Bearing Failure Explained: Common Causes, Warning Signs, and Prevention

The importance of bearings cannot be overstated when it comes to industrial equipment. They provide support for rotating parts and allow for efficient motion under heavy loads. When a bearing fails however; it can quickly spread throughout an entire system.

Common effects of bearing failure include: excessive vibration, overheating, reduced efficiency, unpredictable downtime. In extreme circumstances, failure of a bearing can also have adverse effects on shafts, motors and other critical components.

According to SKF, most bearings last longer than the equipment they serve. Therefore, many premature failures are due to maintenance procedures and operating conditions, rather than the bearings themselves.

Improper Lubrication

One of the leading causes of bearing failure is lubrication. The purpose of lubrication is to decrease friction and manage heat generated from friction.

Industry research indicates that lubrication related issues were responsible for a large number of premature bearing failures. It was reported that in applications involving a wide range of operating conditions, lubrication related failures were estimated at 36% to 80%.

Too Little or too Much Lubrication

If there is too little lubrication, there will be a direct metal to metal contact between the rolling surfaces, increasing friction and wear. If there is too much lubrication, you get increased heat and pressure in the bearing housing. Using the incorrect type of lubricant for your application could make things worse.

Signs of Lubrication-Related Issues

There are numerous signs that point to lubrication-related issues, including:

• Operating temperatures have increased

• Grinding or squealing noises

• Discolored grease

• Increased vibration

• Premature wear patterns

It's recommended to perform routine lubrication checks along with checking manufacturer recommendations for long term reliability.

Contamination and Moisture

Bearing housings in industrial environments are often subjected to dust, dirt, debris and water. Once these contaminants enter the bearing housing, they can damage the rolling surfaces and break down the lubrication.

Common Sources of Contamination

Common contamination sources include:

• Airborne debris/dust

• Moisture intrusion into the bearing housing

• Damaged seals

• Poor quality lubricants

• Metal particles from nearby wear

• Damage to the rolling surfaces

How Contamination Damages Bearings

Once even small amounts of contaminants enter the bearing housing, abrasive wear will begin to occur. Additionally, moisture contamination may lead to corrosion and surface pitting within the bearing.

As contamination increases, lubrication becomes less effective which leads to increased heat, vibrations and potential premature failure.

Misalignment and Excess Load

Misaligned systems place uneven loads on both bearings and rotating system components. Over time, this additional stress increases friction, heat and vibration.

Causes of Misalignment

Common causes of misalignment include:

• Incorrect installation procedures

• Movement of foundations/structures under heavy loading conditions

• Strain due to pipe movement

• Thermal expansion

• Excessive vibration levels

Misalignment will create abnormal wear patterns such as: pitting, scoring, and surface fatigue on bearing raceways.

How Overloading Accelerates Wear

Bearings are designed to operate at specific loading limitations. Additional loading will place additional stress on the rolling elements and surfaces of the bearing which will increase the risk of fatigue failure and overheating.

Shock loads, increased production demand, and poor choice of bearings may all contribute to premature wear.

Early Warning Signs of Bearing Failure

Most bearing failures develop gradually rather than suddenly. Equipment usually has warning signs before complete failure occurs.

Warning Signs of bearing failure include:

• Grinding or humming noises while running

• Temperature changes while running

• Unnormally high vibration while running

• Burnt grease odor

• Decreased equipment performance

These symptoms usually indicate lubrication, contamination, alignment or excessive loading issues.

Visible Wear Patterns

Inspecting maintenance teams may see:

• Pitting on surfaces

• Scoring on surfaces

• Surface discoloration

• Grease leakage

• Metal shave around the housing

Visible wear pattern Signs can assist in detecting the root cause of bearing damage before full blast failure occurs.

Ways Millwrights Identify Problems With Bearings

Routine inspections and predictive maintenance practices help identify bearing issues early on to reduce the risk of unexpected downtime.

Methods used to monitor and inspect:

• Vibration analysis

• Thermal imaging technology

• Grease level inspections

• Alignment checks

• Temperature readings

These methods will assist in detecting developing problems before severe damage occurs allowing for repairs to be scheduled before productivity is affected.

Preventing Premature Bearing Failure

Most premature bearing failures can be prevented through use of good lubrication practices. Alignment practices, contamination control practices, and routine inspections.

Preventive Maintenance Best Practices

Follow suggested lubrication schedules:

• Keep contaminants out of bearing housings

• Check alignment regularly

• Monitor vibration trends

• Monitor temperature trends

• Replace damaged seal immediately

The Importance of Early Detection

Identification of bearing problems early on can help facilities:

• Reduce unplanned downtime

• Extend equipment life expectancy

• Improve reliability

• Lower repair costs

• Prevent secondary equipment damage

A proactive approach to maintenance not only helps Improve equipment performance but also helps reduce the cost of unexpected production interruptions.

Conclusion

Bearing failures are commonly linked to issues such as bad lubrication practices, contamination issues, misalignment issues, overload issues, and excessive heat. Left unaddressed these problems will reduce equipment reliability and create costly downtime.

Combining routine inspections, best practices for maintenance work, and early condition monitoring can help industrial facilities extend bearing life, improve equipment performance, and reduce the chance of unexpected breakdown events.