Good lubrication practices can help cut a site’s energy consumption and, in the process, possibly turn lubrication personnel into corporate heroes.
By Ken Bannister, MEch Eng (UK) CMRP, MLE
If you want to assure a reasonable life span for mechanical equipment with rotational and/or sliding elements built into its design, you must lubricate it. The benefits of doing so, however, go well beyond the health of the lubricated equipment.
Virtually all machine designs facilitate some form of lubrication by incorporating one or more means of lubricating bearing surfaces. These solutions range from something as simple and austere as grease nipples at major bearing points to full-blown, centralized, automated re-circulating-oil systems. Regardless of the method/system, it’s incumbent on the end user to understand all of the benefits that can be achieved through effective lubrication practices, and the importance of implementing and adhering to a lubrication regime based not on OEM recommendations, but rather on ambient and machine operating conditions.
Arguably, of all the interactions that can be performed between a person and a machine, lubrication will be one of the least expensive and, collectively, will deliver the greatest impact on machine performance in terms of its life cycle, availability, reliability, production throughput, quality, energy use, and carbon footprint.
Stamping-press case study
The stamping press featured in this story is one of five 500-ton pure mechanical, straight-side presses at a site. The press stamps out automotive body pieces—requiring significant energy transfer.
This press employs an OEM-designed centralized box-cam-style automated recirculating-lubrication system that delivers a local re-refined (reclaimed) extreme-pressure (EP) 150 Gib and Way oil to rotating main and countershaft bearings and sliding surfaces. The system had not been calibrated since commissioning.
Energy is supplied by an electric variable-speed drive (VSD), and the press is used 12 shifts each week, for a total annual usage of 4,800 hr. Equipment monitors energy consumption over a 48-hr. period calculated an average use of 25.2 kW p/hr.
The press was observed under load with an infrared camera that showed lubrication delivery was unbalanced on the main and counterbalance shaft bearings. A 45 F temperature range between bearings indicated the need for immediate re-calibration of the lubrication system. The lubrication system also had numerous dirty filters. After the lubricant and filters were changed out, the press was restarted and the cam lubricators re-calibrated.
Back in production and monitored over another 48-hr. period, the stamping press showed a dramatic 18% reduction in energy consumption, i.e., with average usage at 20.5 kW p/hr.
Based on 4,800 running hr./yr. and a delivered energy price of 10 cents/kWhr the energy-reduction savings for one press was calculated as follows:
(25.2 x 4,800 x 0.1) – (20.5 x 4,800 x 0.1) = (12,096 – 9,840) = approx. $2,256 per press (or $11,280 for all five presses)
The energy savings of 112,800 kWhr was also calculated against the carbon footprint. Using the Carbon Trust calculation of 1 kWhr = 0.000537 emission tonne equivalency, this automotive manufacturer accrued a carbon credit of approximately 60 tonnes—for just its presses.
Additional accrued benefits from the lubrication program implementation included:
- reduced purchase costs through lubricant consolidation
- reduced lubricant and replacement bearing carry costs
- reduced lubricant stock rotation requirement
- increased inventory real estate
- reduced lubricant waste that could meet corporate environment and sustainability program mandates (ISO 14000 mandate).
Making engineered choices in lubricants, lubricant application devices/systems, and lubrication control will ensure that equipment delivers as designed, and, as an added bonus, help a site significantly cut its annual energy costs. The bottom line? A good-lubrication-practices program can front energy-waste-elimination efforts and be solely underwritten by the energy savings. MT
Contributing editor Ken Bannister is a Certified Maintenance and Reliability Professional and certified Machinery Lubrication Engineer (Canada). The author of Lubrication for Industry (Industrial Press, South Norwalk, CT) and the Lubrication Section of the 28th Edition of Machinery’s Handbook (Industrial Press), he can be reached at firstname.lastname@example.org.
Keeping a close eye on the life-blood of your lubricated equipment systems pays off in many ways, all of them crucial.
By Ken Bannister, MEch Eng (UK) CMRP, MLE, Contributing Editor
When a doctor wants to assess the condition of your health, he or she may order a blood test. Similarly, oil analysis, sometimes referred to as “wear-particle analysis,” is a mature condition-based maintenance approach used to determine the health of a machine and its lubricating oil. The process involves taking a small sample of oil from the equipment’s lubrication system, comparing it to a virgin stock sample through a series of laboratory tests, and examining the results to ascertain the “wellness” of machinery and oil.
