The screw and barrel are the core of every injection molding machine. Over time, even the best machines from brands like ENGEL, ARBURG, Haitian, and JSW will face wear and tear in their plasticizing units. Rather than immediately replacing worn parts, many factories opt for injection molding screw and barrel repair — a cost-effective way to restore performance and extend equipment life.
In this blog, we’ll explore when and how to repair your screw and barrel, what the process involves, and how to ensure long-term reliability.
Why Screw and Barrel Wear Happens
Injection molding machines operate under high temperatures, friction, and pressure. If you’re processing glass fiber-reinforced, flame-retardant, or corrosive materials like PVC, wear accelerates even faster.
📊 According to Plastics Technology (source), more than 50% of plasticizing inefficiencies are linked to excessive wear on the screw and barrel.
Typical signs of wear include:
- Inconsistent melt temperature
- Longer cycle times
- Decreased shot size accuracy
- Black specks or unmelted pellets in parts
- Measured screw-to-barrel clearance over 0.2 mm
Repair vs Replacement: Which Is Better?
While replacement offers a like-new solution, repair is often more cost-effective and faster, especially when the core material remains intact. Repairs may include:
🔧 Screw rebuilding – Hardfacing with wear-resistant alloys like Colmonoy
🔧 Barrel honing – Precision polishing to restore internal diameter
🔧 Relining – Inserting a bimetallic liner inside the barrel
🔧 Thread or flight re-cutting – Restores original geometry
Repair is highly recommended if:
- Wear is localized (e.g., only in feed or compression zones)
- You want to reduce downtime
- The screw or barrel has no structural cracks
Common Repair Materials and Coatings
The most used coatings and materials in screw and barrel repair include:
- Colmonoy 56/83: Excellent wear resistance, applied via PTA welding
- Tungsten carbide: For high-abrasion resins
- Bimetallic liners: Often nickel-based alloys inserted into barrels
📌 The Plastics Industry Association (SPI) states that relining a barrel can extend its service life by 200–300%, especially when processing glass-filled or corrosive polymers (source).
Which Brands Support Repair Solutions?
Top injection molding machine manufacturers recognize the value of professional repair:
- ENGEL – Offers screw rebuilding services through certified partners
- ARBURG – Encourages regular inspection and part refurbishment
- JSW – Recommends screw hardfacing for extended production cycles
- Haitian – Often works with third-party OEM suppliers for re-coating and relining
No matter the brand, regular maintenance and professional repair can restore like-new functionality without the cost of total replacement.
Where to Get Reliable Screw and Barrel Repair Services?
At Zhoushan Juyuan Machinery Co., Ltd., we provide screw and barrel repair solutions for injection molding machines of all types and sizes.
✅ Hardfacing with Colmonoy, tungsten, and other wear-resistant alloys
✅ Bimetallic relining services for all major barrel types
✅ Custom geometry restoration based on OEM specs
✅ Fast turnaround time and global support
🔗 Learn more about our Injection Molding Screw Barrel Products
🔗 Check our Single Screw Barrel Options
Final Tips for Extending Screw and Barrel Life
- Use resin-compatible screw designs
- Monitor wear every 6–12 months
- Avoid frequent cold starts and material contamination
- Choose bimetallic or hardened options for aggressive materials
Contact Us for Expert Repair Support
📞 Have a worn screw or barrel? Let’s fix it — fast.
📱 WhatsApp: +86 13905808474
📧 Email: cxj.job@gmail.com
🌐 Website: https://juyuan-machinery.com
We bring 20+ years of experience in screw and barrel manufacturing and repair to keep your injection molding machines running at their best.