Motor drives the rotor quickly in the crushing cavity. Raw materials enter the crusher through the feeding inlet and are impacted, cut and ground by high-speed hammer heads. There is a grate under the rotor assemblly, so that materials with size smaller than the grate mesh will be screened out and others are left to be further hammered until they reach the standard size. The size of the final product can be adjusted by changing the grate, the gap between the rotor assemblly and the grate can also be adjusted according to different requirements.