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Views: 0 Author: Site Editor Publish Time: 2025-04-17 Origin: Site
| Feature | Single-Screw Extruder | Twin-Screw Extruder |
|---|---|---|
| Screw Count | 1 screw | 2 screws (parallel/conical, co-/counter-rotating) |
| Conveying Mechanism | Drag-induced (relies on friction between material and screw/barrel) | Positive displacement (forced conveying, similar to a gear pump) |
| Shearing Method | Simple shear (depends on screw flight design) | Complex shear (high-intensity shear in intermeshing zone) |
Single-Screw Extruder:
Feed Zone: Material is pushed forward by screw rotation via friction.
Compression Zone: Gradual reduction in flight depth compacts the material and removes air.
Melt Zone: Barrel heating + shear heat melts the plastic.
Metering Zone: Stabilizes pressure for uniform extrusion.
▶ Limitations: Poor mixing efficiency, low conveying efficiency for low-friction materials (e.g., powders).
Twin-Screw Extruder:
Forced Conveying: Intermeshing screws form sealed chambers, ensuring positive material displacement without backflow.
Efficient Mixing: Stretching, shearing, and folding flows in the intermeshing zone, ideal for blending and compounding.
Superior Heat Transfer: Larger surface area enables faster heat conduction/melting.
Self-Cleaning: Co-rotating screws scrape each other, reducing material buildup.
▶ Advantages: Suitable for high-fill, heat-sensitive materials (e.g., PVC, biodegradable plastics)
