The Data from this Case Study comes from a Canadian Pulp & Paper Manufacturing Facility.

In Figure 1, (Pump DE) we can observe the ON-GUARD Configuration on this motor. A CONMONSENSE Sensor affixed to the Grease Line for the most accurate ultrasound readings, and a pressure gauge to monitor for blockages and other pressure related issues.

In Figure 2 (Pump, NDE), we can see the CONMONSENSE drilled and tapped into the side of the bearing housing. The grease line & pressure gauge are not shown in this picture as they’re on the other side of the bearing housing.

In response to the Suspected Bearing Failure, additional follow-up dynamic measurements were recorded using a LUBExpert. We can observe this dynamic data in Figure 4 where we can see the suspected bearing failure was proven correct. The fault frequency cursors indicate this bearing had a BPFO.

In response to the Suspected Bearing Failure, additional follow-up dynamic measurements were recorded using a LUBExpert. We can observe this dynamic data in Figure 4 where we can see the suspected bearing failure was proven correct. The fault frequency cursors indicate this bearing had a BPFO.

By continuously monitoring RMS (overall friction) values of a rotating asset, the ON-GUARD determined that the bearing on the Pumps NDE had a suspected failure.

Rather than blindly pump unnecessary grease into the asset, the maintenance and reliability team were alerted to conduct additional measurements. Their follow-up data acquisition confirmed the findings of the ON-GUARD. Maintenance was scheduled for this bearing during the next planned shutdown!

The ON-GUARD is an automated precision lubrication system designed to monitor friction levels of critical rotating production equipment and inject grease precisely as needed to ensure an optimal separation of surfaces.

The following Case Study looks at an ON-GUARD installation at an Automotive Manufacturing Facility located in Canada. The ON-GUARD was installed to monitor friction levels on two supply fans. The assets can be seen in Figure 1.

The ON-GUARD was installed on these assets roughly six months ago. This case focusses on a two-month snapshot of these assets. In Figure 2 we can observe the two-month trend of one of these fan bearings. In the two months, the ON-GUARD triggered nine greasing events when the asset surpassed its designated alarm threshold.

The Red Line represents the Alarm Threshold designated by the Condition Monitoring Team at this facility. The Yellow Line along the bottom of the trend graph displays Greasing Events and the Blue Trend Line represents the continuously monitored RMS Data, a representation of the friction inherent in this asset.

With the ON-GUARD, we can set a rule requiring the asset spend a certain amount of time in the alarm state before a Greasing Action is initiated. In doing so, we can avoid false positives, such as the two depicted in Figure 2.

We ask lubricant to do a lot for our rotating machinery; reduce friction, dissipate heat and provide a seal that protects against contamination. But after millions of pounding rotations, a lubricant’s additives are spent, therefore requiring replenishment.

By closely monitoring friction levels (The leading indicator for lubricant replenishment requirement), the ON-GUARD knows when to automatically and precisely inject a bearing with the exact amount of lubricant required to return it to optimal operating conditions. Thus saving maintenance and reliability teams expensive grease and precious time, all while providing continuous feedback on the condition of your most critical rotating machinery.

When taking the initial measurement as seen in Figure 1, the technician noticed lots of impacting listening through his headphones.

Examining the ultrasonic FFT closer in UAS3, we observe high energy levels which could indicate elevated friction and the need for lubrication. We can also see the repetitive impacting that was noticed by the technician while listening through their headphones.

In Figure 2, we observe the ultrasonic FFT after the grease injection. The energy levels have dropped significantly, which is an indicator that friction has decreased; however, we still see lots of repetitive impacting, most likely meaning the bearing is broken.

Using the Bearing Toolbox Ultrasound Fault Frequency Calculator, an add on to the UAS3 software, the technician was able to determine that this bearing had a ball pass frequency outer race defect. It will be monitored closely and replaced the next planned shutdown.

The Bearing Toolbox is a database made up of over 50,000 bearing references and fault frequencies. By matching rotational speed and bearing dimensions to the ultrasound emitted from a rotating asset, the Bearing Toolbox can determine different types of common bearing defects.

The additional analysis capabilities of utilizing ultrasound while replenishing grease to a bearing is what sets it apart from traditional time-based lubrication formulas.

Sure, adding a few shots of grease to this bearing would still have reduced friction and even improved the assets condition for a small duration of time, but what it won't do is fix the bearing fault. Without ultrasonically listening to the bearing or taking a closer look at the data in UAS3, the technician likely wouldn't have discovered this fault.

With any luck, the necessary parts for repair will be in stock, but that isn’t always the case. Seeing how most lubrication related failures are unplanned, there’s a chance repair parts won’t be on hand. The longer the downtime persists, the more money will be lost due to this failure that shouldn’t have happened in the first place.

