Why Screw Barrel Need Repair

Screw barrel repair also can call screw barrel regeneration or screw barrel re-condition, it's a repair service applied on used screw barrels. Screw barrels can need repair for a variety of reasons, including but not all reasons:

1. Normal wear and tear: Due to the continuous use of the machine over time, the screw barrel will naturally erode and degrade, leading to reduced efficiency or performance.

2. Damage from foreign objects: If a foreign object enters the machine, it could damage the screw or barrel, causing a breakdown or malfunction.

3. Overheating or warping: High temperatures reaching the screw barrel can cause it to warp or become misshapen, which may require repair or replacement.

4. Corrosion: Chemical reactions between the materials used to make the screw barrels and the materials that are processed can result in corrosion, weakening the structure and leading to failure.

5. Poor maintenance: Lack of proper cleaning and maintenance over time can cause a buildup in the screw barrel, leading to clogs, leaks or reduced performance.

When Screw Barrel Need Repair

What are the indicators for screw barrel repair?

The screw barrel of a machine needs to be repaired when it shows signs of wear and tear, damage to the threads, and deformation. The indicators of a damaged screw barrel include decreased production efficiency, inconsistent extrusion, overheating of the barrel, lack of injection weight, back pressure increase, and increased energy consumption... In addition, if there is excessive wear on the flight, barrel bore, or thrust bearing, it is also an indication that the screw barrel needs to be repaired. Regular maintenance and inspection can help identify these indicators and prevent potential damage to the machine.

Does screw barrel necessary to repair

There are some certain reasons to repair a screw barrel instead of making a new one, and vice versa. When we consider if it's operatable to repair a screw barrel, we need to consider the operability and the economic cost when compare to make a new one. 

Screw Repair

Screw repair can normally be done by welding alloy on demage surface or chrome plating on surface. But it need decide by the size and wear situation. Before considering repair, we need to verify demage position, wear situation by actual measurement onsite to decide if it's need or too late to invervent. Screw can maintain original OD or increased size compare to nominal size. PTA welding on helical flight is proven of economic and good performance for screw repair, and depends on application plastics, there are several alloys can be choose to weld on flight. 

Barrel Repair

Barrel repair basically share same indicators for repair necessary. And there are some ways to repair barrels 

- Sleeve insert on screw sliding area, which is good way to maintain nominal diameter

- Sleeve insert on whole length, by increase barrel OD and make a hardened or casted liner inside, it's higher cost but with much better concentricity and no dead spot for material stuck

- Grind ID bigger and nitride the surface, by this screw need to make a new one with same increased sizes to match

Above all, we should take the cost into consideration when repair is in option. In most cases, repair an old screw barrel could be similar or higher than making a complete new set. Unless very urgent situation, then we suggest make a new one instead of regeneration old ones.