Oil analysis reflects a highly effective and inexpensive means of deciding when to change lubricants based on condition; predicting incipient bearing failure so that appropriate action can be taken in a timely manner to avert failure; and diagnosing bearing failure should it occur. Yet, despite its availability and proven track record since the 1940s, oil analysis is still misunderstood and overlooked as a proactive strategy in many of today’s industrial plants. Relatively easy to set up, this type of program should be implemented in any facility that purchases, stores, dispenses, changes, uses, or recycles lubricants as part of its manufacturing or maintenance process.
Basic implementation steps
A successful oil-analysis program can pay for itself in a matter of weeks, given the fact that it delivers multiple benefits, including:
- oil change intervals (often extended) that are optimized to the machine’s ambient conditions and operational use requirements
- probable reduction in lubricant-inventory purchase costs and spent-lubricant disposal costs
- enhanced understanding of how bearings can fail (or are failing) in their operating environment so that such incidents can be controlled or eliminated
- increased asset reliability, availability, and production throughput.
(NOTE: The potential for program success is greater if a site already has a work-management approach in place, thereby assuring completion of corrective actions in a timely manner whenever oil-analysis reports recommend them.)
Similar to other successful change-management initiatives rolled out across the organization, an oil-analysis program will benefit from a piloted, phased implementation. Taking a stepped approach allows management and workforce alike to become accustomed to the new sampling and reporting processes and quickly iron out any problems prior to a full-scale launch.
Step 1: Appoint a program champion.
All programs require a “go to” decision-making person who advocates on the initiative’s behalf and is committed to making the implementation a success. The champion should be at a supervisor or manager level.
Step 2: Choose a suitable pilot area/machine.
Oil analysis begins with sampling the oil and can include lubricating and hydraulic fluids. Choosing a suitable program pilot will depend on the type of industry and business operation. Typical starting points to evaluate might include:
- critical product, process, line, or major piece of equipment, i.e., criticality determined by constraint and/or lack of back up, downtime costs, and product quality
- mechanical equipment with moving components that include lubricant reservoirs for re-circulating-oil-transmission systems that are mechanical and/or hydraulic in design.
Step 3: Conduct a lubricant audit.
A lubricant audit, required to identify what lubricants are currently employed in service at the plant, calls for the following:
- Check work-order system PM (preventive maintenance) job plans for lubricant specification(s).
- Check on or near the lubricant reservoir for lubricant identification labels or stickers.
- Check for matching MSDS (Material Safety Data Sheets).
If a discrepancy is found at this stage, outside assistance from a lubrication expert or supplier may be needed to determine if the correct lubricants are being specified for particular applications.
Step 4: Choose a laboratory.
Not all oil-analysis laboratories are created equal, making your choice of one an important step. Most oil-analysis reports are divided into four major sections that provide:
- sampling and virgin-oil specification data
- spectral-analysis testing results for wear elements identified as lubricant additives or contaminants
- additional physical test results for viscosity, water, glycol, fuel, soot, and acidity
- associated conclusions and recommendations.
Some laboratories specialize in engine-oil analyses that focus more on physical testing for water, glycol, fuel, and soot. Others specialize in industrial-sample analyses that focus more on wear-particle evaluations and some physical tests for viscosity, water, and acidity, and post-mortem testing for root-failure causes using ferrographic techniques. Some laboratories have technicians that specialize in both areas.
The key to any testing program is receiving results in a timely and consistent manner, especially where critical equipment is involved. When interviewing laboratories, be sure to rate their sample “turnaround” time and how they can assure testing consistency (usually through use of dedicated technicians to test your samples). Working with a laboratory should be viewed as a long-term relationship. The chosen facility will build and analyze your complete data history and make conclusions and recommendations based not only on your current sample versus its virgin sample counterpart, but also on an understanding of your plant ambient conditions and overall trending history of each sample.
Step 5: Set up a pilot sampling program.
A good laboratory will work with you to set up your sampling program, supply (in some way) sampling-point hardware, extraction pumps, and quality sample bottles, as well as train your staff to consistently collect “clean” oil samples.
The best oil samples contain maximum data density with minimum data disturbance—meaning the sample should best represent the oil’s condition and particulate levels as it flows through the system or as it sits in a reservoir. For example, if you extract a sample from the bottom of a reservoir in a non-pressurized gearbox lubrication system, the particulate fallout will be dense due to large wear particles and/or sludge accumulation and not correctly represent the remaining 80% to 90% of reservoir lubricant that actually lubricates the gears.