At SDT Ultrasound Solutions, we take pride in the lubrication programs we’ve helped turn down the path of success. Through our training, technology, and services we’ve helped plant personnel across the globe grease millions of bearings right. After being turned down the path of bearing lubrication excellence you will notice several noticeable differences. The following are 6 signs your bearing lubrication program is on track.

1.  A Change in the Quantity of Bearing Lubricant Consumed

Maintenance departments track their grease consumption to monitor and control costs. A change in consumption is a sure sign that your bearing lubrication program is on the right track.

If your organization was prone to over-lubrication, there's a good chance grease consumption will drop. Bad procedures lead to bearings routinely receiving more lubricant than they're designed to handle. The excess ends up being pushed into the motor casing or purged onto the floor.

Over lubrication happens when re-greasing intervals are scheduled based on time instead of condition. Control lubrication tasks with ultrasound to monitor condition and maintain optimal friction. The time between greasing intervals increases, resulting in less grease used per bearing.

2.  Fewer Bearing Lubrication Related Failures

Do you track failures and perform root cause analysis? >

Organizations with optimized bearing lubrication programs experience fewer lube-related failures. Less fixing and firefighting translates to more creative time for maintenance. Use that time to bring more machines into the bearing lubrication program.

Additionally, with ultrasound you find many non-trendable defects. For example, broken or blocked grease pipes and incorrectly fitted grease paths prevent lubricant from reaching the bearing.

3.  Optimized MRO Spares Management

Your new and improved bearing lubrication program is delivering wins; better control of grease consumption, fewer failures, and more productivity for maintenance. Use this time to study trends and better manage your storeroom.

A decrease in bearing lubrication related failures should improve spares optimization. Share your ultrasonic lubrication data with your MRO Stores manager to create a plan to reduce the number of emergency parts on hand.

Since you're taking stock, why not shift some burden to your suppliers? Ask them to confirm your emergency parts against their own stock. If it can be supplied on the same day then it doesn't need to be on the balance sheet.

4.  Increased Number of Machines Monitored

One benefit of an effective lubrication program is time.

• Time allotted to monitoring machines instead of fixing them.
• Time allotted to correctly assessing the real needs for lubrication.
• Time to look at the big picture.

Take for instance, criticality assessment. Many lubrication programs begin with small steps. All the "A" critical machines receive priority, rightly so. But what about the rest? With more time to plan, organize, and schedule, the number of machines acoustically monitored for optimal lubrication increases in step with your greasing excellence.

5.  Save Time. Combine Acoustic Bearing Lubrication and Condition Monitoring.

You worked hard for these results. It's time to use your data for more than just bearing lubrication.

Acoustic lubrication is the proven method to ensure precise bearing lubrication. New technology from SDT, LUBExpert, combines the power of onboard lubrication guidance with Four Condition Indicators for bearing condition assessment.

The time savings from assessing bearing condition during the lubrication process is beyond valuable and another sign your acoustic bearing lubrication program is on the right track.

6.  Inspector Confidence at an All-Time High

Reliable machines are the product of an effective lubrication program. You have:

• Managed grease consumption
• Fewer grease related bearing failures
• Optimized MRO spares
• More machines under watch
• Increased data collection intervals

The power of adding ultrasound to your greasing program delivers win after win for reliability. Reliability breeds confidence. More confident inspectors making the right calls and inflecting a positive culture throughout the organization.

Are you ready to become a LUBExpert?

If you’ve noticed these 6 key indicators of a successful bearing lubrication program, then congratulations! Your lubrication program is on track, and you’re well on your way to becoming a LUBExpert!

Lubrication contamination occurs regardless of industry, geographic location, facility size, standard operating procedures, and the training and experience of the maintenance staff and lubrication techs on-site. And this is because there isn’t always that much that can be done to completely avoid lubrication contamination. All it takes is one particle of dust, dirt, or other debris to get entangled within your bearing lubricant, for its effects to deteriorate the asset’s reliability. This makes the margin of error for preventing lubrication contamination very small. However, there are steps that can be put in place to minimize the disastrous effects of bearing lubrication contamination. But first, let’s learn a little more about contamination.

What is Lubrication Contamination?

The definition of contamination: The presence of a constituent, impurity, or some other undesirable element that spoils, corrupts, infects, or makes unfit, a material, physical body, natural environment, workplace, etc.

In the case of bearing lubrication, these contaminants vary depending on industry. But they can mean dirt, dust, saw dust, metal shavings, chemicals, and even mixed grease types. When your lubricant becomes contaminated, it is no longer suitable for its purpose and it needs to be taken out of service to prevent severe damage to the asset and production is forced to shut down.

