### Critical speedWikipedia

In solid mechanics, in the field of rotordynamics, the critical speed is the theoretical angular velocity that excites the natural frequency of a rotating object, such as a shaft, propeller, leadscrew, or gear.As the speed of rotation approaches the object's natural frequency, the object begins to resonate, which dramatically increases system vibration.

### Bond formula for the grinding balls size calculation

Oct 19, 2017 · The grinding balls diameter determined by the Bond formula has a recommendatory character and serves as a starting point for calculating the necessary proportion grinding media feeding a new mill. More precisely adjust the ball load in the mill can only by industrial test performing.

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