Twin-Screw Barrel Applications and Maintenance

Twin-Screw Barrel Applications
Twin-screw extruders are primarily used for extrusion of heat-sensitive materials, such as PVC pipes and profiles, and for processing specialty polymers, such as blending, degassing, and chemical reactions. Twin-screw extruders used for profile extrusion feature intermeshing flights and grooves and operate at relatively low speeds, approximately 10 rpm or less. Compared to single-screw extruders, twin-screw extruders offer improved feeding and conveying performance, especially for difficult-to-feed and slippery materials such as fibrous, powdery, and greasy materials. Twin-screw barrels are also suitable for the production of PVC pipes, profiles, WPC, sheets, plates, and pellets.

Twin-Screw Barrel Maintenance
To ensure proper operation and extend the life of the twin-screw barrel, the following maintenance is required:
1. Never start the machine before the barrel screw has reached the preset temperature.
2. Prevent metal fragments and debris from falling into the hopper. If processing recycled materials, add a magnetic hopper to prevent iron filings and other debris from entering the barrel.
3. When using a drool-blocking device, ensure that the plastic in the barrel is completely melted to prevent damage to drive system components when the screw retracts.
4. When using new plastic, clean any remaining material from the barrel.
5. If the molten plastic temperature is normal but black spots or discoloration continue to appear on the molded product, inspect the screw's rubber insert, rubber ring, and rubber ring for wear.
6. During injection molding, ensure uniform plasticization of the material to reduce the torque on the screw and maximize its service life.
7. Whenever the machine is stopped for more than half an hour, close the discharge port, clean the barrel, and set insulation.
8. Prevent the screw from idling or slipping.