Grinding wheel hardness selection

The hardness of the grinding wheel is an important indicator to measure the “self-sharpness” of the grinding wheel. During the grinding process, the abrasive grains gradually become sharp and blunt, and some of the passivated abrasive grains continue to work, and the pressure acting on the abrasive grains will continuously increase; when the pressure is large to a certain value, some abrasive grains will Self-crushing to form a new cutting edge; when the pressure exceeds the bonding force of the bonding agent, the abrasive particles will fall off by themselves. The passivated abrasive particles self-crush or fall off to keep the grinding wheel sharp is called "self-sharpness".

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The hardness of the grinding wheel reflects the difficulty of the abrasive particles falling off the surface of the grinding wheel under the action of the grinding force. If the grinding wheel is hard, it means that the abrasive grains are hard to fall off; the grinding wheel is soft, indicating that the abrasive grains are easy to fall off.

The hardness of the grinding wheel and the hardness of the abrasive grain are two different concepts that must be clearly distinguished.

It is not that the hardness of the diamond grinding wheel must be high. The abrasive of the ordinary abrasive brown fused alumina must be a low hardness level of the grinding wheel. Expressed in English letters: A B C D E F G H I J K L M N P Q... The hard and soft order is incremented. The common hardness is K-P.

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The grinding wheel is selected too hard, the blunt abrasive grains are not easy to fall off, the grinding wheel is easy to block, the grinding heat is increased, the workpiece is easy to burn, the grinding efficiency is low, and the surface quality of the workpiece is affected; the grinding wheel is selected too soft, and the grinding grain is also off when it is sharp. Increases the wear of the grinding wheel, easily loses the correct geometry and affects the accuracy of the workpiece.

Therefore, the selection of the hardness of the grinding wheel should be appropriate. The hardness of the grinding wheel should be comprehensively considered according to the contact area of the grinding wheel and the workpiece, the shape of the workpiece, the grinding method, the cooling method, the type of the bonding agent of the grinding wheel and other factors.