The Relationship Between Extruder and Screen Changer

The extruder and the screen changer are closely interrelated in the processing of plastic products, primarily manifested in the following aspects:

I. Function of the Extruder

An extruder is a mechanical device that shapes fully plasticized and uniformly mixed materials through a die head by applying pressure and shear force. It is characterized by its continuous operation, high efficiency, wide range of applications, and low cost, making it widely used in industries such as rubber, plastics, and synthetic fibers. In the plastics industry, extruders can produce a variety of products including pipes, rods, sheets, films, monofilaments, wires, cables, profiles, and hollow products. They are also used for plastic granulation and mixing.

II. Function of the Screen Changer

A screen changer is a manual or automatic switching device that includes one or more filters used to remove foreign particles and impurities from the plasticized material as it flows through the filter. During the plastic extrusion process, plastic melt undergoes prolonged plasticization and heating, which can lead to the decomposition of residues. Additionally, raw materials may contain impurities. Once these impurities enter the extruder die head, they can cause blockages in the flow channels, leading to defects in the plastic products or even rendering normal production impossible. The primary function of the screen changer is to prevent these impurities and foreign objects from entering the forming die head, ensuring that pure melt can smoothly enter the extrusion forming die head and produce high-quality plastic products.

III. Relationship Between the Extruder and the Screen Changer

Complementary Relationship: The extruder provides the conditions for plasticization and forming of the plastic melt, while the screen changer filters out impurities in the melt to ensure its purity. The two work in tandem to jointly ensure the production quality and efficiency of plastic products.

Installation Position: The screen changer is typically installed between the screw head and the extrusion forming die head, which is the critical passage for the melt to enter the forming die head. By installing the screen changer in this position, it can effectively prevent impurities from entering the forming die head.

Importance: The screen changer is an essential component of the extrusion production process, particularly in plastic recycling and filler production. It enhances the stability and reliability of the production line, reducing downtime and product rejection rates caused by impurities.