The influence of the jet velocity of coolant or cooling oil during grinding is easily overlooked. 

A low jet velocity of grinding oil causes a sharp rise in grinding power, making grinding difficult and resulting in workpiece defects such as burn marks and chatter marks. 

The figure below shows the relationship between cooling oil velocity and grinding power when grinding powder metallurgy high-speed steel:

In the graph above, when the ratio of coolant jet velocity to the wheel peripheral speed equals 0.92, the cooling is sufficient and the grinding power remains relatively stable. 

When this ratio is 0.20, the cooling is inadequate, and the grinding power fluctuates greatly.

To achieve high coolant velocity, not only high coolant pressure is required, but the shape of the nozzle is also extremely important. 

A method for manufacturing nozzles is introduced below:

With proper coolant pressure and a well-designed nozzle shape, the coolant jet velocity can reach the target value. 

This facilitates the grinding process and allows users to rapidly produce qualified workpieces.