Screw Extrusion Machine

Core Structure

1. Drive System: The motor supplies power, driving two screws to rotate at identical speeds via a reduction gearbox.

2. Feeding System: Comprising the main hopper and lateral feeders, it ensures continuous and stable addition of primary and auxiliary materials.

3. Barrel: Typically modular in design, comprising multiple barrel sections. Internal openings may be incorporated for venting, lateral feeding, or additive injection. External sections feature segmented heating and cooling.

4. Screw: The core component, also employing a modular design. Functional elements (such as conveying elements, kneading blocks, counter-rotating thread elements, etc.) are assembled onto the core shaft to achieve specific conveying, shearing, and mixing effects.

5. Die Head: After thorough plasticisation and mixing, the material passes through the die head to form specific shapes, such as strands or sheets.

6. Control System: Precisely regulates process parameters including temperature, screw speed, feed rate, and vacuum level.

Working Principle

Material is fed into the hopper, captured by the rotating screw, and conveyed forward. During conveyance, the material undergoes heating, shearing, compression, and mixing, gradually transforming from a solid to a molten state. Kneading elements subject the material to intense shearing and stretching forces, achieving efficient mixing and dispersion. The degassing section extracts moisture, air, and low-molecular-weight volatiles. Finally, the homogenised melt is forced through the die to form the desired product.

Key advantages of twin-screw extruders

Superior mixing capability: Achieves an optimal blend of distributed and dispersed mixing.
Self-cleaning function (particularly with co-rotating screws): Reduces material degradation, ideal for switching colours and formulations.
High flexibility: Modular design permits flexible combination of screw and barrel configurations to suit process requirements.
High heat and mass transfer efficiency: Suitable for reactive extrusion and devolatilisation processes.
Broad processing range: Capable of handling raw materials in various forms including powders, pellets, fibres, and liquid additives.
Continuous production: High efficiency with stable product quality.