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 email@example.com.
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 firstname.lastname@example.org.
Moving out of the traditional ‘cradle-to-grave’ mode has significant benefits for your operations, and may already be a corporate must-do.
By Ken Bannister, MEch Eng (UK), CMRP, MLE, Contributing Editor
In the past, our cradle-to-grave life spans would have been divided into three distinct phases: birth and formative years, productive years, and end of life. Medical advances over the past two-plus decades, however, have been helping humans “live on” in others through post-mortem tissue and organ donations. This ability to repurpose/recycle ourselves has created a fourth stage of existence, allowing us to progress from a “cradle-to-grave” life cycle to a “cradle-to-cradle” (C2C) model.
Humans, though, still have little control over our conception, and as “finished products,” we are never perfect. Granted, with diligence, reasonable life-style choices, and attention to health and safety, people can be extremely productive for a long time. Our plants’ physical assets, including machinery and facilities, could be more so. With them, we can exercise control from concept through production, to disposal and beyond, through recycle or refurbishment.
Physical assets prior to the 1970s were typically “robust-built.” With design-load factors as high as 1.5, they were capable of absorbing significant abuse and overloading before failure occurred. Since that time, technological advances have led to more-complex designs and “purpose-built” assets loaded with on-board diagnostic capabilities. Today’s design approach enables most OEMs (original-equipment manufacturers) to realize improved reliability and efficiency with leaner (less built-in redundancy) design-load factors.
More recently, asset design and operating elements have been challenged to take into account not only an asset’s ambient operating conditions, but also its lifetime carbon-footprint impact. An asset’s carbon footprint reflects a C2C approach by factoring in lifetime consumable-resource use that includes energy (fuel), lubricants, and water, as well as the impact of materials used in the asset’s manufacture, effluent discharge from the production process, and how the asset and its components will be recycled/repurposed at the end of their lives. The emphasis on carbon footprint and how equipment is designed, operated, and disposed/recycled have moved operations from the cradle-to-grave-style approach of the past to today’s more environmentally sensitive and efficient C2C asset-management approach.
Key strategies and tactics to be addressed and employed when implementing C2C asset life-cycle management can be defined by five elements: design, operational, maintenance, performance, and disposal/recycle.
When asset designers or architects first put pen to paper (or hands to CAD programs) for new projects, they’re usually working toward an end-user specification. This specification is usually wrought through a combination of customer surveys and actual client specification requests (all based on the customers’ understanding of their requirements—be it good or bad) and the designer’s knowledge of engineering, maintenance, the production process, and typically encountered ambient-condition factors. When budget is also factored in, however, many designs can be highly compromised. If specifications are too vague, and the designer has little experience with maintenance and operation reliability needs, the end product may suffer from built-in redundancy, operational inefficiency, and reduced ability to ensure successful life-cycle management.
The more open designers are to collaborating with end-user engineering, production and, most important, maintenance staffs to build an asset specification and design, the more likely they are to achieve operational reliability, operability, and sustainability—all hallmarks of a successful design. Such thinking is already employed with great success in factories and production lines designed and built to manufacture a product for a specified contract and/or time period after which the line is dismantled and recycled. This approach dictates a very different design mindset that employs maintenance strategies and design elements to include:
Perimeter-based maintenance design. With this approach, an asset is designed to allow the maintainer or operator to perform basic preventive and diagnostic maintenance tasks while the equipment is running. The design includes setting up go/no-go gauging systems to view fluid levels; pressure/flow/temperature indicators; minor mechanical adjustments; filter change-outs; and data-collection-point arrangements for predictive maintenance (PdM) and oil sampling.
Engineered lubrication systems. As much as 70% of rotating-equipment failure is caused by ineffective lubrication systems and practices. Including an engineered centralized lubrication-delivery system with a reservoir that can be filled in a perimeter-based approach will effectively increase bearing and rotating equipment life by as much as three times. Use of engineered lubricants can not only extend lubricant change-out intervals and reduce their associated lubricant-disposal requirements, but also significantly reduce operational energy costs by as much as 18%.
Mistake-proofing (poke-yoke). Designing a device, mechanism, component, sub-assembly, or perishable tooling
system in a fail-safe manner—so it will only operate or go together one way and, for assembly or defect-detection purposes, that there is no confusion as to how the device is to be positioned or used—has been proven to reduce production errors, manufacturing defects, asset downtime, and MTTR (mean time to repair).
