The extrusion process is a cornerstone of modern manufacturing, widely used across industries ranging from plastics and metals to food processing and pharmaceuticals. In plastics manufacturing, extrusion transforms raw polymer materials into continuous shapes — such as films, sheets, pipes, or pellets — through the application of heat, pressure, and shear.
Understanding the two main types of extrusion processes is essential for anyone involved in polymer production or recycling. These are the single screw extrusion process and the twin screw extrusion process. Each system has distinct mechanical designs, advantages, and ideal use cases depending on the material type and production goals.
At HONGQI, we specialize in both technologies through our Single Screw Plastic Pelletizing Extrusion Machine and Twin Screw Plastic Pelletizing Extrusion Machine. Both systems are engineered for exceptional efficiency, high output, and precision control — making them indispensable for recycling and compounding applications.
This article explores in depth how these two extrusion processes work, their differences, advantages, and the role each plays in modern plastic manufacturing.
Extrusion is a continuous forming process that converts solid polymer feedstock into uniform products by forcing the material through a shaped die under controlled heat and pressure.
The raw material — usually in the form of plastic granules, flakes, or powder — is fed into the extruder, where it is melted, mixed, and homogenized by rotating screws inside a heated barrel. The molten polymer is then pushed through a die to produce a continuous profile, which can later be cut, cooled, or pelletized.
Material Transformation: Converts raw or recycled plastic into usable shapes.
Homogenization: Ensures consistent blending of polymer and additives.
Continuous Production: Enables high-volume manufacturing with minimal waste.
Versatility: Supports diverse end products like films, sheets, pipes, and pellets.
While the basic principle is the same, the internal mechanics — especially the screw configuration — define how the material behaves during processing. That’s where single screw and twin screw extrusion differ significantly.
HONGQI’s advanced extruders utilize optimized screw geometry and precise temperature control to ensure smooth, energy-efficient operation and superior product uniformity, whether for basic recycling or complex compounding.
The single screw extrusion process uses one rotating screw housed within a heated barrel. It is the most common and straightforward extrusion system used in plastic pelletizing, film blowing, and pipe manufacturing.
Feeding: Plastic material enters the extruder through a hopper.
Melting: As the screw rotates, friction and heater bands soften and melt the material.
Conveying: The molten polymer is moved forward by the screw’s rotation.
Pressurizing: The screw compresses and homogenizes the melt before it reaches the die.
Extruding: The plastic exits the die in a continuous form, such as strands for pelletizing.
The screw is divided into three functional zones — feed, compression, and metering — each responsible for a specific stage of the material’s transformation.
HONGQI’s Single Screw Plastic Pelletizing Extrusion Machine is designed for maximum thermal stability and consistent output. Its high-torque motor, precision barrel design, and advanced heating zones ensure steady melting and efficient material flow even under continuous operation.
Simple structure and easy maintenance.
Excellent stability for processing uniform materials.
Lower energy consumption compared to complex systems.
Ideal for PE, PP, PS, and recycled plastics.
Cost-effective for small to medium-scale operations.
Single screw systems are perfect for general-purpose applications where mixing requirements are minimal and output consistency is the priority.
The twin screw extrusion process utilizes two intermeshing screws rotating within a barrel. It is primarily used in compounding, blending, and advanced polymer modification applications where mixing precision and high throughput are required.
Feeding: Material is fed through one or multiple hoppers into the barrel.
Melting and Mixing: The twin screws rotate either co-rotating (in the same direction) or counter-rotating, generating controlled shear and strong mixing forces.
Degassing: Volatile components, moisture, and gases are removed through venting ports.
Extruding: The homogenized melt is pushed through the die to form strands.
Pelletizing: The strands are cooled and cut into uniform pellets for further processing.
Intensive Mixing: Superior dispersion of fillers, colorants, and additives.
High Flexibility: Can handle multi-component formulations.
Effective Degassing: Removes air and moisture efficiently, ensuring stable pellets.
Process Customization: Modular screw design allows tuning of shear intensity and throughput.
HONGQI’s Twin Screw Plastic Pelletizing Extrusion Machine features co-rotating intermeshing screws that deliver high-performance compounding. With modular barrels and venting zones, it handles a wide range of polymers — from engineering plastics to filled composites — with exceptional precision.
Excellent for complex formulations and high-viscosity materials.
Ensures uniform blending and improved mechanical properties.
Suitable for producing color masterbatch, glass-filled materials, and engineering resins.
Offers higher production capacity than single screw systems.
For industries that demand high mixing performance and consistency, the twin screw process is the clear choice.
Though both processes share similar goals — melting, homogenizing, and extruding polymers — their design philosophies and processing outcomes differ substantially. The table below summarizes their core distinctions:
| Feature | Single Screw Extrusion | Twin Screw Extrusion |
|---|---|---|
| Number of Screws | One | Two (Co-rotating or Counter-rotating) |
| Mixing Capability | Moderate | Superior |
| Material Handling | Uniform materials | Multi-component blends |
| Degassing Efficiency | Limited | Excellent |
| Maintenance | Easier, fewer parts | More complex but versatile |
| Cost Efficiency | Lower initial cost | Higher output and flexibility |
| Best Applications | Recycling, regranulation | Compounding, modification |
In practical terms, single screw extruders are ideal for applications where consistency and simplicity are key, while twin screw extruders excel in scenarios requiring advanced mixing, venting, and dispersion.
At HONGQI, both systems are built with a shared focus on energy efficiency, easy operation, and superior material handling. Each line can be customized with different screw geometries, heating profiles, and automation levels depending on the user’s specific process requirements.
The choice between single and twin screw extrusion is largely determined by the intended application and material properties. Both systems are vital to the production of high-quality pellets that serve as raw materials for countless end products.
plastic recycling and regranulation.
Production of simple thermoplastic compounds.
Film and pipe extrusion.
General-purpose pelletizing lines.
Polymer modification and reinforcement.
Masterbatch and color compound manufacturing.
Filler and additive blending.
Engineering plastic compounding.
HONGQI extrusion systems are used in diverse industries, including automotive, packaging, electronics, and construction. Their reliability and adaptability make them an excellent choice for manufacturers who value both performance and sustainability.
Together, these two extrusion processes form the foundation of global polymer processing. They enable:
Continuous recycling of plastic waste into reusable pellets.
Precise formulation of custom materials with desired mechanical or aesthetic properties.
Efficient mass production with minimal energy consumption.
HONGQI’s technology supports both environmental goals and industrial productivity, helping clients transition toward more sustainable, circular manufacturing.
The two types of extrusion processes — single screw and twin screw — represent distinct approaches to achieving the same goal: transforming raw or recycled polymers into usable forms. The single screw process emphasizes simplicity, reliability, and efficiency for uniform materials, while the twin screw process offers advanced mixing, flexibility, and high throughput for complex formulations.
At HONGQI, we provide both solutions, each designed for maximum performance and adaptability. Our Single Screw Plastic Pelletizing Extrusion Machine and Twin Screw Plastic Pelletizing Extrusion Machine combine innovative engineering with intelligent control to meet the growing demands of the global plastics industry.
Explore our full range of extrusion systems at:
HONGQI continues to drive innovation in extrusion technology — ensuring that every pellet produced contributes to efficiency, quality, and a more sustainable future for plastics manufacturing.
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