In modern plastic extrusion and injection molding, a vented screw barrel plays a crucial role in ensuring product quality and production stability. Whether processing PVC, PE, PP, ABS, or other engineering plastics, removing moisture and volatile gases during extrusion is essential. This is exactly where the vented screw barrel shows its advantages.
What Is a Vented Screw Barrel?
A vented screw barrel (also known as a degassing screw barrel) is a type of extruder screw barrel equipped with a venting zone. It’s specially designed with two-stage compression — the first stage melts and conveys the material, while the second stage removes trapped moisture and air through an open vent. This ensures that the molten material becomes completely homogeneous and free of bubbles.
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Why Choose a Vented Screw Barrel?
During extrusion, raw plastic materials often contain small amounts of moisture, monomer residues, or other volatile components. If these are not effectively removed, the final product may show defects such as:
- Bubbles or voids inside the product
- Poor surface gloss
- Low mechanical strength
- Unstable extrusion pressure
A vented screw barrel helps solve all these issues by releasing gases at the venting port. The result is:
- Improved product quality (smooth surface, no bubbles)
- Higher extrusion stability
- Better mechanical properties
- Longer service life of downstream equipment
Applications of Vented Screw Barrel
Vented screw barrels are widely used in:
- PVC pipe and profile extrusion
- WPC (Wood Plastic Composite) production
- Masterbatch and color concentrate extrusion
- Film blowing lines
- Recycling granulation of wet materials
If you are dealing with recycled materials or hygroscopic plastics such as PA, PET, or PC, using a vented screw barrel will significantly enhance production stability and material quality.
Explore more twin screw barrel for PVC and WPC extrusion options designed by Zhoushan Juyuan Machinery.
How the Vented Screw Barrel Works
- Feeding Section – Plastic granules enter and begin to melt.
- Compression Section – Material is melted and homogenized under heat and pressure.
- Venting Section – The vent opening allows trapped gases and vapors to escape under vacuum or atmospheric pressure.
- Metering Section – The degassed, homogeneous melt is conveyed steadily to the die.
This multi-zone design ensures consistent extrusion output and product uniformity.
Quality and Manufacturing from Zhoushan Juyuan Machinery
At Zhoushan Juyuan Machinery Co., Ltd., we manufacture high-precision vented screw barrels using advanced CNC equipment and strict material selection.
- Material options: 38CrMoAlA, SKD61, or bimetallic alloy for extended wear and corrosion resistance
- Surface treatment: Nitriding, hard chrome plating, or bimetallic coating
- Customized design: We tailor venting depth, screw compression ratio, and L/D ratio according to your specific extrusion application
With over 20 years of experience, we have supplied vented screw barrels to customers across Europe, South America, Russia, and Southeast Asia — earning long-term partnerships based on consistent quality and on-time delivery.
Check our full range of screw and barrel products to find the ideal solution for your extrusion line.
Why Work with Us
- Fast delivery: 25–30 days for standard models
- Customization: Tailored solutions for each extruder type
- Global shipping: Reliable export packaging and logistics support
- Technical support: Experienced engineers to assist with installation and operation
If you are looking to upgrade your extruder with a vented screw barrel, or need technical consultation, we are here to help.
📩 Email: cxj.job@gmail.com
📱 Phone/WhatsApp/WeChat: +86 13905808474
🌐 Website: https://juyuan-machinery.com/
Zhoushan Juyuan Machinery Co., Ltd. – Your trusted vented screw barrel manufacturer for high-efficiency extrusion performance.