CBN Abrasive Particle Size Selection of Cubic Boron Nitride

When producing CBN grinding wheels, different abrasive grain sizes have different effects on surface quality, processing efficiency, durability, wheel speed, and more. Choosing the appropriate abrasive grain size is essential to achieve the desired results. So, what is the grain size of CBN cubic boron nitride abrasives? How to choose the appropriate grain size?

What Is CBN Abrasive Grain Size?

Abrasive grain size, more accurately, should be described as "grain size composition". When referring to CBN abrasives, terms like "80/100, 100/120, 120/140..." are often mentioned. These are the grain size numbers of CBN abrasives, indicating the range of grain sizes, including the coarsest grain, coarse grain, basic grain, fine grain, and the finest grain.

Grain size number is a marker to distinguish the coarseness of abrasives, usually inspected using the sieving method. For example, the grain size number of CBN 100/120 has a nominal sieve size range of 125~150μm, which means that the CBN abrasives fall between the sieve sizes of 150μm and 125μm.

Additionally, the coarsest grain in the range refers to the abrasives on the upper limit sieve, coarse grain is on the upper inspection sieve, the basic grain is on the lower inspection sieve, fine grain is below the lower inspection sieve, and the finest grain is below the lower limit sieve.

How to Choose the Appropriate CBN Abrasive Grain Size?

The grain size of CBN abrasives directly relates to the quality of grinding, especially the surface roughness. Therefore, to achieve good surface roughness, it is essential to pay attention to the selection of abrasive grain size.

• The choice of CBN abrasive grain size is similar to that of ordinary abrasives. Due to the sharpness and wear resistance of CBN abrasives, if aiming for the same surface roughness, the grain size of CBN abrasives should be 1~2 grain sizes finer than ordinary abrasives. Additionally, if the surface roughness is already satisfactory, a coarser grain size can be selected to improve processing efficiency.

  
  

• According to different binding agents, choose the optimal grain size range suitable for the current binding agent. For resin-bonded CBN wheels, select a grain size finer than 100/120; for metal-bonded CBN wheels, choose a grain size between 80/100~270/325; for ceramic-bonded CBN wheels, choose a grain size between the two mentioned ranges.

  
  

• If the grinding stock is large and the grinding depth is deep, using a coarse grinding method, it is recommended to choose a coarse grain size; if the grinding stock is small and high grinding precision is required, using a fine grinding method, it is recommended to choose a fine grain size.

Finally, as one of the three main elements of abrasives, the stability of abrasive quality directly determines the stability of the grinding wheel quality. When selecting abrasives, it is essential to consider not only the grain size but also compare indicators such as impact toughness, crystal shape, and single-grain strength to choose the most suitable abrasive.