Screw Barrel Guide: Types, Applications, and Specifications

Zhejiang Guangming Plastics Machinery Co., Ltd. (Guangyou Screw) is a leading manufacturer of high-precision barrels and screws for plastics and rubber machinery, established in 1992 with over 30 years of experience. The company operates a 100,000 m² smart facility employing about 800 staff, including an R&D team of 25 engineers, and produces approximately 32,000 units annually. Major markets include the EU, with export business accounting for 30% of total sales.

What Is a Screw Barrel and Why Does It Matter?

A screw barrel is the core component of plasticizing and extrusion systems in injection molding machines, extruders, and rubber processing equipment. It consists of a rotating screw inside a stationary barrel that conveys, melts, mixes, and pressurizes materials. Choosing the wrong screw barrel type — or one with inadequate wear resistance — can reduce output, degrade product quality, and shorten service life.

Industry Background

The global plastic processing machinery market reached USD 25.9 billion in 2025, with injection molding machines accounting for 50.9% of the market share (Grand View Research). Single-screw extrusion machinery dominates the extrusion market with approximately 62% market share as of 2024 (Fortune Business Insights). The feed screw barrel market is projected to grow from USD 1.89 billion in 2024 to USD 3.33 billion by 2034 at a CAGR of 5.8% (Global Insight Services). This growth underscores the need for reliable, precision-engineered screw barrels that can handle diverse materials and operating conditions.

Guangyou Screw Barrel Product Portfolio

Guangyou Screw offers five main screw barrel categories, each engineered for specific applications and material systems.

1. Single Screw Extruder Screw and Barrel (Model Φ20-Φ500)

This product belongs to the film blowing/pipe extrusion category and is intended for plastics packaging and pipe manufacturing. It is available in materials including 38CrMoAl, D2, AISI316, and others. Key specifications: alloy depth 0.8-2.0 mm, alloy hardness HRC50-65, chromium-plating depth 0.025-0.10 mm, surface chromium-plating hardness after nitriding ≥900 HV, nitrided case depth 0.45-0.7 mm, nitrided hardness HV850-1000, hardness after hardening and tempering HB260-310, surface roughness Ra 0.4, screw straightness 0.015 mm, nitrided brittleness less than Grade 2.

2. Parallel Twin Screw Barrel (Model Φ45-Φ350)

This product is classified as Compounding & Pelletizing equipment and intended for the Plastic Recycling & Compounding industry. It is made of materials such as 38CrMoAl (1.8509), D2, and AISI316. Technical specifications: alloy depth 0.8-2.0 mm, alloy hardness HRC50-65, chromium-plating depth 0.025-0.10 mm, surface chromium-plating hardness after nitriding ≥900 HV, nitrided case depth 0.45-0.7 mm, nitrided hardness HV850-1000, hardness after hardening and tempering HB260-310, surface roughness Ra 0.4, screw straightness 0.015 mm.

3. Conical Twin Screw Barrel (Model Φ25/50-Φ185/340)

This product is a PVC extrusion product intended for the plastics machinery and construction materials industries. Available materials include 38CrMoAl (1.8509), D2, AISI316, as well as 31CrMoV9 (1.8519), Gr12MoV, and 9Cr18MoV. Technical specifications: alloy depth 0.8-2.0 mm, alloy hardness HRC50-65, chromium-plating depth 0.025-0.10 mm, surface chromium-plating hardness after nitriding ≥900 HV, nitrided case depth 0.45-0.7 mm, nitrided hardness HV850-1000, hardness after hardening and tempering HB260-310, surface roughness Ra 0.4, screw straightness 0.015 mm.

4. Injection Molding Machine Screw and Barrel (Model Φ20-Φ300)

This product belongs to the plastic injection molding category and is designed for use in automotive, electronics, and toy manufacturing. Available materials include 38CrMoAl, D2, AISI316, and others. Specifications: alloy depth 0.8-2.0 mm, alloy hardness HRC50-65, chromium-plating depth 0.025-0.10 mm, surface chromium-plating hardness after nitriding ≥900 HV, nitrided case depth 0.45-0.7 mm, nitrided hardness HV850-1000, hardness after hardening and tempering HB260-310, surface roughness Ra 0.4, screw straightness 0.015 mm, nitrided brittleness less than Grade 2.

5. Rubber Machine Screw and Barrel (Model Φ20-Φ650)

This product is a rubber extrusion component for the tire & rubber product manufacturing industry. Available materials include 38CrMoAl, D2, AISI316, and others. Specifications: alloy depth 0.8-2.0 mm, alloy hardness HRC50-65, chromium-plating depth 0.025-0.10 mm, surface chromium-plating hardness after nitriding ≥900 HV, nitrided case depth 0.45-0.7 mm, nitrided hardness HV850-1000, hardness after hardening and tempering HB260-310, surface roughness Ra 0.4, screw straightness 0.015 mm, nitrided brittleness less than Grade 2.

How to Choose the Right Screw Barrel for Your Process

Selection depends on the polymer material, the processing method, and the required throughput.

• PVC Extrusion (pipe, profile, sheet): Use a conical twin screw barrel. The counter-rotating design provides efficient PVC powder melting, high-shear plasticizing, and stable extrusion shaping. A bimetallic lining is recommended for high CaCO₃ filler content.
• Compounding & Pelletizing / Recycling: Use a parallel twin screw barrel for high mixing efficiency and good devolatilization.
• Film Blowing & Pipe Extrusion: Use a single screw extruder screw and barrel. It handles a wide range of thermoplastics with consistent output.
• Injection Molding (automotive, electronics, toys): Use an injection molding machine screw and barrel designed for precise shot control and fast plasticizing.
• Tire & Rubber Product Manufacturing: Use a rubber machine screw and barrel with extra wear resistance for high-viscosity rubber compounds.

Use Cases

PVC Pipe, Profile, and Sheet Extrusion

In continuous counter-rotating conical twin-screw extrusion, the conical twin screw barrel (model Φ25/50-Φ185/340) efficiently melts PVC powder with high shear plasticizing. Special requirements include high wear resistance, bimetallic lining for CaCO₃ high-filler processing, and nitrided finish.

Plastic Recycling & Compounding

The parallel twin screw barrel (Φ45-Φ350) excels in processing recycled materials, providing thorough mixing and controlled residence time for consistent pellet quality.

Automotive, Electronics, and Toy Injection Molding

The injection molding machine screw and barrel (Φ20-Φ300) delivers the precision and repeatability needed for complex molded parts in high-volume production.

Comparison of Guangyou Screw Barrel Types

Frequently Asked Questions

Conclusion

Selecting the right screw barrel is a critical decision that impacts production efficiency, product quality, and equipment longevity. Guangyou Screw provides a comprehensive range of precision-engineered single, twin, conical, injection, and rubber screw barrels backed by decades of manufacturing expertise and stringent quality control. Whether you need a nitrided or bimetallic solution, our team is ready to support your project from sample to volume production.