Shredder in Extrusion Lines: Working Principle & Core Role

Working Principle of the Shredder in an Extrusion Production Line In an extrusion production line, the working principle of the shredder is to break large, irregular plastic raw materials (especially recycled plastic waste) into uniformly sized fragments or granules through mechanical shearing, tearing, and extrusion. This provides materials that meet the feeding requirements for subsequent extrusion processes, ensuring the continuous and stable operation of the production line. Its specific workflow integrated into the production line can be divided into the following key stages:

Raw Material Pretreatment : Recycled plastics (such as plastic bottles, films, blocks, etc.) enter the shredder's feeding hopper through a conveying device, avoiding the inefficiency and safety hazards of manual feeding.

Shredding Operation: The rotating cutters (rotary cutters) inside the shredder form relative motion with the fixed cutters. Through the shearing and tearing forces generated by high-speed rotation, large raw materials are gradually shredded. For plastics with high toughness, the toothed design of the cutters enhances grabbing and tearing effects to ensure uniform shredding.

Screening and Separation: The shredded materials must pass through a screen (or grid) at the bottom of the machine chamber. Only fragments that meet the required size (usually set according to subsequent extrusion processes, such as 10-30mm) can pass through the screen holes and enter the next-level conveying system (such as screw conveyors, pneumatic conveying pipes). Materials that do not meet the standards will be repeatedly shredded in the chamber until they meet the specifications.

Connection to Extrusion Process: Qualified shredded materials are conveyed to the extruder's hopper and enter the screw extrusion system. After melting, mixing, and plasticizing, they form a uniform melt, which is finally extruded through a die (such as pelletizing, pipes, plates, etc.). In the entire extrusion production line, the core function of the shredder is to solve the problem of inconsistent raw material sizes, preventing large raw materials from blocking the extruder's feed inlet or causing uneven screw feeding. Meanwhile, through shredding pretreatment, it can increase the specific surface area of raw materials, accelerate the subsequent melting process, and improve extrusion efficiency and product quality stability. It is an indispensable key pretreatment equipment especially in recycled plastic extrusion production lines.