The feed material is presented into PMS HAMMER MILL® through adjustable-angle feeding tray or through feeding chute. Swinging blades are affixed to a high-speed rotor mounted in a chamber. The chamber is bounded on the bottom by an interchangeable screen through which the milled material must pass. The rapidly rotating hammers strike against the feed material, breaking it into smaller fragments, which are swept against the screen. Particles, that are small enough to pass through the screen, drop through the discharge chute into a collection container.

Type of hammer, rotor speed and size of the screen openings are important factors governing the particle size of the product. Flat-edge hammers are generally used for pulverizing and tend to create a large number of fines. Knife-edge hammers are generally used for chopping and sizing when fines are undesirable or when fibers and tissues must be severed. 

Product particle size varies for a given screen according to the rotor speed. The discharge product is actually smaller than the nominal dimensions of the screen opening. Finer particles are produced with a given grid at higher speeds.  

The driving is through belts and pulleys. The bearing and seal design in such a way that no contamination from driving unit would enter the processing chamber. The motor and mill assembly are mounted on a common baseplate which carries the ground product discharge chute and a rigid support frame, resulting a compact design configuration.