• Lubrication contamination can reduce the amount of time an asset is able to operate without maintenance from years to months… and in some cases weeks or days.
• Lubrication contamination can cause machinery bearings to seize up as the grease thickens and eventually hardens.
• Lubrication contamination can degrade lubrication pumps and metering systems.
• Lubrication contamination can scratch, wear and shave off pieces on metal bearings leading to faster and more unpredictable failures.

The bottom line is that lubrication contamination is bad… very bad. It costs manufacturers unplanned downtime, otherwise unnecessary repairs, and plenty of man hours. It creates headaches for lubrication technicians and maintenance staff in addition to the nuisance of cleaning contaminated bearing grease from bearings.

So, Who’s to Blame for Lubrication Contamination?

Well, to be frank, it is us… all of us! The lubrication technicians greasing bearings, the transport truck drivers delivering the lubricants from one facility to the next, the factory workers moving lubricants from shipping and receiving to the lubrication storage room, the facility policy makers not enforcing more stringent rules regarding facility cleanliness, the condition monitoring team for not detecting tell-tale signs of contaminated lubricant, the factory for not having the necessary condition monitoring program in place to discover a deteriorating asset before it reaches a critical stage, and the list goes on.

Lubrication contamination is caused by the operational environment in which the grease is transported, stored, and injected into bearings. Bearing lubrication can collect contaminants from airborne dust and dirt particles if its storage container isn’t sealed correctly. It can become contaminated from the leftover soap residue in and on the bearing housing, zerk fittings, and lubrication storage containers. And a major source of contaminated lubrication is the mixture of incompatible lubricants.

The Design, Installation, Potential for Failure, and Failure Curve (DIPF Curve) overviews the lifetime of an asset. One of the harsh truths that the DIPF curve reveals is that no amount of maintenance can save a poorly designed, and poorly installed asset from failing. This should also apply to bearing lubrication. But in many cases, a drum of grease isn’t considered an asset to maintenance and reliability professionals. And the job of lubrication technician isn’t regarded as a noble and prestigious title. It is typically given to the young, inexperienced, new person on the job.

To attain the maximum lubrication effectiveness, while minimizing the damage caused by contamination, maintenance professionals must first hold their inventory of grease to the same regard as other assets. Precision bearing lubrication is essential to maximising uptime and prolonging the life all assets. If contamination control is not part of your lubrication strategy, then you simply have not achieved a world-class lubrication program yet.

Filtering out Lubrication Contamination

By reading the above-mentioned ways your lubrication can become contaminated, you can draw your own conclusions as to how this risk can be mitigated. The first step is to consider lubricants as an asset.

After this, consider the design of your lubrication storeroom. Is it dirty, cluttered, unorganized, improperly labeled? Are the lubrication storage containers left open? Are the funnels used to fill the grease reservoirs cleaned after each use? Is it adequately climate controlled? These are all signs of a lubrication program lacking precision.

After realizing what is necessary, goals must be set accordingly, and a system put in place to measure these goals. And facility cleanliness should be at the top of this list. While in many industries such as pulp & paper and steel production, facility cleanliness isn’t always an option. Having a clean, dedicated lubrication storage room, and strict cleaning routines for tools used in the bearing grease replenishment process should be.

The next step should include the installation of sampling ports and an on-site particle counter, so that bearing lubrication samples can be taken very fast and easily and contaminated lubricants can be identified and disposed of.

Finally, every world-class lubrication program needs well trained lube techs. The job performed by lubrication technicians is vital to the reliability of a factory. A well-trained lube team will be better organized and have a better understanding about the necessity of eliminating lubrication contamination by doing the little things.

What You’ll Notice on the way to Achieving a World Class Lubrication Program

On your journey to achieving a world class lubrication program you will notice these tell-tale signs that you’re on the right track.

• A reduction in the amount of grease consumed
• Less unplanned, unwarranted bearing failures leading to costly downtime
• Less bearing purchases to keep storerooms stocked
• Less waste from contamination

To cap this off, we at SDT want to remind you to not be surprised if you don’t see immediate results. Transforming your lubrication program and eliminating bearing lubrication contamination doesn’t happen overnight. It requires patience and most of all, dedication and diligence. But the results will certainly be worth it.

If you wish to discuss this article with me please reach out to me at: Tristan.Rienstra@sdtultrasound.com

Source: Paul Llewellyn, Ultrasound… Beyond the Essentials, Lubrication Best Practices: It’s Not the Destination… It’s the Journey.