In a pressurized re-circulating lubrication system, samples are best taken as the machine is running and at operating temperature, from a live fluid zone where the lubricant is flowing freely. Whenever possible, the sample should be extracted from an elbow, thereby taking advantage of the data density caused by fluid turbulence. Sample points are best located downstream of the lubricated areas to catch any wear elements before they’re filtered out by inline pressure or gravity filters.
Virgin samples of all lubricants in the pilot program will need to be collected and sent to the laboratory for checking. They’ll be used as a benchmark for the laboratory to measure and understand what additive ingredients and lubricant condition represents a normal state. This type of benchmarking will lead to easier identification of additive depletion and wear elements in subsequent samples.
Outside assistance/training from a lubrication expert or oil-analysis laboratory is advisable when setting up the pilot sample points.
Step 6: Set up a work-management approach to sampling.
Lubricant sampling must be performed consistently, on a frequent basis—making it a suitable candidate for a maintenance/asset-management work-order system. Using the written sampling procedure as a job plan, the task can be set up effectively through PM scheduling software.
Extracting and sending a sample to the laboratory is only the first half of the oil-analysis process. Someone (usually the planner, if one exists) has to receive the results electronically by email, read the recommendations, and take any necessary corrective action and/or file the laboratory report electronically to history, usually as an attachment to the PM sampling work order. This will require development of a workflow procedure—and training all maintenance staff involved in the program on the procedure.
Step 8: Commence sampling and program roll-out.
An oil-analysis program will identify major contamination and wear problems with the first sample set. Sample trending can begin with the third set, wherein the site starts identifying/predicting any negative trend toward potential failure and schedule corrective action before failure occurs. Ideally, a pilot program should be allowed to run for approximately three months or longer to show basic results before tweaking it and rolling out to the next area within a plant.
Once a program is working and providing results, larger-sized enterprises may wish to consider investing in an in-house staffed laboratory that will deliver faster results turnaround. MT
Contributing editor Ken Bannister is a Certified Maintenance and Reliability Professional and certified Machinery Lubrication Engineer (Canada). He is the author of Lubrication for Industry (Industrial Press, South Norwalk, CT) and the Lubrication Section of the 28th Ed. of Machinery’s Handbook (Industrial Press). Contact him at email@example.com.
simatec Inc. (Charlotte, NC) refers to its recently launched simalube IMPULSE pressure booster (up to 145 psi) as “the perfect complement” to its 60-, 125-, and 250-ml simalube lubricators. An addition to the company’s portfolio of smart technologies, simalube IMPULSE is well suited for high-counterpressure applications and systems with long lubrication lines (up to 4 meters, or approximately 13 feet, in length.). The unit’s compact size allows installation in the smallest of spaces, in all positions, even underwater. As an IP68 protection class device, it’s dustproof, waterproof, and appropriate for use in a wide range of industries.
How It Works
According to the manufacturer, users simply affix the simalube IMPULSE to the selected lubrication point, screw on the required simalube lubricator and activate the unit for the desired dispensing time. The device starts operating as soon as a battery pack is inserted and the lubricator is attached. Continuous lubrication impulses of 0.5 ml supply the lubrication point with oil or grease up to NLGI 2 at a pressure of up to 10 bar. This action is gentle on the lubricant, as only the dosing volume is placed under pressure.
This simalube IMPULSE also continually signals its operating state. When the unit is properly installed, an LED indicator flashes green at regular intervals. Red flashes indicate overpressure, inactive, and empty conditions. Although dispensing intervals set by the lubricator may change, this intelligent pressure-boosting device will automatically adjust.
Maintainability and Service Life
During lubricator change-outs, the simalube IMPULSE stays firmly affixed to the lubrication point. The connection point remains sealed throughout the process, and no lubricant back-flow occurs. Equipped with a fresh battery pack after each lubricator change-out, the pressure-booster can be used multiple times (for 10 simalube 125 ml dispensing cycles or for up to three years).
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Learn the latest on the top five causes of failed motor bearings to help stop these problems in their tracks.
According to the bearing experts at SKF (Gothenburg, Sweden, and Lansdale, PA) these five damage mechanisms are the most common causes of motor-bearing failures. Understanding them as you examine a failed bearing can help you prevent their recurrence.
Electric erosion (arcing) can occur when a current passes from one ring to the other through the rolling elements of a bearing. While the extent of the damage depends on the amount of energy and its duration, the result is usually the same: pitting damage to the rolling elements and raceways, rapid degradation of the lubricant, and premature bearing failure. To prevent damage from electric-current passage, an electrically insulated bearing at the non-drive end is usually installed.
