The screw and barrel are the heart of an injection molding or extrusion machine. They directly influence melting quality, production efficiency, and final product performance. To choose the right components — whether for a new machine or a replacement — it’s essential to understand their type, structure, material, wear and corrosion resistance, and applicable plastics.

1. Types of Screws and Barrels

• General-Purpose Screw & Barrel
  Suitable for processing common plastics such as PP, PE, and PS.
• Specialized Screw & Barrel
  Designed for engineering plastics, PVC, PET, or high-filler materials.
• Bimetallic Barrel
  Features a wear- and corrosion-resistant alloy lining for longer service life.
• Custom Design
  Tailored for unique materials or specific machine configurations.

2. Structure of the Screw and Barrel

• Screw Zones
  1. Feed Zone – Receives and begins melting the raw material.
  2. Compression Zone – Applies pressure, ensuring proper melting and mixing.
  3. Metering Zone – Delivers consistent melt flow to the mold.
• Barrel Design
  Includes heaters, cooling channels, and precise inner diameter tolerances to match the screw perfectly.

3. Material Selection

• 38CrMoAlA Nitrided Steel – Cost-effective, good for general-purpose use.
• SKD61 / H13 Tool Steel – High strength, suitable for high-temperature applications.
• Bimetallic Alloy Lining – Exceptional wear and corrosion resistance, ideal for abrasive and corrosive materials.

4. Wear Resistance

Wear resistance is critical when processing glass fiber–reinforced plastics, mineral-filled resins, or other abrasive materials.

• Hardened tool steel and bimetallic barrels can extend service life by 2–3 times compared to standard nitrided steel.

5. Corrosion Resistance

For corrosive plastics such as PVC, fluoroplastics, or flame-retardant resins, corrosion protection is essential.

• Nickel-based alloys and chrome plating protect against chemical attack.
• Stainless steel offers high corrosion resistance but may have lower wear resistance.

6. Applicable Plastics

• PP, PE, PS – General-purpose screws and barrels are sufficient.
• PA, POM, PC, PET – Engineering plastics may require specialized screw designs.
• PVC – Needs corrosion-resistant materials and precise temperature control.
• Glass-filled Nylon – Demands high wear-resistant solutions.

Choosing the Right Combination

Selecting the best screw and barrel is about balancing material performance, wear resistance, corrosion resistance, and cost while ensuring compatibility with your machine model and processing needs. A trusted supplier can analyze your production requirements and recommend the optimal solution.

Your Partner for Precision Screw and Barrel Solutions

At Zhoushan Juyuan Machinery Co., Ltd., we manufacture a full range of customized screws and barrels for injection molding and extrusion machines, with:

• Options for general-purpose and special plastics
• Wear- and corrosion-resistant designs
• Fast delivery to customers worldwide
• Compatibility with major brands like Haitian, ENGEL, JSW, and KraussMaffei

📩 Contact us today for expert advice on selecting the right screw and barrel for your application:
Email: cxj.job@gmail.com
Phone/WhatsApp/WeChat: +86 13905808474
🌐 www.juyuan-machinery.com