The two most common grinding machines used by industry are the pin mill and hammer mill. Both mills have fundamentally unique features that make them suited for a wide range of materials production.
The Pin Mill, unlike the Hammer Mill, consists of a series of pin breakers hinged to discs in the grinding head where it delivers high-energy impact. Pin Mills use shearing and impact methods; however, with a faster tip speed of intermeshing pins when compared to a Hammer Mill. Centrifugal force brings the particle sizes to the grinding chamber’s periphery for collection or further processing. The milling process will produce particle sizes down to ultra-fine micronized sizes +/- 10 µm. Particle sizing generated by the pin mill is the product of rotor tip speed, airflow rate, the feed rate of the material, as well as the morphology of the feed material. The milling process balances additions and reductions of airflow, feed rate, and rotor speed.
The Hammer Mill, one of the oldest and widely used grinding mills, typically consists of four or more hammers attached on a central shaft enclosed by a metal casing. The mill performs particle size reduction via high-speed impact of hardened steel rotating hammers. Particle size reduction occurs in three actions: repeated hammer impact, particle collisions with the chamber wall, and particle-to-particle impact. Screens (set at a specified cut point) retain coarse particles for further grinding while allowing product sizes below the cut point to pass. Achieving the target particle sizing is a function of rotor speed, feed rate, hit resistance, clearance between grinding plates and hammers, and screen size.
At Classifier Milling Systems, we manufacture both pin mills and hammer mills as well as the leading air classifier mills and a broad range of milling technologies and products designed to give you the fine grind that suits your unique needs. We are a dedicated team with expert knowledge of particle size reduction. We guarantee exceptional service every time. We also guarantee performance!