Co Rotating vs. Counter Rotating Twin Screw Extruders

In the realm of industrial manufacturing and processing, twin-screw extruders stand as indispensable tools, driving innovation and efficiency across various sectors. Among the diverse array of twin-screw extruders available, Co-Rotating and Counter-Rotating configurations emerge as prominent contenders, each offering unique advantages and applications.

Co-Rotating twin-screw extruders, characterized by intermeshing screws rotating in the same direction within a barrel, have long been favored for their versatility and intensive mixing capabilities. On the other hand, Counter-Rotating twin-screw extruders, with screws rotating in opposite directions, boast distinct advantages in certain specialized processes. As industries continue to evolve and demand ever-advanced processing solutions, understanding the differences and strengths of these two extruder types becomes increasingly crucial.

Let’s delve deeper into the comparative analysis of Co-Rotating and Counter-Rotating twin-screw extruders to elucidate their respective roles and contributions in modern manufacturing.

Co Rotating vs. Counter Rotating Twin Screw Extruders

Co-Rotating Twin Screw Extruders:

Working Principle:

Co-Rotating twin-screw extruders feature two intermeshing screws that rotate in the same direction within a barrel. Material is fed into the extruder at one end, and as it progresses through the barrel, it undergoes intense mixing, kneading, and shearing action due to the interaction of the screws. This results in thorough blending of components, dispersion of additives, and processing of various materials.

Co-rotating Twin Screw Extruder

Co-rotating Twin Screw Extruder


  • Versatility: Co-Rotating twin-screw extruders are highly versatile and can process a wide range of materials, including polymers, plastics, rubber compounds, food ingredients, and pharmaceutical formulations.
  • Intensive Mixing: The co-rotating motion of the screws facilitates intensive mixing, leading to uniform dispersion of additives and consistent product quality.
  • Precise Control: These extruders offer precise control over processing parameters such as temperature, pressure, screw speed, and residence time, enabling tailored processing for specific materials and formulations.
  • High Throughput: Co-Rotating twin-screw extruders are capable of high throughput rates, making them suitable for large-scale production operations.
  • Compounding and Reactive Processing: They are commonly used for compounding materials by incorporating additives, fillers, and modifiers, as well as for reactive processing techniques like polymerization and cross-linking.

Application Areas:

Co-Rotating twin-screw extruders find extensive use in industries such as plastics and polymer processing, compounding, food processing, pharmaceuticals, and chemical manufacturing.

Counter-Rotating Twin Screw Extruders:

Working Principle:

Counter-Rotating twin-screw extruders feature two screws that rotate in opposite directions within a barrel. Material is introduced into the extruder, and as it moves along the barrel, it undergoes mixing and processing due to the counter-rotating motion of the screws. This configuration enables efficient conveying, mixing, and compounding of materials.

Counter Rotating Twin Screw Extruder

Counter Rotating Twin Screw Extruder


  • Gentle Processing: Counter-Rotating twin-screw extruders offer gentle processing, making them suitable for shear-sensitive materials and delicate formulations.
  • Enhanced Conveying: The counter-rotating motion of the screws enhances material conveying and facilitates uniform blending of components.
  • Excellent Degassing: These extruders are effective for degassing volatile components from materials, ensuring product purity and quality.
  • Wide Range of Viscosities: They can handle materials with a wide range of viscosities, including high-viscosity melts and low-viscosity fluids.
  • Reduced Residual Stress: The counter-rotating motion helps reduce residual stress in the processed materials, leading to improved product properties.

Application Areas:

Counter-Rotating twin-screw extruders are commonly used in industries such as food processing, pharmaceuticals (especially for sensitive formulations), specialty chemicals, and polymer processing applications where gentle processing and precise control are essential.

How to choose Twin Screw Extruders suitable for production?

Choosing the right extruder for your needs involves considering several factors based on your specific requirements and production goals. Here’s a guide to help readers select the appropriate extruder from Co-Rotating and Counter-Rotating Twin Screw Extruders:

Material Compatibility:

Evaluate the types of materials you’ll be processing. If you need to handle a wide range of materials, including polymers, plastics, rubber compounds, and food ingredients, a Co-Rotating Twin Screw Extruder might be the better choice due to its versatility.

If your application involves shear-sensitive materials or delicate formulations, such as in food processing or pharmaceuticals, consider a Counter-Rotating Twin Screw Extruder for its gentle processing capabilities.

Processing Requirements:

Determine your processing needs, including mixing, compounding, degassing, or reactive processing. Co-Rotating Extruders excel in intensive mixing and compounding applications, making them suitable for industries like polymer processing and compounding.

If your priority is to achieve excellent degassing or reduce residual stress in materials, a Counter-Rotating Extruder might be more suitable, especially for applications requiring high-quality, shear-sensitive products.

Throughput and Production Rate:

Consider your production volume requirements. Co-Rotating Twin Screw Extruders typically offer higher throughput rates and are well-suited for large-scale production operations.

If your production volume is smaller or your focus is on producing high-quality, specialized products, a Counter-Rotating Twin Screw Extruder may be sufficient, even if it has slightly lower throughput rates.

Product Quality and Integrity:

Assess the importance of product quality and integrity for your application. Co-Rotating Extruders are known for their ability to provide consistent product quality through intensive mixing and precise control over processing parameters.

If maintaining product integrity, avoiding material degradation, or ensuring purity is critical, Counter-Rotating Extruders, with their gentle processing capabilities, may be the better choice.

Budget and Space Constraints:

Consider your budget and available space for the extrusion equipment. Co-Rotating Twin Screw Extruders are typically larger and may require more investment and floor space.

Counter-Rotating Twin Screw Extruders are often more compact and may be more cost-effective for smaller-scale production or applications with space limitations.

By carefully evaluating these factors based on your specific requirements and production goals, you can make an informed decision when choosing between Co-Rotating and Counter-Rotating Twin Screw Extruders for your extrusion processes.



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