Plastics size reduction equipment is integral to plastics cycling. Whether the plastic to be recycled is post-consumer or industrial, the product needs to be reduced in size to be reprocessed.
Post-consumer Plastics Processing and Size Reduction Equipment
In the case of post-consumer plastics, the items must be washed and separated from any non-plastics elements such as metal or paper. Large and dense items are processed with a series of size reducing machinery; and typically must be shredded before being granulated.
- Shredding: Shredders can either be dual shaft or single shaft depending on the product to be reduced. Items are usually conveyed to the shredder where they are essentially ripped or torn apart to create course uneven shapes of a smaller size. From the shredder, the plastics is usually conveyed to the granulator for further size reduction.
- Granulating: The granulator takes the shredded material and grinds it through a screen to create a more uniform size. Shredding is not necessary for smaller items; in such cases, the product can be directly placed in the granulator. This regular-sized piece produced from the granulator can be sold as is in bulk to a recycler or can be processed inhouse.
- Pelletizing: The granulated plastic is fed into pelletizing extrusion line or directly back into the process stream. A strand, underwater or liquid ring pelletizing line will then be used to create fairly uniform plastic pellet. The resulting pellet can then be extruded or molded into various products.
Size Reduction Machines for Plastic Film Recycling
Plastic film requires its own unique step and alternate size reduction machinery. Its properties won’t allow it to be placed immediately in an extruder. It must be densified in a densifier (agglomerator). This process takes the light and fluffy film and processes it to just before its melting point to produce a viscous material that can be fed into the extruder.
Processing Plastics for Recycling
Many plastics operations have beside-the-press granulators to granulate their defective parts or sprues as they are removed from the process. Some processors have large central granulators or shredder granulator systems that immediately convey the granulated plastic back into the processing stream.
While there are hundreds of configurations for every application, the key to recycling plastics is size reduction equipment such as wash lines, granulators, shredders, pelletizers, densifiers and guillotines.