Inadequate lubrication and contamination
If the lubricant film between a bearing’s rolling elements and raceways is too thin due to inadequate viscosity or contamination, metal-to-metal contact occurs. Check first whether the appropriate lubricant is being used and that re-greasing intervals and quantity are sufficient for the application. If the lubricant contains contaminants, check the seals to determine whether they should be replaced or upgraded. In some cases, depending on the application, a lubricant with a higher viscosity may be needed to increase the oil-film thickness.
Damage from vibration
Motors transported without the rotor shaft held securely in place can be subjected to vibrations within the bearing clearance that could damage these components. Similarly, if a motor is at a standstill and subjected to external vibrations over a period of time, its bearings can also be damaged. To prevent these problems, secure the bearings during transport in the following manner: Lock the shaft axially using a flat steel bent in a U-shape, while carefully preloading the ball bearing at the non-drive end. Then radially lock the bearing at the drive end with a strap. In case of prolonged periods of standstill, turn the shaft from time to time.
Damage caused by improper installation and set-up
Common mistakes in installation include using a hammer or similar tool to mount a coupling half or belt pulley onto a shaft; misalignment; imbalance; excessive belt tension; and incorrect mounting resulting in overloading. To prevent these problems, use precision instruments such as shaft-alignment tools and vibration analyzers and other appropriate tools and methods when mounting bearings.
Insufficient bearing load Bearings always need to have a minimum load to function well. If they don’t, damage will appear as smearing on the rolling elements and raceways. To prevent these problems, be sure to apply a sufficiently large external load to the bearings. This is crucial with cylindrical roller bearings, since they are typically used to accommodate heavier loads. (This, however, does not apply to preloaded bearings.)
SKF is s a global supplier of bearings, seals, mechatronics, lubrication systems, and services that include technical support, maintenance and reliability services, and engineering consulting and training. For more information on motor bearings and other technologies and topics, visit skf.com.
Working together, an end user, an oil lab, and a reliability service provider improved an important predictive-maintenance technique and gained a wealth of reliability benefits.
By Jane Alexander, Managing Editor, with Kevin McGehee, Reliability Manager, Chemicals Div., Axiall Corp.
For years, the oil-sample analysis process was swimming in paper. Each sample was documented in its own analysis report, and all reports were emailed to the responsible plant employee. From a reliability perspective, questions remained: Was a work order generated? If not, why? What was found at the repair? Is this a repetitive problem? Did the corrective work order solve the problem?
Companies are finally starting to drop the spreadsheets and approach oil analysis from a more systematic, interactive perspective and, as a result, are increasing equipment reliability and performance.
U.S. chemicals manufacturer Axiall Corp., headquartered in Atlanta, is one example. Within just four years, the number of machines tested has tripled and is growing with help from cloud-based, automated systems for oil-analysis and reliability-information management.
Reliability-service providers and oil labs are also using browser-based systems to improve their oil-analysis processes. Acuren Group (Acuren), a Canadian-based supplier of asset reliability, nondestructive, and materials testing services in the U.S. and Canada, and Tampa-based R&G Laboratories (R&G), a full-service oil-analysis lab, are among those leveraging cloud technologies to better meet the needs of their customers. (Acuren is a division of Rockwood Service Corp., Greenwich, CT.)
All three companies recognize the crucial role of oil analysis in a predictive-maintenance (PdM) program and have succeeded in using the potential of the cloud to make oil analysis more timely, accurate, scalable, and visible. Their experiences and recommendations can help others optimize oil analysis.
Why analyze oil
Oil analysis is like blood work from a doctor. Axiall takes samples and looks for problems before they manifest into an emergency situation. Oil samples are relatively cheap compared with the cost or value of the equipment. If a machine is worth $700,000/day in profit, then it’s well worth taking an occasional $30 sample to keep it running.
Leading performance indicators such as ISO particle count or the contamination level in the lubricant can be considered a measure of the performance of the lubrication tasks. Viscosity or mismatched additives can be an early indication of cross contamination of lubricants. Alternatively, lagging performance indicators, such as the acidity of the lubricant, signs of wear, or progressing failures, signify existing problems.
Oil analysis complements other PdM methods such as vibration analysis, infrared thermography, and ultrasound. Sharing oil-sample data with a cloud-based reliability information system that tracks all PdM techniques enables better decisions from a more complete picture of asset health. When the reliability information is integrated with an existing computerized maintenance management system (CMMS), it further simplifies the execution and tracking of recommended actions.