Technology choice. Asset designs that use unproven cutting-edge technology aren’t easily embraced in work environments—especially when the end user has standardized on one or two control-system manufacturers and computer-platforms/architectures. Using proven technology can better position users with regard to spare-parts management and training for operational and maintenance purposes. The decision to adopt new technology must be a wholesale, multi-departmental decision that helps build a life-cycle strategy for training on, using, and maintaining that technology.
The green machine. An asset’s conceptual and design phases are when its eventual disposal and environmental issues should be considered. Many forward-thinking corporations now mandate that all new equipment must be recyclable upon retirement.
Ideally, in a best-practice organization, maintenance works cooperatively with operations to drive continuous improvement initiatives such as RCM (reliability-centered maintenance), CBM (condition-based maintenance), 5S, and lean manufacturing, all of which are designed to maximize throughput and asset-life-cycle longevity. Collaboration in C2C asset management entails decision making in the following areas:
Operation within design specs. In the equipment’s design stage, operational specifications, such as production throughput and operational speeds, are determined. Each time the asset is operated beyond the design parameters, reliability is challenged and asset failure can be accelerated. Operations and maintenance must agree to operate within operational design limits.
Constraint recognition. Under the theory of constraints, an asset is designated either as a constraint bottleneck or a non-constraint. Bottleneck assets usually operate at maximum design throughput, whereas non-constraint assets will operate at a reduced rate of speed or intermittently due to their built-in redundancy. Recognizing constraints improves maintenance-scheduling requirements.
Autonomous operator maintenance. Both RCM and CBM recognize the value of autonomous operator maintenance. Through basic perimeter-based maintenance engineering and training, standardized routines, and checks can be performed by operations staff and allow maintenance to perform more complex and intensive tasks. Additional benefits include facilitation of operator asset ownership and improved communication between operations and maintenance.
Production-evidence data capture. Successful asset life-cycle management demands a forensic understanding of all equipment failure occurrences. Each time an asset is unavailable because of a forced stoppage or slowdown, the event is recorded and classified. These evidence data are then analyzed to determine the root cause and build asset-management decisions based on facts, not opinions.
Maintenance must work smart, not hard. Employing strategies and tactics that enhance maintenance effectiveness is paramount to maximizing asset effectiveness and longevity:
Reliability-based maintenance. A reliability approach to maintenance requires maintenance to understand which components are more likely to fail, how they will fail, and the consequence of their failure. Following an RCM approach, maintenance can choose a suitable approach to failure prediction and prevention, or decide to allow the component or assembly to run to failure and simply replace. Following RCM ensures maintenance does not cause downtime through ineffective overhaul strategies and preventive maintenance (PM) tactics.
Condition-based scheduling. Moving from a fixed PM/PdM schedule in which preventive/predictive work is scheduled on a fixed calendar or meter basis, to a condition-based approach—which schedules the work based on pre-set condition parameters—is a normal progression toward asset life-cycle management. Maintenance requirements are dependent upon ambient condition factors and how well an asset was assembled during its manufacture. PM/PdM that’s performed in a just-in-time (JIT) fashion is less taxing on maintenance resources and the production asset. Note that condition-based maintenance demands a disciplined, proactive maintenance-management approach that allows the immediate planning and scheduling of necessary repairs anytime a downtime-threatening event becomes evident.
Purchasing spare parts based on a life-cycle costing (LCC) model. Buying spare parts based on price alone has caused infinite grief and downtime in every organization. Buying spare parts based on quality and reliability first, then price, is mandatory in a life-cycle asset-management approach. Consider the following LCC example. Component A is priced at $100, and fails approximately every three years. Component B is priced at $50, and fails annually. If the maintenance cost of replacement is $200, component A’s replacement cost over three years amounts to $300. Component B’s replacement cost is $750 plus the cost of two additional downtime occurrence losses—which could amount to substantially more.
Standardization. Once reliable components and supply distributors are established, their use can be standardized throughout an organization—and included in any new design. Employing this strategy facilitates spare-part management and decisions based purely on service and life-cycle reliability.
The adage “what gets measured, gets done” applies to the C2C management approach. Concurrent performance measurement of production, maintenance, and human resource (HR) issues will tell a complete story of expectations and the reality of the operational state. Performance measurement vindicates the management approach and exposes improvement opportunities. True performance measurement will include:
Set goals and expectations. Achieving success means you must first define success. Knowing your stakeholders and their objectives is the first step in setting up deliverable goals and expectations for the asset and its management.
