Physical properties of abrasives

Particle size of abrasive

Abrasive particle size refers to the particle size of the abrasive. Abrasives can be divided into four groups according to their particle size: abrasive, grinding powder, micro powder and ultrafine powder. Among them, the particle size number of the two groups of abrasive particles and grinding powder is expressed by the number of mesh on each inch of screen length, which is marked by the "#" symbol in the upper right corner of the number of particle size. For example, 240# means that there are 240 holes on each inch of screen length, and the larger the value of the particle size, the smaller the wear particles. The particle size number of the two groups of abrasive powder and ultrafine powder is expressed by the actual size of the particle, and its symbol is to add a letter "W" in front of the particle size number. Sometimes it can also be converted into a sieve number. For example, W20 indicates that the actual size of the abrasive particle is between 20μm and 14μm, which is 500#.

There are coarse, medium and fine particles in the particle size of various abrasives. Medium particle is the basic particle size of grinding powder, which is the main factor determining the grinding ability of abrasive, and occupies a large proportion in the composition of Lido. The practice shows that the grinding ability of the grinding powder after centrifugal separation is 20% higher than that before separation. Fine particles play a small grinding role in grinding, particle size in addition to the quality of the grinding workpiece, but also reduce the grinding efficiency, should be in the particle size composition to minimize their number. Therefore, from the efficiency of grinding and the quality of work, it is required that the abrasive particles are uniform. The abrasive particle group with the particle size of 12#~80# has a large particle size and is not suitable for abrasive processing.

Hardness of abrasive

The hardness of the abrasive refers to the ability of the abrasive surface to resist local external action, and the hardness of the abrasive (such as the whetstone) is the firmness of the adhesive bonded abrasive when subjected to external force, which is one of the basic characteristics of the abrasive. Grinding processing is to use the hardness difference between the abrasive and the ground workpiece to achieve, the higher the hardness of the abrasive, the stronger its cutting ability.

The strength of the abrasive

The strength of the abrasive refers to the firmness of the abrasive itself. That is, when the abrasive edge is still quite sharp, the ability to withstand external pressure without being broken. The abrasive with poor strength has fast grinding speed, low cutting ability and short service life. This requires that in addition to having a high hardness, the abrasive particles should also have sufficient strength to better grind.