Upgrading the process
At Axiall’s plant in Plaquemine, LA (near Baton Rouge), some machines hold 3,000 gal. of oil while others hold just 2 qt. Those most important to the business are monitored with oil analysis, regardless of their size.
The site’s prior oil-analysis approach was manual and inefficient. Oil samples were sent to a free service for testing, and Axiall’s analysts would later log into the service-provider’s system to view the findings. There was no follow-through and no one to call when questions arose. The new approach is more automated, interactive, and effective.
Now, preventive-maintenance work orders in the CMMS tell the plant to take oil samples at predetermined frequencies—usually quarterly. A trained technician takes and labels the samples and has them shipped to the lab. For the plant, the rest of the process is automated.
The lab runs the samples and performs analysis using standard limits that determine whether they are good or bad. It automatically populates the information in Oilography, a web-based oil-sample management solution used by the lab and the plant. That system, in turn, automatically updates Tango, the reliability information-management system used by the plant. Both are products of Louisville, TN-based 24/7 Systems.
Next, a plant engineer reviews each sample using a web browser and determines what actions, if any, need to be taken. If there is a question about a sample, the lab is called to discuss the findings and interpretation. The engineer’s recommendations are then entered in the reliability information-management system where they are tracked to completion.
Between the Samples Waiting Review screen, Integrated Condition Report, and metrics that show the number of assets in the oil-sampling program and percentages of samples that are good or bad, Axiall has a good understanding of equipment health and also where to concentrate efforts for improvement.
“The beauty of it is not having to enter anything; the results show up in the oil sample-management system,” explained Forrest Pardue, president of 24/7 Systems. “Having that system connected to the plant’s reliability information-management solution is an almost seamless method to create and track action items, and to force them to completion.”
R&G Laboratories uses the cloud to help its clients perform timely and accurate oil analysis without cumbersome paperwork. According to Cheryl Huff, R&G’s customer-service coordinator, “When samples are received from the customer, sample points are set up in our database and the assessments are posted online in Oilography. From there, the customer can access their records and take appropriate maintenance actions.”
Results are provided in the customer’s format of choice, whether online or through email, an interface with their CMMS, or some other preferred export format. “The lab’s oil analysis results can potentially feed into the customer’s failure-mode assessments, improving the visibility and quality of actionable information,” added Huff.
Bridging knowledge and communication gaps
Program success comes from understanding the equipment, the results of the oil analysis, and what to do about it. Unfortunately, managing PdM programs entirely in-house is often an unsustainable goal. To counter the situation, Acuren Group provides fully trained and equipped PdM technicians who translate test results into meaningful maintenance actions to its clients across North America. Moving to the cloud has streamlined the company’s service delivery.
“Our recommendations are entered in Tango alongside the results from other technologies. They flow directly to the CMMS used by our clients in the form of work requests, which are then planned and executed,” noted Wesley Albert, senior reliability engineer at Acuren Group. “By interpreting the results of all PdM technologies in a holistic manner, we are able to pinpoint issues and their severity.”
The specific test slate is determined by the asset’s criticality and type, as well as the goal of the testing. Improvements to the lubrication systems include the addition of proper filtration, desiccant breathers, and external filtering to achieve particle count targets.
Steps to oil-analysis optimization
Integrating oil-sample management, reliability information management, and the CMMS puts plant professionals, oil labs, and reliability service providers on the same page. Online visibility, dynamic interactivity, and instant information updates improve the availability and quality of actionable information and assure completion of recommended actions. Combining that platform with the following recommendations optimizes program results:
Educate the masses. Companies beginning or improving an oil-analysis program should start with a fairly broad lubrication-training program for anyone who touches the oil and grease. Everyone needs to understand the importance of oil and oil analysis, that it’s worth a lot of money to the company, and that machines don’t run without proper lubrication.
Training should include how wear works, how particle contamination works, how important it is to keep it the oil clean and dry, and how all of that impacts the machine. It should also include the different places where someone can make a mistake or contaminate oil, and how that will lead to reduced machine life. Ultimately, it should encourage more attention to oil-related practices. For instance, an operator on shift may rethink storing an oil container outside near a machine if rainwater is getting into it.
