Shredder Guide -- Glossary of Terms

Automobile Shredder – a hammermill-type shredder large enough to shred whole cars into fist-sized chunks in less than a minute.

Automotive Shredder Residue – the material left over after an automobile has been shredded and the ferrous metal removed (nonferrous metals and nonmetallic material).

Burden depth – the depth at which material is spread on a conveyor belt.

Downstream Separation – separation of material into ferrous, nonferrous and nonmetallic streams after it has been shredded. Usually material leaves the actual shredder on a conveyor belt and then is sent through magnets, eddy current separators, trommels, and other downstream separation equipment.

Eddy Current Separator – a device for separating nonferrous metals from nonmetallic material that works by creating a mechanically driven rotating or alternating magnetic field and moving a non-magnetic metallic particle into this field. An eddy current is created in the particle, producing a magnetic field with a like polarity, and ejecting it from the fixed field generator. 

Ferrous – iron-based metals such as steel.

Granulator – a machine for grinding small materials such as plastics into small pellets.

Hammermill – a high-speed rotor equipped with large hammers for pulverizing material into smaller sizes. Large machines are often used to shred automobiles and other heavy-duty scrap metal.

Material burden – material on a conveyor belt on its way to being sorted.

Medium-Speed Shredder – a round drum with multiple replaceable cutter inserts which cut against a fixed bed knife. Used for reducing materials such as plastics, electronic scrap, wood waste and nonferrous metals.

Nonferrous – non-iron based metals such as aluminum and copper.

Shredder Drive – the motor on the shredder, which can be configured a number of different ways including electric or hydraulic.

Shredder fluff – the nonmetallic and generally non-recyclable material left over after an automobile or appliance has been shredded and the ferrous and nonferrous metals removed.

Slow Speed, Shear Type Shredder – a high torque, low speed industrial shear machine consisting of two or more counter rotating shafts equipped with hooked knives capable of cutting a wide variety of materials such as tires, paper, and baled metals such as aluminum.

Super Sized Shredder – a hammermill-type shredder with an even larger capacity than the typical hammermill used for shredding cars.

Tub Grinder – a shredder used primarily for woody, vegetative debris. The basis of a tub grinder is a hammermill, the top half of which extends up through the stationary floor of a tub. As the hammers encounter material, they rip and tear large pieces into smaller pieces, pulling the material down below the tub floor and ultimately forcing it through openings in a set of grates below the mill. Various sized openings in the removable grates are used to determine the size of the end product.

Unshreddables – materials that a shredder is unable to handle because they are too large or too thick to be shredded.