MILL CRITICAL SPEED:

Calculations of the actual mill critical speed (in RPM) and the percent critical speed of a given mill speed.
The critical speed is the speed at which the grinding media will not fall from the mill shell because the centrifugal forces are equal to or greater than the gravitational forces. Consequently, the grinding efficiency significantly decreases when the mill is rotating faster than the critical speed.
Theoretically, the critical speed is calculated by: However, the grinding media diameter d is normally negligible compared to the mill diameter D and is not accounted for in the calculations below.

To use:

Enter the effective mill diameter (m) to calculate the actual critical speed (in RPM).

Enter a given mill speed (in RPM) to convert to percent critical speed.

Click on "Calculate".

Scroll down to see the result.

Watch a Youtube video example.

Effective mill diameter:		meters feet value="
Mill speed (RPM) to convert to percent Critical Speed:		RPM