How to Know When It's Time to Replace the Twin Screw Extruder Barrel?

The barrel of a twin screw extruder is a key wear part that directly affects extrusion performance, mixing efficiency, and product quality. Replacing the barrel at the right time can prevent equipment failure and reduce overall production costs. So, how can you tell when the barrel needs to be replaced?

1. Increased Clearance Between Screw and Barrel

When the gap between the screw and the barrel increases beyond the standard value (typically 0.1–0.4 mm depending on size), the material seal is no longer tight. This can lead to pressure instability, poor plasticization, and material backflow.

2. Visible Inner Surface Wear

If the inner wall of the barrel shows significant wear, scratches, or even grooves, especially at the feeding and degassing zones, it indicates serious wear and reduced shear efficiency.

3. Decline in Product Quality

If you observe unstable extrusion output, inconsistent pellet size, or poor material dispersion, it may be a result of barrel wear that affects the mixing and conveying processes.

4. Frequent Overheating or Vibration

Abnormal temperature rises or mechanical vibrations during operation may be caused by uneven wear or misalignment in the barrel.

5. Maintenance Record and Service Life

Regularly track the operating time of the barrel. For standard nitrided steel barrels, the typical service life is around 12–18 months. For bimetallic or wear-resistant barrels, it can extend to 2–3 years. Once the expected lifespan is reached, a detailed inspection is recommended.

FAQ

Q: What’s the most common cause of barrel wear?
A: High filler content, glass fibers, corrosive additives, and poor material selection are major factors.

Q: Can I repair a worn barrel instead of replacing it?
A: For slight wear, inner surface grinding or re-lining may help. But for severe wear, replacement is more cost-effective.

Q: How to extend the service life of a barrel?
A: Choose the right material (e.g., ZHITIAN’s ZT715/ZT818 with carbide content up to 82%) and ensure proper cooling, lubrication, and maintenance.