How to Choose the Right Plastic Extruder Screw and Barrel?

In this era of rapid development in the plastics industry, the application of plastic extruders is increasingly being recognized and valued. The screws and barrels used in plastic extruders are one of the core components of the equipment, significantly affecting the plasticizing, kneading, and shaping processes. Therefore, the rational selection of screw structure and parameters is one of the prerequisites for improving product quality and output value. High-quality parts can better ensure normal production and enhance key data such as yield rate and production volume. To meet the needs of different plastic processing requirements.

How to choose the right screw for a plastic extruder? Suggest selecting high-quality screws and barrels based on the following points:

1. To meet the requirements of extruder production, it's essential to rationally select the manufacturing materials for the barrel and screw, typically opting for alloy steel with low thermal deformation, wear resistance, and corrosion resistance. Currently, 38CrMoAIA alloy steel is widely used domestically, and material performance optimization is achieved through secondary heat treatment or coating/spraying on the metal surface in contact with the material. We have a certain degree of material selection.

2. The choice of billet for screw blanks will result in superior physical properties through forging.

3. The inner wall of the cylinder and the outer round of the screw must undergo precise mechanical processing, with the required accuracy to meet or exceed 8th grade precision standards.

4. The screw thread's outer diameter maintains concentricity with the drive shaft, with theoretically higher precision being preferable. However, due to inherent errors in actual mechanical processing, these errors must be controlled within 10μm.

5. If the barrel and screw require the installation of a water-cooling channel, a hydrostatic test must be conducted in advance, with no leakage observed under a continuous water pressure of 0.3 MPa for 5 minutes.

The gap between the cylinder inner wall and the screw outer circumference is strictly controlled; it should not be too large or too small.

7. For instance, some parallel twin-screw extruders utilize segmented, detachable barrels. Each barrel section must be properly aligned and continuous, ensuring that the center is concentric and the material does not leak at the joints.