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Jaw Crusher: Functions, Common Problems, Troubleshooting, and Maintenance Guide

Dec 29, 2025

Introduction: Jaw Crusher as the Core of Primary Crushing Operations

In mining, quarrying, construction aggregate processing, and infrastructure projects, crushing is the first and most critical stage of material processing. As the primary crushing equipment at the front end of crushing lines, jaw crushers play a decisive role in overall production efficiency, operational stability, and downstream product quality.

With advantages such as a simple yet robust structure, large crushing ratio, and strong adaptability to high-hardness materials, jaw crushers are widely used to process granite, basalt, river stones, ores, and construction waste. Their performance directly affects the efficiency of secondary and tertiary crushers.

This article serves as a comprehensive technical and operational guide for quarry operators, mining engineers, and maintenance managers. It systematically explains jaw crusher functions, common operational problems, troubleshooting methods, and daily maintenance practices to help reduce downtime, control operating costs, and ensure long-term stable operation.

Jaw Crusher Functions and Working Principles

Role of Jaw Crushers in Crushing Production Lines

Jaw crushers mainly undertake the front-end primary crushing task in the crushing production line, receiving large-sized raw materials with a particle size of tens of centimeters or even more than one meter after mining, and crushing them to a particle size (usually 10-30 cm) that meets the feeding requirements of secondary crushing equipment through extrusion and shearing. Without the preliminary pretreatment of jaw crushers, subsequent equipment such as cone crushers and impact crushers cannot directly process large-sized materials, and the entire production line will be shut down.

Its application scenarios are extensive. Whether it is the initial processing of stone in quarries, ore crushing in mining, recycling and reuse of construction waste, or aggregate preparation in highway and railway construction, jaw crushers can stably play their role with strong adaptability.

Key Advantages of Jaw Crushers

The reason why jaw crushers can become the mainstream primary crushing equipment in the industry lies in three core advantages: first, simple and durable structure. Composed of core components such as a frame, movable jaw, fixed jaw, eccentric shaft, and flywheel, it has no complex transmission structure, can adapt to harsh working conditions such as high temperature, high dust, and high load in mines, and has low maintenance costs; second, excellent crushing performance. The crushing ratio can reach 4-6, the feed port design meets the feeding needs of large-sized materials, and the processing capacity ranges from several tons to hundreds of tons per hour, adapting to production lines of different capacity scales; third, flexible adjustment. The discharge particle size can be accurately controlled by adjusting the opening distance (discharge port) between the movable jaw and the fixed jaw, meeting the differentiated needs of different projects for aggregate particle size.

Core Components and Their Impact on Performance

The crushing function of jaw crushers relies on the coordinated operation of various core components, and the state of each component directly affects the crushing effect: the frame, as the equipment foundation, bears the huge impact force during the crushing process and must have sufficient rigidity; the movable jaw and fixed jaw are components directly in contact with materials, and the movable jaw is driven by the eccentric shaft to make reciprocating swings to achieve material extrusion and crushing, and the jaw plates (lining plates) on their surfaces are wearing parts; the eccentric shaft provides power support for the movable jaw, and the flywheel plays a role in balancing the speed and stabilizing operation; the toggle plate not only transmits power but also breaks when the equipment is overloaded, playing a safety protection role.

Among them, the wear or damage of wearing parts such as jaw plates and toggle plates will directly lead to reduced crushing efficiency, uneven discharge particle size, and even equipment fault shutdown, which are also high-frequency incentives for subsequent operational problems.

Common Jaw Crusher Problems and Causes

Core Component Problems

Toggle Plate Breakage

The toggle plate is the “safety weak point” of jaw crushers, and breakage occurs frequently. The core causes include: the discharge port is adjusted too small, resulting in the failure of materials in the crushing cavity to be discharged in time, causing internal congestion and overload; large-sized materials or iron blocks exceeding the equipment’s processing capacity are mixed during feeding, instantly increasing the impact force; there is a deviation in the installation of the toggle plate, leading to local stress concentration due to uneven force; the eccentric shaft is worn or deformed, driving the toggle plate to bear abnormal force; the toggle plate itself has poor material quality and insufficient wear resistance and compression resistance.

