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screw barrel
EJS Screw Barrels are core components of plastic extruders and injection molding machines. They efficiently process various plastic raw materials, transforming granular resins into a uniform melt and delivering it to the mold or die under stable pressure and temperature. Whether producing high-precision parts, plastic films, pipes, or profiles, EJS Screw Barrels ensure consistent quality and output.
Core Functions
| Function | Description |
|---|---|
| Feeding | Plastic pellets are drawn from the hopper into the barrel, and the screw starts conveying. |
| Compression & Melting | As the screw rotates, pellets are compressed by decreasing channel depth. Shear heat and barrel heaters melt the plastic completely. |
| Mixing & Homogenizing | Screw flight design ensures thorough mixing, uniform temperature, viscosity, and color. |
| Metering & Pumping | The screw end meters precise melt volume and generates pressure to push the material to the nozzle or die. |
Construction Materials
| Component | Standard Material | Premium / Special Options | Key Advantages |
|---|---|---|---|
| Screw | Nitrided 4140 Steel | Powder Metallurgy Steel (PM), Hastelloy, Bimetallic, Tungsten Carbide Coating | High wear resistance, excellent toughness, corrosion resistance |
| Barrel | Nitrided 4140 Steel Liner | Bimetallic Liner (Xaloy, Borealis), Ceramic Lined, Dual Alloy | Superior inner surface hardness, wear and adhesion resistance |
Technical Specifications
| Parameter | Description | Standard Range / Options |
|---|---|---|
| Screw Diameter (D) | Outer diameter of the screw | 20mm – 300mm+ |
| Length-to-Diameter Ratio (L/D) | Determines plasticizing capacity and mixing quality | 20:1, 24:1, 28:1, 32:1, 36:1, Custom |
| Compression Ratio (CR) | Ratio of flight depth in feed zone to metering zone | 2:1 – 3.5:1 (general purpose), material-specific designs available |
| Screw Design Type | Geometry tailored to material processing | General Purpose (GP), Mixing (Barrier, Maddock), Vented (Two-Stage), PVC (Conical, Low Shear) |
| Surface Hardness | Hardness of screw flight and barrel inner surface | Screw: 60-70 HRC |
| Clearance | Radial gap between screw flight and barrel wall | Precisely machined to 0.1% – 0.15% of diameter |
| Heating & Cooling | Compatible with machine heating/cooling layout | Customized per customer machine |
How to choose the right Screw Barrel?
There is no one-size-fits-all answer to choosing the right screw and barrel combination. The following factors should be considered:
Main processing material: Each plastic (such as Nylon, PET, PVC, LDPE, HIPS) has different melt characteristics, requiring different shear sensitivity and corrosion resistance.
Production and quality targets: Consider production output (kg/hr), mixing uniformity, and energy efficiency.
Equipment parameters: Clamping force, screw drive capacity, and motor torque of the existing injection molding/extrusion machine.
Final product type: High-precision parts, films, sheets, pipes, and profiles have different requirements for melt uniformity and pressure stability.
The EJS engineering team can analyze materials, production requirements, and machine types based on customer needs to recommend the optimal screw design, materials, and surface hardening solutions, ensuring high productivity, stable quality, and long service life, even under high-load production conditions.
Customization Services & CertificationsNo drawing? EJS can solve it on-site.
Customer provides a sample, old screw, or just process parameters.
On-site measurement (exclusive): Our technical engineers can travel to your factory for laser mapping, ensuring 100% fit with your existing machine.
Recommendation of compression ratio, L/D ratio, and surface hardness based on your material (Nylon, PET, PVC, etc.).
3D drawing confirmation → 5-axis CNC machining → Factory inspection.
Quality Certifications (Data available)
Material batch traceability report (38CrMoAla, 1.8550, Hastelloy, etc.)
Surface hardness test record (60-70 HRC)
Radial clearance inspection report (controlled to 0.1% – 0.15% of diameter)
Non-destructive testing report (ensuring no internal cracks in bimetallic products)
After-Sales Service & Shipping DetailsProfessional Packaging & Shipping
Anti-rust oil + VCI vapor phase anti-rust film wrapping.
Independent wooden case with anti-deformation support frame to prevent bending during long sea freight.
After-Sales Support
24-hour response: English-speaking sales + technical team responds via email/video call promptly.
Long-term spare parts support: For machines purchased 5 years ago, provide the serial number and we can retrieve historical drawings for reproduction.
Refurbishment service: Repair worn screws via hardfacing welding + recoating. Cost is only 40% of a new screw, with 95% performance recovery.
Main Export Markets
UK, Germany, France, Italy, Poland, USA, Brazil, Turkey, Russia, India, South Africa, and 30+ other countries across 6 continents. Door-to-door service available.
Exhibitions & Factory Strength
Global Professional Exhibitions
K Show (Germany) | NPE (USA) | ChinaPlas (China)
You are welcome to visit our booth for a face-to-face discussion with our technical engineers.
Factory Scale
40,000㎡ facility, 21 workshops, 400 full-time employees. Annual output of 30,500+ screw barrels.
Equipment: Imported CNC screw milling machines, automatic heat treatment lines, plasma spray welding equipment (for bimetallic/hardfacing coatings).
Finished product racks with ample inventory, supporting fast delivery.
Team
Experienced technical team available for on-site problem solving.
Foreign trade team receives daily training on screw barrel technology, ensuring zero miscommunication.
Why Choose EJS
Very competitive pricing due to structured production and "Made in China" efficiency.
Full product range: Single/Twin screw, Injection/Extrusion/Blow Molding/Rubber screws, Bimetallic, Gearboxes, Dies, Nozzles, and more.
Highly educated and skilled engineers.
On-site measurement service available (production possible even without a drawing).
Highest standard quality control based on international standards.
Fluent English-speaking sales team (daily technical training on screw barrels).
You are always welcome to visit our Ningbo office or Jintang factory.
We guarantee our products and service are the best you can find.
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