Leverage KPIs (key performance indicators). KPIs are the currency of performance measurement and the primary indicators in determining an operational state. Begin with baseline measures and use them, initially, to identify internal areas of strength and improvement opportunities. Overlay the objective goals and expectations to establish the gap analysis from which business-improvement strategies can be mapped.
Use measurement trending. As the asset life-cycle management program, or improvement initiative, is rolled out, the performance measures are gathered on a regular basis and compared with the original baseline, previous measures, and target goals. With three measurement sets, a trend can be plotted to determine either a positive or negative trend for achieving set targets.
Manage by facts, not opinion. To simultaneously measure the impact of production, maintenance, and HR (training) on a facility and its asset lines and individual asset pieces, we must synergize data collected in our ERP (enterprise resource planning), CMMS (computerized maintenance management software), EAM (enterprise asset-management), and production and other management systems. Through performance measurement, the data are turned into interpretable information that allows management to make decisions based on facts, not opinions.
When an asset no longer serves its purpose, the maintenance department is usually involved in its decommission and disposal/recycle.
Disposal. Asset disposal involves a pre-built workflow/business process that defines which department—and specific people in that department—performs what actions throughout the event. Maintenance is tasked with retiring the asset in the asset-management program and safely managing its records according to corporate record-retention requirements.Preparing the asset for physical disposal calls for maintenance to decommission it by dismantling the equipment and determining which material is salvageable, recyclable, and hazardous, and which is saleable for profit.
Recycling. In a C2C design, the maintenance department will already know what percentage of the asset’s materials are recyclable and how they are to be treated for recycling purposes. Components and base materials are sorted and can be recycled as spares or sold for profit as scrap material. If an asset has completed its initial end-user contract purpose and is still deemed usable, it can be refurbished for reuse and sold whole, providing it doesn’t contain any design issues.
Cradle-to-cradle asset life-cycle management is a highly disciplined strategy involving long-term thinking and harmonization of strategies and tactics. This holistic framework for improving business performance calls for excellent interdepartmental cooperation between engineering, operations, purchasing, and maintenance. MT
Ken Bannister is principal asset-management consultant with EngTech Industries Inc., Innerkip, Ontario, Canada. He has specialized in asset-data-register development, CMMS implementations, and lubrication-management programs for almost three decades. Contact him at email@example.com.
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.
Temperature is critical to the performance and life expectancy of lubricants and the components they protect.
By Ken Bannister, MEch Eng (UK), CMRP, MLE, Contributing Editor
In the lubrication world, temperature presents an interesting paradox and irony.
The paradox is that lubricants require heat to flow efficiently over and around surfaces, most commonly bearings. However, if the temperature gets too hot (exceeds 210 F), lubricants tend to undergo chemical changes that can drastically reduce life expectancy. Conversely, if the temperature becomes too cold, a lubricant will thicken and lose its ability to lubricate bearing surfaces. The irony is that lubricating oil is designed not merely to separate and lubricate a bearing surface, it’s also designed to absorb and carry away frictional heat from the bearing surface.
While the old adage “oil is oil and grease is grease” may have been true in agrarian societies of yesteryear, things have changed. To guarantee asset availability and reliability in today’s complex, high-speed industrial environments, lubricants must be tailored and managed to their machine-host’s specific needs and operating conditions.
The fundamental reason for lubrication is to provide a film that reduces friction between two, often metal, surfaces. If the film is insufficient, the surfaces collide and transfer energy, resulting in rapid heat buildup and metal expansion, which further retards motion until both surfaces eventually weld to one another. To avoid this worst-case scenario, the ideal intent is to guarantee the correct lubricant is available in sufficient quantity to consistently separate the moving surfaces. This ensures that temperatures stay below the magic 210 F operating temperature.
Choosing the correct lubricant for a bearing means selecting one that best matches the ambient and operating temperatures and conditions under which the component will function. This also means choosing a lubricant with the correct viscosity and additive package.
Viscosity—arguably a lubricant’s most important attribute—is a measure of its resistance to flow. A highly viscous oil is thick and resists flow. A low-viscosity oil is thin and flows easily. Again, temperature can have a dramatic impact on lubricant viscosity. A high-temperature condition, depending on the load in the bearing area, could easily collapse the film thickness of a low-viscosity product and create a metal-to-metal contact or “boundary layer” condition detrimental to the bearing and the lubricant.
