The basic principle is straightforward. A hammer mill is essentially a steel drum containing a vertical or horizontal rotating shaft which hammers are mounted. The hammers are free to swing on the ends of the cross, or fixed to the central rotor. The rotor is spun at a high speed inside the drum while material is fed into a feed hopper. The material is impacted by the hammer bars and is thereby shredded and expelled through screens in the drum of a selected size.

It's ideal crushing machinery for the medium hardness and fragile materials which compressive strength under 200 MPA, calcium content greater than 40%.