Be selective and precise in sampling. Albert suggests beginning with a small number of the most critical assets and those with the largest volumes of oil, and aligning the test slates and sample frequencies with the asset-maintenance strategies. Label the sample location points with the equipment/component identifier, oil brand/type/viscosity, sample type, sample volume, and purge volume. Then, perfect the process on these assets before expanding the program to include others.
The most important thing is not to start “too big.” As R&G’s Huff put it, “A company that wants to begin oil analysis on 400 components might not have planned how to handle the lab’s analysis on 400 samples. “If it pulls too many samples at once and doesn’t have enough time to make the necessary system improvements,” she said, “we’ll repeatedly get samples rated critical and severe, and the client will be throwing its money out the window.” The better approach is to start out small in one section of the plant or in a problem area, make good decisions based on the analysis results, and grow from there.”
Fine-tune the sample frequency. Sampling frequency depends on the machine’s criticality. Quarterly is most common at Axiall, but samples are taken monthly on extremely important machines, such as those that could shut the entire complex down if they failed.
More-frequent sampling provides more resolution when trending the condition of the oil and detecting problems when they occur. For instance, if someone inadvertently adds the wrong oil to a machine, with monthly sampling, a step change in the properties will be visible so questions can be asked and actions can be taken before there is unintended machine wear. Quarterly sampling is probably too late to catch an issue such as this.
Optimal sampling regularity reduces the urgency of problems, i.e., being proactive vs. reactive. Don’t wait until a machine is behaving erratically and then take a sample to send to the lab. Companies should routinely take and send oil samples and monitor the trends to see when a problem is coming.
Focus on continuous improvement. Pardue stated that using web-based systems to integrate oil-sample analysis and other PdM technology is a best-practice type of approach. “Cloud systems allow labs, contractors, plant teams, planners, and managers to all have access to the reliability system and its centralized dashboards of condition problems and statuses, enabling continuous improvement.”
It’s important to review the status of work orders with plant production areas weekly—and to hold people accountable for completing the work. Get to the root cause of failure by aggregating all problems into equipment and fault types and looking for patterns that provide opportunities to improve the lubrication program.
For example, if consecutive oil samples indicate that water is getting into a machine during normal operations, then better seals or machine-cleaning procedures should be applied. If most oil samples sent to a lab come back either too wet or too dirty, then a persistent systemic problem with the facility’s lubrication process needs to be isolated and improved.
Finding and controlling contamination is probably the most important step in an oil-analysis program, but, too often, it lags in priority, according to Huff. She believes companies that look at contamination control on the front end will usually have a more successful oil program.
“A sample rated severe could have an equipment condition, such as a failed bearing,” she said, “but frequently it’s a water condition or high particle count that takes the life out of the component and contributes to premature failure.” The bottom line is that an operation can’t get the estimated life span out of a component without having clean oil running through the system.
For Axiall, the overall oil-analysis program itself is also a candidate for continuous improvement. The site is working to achieve a higher level of maturity with its program.
Eventually, between 1,000 and 1,500 total machines will be on the oil-sampling route. The plant is also increasing utilization of its systems. As time permits, it is setting up customized high/low limits for individual machines in the oil sample-management system so it can automatically alert to problems. MT
Based in Plaquemine, LA, Kevin McGehee is reliability manager of the Chemicals Div. of Axiall Corp. He has spent 20 years in industry, working in the areas of capital-project management, maintenance, six sigma continuous improvement, and reliability.
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The actions of personnel can either lead to great success in lubrication programs or, as this case study shows, to costly calamity.
By Ken Bannister, MEch Eng (UK), CMRP, MLE, Contributing Editor
Winston Churchill wrote, “Responsibility is the price of greatness.” These words have special meaning for those of us in the lubrication field.
In organizations that seek to become great, all personnel must understand the negative upstream and/or downstream impact that their individual actions could have should they neglect to effectively and efficiently fulfill their roles. This is especially true of lubrication team members, who, through daily interaction with machinery and moving parts, are directly responsible for the successful lubrication of equipment in their charge—as well as for any consequences resulting from their activities. Their failures will manifest directly in the loss of equipment availability, reliability, and life-cycle longevity, and indirectly through production yield and quality losses.
A case in point
My look into the oil and grease purchasing patterns of a major North American automotive-assembly manufacturer during a lubrication-operations effectiveness review (LOER) was a real eye opener. I was astounded by the many tens of thousands of dollars per month the corporation was spending on just one type of chain-lubricant oil.
