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1. The choice of superabrasives

Superabrasives mainly include two categories: Diamond and Cubic Boron Nitride.

Diamond is currently known as the hardest material in nature. As superabrasive, it shows superior strength, hardness, brilliant grinding capacity, thermal conductivity and thermal expansivity. Diamond shows great advantages in processing many hard and fragile materials, such as hard alloy, ceramic, stone, glass, concrete and semiconductor materials, etc.

But diamond is an allotrope of carbon, it’s easy to have chemical reaction with iron group elements at high temperature, which directly decrease tool’s processing efficiency, thus it’s not suitable to process this kind of material.

Although the hardness of CBN is lower than diamond, it is still much higher than ordinary abrasive. Moreover, its thermal conductivity, thermal expansion and grinding ability is much better too. CBN’s stability and chemical inertness is greatly superior to that of diamond, so CBN is very suitable for processing hard and tough metal, such as tool steel, die steel, stainless steel, heat-resistant alloy, high speed steel.

Diamond and CBN can coat a layer of other material on its surface.

Generally we recommend copper coating for diamond used in resin bond dry grinding tools, and nickel coating for resin bond wet grinding tools. Vitrified bonded tool use diamonds coated with non-metal material, which help to improve the retention between diamond and bond, prolong tool life and reduce cost.

 

2. The choice of grain size:

The grain size is chosen according to the workpicec’s surface roughness, processing efficiency and type of processing as well as bond type. References are listed below.

When selecting size of superabrasive, we should also consider the tool’s bond, because all sorts of bonds have their own optimum superabrasive size range. Too coarse or too fine will affect grinding process. In general, resin bond grinding tools use size 100/120 and finer; vitrified bond grinding tools choose 100/120 ~ 170/200; Metal bond grinding tools commonly use 70/80 ~ 230/270. Of course, choice of size also depends on the required efficiency and surface roughness. When requiring high efficiency, coarser size is selected, conversely, choose finer size.

Of course, after we decide the superabrasive size, we also must choose the appropriate concentration, the right bond and tools shape, and adopt the right procedures, so that we can produce high- quality grinding tools. In a word, this revolves abundant knowledge, we welcome you to contact us for further discussion.