Jaw Plate Wear or Breakage

Jaw plates are in direct friction and extrusion with high-hardness materials, making them one of the fastest-wearing components. The main causes of abnormal wear or breakage are: the hardness of the processed materials exceeds the bearing range of the jaw plate material, such as using ordinary high manganese steel jaw plates to process ultra-hard materials such as basalt; uneven feeding leads to excessive local force on the jaw plates and local excessive wear; the fixing bolts of the jaw plates are loose, resulting in additional impact wear with materials during operation; insufficient lubrication increases the friction resistance between the jaw plates and materials, accelerating wear.

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Eccentric Shaft Wear or Bending

As the core component driving the operation of the movable jaw, the eccentric shaft will directly cause equipment shutdown if it fails. The causes of its wear or bending include: lubrication system failure, insufficient lubrication between the eccentric shaft and the bearing, resulting in increased friction and wear; the bearing is not replaced in time after damage, driving the eccentric shaft to run eccentrically, and long-term uneven force causing bending; the equipment works under overload for a long time, and the torque borne by the eccentric shaft exceeds the rated range; the material impact during feeding is too large, and the instantaneous impact force is transmitted to the eccentric shaft, causing deformation.

Bearing Failure

Bearings are responsible for supporting the operation of the eccentric shaft and are one of the wearing parts. The main causes of damage are: insufficient lubricating oil, blocked oil circuit, or inappropriate type of lubricating oil, leading to poor internal lubrication of the bearing and increased wear due to dry friction; dust and debris generated during the crushing process invade the bearing, causing wear and jamming; the bearing installation clearance is unreasonable, either too loose or too tight, which will affect the operation stability and accelerate damage; the equipment operates at high temperature for a long time, leading to the failure of bearing grease and increased wear.

Abnormal Operation Symptoms and Diagnosis

Excessive Vibration

Excessive vibration amplitude of the equipment during operation is mostly caused by the following reasons: loose fixing bolts of the equipment, including the fixing bolts between the frame and the ground and the connecting bolts of components, leading to displacement vibration during operation; excessive swing clearance of the movable jaw or damage to the buffer components, resulting in abnormal movement trajectory of the movable jaw; deformation of the eccentric shaft and damage to the bearing, driving the overall vibration of the equipment; uneven feeding leading to unbalanced internal force of the crushing cavity and vibration.

Abnormal Noise

The occurrence of harsh abnormal noises such as squeaking and impact sounds during operation requires timely investigation: loose components, such as loose fixing components such as jaw plates, flywheels, and pulleys, resulting in impact noise during operation; bearing damage, wear or jamming of internal balls, resulting in friction noise; insufficient tension or wear of the belt, resulting in slipping noise during operation; poor gear meshing, if the equipment adopts gear transmission, excessive wear or clearance of gears will cause meshing noise; material blockage in the crushing cavity, and abnormal noise caused by mutual extrusion and impact of materials.

Discharge Opening Adjustment Problems

The failure to adjust the discharge port smoothly or the instability after adjustment is caused by: wear of the adjustment mechanism, such as severe wear of the adjusting screw and nut, which cannot accurately control the opening size; blockage of debris and accumulated materials at the discharge port, hindering the adjustment action; failure of the hydraulic system of the hydraulic jaw crusher, such as oil cylinder leakage and hydraulic valve blockage, leading to insufficient adjustment power; in the gasket-type adjustment structure, the gasket is improperly installed, deformed, or damaged, affecting the adjustment accuracy.

Insufficient Capacity or Uneven Product Size

The core reasons for failure to reach the designed capacity or excessive fluctuation of discharge particle size are: uneven feeding, resulting in unstable load and reduced efficiency of the crushing cavity; severe wear of the jaw plate, insufficient flatness of the crushing surface, inability to effectively extrude materials, leading to uneven discharge particle size; unreasonable setting of the discharge port, too small leading to congestion, too large requiring secondary crushing, affecting capacity; blockage of the crushing cavity, poor material flow, restricting processing efficiency.