This automatic-chain-lubricator oil was a name brand, premium-quality, molybdenum disulphide, high-temperature formulation. Designed specifically to lubricate power- and free-conveyor chain pins and bearings passing through the types of high-temperature paint-bake ovens found in automobile assembly lines, it was an ideal match for the application. So, given those facts, why was the facility using so much of the product for just four conveyor-lubricator systems? Moreover, why had the lubrication staff or the lubricant supplier neither noticed nor brought to management’s attention the systems’ dramatic (more than 10-fold) increase in lubricant consumption over the past two years?
Further investigation revealed that the chain-oil consumption increase had coincided with the hiring of a new lubrication technician. The PM (preventive maintenance) job plan and frequency for checking and filling the automated lubricator reservoirs, though, had remained unchanged—from the time the devices were installed and commissioned more than three years prior. This discovery prompted a physical investigation of the four lubricators themselves. The findings were more than surprising!
The four lubricators were a popular, highly reliable brand. Low-tech in design, they used a pneumatic pump-to-point-style pump connected to dynamic injectors that would “volley” or “shoot” a small fixed amount of oil into either the unshielded trolley rolling-element bearings or the chain-link pins that connected the trolleys.
All of the devices were in excellent condition—and still located where they had been originally installed—complete with reservoirs full of oil. Curiously, though, all had been shut off electrically at the breaker and their pneumatic air supplies had been shut off at the feed-line valves. As a result, all of these units were totally useless.
Investigators subsequently learned that the four original lubricators had been “replaced” further down the conveyor line by a makeshift gravity-lubrication system that featured 1-gal. paint cans clamped to the conveyor I-beam as oil reservoirs. Installed in the bottom of each can were two small cock valves fitted with copper lines dropping down to two commercial, adjustable oil-drip brushes that were very wet with lubricant—just like the over-lubricated conveyor chain and roller bearings they served.
Questioned about this state of affairs, the plant’s production and quality supervisors told a story of numerous paint-quality problems that, they believed, had been caused by lubricant over-spray. After complaining about the matter to the new lubricant technician, they said, the situation eventually seemed to improve, i.e., fewer quality incidents occurred.
When interviewed, the lubrication technician reported that upon assuming his new role he had received no formal training or direction other than to follow the instructions on the work orders and use common sense. Shortly after starting the job, because of the workload, he decided to ignore the automated lubricator PM work order and, instead, rely on the lubricator-reservoirs’ low-level lights as condition indicators for adding oil. After the first three months, all low-level indicators had activated, at which time the technician had correctly filled the reservoirs with the correct oil (or so he thought).
During later lubricant checks, however, the reservoirs appeared full, and didn’t seem to be dispensing oil at all. Consequently, after multiple unsuccessful attempts to alert his supervisor to the situation, the technician took it upon himself to exercise his personal version of common sense and engineer a new system. Thus was born the gravity system of paint cans and brushes—for which, incidentally, almost a year had been spent working out the settings so that oil wouldn’t drip off the conveyor on to the painted vehicles. (To his credit, the technician did show the new system to the lubricant supplier’s representative. Accordingly, after approving the design, the rep also began enjoying increased orders and commissions for his product.)
In the end, simple diagnostics performed on the automated chain-oil lubricators found the units to be in perfect working order. The reason they had failed to dispense lubricant? At some point, their oil levels had been allowed to drop so low that the injectors and pumps lost their prime. The devices simply needed to be re-primed.
As this case study shows, a few simple lapses in responsible behavior resulted in serious quality issues requiring many hundreds of thousands of dollars in vehicle repaint costs, many tens of thousands of dollars in excess lubricant costs, and overall reduced conveyor life due to ineffective lubrication practices.
Many readers might vote to place blame wholly on the lubricant technician for this calamity. In this story, though, he should only take partial blame: A millwright by trade, with no formal lubrication training, he had been placed in his position based solely on seniority. To exacerbate the situation, there were no specific priming instructions regarding the automated lubricators, either in the work-order job plan or on or near the units themselves.
Still, while the technician tried unsuccessfully, on several occasions, to notify his supervisor of the lubricator problem, he also chose to ignore the initial PM in favor of a different lubrication approach without performing a risk analysis. His McGyver-style paint-can fix could definitely be construed as irresponsible for a tradesperson. He should, at the very least, have tried to find an operations manual or learn more about the specific lubricators he was dealing with before condemning them so quickly and creating a bigger downstream problem.
Much of the blame, however, really belongs to the site’s supervisory personnel:
- the maintenance supervisor who irresponsibly did not adequately support his technician or notice the makeshift lubricators and/or the massive increases in his monthly lubricant spend
- the production supervisor who irresponsibly bypassed the maintenance supervisor in favor of speaking directly to the lubrication technician.
