They are mostly used to process scrap and used plastic products before they are melted down and reformed into new products. While plastic is a vital and extremely useful material, when a plastic product is no longer useful, it can be difficult to dispose of.
Most plastics are not biodegradable. Many are recyclable, though, and in order to prevent pollution, reduce the demand for the petrochemicals from which plastics are processed and to cut production costs, a used plastic part should be recycled if possible. Plastic shredders are a step in the plastic recycling process. They can be designed to process a wide range of plastic items from large bulky products like profiles, drums, car parts, plastic bales and pipes to small bottles, bags and packaging material.
All plastic shredders of every size and configuration take products like those and shred them into fine particles called granules. Outside of the recycling industry, cosmetic, pharmaceutical and electronic manufacturers use plastic shredders to reuse scrap materials. In some processes, when a plastic shredder doesn’t produce fine enough pieces, the shredded plastic will undergo secondary processing, often through a granulators, which is a machine designed to make small pieces even smaller.
Plastic shredders are designed in many different configurations. They range in size and can be equipped with multiple processing shafts, depending on the scale of the shredding operation. When shredding long, linear products like profiles and siding, horizontal shredders are often preferred.
All other plastic products are fed into a vertical shredder. In each processing shaft, all of which may be designed (to some degree) to be vibration and sound absorbent, at least two rotors equipped with large, sharp blades rotate toward each other and rip, break, shear and shred plastic. The rotors are often made out of steel or stainless steel and are therefore strong, corrosion resistant and easy to clean.
A dispenser basket collects all the granules, which sometimes must fit through a screen acting as a sifter, to ensure the particles are small enough to be melted down. All kinds of plastics are shredded in these machines including PVC, HDPE, HIPE and LDPE. Some shredders are used for specific kinds of products.
Recent research suggests that people working in close proximity to plastic shredding machinery may be at risk for inhalation of potentially harmful dust expelled by the shredded plastic products. As is true in any industrial workplace, proper provisions for air quality and general workspace safety should be made near plastic shredders.
Plastic Shredder Informational Video