Auxiliary System and Other Problems

Lubrication System Failure:

The lubrication system is crucial for ensuring the smooth operation of the equipment. Common faults include: insufficient lubricating oil reserve, failure to supplement in time leading to insufficient oil supply at lubrication points; blocked oil circuit, dust and impurities accumulating at oil pipes and nozzles, hindering the circulation of lubricating oil; deterioration of lubricating oil, reduced lubricating performance after long-term use, failing to play an effective lubricating role, and accelerating component friction.

Electrical System Problems:

Electrical system faults are mostly manifested as failure to start the equipment and frequent tripping: wrong wiring or poor contact, leading to unsmooth circuit or unstable current; sensor faults, such as failure of temperature sensors and vibration sensors, unable to accurately monitor equipment status, triggering protection tripping; excessive motor load, excessive feeding or equipment jamming, leading to motor current exceeding the rated range, triggering overload protection; aging of electrical components, such as wear of contactors and relays, affecting the reliability of circuit control.

Material Jamming/Blockage:

Material jamming or blockage in the crushing cavity is mostly caused by improper operation or poor feeding control: the feeding particle size exceeds the rated feed port size of the equipment, and large-sized materials are stuck at the top of the crushing cavity; the feeding speed is too fast, and the crushing efficiency cannot match the feeding speed, leading to material accumulation; the material humidity is too high, which is easy to adhere to the inner wall of the crushing cavity and gradually form blockage; non-crushable foreign objects such as iron blocks and steel bars are mixed in, jamming the movable jaw and fixed jaw, resulting in failure to discharge materials.

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Jaw Crusher Troubleshooting and Repair Solutions

Solutions for Core Component Faults

Solutions for Toggle Plate Failure

After finding the toggle plate breakage, immediately shut down the machine and cut off the power supply, and clean up the residual materials in the crushing cavity; replace with a new toggle plate, selecting a toggle plate matching the equipment model and with qualified material (preferably wear-resistant alloy steel); check the state of the eccentric shaft, and repair or replace it synchronously if there is wear or deformation; adjust the discharge port to a reasonable size, strictly control the feeding particle size, and avoid re-overload; install the toggle plate standardized to ensure uniform force and no installation deviation.

Jaw Plate Maintenance and Optimization

For jaw plate wear, if the wear is slight, it can be turned over to extend the service life; if the wear is severe, it should be directly replaced, and jaw plates made of wear-resistant materials such as high manganese steel and bimetallic composite materials are preferred; fasten the fixing bolts of the jaw plates, replace the worn bolts and nuts if necessary, and install lock washers; optimize feeding management, control material hardness and particle size, feed evenly, and avoid excessive local force; strengthen lubrication, and properly apply grease to the contact end between the jaw plates and materials to reduce friction wear.

Repair of Eccentric Shaft and Bearings

When the eccentric shaft is slightly worn, it can be repaired by grinding and electroplating; if it is severely bent or worn, it should be directly replaced; after the bearing is damaged, disassemble the eccentric shaft and replace it with a bearing of the same model, and clean the dust and impurities in the bearing seat before replacement; adjust the bearing installation clearance to meet the equipment technical requirements; optimize the lubrication scheme, replace the suitable lubricating oil, clean the oil circuit, and ensure sufficient lubrication.

Investigation and Treatment of Abnormal Operation Problems

Investigation Steps for Abnormal Vibration/Noise

When the equipment vibrates abnormally, shut down the machine to check all fixing bolts, and fasten the bolts of the frame, movable jaw, flywheel and other components one by one; check the swing clearance of the movable jaw, replace the damaged buffer components, and adjust to a reasonable range; investigate the state of the eccentric shaft and bearing, and repair in time if there is a fault; optimize the feeding method to ensure uniform feeding and avoid unbalanced force.

For abnormal noise, investigate according to the principle of “from external to internal”: first check the belt tension, adjust or replace the worn belt; fasten loose components, and check whether the jaw plates, flywheels, etc. have loose impact; disassemble the bearing end cover, check the bearing state, and replace if damaged; clean the blocked materials in the crushing cavity, check the gear meshing condition, and adjust the gear clearance or replace the gear if necessary.

