The Role of Screw Barrel in Plastic Machinery

Screw Barrel is the core component of plastic extrusion, injection molding and other processing equipment. It undertakes key functions such as material transportation, plasticization, mixing, and extrusion in plastic machinery.

1. Material Conveying and Compression

The spiral structure of the screw rotates to push plastic raw materials (such as PE, PP, PVC, etc.) from the feed port to the processing area inside the barrel. At the same time, it uses the gap between the screw and the barrel to compress the material, expel air from the raw materials, and prepare for subsequent plasticization.

2. Material Plasticization and Melting

The barrel is equipped with heating devices (such as electric heating rings) on the outside. Combined with the shearing and stirring action of the screw, it gradually heats the solid plastic raw materials to a molten state. This process requires precise control of the temperature gradient (temperature differences in the feed section, compression section, and metering section) to ensure uniform melting of the material and avoid local overheating or unmelted areas.

3. Material Mixing and Homogenization

The special structure of the screw (such as barrier type, pin type, etc.) can perform dispersive mixing (breaking agglomeration) and distributive mixing (uniformly dispersing additives, color masterbatches, etc.) on the molten material. This ensures the composition uniformity of the plastic melt and improves the mechanical properties and appearance consistency of the final product.

4. Stable Extrusion and Pressure Control

The precise fit between the screw and the barrel (the gap is usually 0.1 - 0.3mm) forms a closed space. The rotation of the screw generates extrusion pressure, so that the molten material is extruded from the die head mold at a stable flow rate and pressure. This ensures the dimensional accuracy and production stability of products such as pipes, sheets, and profiled materials.

Screw Barrel Product Series of Zhoushan Microwave Screw Machinery Co., LTD

1. WB - WE Series Planetary Screw and Barrel

Structural Features: Adopting a "planetary" screw layout (multiple small screws rotating around the central screw) and special barrel cavity design, it greatly improves material mixing efficiency.

Application Scenarios: Suitable for processing high - filled, high - viscosity plastics (such as calcium carbonate - filled masterbatch, color masterbatch, functional plastics). It can achieve uniform dispersion and efficient plasticization, and is commonly used in masterbatch production lines and special plastic modification fields.

2. SJS Series Conical Twin - Screw and Barrel

Structural Features: The screw has a "conical" design (the diameter gradually decreases from the feed end to the discharge end), and the barrel is matched with the taper to achieve gradual compression, reducing material shear heat, which is suitable for heat - sensitive plastics.

Application Scenarios: Widely used in the extrusion of hard plastics</ as PVC pipes, profiles, and plates. It can also be used for pelletizing and profile production of general plastics such as PE and PP. Its advantages lie in low energy consumption and high output.

3. SJ Series Single Screw and Barrel

Structural Features: A single screw is matched with a standard barrel. The structure is simple and low - cost. By adjusting the screw parameters (such as pitch, depth), it can meet the processing needs of different plastics.

Application Scenarios: It covers the extrusion of general plastics (PE, PP, PS) such as pipes, sheets, and films, as well as auxiliary feeding for injection molding in the fields of food packaging and daily necessities. It is a cost - effective choice for entry - level plastic processing.

4. Customized Screw Barrel (Including EPE Foam and Profile - Specific Types)

Customization Logic: For customers' specific needs (such as EPE foam extrusion process, complex cross - section of profiled materials), optimize the compression ratio, mixing section length, and barrel cavity structure of the screw to ensure that the material is fully foamed and uniformly formed during processing.

Application Scenarios: EPE foam screw barrels are used for the continuous extrusion of EPE foam materials; profile - specific screw barrels are adapted to the stable production of complex sections such as doors and windows and decorative lines, meeting high - end customization needs.