What causes rapid wear on the throwing wheel and poor cleaning results?

Accelerated wear of the throwing wheel and poor cleaning performance are primarily caused by a disrupted shot trajectory (resulting in ineffective impacts) and improper operation of critical wear parts. These problems can generally be divided into the following four categories:

1. Installation or wear issues with the distributor bushing (most common cause)

Incorrect installation: Failure to calibrate the distributor bushing when replacing the blades or misalignment of the window relative to the direction of rotation (the standard angle is approximately 45°) result in scattered abrasive instead of directed ejection. As a result, a significant portion of the steel shot impacts the chamber liner rather than the workpiece, accelerating wear of the liner and the throwing wheel housing, simultaneously reducing cleaning efficiency.

Window wear: Increasing the width or deformation of the distributor bushing window increases the divergence angle of the jet, leading to dissipation of the impact energy. This leads to incomplete cleaning of certain areas and accelerates premature wear of mating components.

2. Defective blades and impellers

Uneven wear or partial replacement of blades: Blades worn more than a third of their thickness, chipped, or with uneven wear disrupt the dynamic balance of the impeller. This causes severe vibration, accelerating wear of the bearings and the throwing wheel structure. Replacing only one blade creates a mass imbalance, completely disrupting the jet structure, leading to fluctuations in the abrasive flow and the formation of "dead zones" during cleaning.

Excessive impeller clearances: Enlargement of the impeller's internal bore or cracks in its windows lead to uneven distribution of abrasive (e.g., excess flow through one channel while the others are empty) and jet deflection. This significantly reduces the impact force and concentrates the impact on specific points, accelerating localized wear.

3. Problems with abrasive circulation and feed

Poor abrasive quality: A high abrasive breakage rate (>15%), the presence of excessively fine particles, or contamination with dust and scale reduce the impact force, requiring longer processing times and indirectly increasing the load on the equipment. Broken abrasive can also clog the abrasive feed pipe, causing interruptions in the feed, leading to idle operation of the throwing wheel or uneven loading. Insufficient abrasive flow: Problems such as elevator belt slippage, clogged separator screen, or improper pneumatic valve adjustment can cause the throwing wheel motor current to drop below 90% of the rated value. This results in low abrasive feed rate and low cleaning speed; Furthermore, the lack of a cushioning medium causes "dry friction" of the blades, accelerating their wear.

4. Drive and mechanical transmission malfunctions

Insufficient rotation speed: Reduced engine power, V-belt slippage, or a frequency converter (FC) setting that is too low can cause the pellet ejection velocity to drop below 75 m/s. Insufficient kinetic energy impairs rust removal, requiring longer processing times and increasing overall wear.

Loose fasteners: Loose bolts on the throwing wheel housing or excessive gaps between the armor plates can cause mechanical resonance. This accelerates bearing damage and seal failure, leading to pellet leakage and increased wear of internal components.

Troubleshooting Tips: First, check the guide bushing installation angle and ensure the blades are replaced as a complete set. Monitor the throwing wheel's operating current to ensure it remains within 85–95% of the nominal value and regularly sift the abrasive to remove any foreign matter.