Solution for Difficulty in Adjusting the Discharge Port

For mechanically adjusted jaw crushers, disassemble the adjustment mechanism, grind or replace the worn screws and nuts, and clean the debris and accumulated materials in the adjustment part; for hydraulic jaw crushers, check the hydraulic system, repair the oil cylinder leakage problem, clean the blockages in the hydraulic valve and oil pipe, and supplement hydraulic oil; for gasket-type structures, replace the deformed and damaged gaskets, install the gaskets standardized according to the discharge requirements to ensure tight fitting and uniform force.

Optimization Measures for Capacity/Discharge Problems

To improve capacity and optimize discharge quality, measures should be taken from three aspects: feeding, components, and discharge: adopt an uniform feeding device to control the feeding speed and quantity, avoiding overload or no-load; replace the worn jaw plates, repair the flatness of the crushing surface, and ensure the crushing effect; reasonably adjust the discharge port according to production needs, avoiding being too large or too small; regularly clean the crushing cavity, optimize the material flow path, and install wear-resistant lining plates if necessary to reduce material adhesion.

Emergency Handling and Safety Precautions

Standardized Fault Shutdown Process

After finding equipment faults, immediately cut off the power supply, turn off the feeding device, and prohibit continuous feeding; after the equipment completely stops running, clean up the residual materials and foreign objects in the crushing cavity, and it is strictly prohibited to reach into or use tools to clean during equipment operation; investigate the cause of the fault, formulate a repair plan, conduct no-load test run first after repair, confirm no abnormality before resuming load operation, and prohibit starting the equipment with faults.

Operation and Maintenance Safety Protection

Operators must wear protective equipment such as safety helmets, gloves, and dust masks to avoid dust and debris damage; install iron removal devices at the equipment feed port to prevent foreign objects such as iron blocks from entering the crushing cavity; regularly check safety protection components such as guardrails and safety covers to ensure they are intact; during maintenance, hang a “No Closing” warning sign to avoid accidental startup by others.

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Jaw Crusher Maintenance and Daily Operation Guide

Preliminary Commissioning:

Pre-Commissioning Preparation Work

After the equipment is installed, three preparations should be made before commissioning: check the safety protection components to ensure the guardrails and safety covers are installed in place without loosening; investigate the power lines and terminals to ensure correct wiring, good contact, and reliable grounding; commission the lubrication system, add sufficient suitable lubricating oil, check whether the oil circuit is smooth, and whether the oil supply at lubrication points is normal.

Comprehensive Mechanical and Electrical Inspection

Check each fastener one by one, including the fixing bolts of jaw plates, eccentric shaft, flywheel, pulley and other components, to ensure no loosening; check the transmission system, whether the belt tension is appropriate, whether the gear meshing is smooth, and whether the chain is worn; investigate the electrical components, whether contactors, relays, sensors, etc. work normally, and whether the motor insulation performance meets the standard.

No-Load and Load Test Runs

First conduct a no-load test run, start the equipment to run for 30-60 minutes, monitor parameters such as eccentric shaft speed, bearing temperature, equipment vibration, and current to ensure they are within the normal range; after no-load is normal, conduct a load test run, gradually increase the feeding amount, check the crushing efficiency, discharge particle size, and equipment operation stability, adjust the discharge port to the design requirements synchronously, record various operation parameters, and form a test run account.

Daily Operation and Maintenance:

Regular Inspection to Find Hidden Dangers in Time

Establish a daily inspection system. Operators check the equipment appearance, fasteners, lubrication system, and electrical lines before starting, monitor vibration, noise, temperature and other states during operation, clean the crushing cavity after shutdown, and check the wear condition of wearing parts; conduct a comprehensive inspection once a week, focusing on key components such as the eccentric shaft, bearing, hydraulic system, and adjustment mechanism, and handle slight wear and loosening in time to avoid expanding small hidden dangers.

Scientific Lubrication to Extend Component Service Life

Formulate a lubrication management plan, replace the lubricating oil regularly according to the equipment manual, generally every 3-6 months, and shorten the replacement cycle under harsh working conditions; regularly clean the oil circuit, oil nozzle, and oil filter to remove dust and impurities, ensuring smooth circulation of lubricating oil; select suitable viscosity lubricating oil for different seasons, low viscosity lubricating oil in winter, and high viscosity lubricating oil in summer, avoiding the impact of temperature on lubrication effect.