Our comprehensive body of knowledge is designed to help you Grease Bearings Right. Whether you are a Lube Tech, Lube Engineer, Lube Strategist, Reliability Engineer, or Reliability Leader, LUBExpert Essentials starts you on the journey to creating a world-class lubrication team.

LUBExpert Essentials™ is a two-part course consisting of 16 modules. In total, there are more than 20 hours of mentor-lead instruction, inter-modular quizzes, followed by an exam that, challenged successfully, awards you with your very own digital LUBExpert Essentials Badge.

While almost every plant in the world has rotating equipment and almost every maintenance technician is familiar with bearing grease replenishment, bearings are still a sadly misunderstood asset. Which is why as much as 80% of all bearings fail prematurely.

SDT Ultrasound Solutions has helped manufacturers across the globe properly grease millions of bearings through training, technology, and services. Throughout our journeys across the world trying to improve bearing reliability we’ve noticed these three common bearing greasing mistakes, and we want to share them with you.

Bearing Grease Replenishment Mistake 1: Calendar Base Greasing

Performing bearing grease replenishment once per week or once a month may seem like a sensible thing to do. After all, performing scheduled maintenance at regular periods is an age-old concept ingrained in each of us early on. Even OEMs still advise best practices based on time intervals to ensure maximum asset lifespan.

The problem with any blanket solution is that they ignore the effects of variables.

Two motors may be the same out of the box but end up in entirely different situations. While one lands in a hot and humid climate, another could be installed in a cold and arid climate. One may be used in a high-speed low load application while another at low speeds but with frequent starts and stops.

Bearings need grease for one reason only; to reduce friction. As long as the grease is performing that service well, there should be no need to change it. Yet we frequently do, with catastrophic results.

Replenishing bearing grease just because your calendar told you “time’s up!” is the first mistake. Monitor ultrasound friction and know when it’s the right time to grease

Bearing Grease Replenishment Mistake 2: Over and Under-Greasing your Bearings

The second mistake we should all avoid is adding too much, or not enough bearing grease. Too much grease builds up pressure pushing the rolling elements through the fluid film and against the outer race. Increased friction and temperature dramatically shorten your bearing’s life. Not enough grease will have the same life-shortening effect.

How do we know when just the right amount of grease has been added? Ultrasound of course. Listen to the bearing and measure the drop-in friction as the grease fills the bearing cavity. As the decibel level approaches normal baselines and stabilizes carefully slow the application of lubricant. Should the decibel level begin to increase slightly, STOP! The job is done.

Bearing Grease Replenishment Mistake 3: Relying on Subjective Bearing Data

Like any job there is a right way and a wrong way to do things. Simply listening to a bearing with an ultrasound device that gives no quantitative feedback is a recipe for disaster. The audible feedback is too subjective to draw any comparative conclusions. No two people hear the same and there is no way to remember what the bearing sounded like a month ago.

The third mistake is depending solely on subjective ultrasound data when precise quantifiable data is available. Always use an ultrasound instrument with digital decibel metering. Better still, use a device that provides multiple condition indicators. Max and Peak RMS decibel measurements indicate alarm levels and greasing intervals while Ultrasonic Crest Factor provides insight about the bearing condition in relation to its lubricant. Crest factors help us differentiate between bearings that need grease and bearings that need to be replaced.

Bearings produce less friction when they are properly greased. But how do we know?

• How can you be confident that friction forces are where they should be?
• How can you confidently apply just the right amount of grease to return friction levels to normal?
• How can you distinguish between a bearing that need grease and a bearing that is failing?

Ultrasound Helps!

Using an ultrasound measurement tool with digital decibel metering is a proven method for:

• Establishing a historical baseline for friction levels
• Monitoring changes in friction levels at regular intervals
• Triggering alarms when friction levels elevate
• Evaluating data to differentiate failure from friction

The basic concept of CBM (Condition Based Maintenance) is to monitor the condition (CM) of a machine over time and use conditional data to predict the need for maintenance to take action (PdM). Let’s apply this concept to a bearing grease replenishment task on a rolling element bearing

Using an SDT ultrasound instrument (simple or advanced), lube-techs collect data which indicates the current condition of the bearing. What are some of the Condition Indicators collected by SDT?

Simple “STATIC” Condition Indicators

Ultrasound STATIC data provides an instantaneous snapshot about bearing condition.

• RMS – The average of the ultrasound signal over the duration of the measurement time
• Max RMS – The highest RMS signal observed over the duration of the measurement time
• Peak – The highest amplitude observed over the duration of the measurement time
• Crest Factor – A linear ratio between the Peak and the RMS (CF=Peak/RMS)