High Quality Single Screw Extruder Machine Efficient Cable Extruding Tool for Silicone Rubber Insulation Rubber Making Machinery

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ZL-3017 Lab Single screw extruder.pdfZL-3017 Lab Single screw extruder.pdf

1. Overview

The single-screw extruder is the most versatile, widely used, and fundamental piece of continuous mixing and shaping equipment in the polymer processing industry. Acting as the "heart" of plastics production, it utilizes a rotating screw inside a heated barrel to perform a series of sequential operations on materials like plastics and rubber: feeding, compaction, melting (plasticating), mixing, homogenization, metering, and pumping. The final melt is continuously forced through a shaped die to produce products with a constant cross-section (e.g., pipes, sheets, profiles, films) or to feed subsequent processes like blown film, cast film, or pelletizing.

2. Working Principle (The Three-Zone Model)

The core principle relies on drag-induced flow from the rotating screw, combined with friction and external heating from the barrel. The material undergoes three physical transitions:

• Feed Zone (Solid Conveying):

  • Granular or powdered material enters from the hopper.

  • This zone has the deepest screw channel. Its primary function is solid conveying. The screw rotation pushes the material forward, while heating and friction begin to preheat and compact it into a solid "plug."

• Compression Zone (Melting / Plasticating):

  • The screw channel depth gradually decreases, creating a compression ratio.

  • The compacted solid plug is subjected to increasing shear and pressure. Heat from the barrel and internal viscous shear melting forms a thin melt film at the barrel wall. This film is scraped off and collected, and the solid bed gradually disappears until the material is fully molten.

  • The compression ratio is critical for removing air, building up melt pressure, and densifying the material.

• Metering Zone (Melt Pumping):

  • This zone has the shallowest and constant channel depth.

  • Its functions are to homogenize the melt (achieving uniform temperature and composition), provide stable conveying, and act as a precision pump.

  • The melt undergoes consistent shear for mixing and is then delivered to the die at a constant pressure, temperature, and flow rate.

3.Technical Parameters: