinding high-hardness thermal spray coatings.

Diamond abrasive belt grinding

The diamond abrasive belt is mainly used for the processing of rollers and shafts, and the diamond abrasive disc and the diamond impeller are mainly used for the grinding and polishing of plane, curved and complex surfaces.

Grinding process of ceramic piston rod with diameter of 540mm× length of 15m

Characteristics of diamond abrasive belt grinding process

Advantages:
(1) The equipment is simple, easy to operate, and no expensive special grinder is needed. It can be stuck on the lathe tool rest of common specifications to carry out work.
(2) High grinding speed, high efficiency, good grinding effect.
(3) Because of the special orderly arrangement design of diamond particles on the surface of diamond sand belt, the grinding is sharp, the chip removal is good, and there is no need for dressing. The processing requirements can be achieved by replacing the sand belts with different grain sizes.

Disadvantages:

This kind of non-contact wheel grinding processing accuracy is slightly lower (cylindricity), if the use of contact wheel grinding (contact wheel hardness 90) can greatly shorten the processing time and can achieve the workpiece processing accuracy requirements.

Grinding scheme of plane and surface thermal spraying coating
For the grinding of some plane and surface after thermal spraying, such as automobile stamping die, steam turbine blade and aviation parts, the most advanced grinding method is to adopt:
Diamond impeller grinding plane and surface: installed in pneumatic and electric grinding machine, speed 10000 ~ 20000rpm, high grinding efficiency, good effect, flexible and convenient operation.
Grinding process of diamond disc: installed in pneumatic and electric Angle grinder, grinding speed is fast, good smoothness.
Diamond lapping disc :

Diameter 2 inch, grit 200#, 400# mounted on high speed pneumatic tools, tools, has the characteristics of compact, flexible operation, fast loading and unloading.