What Are Common Problems With Jaw Crushers?

Jaw crushers are primarily suited for crushing various ores and rocks of medium hardness or below. They find extensive application across industries including mining, metallurgy, building materials, railways, highways, water conservancy, and chemical engineering. When operating jaw crushers, it is imperative to adhere to relevant operational safety procedures. Regular maintenance and servicing of the equipment must be conducted, including the timely replacement of wear parts. This ensures the machinery operates normally, stably, and efficiently. Any malfunctions must be promptly diagnosed and rectified. This article details common issues with jaw crushers and their solutions.

What Are Common Problems With Jaw Crushers?

1. Increased Final Product Size

Cause: Severe wear on the lower crushing jaw plate enlarges the discharge opening. Typically, the lower jaw plate wears nearly three times faster than the upper plate.
Solution: If the jaw plates are symmetrical, rotate them 180° for continued use. If wear exceeds 30% of the original thickness, replace the jaw plates. Replacement of new tooth plates is required. Concurrently, the discharge opening must be adjusted. If wedge stones are used for adjustment, the opening should be reduced to the required size.

2. Feed Opening Blockage

Cause: This may result from excessive feeding or uneven material supply, causing blockage at the feed opening. Another scenario involves oversized material, which can readily cause blockage at the feed opening.
Solution: Control feed rates to prevent excessive single-batch loading. Adjust feeding methods; jaw crushers may be fitted with vibrating feeders to ensure uniform material supply. Pre-crush or screen oversized material to optimise crusher throughput. For high-hardness materials, consider replacing jaw plates and hammers with more wear-resistant alternatives.

3. Vibration and Internal Noise in Crushing Plates

Causes: Loosening of crushing chamber liners or gears. Loosening or fracture of fixing bolts.
Solutions: Immediately halt operation for maintenance. Tap the sidewall fixing wedges with a hammer to assess tightness. Tighten loose bolts; replace fractured bolts with Grade 8.8 high-strength bolts (e.g., M20 bolts).

4. Loose or damaged jaw plates

Causes: Loosening of jaw plate fixing bolts. This results in overall loosening of the jaw plates. Severe damage to the jaw plates prevents normal crushing operations.
Solutions: Regularly inspect the jaw plate fixing bolts of the jaw crusher. Tighten them to the specified torque. Tighten immediately if any looseness is detected. Simultaneously, periodically check the wear condition of the jaw plates. Replace them promptly if severe wear is observed. When replacing jaw plates, ensure selection of plates conforming to the specified dimensions and material grade. Follow the equipment manufacturer’s requirements for replacement.

5. Elbow Plate Fracture

Causes: Exceeding the jaw crusher’s rated power capacity or processing excessively hard materials may cause elbow plate fractures. Material defects during manufacturing or poor welding quality can also lead to fractures. Prolonged use and wear may reduce the elbow plate’s strength, ultimately resulting in breakage.
Solutions: Strictly adhere to the jaw crusher’s rated power requirements, never exceeding its design-specified power range. Select an appropriate crusher model and specification based on material hardness to ensure proper processing. For high-hardness materials, consider pre-treatment measures to reduce impact force on the crusher. Conduct regular inspections and maintenance to check jaw plates for damage or wear, repairing or replacing them promptly. Avoid excessive or improper usage to minimise damage to the elbow plate.

6. Impact noise from thrust plate support pads

Causes: Insufficient tension in tie rod springs or spring breakage. Wear on support pads. Support pad thickness reduced by over 2mm.
Solutions: Adjust spring compression; replace broken springs. Replace support pads when thickness exceeds limit, along with the thrust plate. This is critical for ensuring transmission stability in common equipment troubleshooting.

7. Bearing temperature exceeds 70°C

Causes: Insufficient lubrication or degraded oil quality (darkened, contaminated). Over-tight bearing assembly or excessively tight drive belt.
Solutions: For oil deficiency, replenish with Grade 45 anti-wear hydraulic oil to two-thirds of the oil gauge level. Replace oil entirely if degraded. Adjust assembly clearance if over-tight. For excessively tight belts, loosen the motor foot screws and adjust the belt tension. This is crucial in preventing component burnout during common troubleshooting for jaw crushers.

8. Sudden shutdown of the main unit

Causes: Blockage at the feed inlet causing chamber overload. Excessively loose drive V-belt causing slippage. Low voltage at the worksite. Bearing damage. Motor burnout or power cable breakage.
Solutions: First, clear obstructions from the discharge opening to ensure unimpeded material flow. Subsequently, inspect the tension and wear of the V-belt, making appropriate adjustments or replacing it promptly. Verify voltage stability or low voltage levels; rectify any deficiencies. Ageing power cables may cause voltage drops, necessitating replacement. A burnt-out motor requires repair or replacement.

Jaw Crusher

For further maintenance guidance on jaw crushers, please contact us. Common issues with jaw crushers are straightforward to address. Regular inspections and maintenance significantly reduce malfunctions, ensuring efficient and stable production line operation.