Final blame goes to the irresponsible actions of the lubricant supplier. From an ethical standpoint, its representative certainly should have discussed the massive increase in chain-oil consumption with the plant’s maintenance supervisor and/or the purchasing department.
Responsibility is born out of knowing what to do and when to do it. In the case of the four referenced automated chain lubricators, problems could have been prevented with:
- lubrication certification training
- clear workflow processes
- improved PM work-order job plans
- standardized operating procedures
- failure risk analysis on critical equipment
- improved inter- and intra-departmental communications.
To be sure, the lubrication technician in this story was out of his depth. With a little effort, however, the costly scenario that he created could have been avoided. MT
Lubrication expert Ken Bannister is principal consultant with EngTech Industries, Innerkip, Ontario. He is the author of Lubrication for Industry and the Lubrication Section of the 28th Edition of Machinery’s Handbook (both Industrial Press, South Norwalk, CT), contact him at firstname.lastname@example.org.
To realize maximum life from the gears and reducers in your plant, pay attention to their metallurgies and the operating viscosities of their lubricants.
By Neville Sachs, P.E.
In a typical facility, gears are usually the most common method of transmitting power and changing shaft speeds. Vast numbers of equipment systems, from cooling towers to paper machines, will rapidly grind to a halt if their gears aren’t kept in good condition. Gear hardness and lubricant viscosity are two factors in the health of these components.
Metal hardness concerns
Understanding gear hardness is an important first maintenance step. This is necessary because of the very different metallurgies commonly used in these components and their varying damage tolerances.
Case-hardened gears (also called surface-hardened gears) have an extremely hard outer layer over a tough, yet softer, core. This case is usually somewhere between 0.015 and 0.125-in. thick, and as hard as bearing steel. Because their cases are so hard, these types of gears have great wear resistance and should run for many years with no visible pitting.
On a case-hardened gear, any pitting you can see is cause for concern. If the load is strong enough to break down a gear’s hard case, the lifespan for the underlying metal is guaranteed to be shorter.
Through-hardened gears reflect the same hardness all the way through the tooth. Some are very soft steel; others are about as hard as a Grade 8 bolt. Although through-hardened gears aren’t anywhere near as hard as case-hardened types, and their hardness will vary based on application, they are designed to withstand significant wear. (Note: Sixty years ago, almost all North American gears, whether open designs, such as those found on a kiln, or enclosed designs, such as small reducers, were through hardened. Because of economics and market pressures, however, almost all enclosed reducer gears today are case hardened.)
In short, case-hardened gears should not show any wear, i.e., pitting. Through-hardened gears, however, can take a tremendous amount of wear before you need to begin worrying about failure.
How do you know whether a gear is case or through hardened? Perform a hardness test. No expensive equipment is required (although a good hardness tester is a valuable tool in a maintenance department). The procedure is simple.
If you don’t have a hardness tester, simply rub a file over the corner of a gear tooth:
- If the file skids across the tooth, the gear is case hardened.
- If the file cuts the tooth, the gear is through hardened.
(Note: You can skip this hardness test for enclosed reducers made in the past 20 years. Almost all of them incorporate case-hardened components.)
Prior to shutting gears down, measure the lubricant temperature while the components are running at close-to-the-peak loads—preferably on a hot day. Then, referring to a viscosity chart for that oil, determine if the actual operating viscosity meets the manufacturer’s specifications.
This test is crucial for enclosed reducers purchased in the past 20 years. It was during this time that suppliers began downsizing the casings and increasing the power density of these units. The result is that normal heat generated by the gear and seal action has been transmitted out to the environment through ever-smaller surfaces, leading, in turn, to reducers that tend to run hot. The presence of a thin layer of dust—a common occurrence in plants—acts as insulation, which can make the problem even worse.
Improved maintenance procedures
Hardness and lubricant viscosity are two key factors to consider in your inspections of gears and reducers. Tips for improving the maintenance of these components, which can vary somewhat based on specific type, will be discussed in future Maintenance + Reliability Center sections. MT
Neville Sachs has spent many years working in the field of machinery reliability and lubrication for a wide range of industries. The author of two books on failure analysis and a contributor of sections to others, he has also written more than 40 articles on these topics. A Registered Professional Engineer, Sachs holds STLE’s CLS certification, among others. Contact him at email@example.com.