Strict Feeding Control to Avoid Overload Risks

Screen materials before feeding, strictly control the material particle size, and prohibit materials exceeding the rated feed port size of the equipment from entering; control the material humidity, and dry in advance if the material humidity is too high to avoid adhesion and blockage; use an automatic feeder for uniform feeding, avoid too fast or too much manual feeding, ensure stable load of the crushing cavity, and install an iron removal device to remove foreign objects such as iron blocks and steel bars in materials in time.

Special Maintenance of Wearing Parts to Reduce Replacement Costs

Establish a maintenance account for wearing parts such as jaw plates, toggle plates, and lining plates, recording the wear condition and replacement time; regularly grind the jaw plates to repair slightly worn crushing surfaces and extend the service life; reserve a certain number of wearing parts, select original or high-quality matching parts, avoiding prolonged shutdown due to lack of parts during faults; when replacing wearing parts, check the associated components synchronously, such as checking the fixing bolts and buffer components when replacing jaw plates, to ensure standardized installation.

Long-Term Maintenance:

Formulate a hierarchical maintenance cycle according to the equipment operation time, clarifying the maintenance content of each cycle: daily maintenance, focusing on cleaning, inspection, and supplementing lubricating oil; weekly maintenance, fastening components, checking the transmission system, and cleaning the oil circuit; monthly maintenance, investigating bearings, eccentric shafts, hydraulic systems, and replacing severely worn small components; annual maintenance, conducting a comprehensive disassembly and inspection of the equipment, replacing aging components, correcting deformed structures, and performing anti-rust treatment on key components such as the frame and movable jaw.

Establish an equipment operation account, detailedly recording each fault condition, maintenance content, maintenance items, and operation parameters, optimizing the operation and maintenance plan through data analysis, strengthening preventive measures for high-frequency fault points, and improving the overall operation stability of the equipment.

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How to Choose the Right Jaw Crusher

Scientific Selection:

Improper selection is an important reason for frequent equipment faults and insufficient capacity. Accurate selection should be based on working conditions: select according to material properties. For processing ultra-hard materials such as granite and basalt, select heavy-duty jaw crushers with robust frames and wear-resistant jaw plate materials; for processing medium and low-hardness materials such as construction waste and limestone, light or medium-sized jaw crushers can be selected to balance cost and efficiency; select according to capacity requirements. Small production lines can use ordinary PE series jaw crushers, and large production lines use PEX series fine crushing jaw crushers or hydraulic jaw crushers to ensure matching processing capacity; pay attention to supplier strength, and prefer manufacturers with perfect after-sales service and timely spare parts supply to facilitate subsequent operation and maintenance support.

Technological Upgrade:

With the development of intelligence and environmental protection of mining machinery, old jaw crushers can optimize performance through technological upgrading: crushing cavity optimization, adopting deep-cavity crushing cavity design to increase material capacity, reduce blockage, and improve crushing efficiency; intelligent upgrading, installing remote monitoring systems and intelligent maintenance sensors to real-time monitor equipment vibration, temperature, current and other parameters, early warn faults, and realize remote operation and maintenance; environmental protection upgrading, installing dust collection devices and noise reduction facilities to reduce dust and noise pollution during crushing, meeting industry environmental protection standards; hydraulic system upgrading, upgrading ordinary mechanically adjusted jaw crushers to hydraulically adjusted ones to improve the adjustment accuracy and efficiency of the discharge port and add overload protection functions.

Conclusion

As the cornerstone of primary crushing systems, jaw crushers directly determine production efficiency, operating costs, and plant stability. Most operational problems originate from improper operation, inadequate maintenance, or incorrect equipment selection.

By adopting a prevention-first strategy, standardizing operation procedures, and implementing scientific maintenance practices, operators can significantly reduce downtime, extend equipment service life, and improve overall crushing efficiency.

With ongoing advancements in intelligent monitoring and environmental protection technologies, modern jaw crushers are evolving toward higher efficiency, greater stability, and greener operation—providing solid support for sustainable development in the mining and aggregate industries.