Jaw Crusher Maintenance and Key Considerations

It is common to see newly installed or recently serviced hammer crushers experiencing intense vibration during trial runs.

As a crushing equipment manufacturer, we outline the primary causes for this issue:

1. Incorrect Hammer Installation During Assembly: When turning hammers to use the opposite side or end, all hammers inside the crusher must be turned simultaneously. Failure to do so disrupts the rotor's balance, causing severe vibration during operation.

2. Weight Mismatch Exceeding 5 Grams Between Corresponding Hammer Sets: The solution is to adjust the hammer weights, ensuring the difference between any two corresponding sets is less than 5 grams.

3. Overly Tight Hammers Failing to Swing Freely: After shutdown, manually rotate the rotor to check. Find a way to ensure the hammers can swing freely.

4. Imbalance from Other Rotor Components: This requires a careful, individual inspection and rebalancing of all parts on the rotor.

5. Bent Main Shaft: The remedy is to straighten or replace the shaft.

6. Excessive Bearing Clearance or Damage: Typically, replacing the bearings with new ones is the only solution.

Crusher Manufacturer Insights: Design and Material Selection

• Jaw Plate Design: The fixed and movable jaw plates should be designed with the peaks of one plate facing the valleys of the other. This configuration applies both squeezing and bending forces to the material, making it easier to fracture.

• Plate Longevity & Symmetry:

  • For small and medium-sized crushers, jaw plates are often designed to be symmetrical top-to-bottom, allowing them to be inverted for use after the bottom half wears out.

  • For large jaw crushers, the jaw plates are designed as several interchangeable, symmetrical sections that can be rotated or swapped as they wear.

• Material Selection:

  • White Iron: This is a common choice due to its high hardness, good wear resistance, easy availability, and low cost. Its main drawbacks are brittleness, susceptibility to breakage, and a relatively short service life.

  • Manganese Steel (e.g., ZGMn13): For significantly extended service life, manganese steel with over 12% manganese is superior. While its initial hardness is modest (approx. 210 HB), manganese steel possesses excellent toughness and a crucial work-hardening property. Under repeated impact and pressure, its surface continuously hardens, leading to a long service life as it wears and hardens simultaneously. Cast manganese steel plates must undergo water toughening treatment – a process similar to quenching involving heating to 1,000-1,100°C followed by rapid water cooling. This stabilizes the microstructure, preventing undesirable phase changes during service. Although more expensive initially, ZGMn13 often proves more cost-effective overall due to its dramatically longer lifespan compared to white iron.