After plastic products are discarded, they must be crushed by some means before they can be recycled or further molded into various recycled products. In the process of secondary utilization of waste plastics, attention should be paid to these links to avoid secondary pollution and make waste plastic recycling lose its environmental protection significance.
The material is crushed into small pieces under the action of the relative compression force of the material, which is suitable for waste plastic products with large volume. Its mode of action includes the mutual extrusion of two relatively moving metal plates, the rolling action of two relatively rotating rollers, and the extrusion action of the inner cone rotating eccentrically in the outer cone.
The material is crushed by the external impact force, which is suitable for brittle materials. Its mode of action includes the impact on foreign hard objects (such as hammering with a hammer), the high-speed impact between the material itself and the fixed hard steel plate, and the impact between the materials.
The material is crushed into fine particles by rolling between different shapes of grinding bodies, which is suitable for block materials.
The material is broken into small pieces or fragments under the action of cutting, puncturing, shredding of plastic crushing and washing machine, etc. by sharp tools such as blades, and is suitable for tough materials, films, sheets, and soft products.
The choice of crushing equipment mainly depends on the type and shape of the material to be crushed and the degree of crushing required. Different materials of waste plastics have different properties, and the crushing equipment used may also be different.
For example, rigid PVC, PS, plexiglass, and other materials are brittle plastics, which are easily broken into small pieces under the action of compression force or impact force. Such plastics are suitable for compression or impact crushing equipment such as hydraulic compression moulding machine; while PE, PP, PA, ABS, and other materials with good toughness at room temperature, it is suitable to use shear crushing equipment; for some low-temperature brittle materials, such as soft PVC, it is suitable to use low temperature crushing equipment.