After sorting waste plastics there are difference processes for
size reduction of them such as cutting processes, densification processes, pulverization
processes, and chemical size reduction processes etc.
Cutting process
There are large ranges of plastic shredder machines. Shredders are usually based on two asynchronized or four synchronized contra operating shafts equipped with cutting discs and distance collars. The shredding action occurs between adjacent discs. The degree of crushing is determined by the number of hooks on the circumference of cutting disk and the width of the cutting edge.
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| Industrial plastic shredder with four cutting shafts |
- Granulators (rotary knife cutters) are one of most common types of size reduction machines used in plastic recycling industry. These types of machines employ a system of rotating knife blades. These cutters are widely used for both house reclamation of scraps as well as the size reduction of post consumer plastic waste.
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| Industrial granulators |
- Rotary grinders are equipped with steel blocks about 2.5-5 cm in size mounted on a rotor. This is more suitable for size reduction of automotive and durable plastics.
- Slicers also known as guillotine shears are generally used for the size reduction of waste plastic items like fibers rolled up web or rubber bales.
- Screw cutters are employed for the size reduction of voluminous plastic materials that have low toughness like polymer foams.
