The twin screw extruder is a highly complex plastic processing equipment, based on the principles of the single-screw extruder, but with more efficient material handling capabilities. It uses two intermeshing screws rotating inside a barrel to perform functions such as solid conveying, melting, mixing, degassing, and pumping. Compared to the single-screw extruder, the twin-screw extruder offers advantages such as stronger mixing and plasticizing performance, better feeding capacity, and efficient degassing, making it ideal for plastic modification, compounding, filling and reinforcement, as well as processing complex formulations.
Chuangbo is a leading China twin screw extruder manufacturer. The company focus...
The twin screw extruder is a highly complex plastic processing equipment, based on the principles of the single-screw extruder, but with more efficient material handling capabilities. It uses two intermeshing screws rotating inside a barrel to perform functions such as solid conveying, melting, mixing, degassing, and pumping. Compared to the single-screw extruder, the twin-screw extruder offers advantages such as stronger mixing and plasticizing performance, better feeding capacity, and efficient degassing, making it ideal for plastic modification, compounding, filling and reinforcement, as well as processing complex formulations.
Chuangbo is a leading China twin screw extruder manufacturer. The company focuses on the R&D, production, and sales of twin-screw extruders, offering a variety of high-performance extrusion products, including masterbatch extruders, PVC compounding machines, thermoplastic elastomer extruders, and more. Nanjing Chuangbo Machinery Equipment Co., Ltd. has also developed China’s first intelligent control system for twin-screw extruders and achieved technological breakthroughs in areas such as co-rotating twin-screw extruders. The company has made significant achievements in high polymer compounding and modification, reactive extrusion, post-reactive processing, integrated compounding and molding, long-fiber reinforced thermoplastic composite pelletization, supercritical fluid extrusion foaming, and other process technologies.
Main Components
• Screw: Can be either intermeshing or non-intermeshing, and classified into co-rotating and counter-rotating based on the screw rotation direction.
• Heating and Cooling Zones: Used for melting and cooling plastics.
• Control System: Includes temperature controllers and speed regulators for automated operation.
A twin-screw extruder consists of two parallel screws, with the gap between the screws controlling the material’s conveying speed and pressure to ensure uniform mixing and plasticizing. When the screws rotate in the same direction, it is called a co-rotating twin-screw extruder, suitable for mixing additives, pigments, and fillers. The counter-rotating twin-screw extruder is suitable for gentle processing, especially for shear-sensitive materials.
Features of Twin Screw Extruders
• High Mixing Efficiency: Improves material mixing and plasticizing.
• Flexibility: Configurable to meet different material and process requirements.
• Modular Design: Easy to maintain and upgrade.
• Wide Application: Used in various industries such as plastics, rubber, food, and pharmaceuticals.
• High Output and Low Energy Consumption: Certain types, such as conical counter-rotating twin-screw extruders, offer high output with low energy consumption.
Applications
• Plastic Processing: Polymer compounding, pelletization, and modification.
• Food Industry: Ingredient mixing and molding.
• Pharmaceutical Production: Uniform mixing of drug components.
Twin-screw extruders are widely used in plastic processing, extrusion molding of heat-sensitive plastics (such as PVC), and the processing of special plastics. They are also used in pharmaceutical, food processing, and composite material manufacturing.
Principles and Research Directions
Current research focuses on establishing physical and mathematical models to optimize the design and processing techniques. It involves understanding the phase changes of polymers during the extrusion process, the transfer mechanisms of solids to melts, and the degassing process. Research also focuses on the mixing mechanisms of multiple polymers and materials, structural changes, and the control of reactive extrusion.
In recent years, the technology of twin-screw extruders has advanced rapidly, with the development of new high-shear twin-screw extruders and lattice-blade extruders. Laboratory and pilot-scale solutions have also been further optimized.
How to Optimize Twin-Screw Extruders
• Increasing Output: By adjusting process parameters, screw combinations, and hardware configurations.
• L/D Ratio: The length-to-diameter ratio can reach up to 80:1, depending on the product type.
• Maintenance and Startup: Manually rotate the motor coupling before startup to check for resistance between the screw and barrel, preventing equipment damage caused by incomplete material melting.
• Structure and Material: The barrel is typically designed with a modular structure, and materials such as nitrided steel and alloy inserts are commonly used for their corrosion resistance and wear resistance.
