In-depth comparison of screw barrel types and technical features

In the plastic processing industry, screw barrels are core equipment, and their types and technical features directly affect production efficiency, product quality and energy consumption. This article will compare in detail the differences in design principles, applicable scope, production efficiency, energy consumption, cost, etc. between different types of screw barrels such as single screw, twin screw, and conical screw, and explore the effects of technologies such as variable pitch, mixing section design, and temperature control system on processing performance to help readers choose the right screw barrel according to their needs.

1. Design principles and applicable scope

Single screw barrel

Design principle: The single screw barrel rotates in the barrel through a spiral screw to push the plastic raw material forward and heat it to melt. The design of the screw usually includes a conveying section, a compression section, and a metering section to achieve the conveying, compression, and melting of the raw materials.

Scope of application: Suitable for processing thermoplastics such as polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), etc. For plastics with higher viscosity or poor thermal stability, the applicability of single screw barrels may be limited.

Twin-screw barrel

Design principle: The twin-screw barrel consists of two intermeshing screws. Through the rotation and mutual shearing of the screws, the plastic raw materials are melted and mixed evenly. The design of the twin-screw barrel usually includes a conveying section, a compression section, a mixing section and a homogenizing section.

Scope of application: It is suitable for processing various thermoplastics, especially plastics with high viscosity, high filling or high mixing uniformity. Twin-screw barrels are also suitable for processing thermosetting plastics and rubber.

Conical screw barrel

Design principle: The screw of the conical screw barrel is conical. Through the rotation of the screw and the change of the conical structure, the plastic raw materials are conveyed, compressed and melted. The design of the conical screw usually includes a gradual section and a sudden change section to meet the processing requirements of different plastics.

Scope of application: It is suitable for processing plastics with poor thermal stability, such as PVC, polystyrene (PS), etc. Conical screw barrels are also suitable for processing plastics that require high shear force and high mixing effect.

2. Production efficiency and energy consumption

Production efficiency

Single screw barrel: relatively low production efficiency, suitable for small and medium-scale production.

Twin screw barrel: high production efficiency, suitable for large-scale production. The shearing and mixing action of the twin screw helps to improve melting efficiency and mixing uniformity.

Conical screw barrel: production efficiency is between single screw and twin screw, suitable for certain types of plastic processing.

Energy consumption

Single screw barrel: relatively low energy consumption, but as the scale of production increases, energy consumption may gradually increase.

Twin screw barrel: high energy consumption, but due to high production efficiency, the energy consumption per unit product may be low.

Conical screw barrel: energy consumption varies depending on the design, but is generally between single screw and twin screw.

3. Cost and maintenance

Cost

Single screw barrel: relatively low cost, suitable for occasions with limited budget or small and medium-scale production.

Twin screw barrel: high cost, but considering the high production efficiency and good product quality, the long-term return on investment may be higher.

Conical screw barrel: The cost varies depending on the design, but is usually between single screw and twin screw.

Maintenance

Single screw barrel: Maintenance is relatively simple, and the cost of replacing the screw and barrel is low.

Twin screw barrel: Maintenance is more complicated, and regular inspection and replacement of screws, bearings and other components are required.

Conical screw barrel: Maintenance costs vary depending on the design, but are usually between single screw and twin screw.

4. Impact of technical characteristics on processing performance

Variable pitch

Impact: Variable pitch design can optimize the conveying efficiency and melting effect of the screw, improve production efficiency and product quality.

Applicable: Applicable to plastic processing that requires high melting efficiency and mixing uniformity.

Mixing section design

Impact: The mixing section design can enhance the shearing and mixing action of the screw, improve the mixing uniformity of the plastic and product quality.

Applicable: Applicable to processing plastics with high viscosity, high filling or high mixing uniformity.

Temperature control system

Impact: Accurate temperature control system can ensure the temperature stability of plastics during processing, improve product quality and production efficiency.

Applicable: Applicable to all types of plastic processing, especially plastics with high heat sensitivity.