Avoiding this situation means choosing a lubricant viscosity designed for the maximum operating temperature expected in the bearing area. This is achieved by paying particular attention to a lubricant’s viscosity index (VI). The VI measures the rate of viscosity change due to temperature. Better-quality lubricants have a more-desirable, narrow rate of viscosity change over a standard temperature range and allow good flow at low temperatures while maintaining their thickness at higher temperatures. Generally speaking, the higher the VI, the more stable and desirable the lubricant.
In cold-temperature conditions, hydrocarbon-based oil can thicken to the point at which it will no longer pour, largely due to its wax content. More expensive hydro-treated and synthetic-based oils will largely resolve this problem, or the user can heat the oil reservoir to a temperature that will allow it to flow again.
Heat-related lubricant failure
In the late 19th century, the Swedish Nobel Laureate Svante Arrhenius discovered a direct relationship between temperature change and the chemical-reaction rate in fluids that he put into an equation known as the Arrhenius rule. As summed up in the following statement, this rule is used in the lubrication field to express the temperature-change-dependent failure rate of oils: “For every 18-deg. F (10-deg. C) increase in oil temperature, the lubricant’s life is reduced by half.” Conversely, reducing oil temperature by the same rate doubles the lubricant’s life (see Fig. 1).
Two predominant failure mechanisms occur as oil heats up. The most common is categorized as oxidation failure and the lesser categorized as thermal failure.
Oxidation failure occurs when oxygen reacts with the lubricant base oil. Anti-foaming and anti-oxidant additives, if present in the oil, are designed to slow the process. Once they are depleted, however, the rate of oxidation will accelerate, especially in the presence of water and reactive bearing materials such as copper and iron.
In an oxidized state, hydrocarbon molecules in the oil will transform into a greasy sludge containing harmful, corrosive acids. These will cause the oil to degrade and lose its lubricating properties, effects that are manifested by an increase in lubricant viscosity, specific gravity, acidity (TAN), rapid additive depletion, darkening of the oil, a “rotten egg” odor, and varnishing of the bearing surfaces.
Thermal failure can occur when localized/external heat is transferred to the lubricant or through the adiabatic compression (a thermodynamic process that occurs when entrained air compresses and heats up according to Boyle’s law) of entrained air bubbles in pumps, bearings, and pressurized hydraulic and lubricating systems. The resulting heat causes the lubricant to decompose and its corresponding hydrogen loss to create carbon-rich particles in the form of sludge and carbon deposits. This leads to a decrease in lubricant viscosity indicated by dark fluid with greasy suspensions that smell of burned food, and evidence of coking and varnishing on the bearing surfaces.
Once a lubricant has failed, the molecular-change state is usually irreversible. At the very least, this situation calls for a lubricant change.
Oil-analysis programs monitor lubricant conditions and alert users to possible failures before they occur. The propensity of a lubricant to fail can be checked by subjecting a sample of it to a rotary pressure vessel oxidation test (RPVOT). By simulating failure through a speeded-up oxidation process, this test can provide a good indication of a lubricant’s suitability. It also can predict remaining life in virgin and used oil samples.
Prevent temperature-related failures
Whether your lubricant choice is grease or oil, once the correct product is chosen and employed it will require assistance from the maintainer to ensure that it has a fighting chance to perform and deliver a reasonable life expectancy. This can be achieved by implementing some of the following best practices:
- Keep lubricant transfer-delivery systems immaculately clean. This prevents the ingress of solid contamination that can create sludge, raise lubricant viscosity, and accelerate the oxidation process.
- Ensure the oil/grease delivery method/system is tuned to provide the correct amount of lubrication in a timely manner. Over-lubrication will create fluid-friction heat, compounded by the bearing ball/rollers working overtime to mechanically push through the excess lubricant. Both conditions cause the lubricant to heat up rapidly. Under-lubrication can allow the bearing to go into boundary lubrication, creating surface interaction frictional heat that can “cook” the lubricant.
- Maintain the oil reservoir level between the minimum (“MIN”) and maximum (“MAX”) fluid level to prevent cavitation in the oil pump or oil churn in the reservoir. Either can result in air bubbles accelerating the oxidation process.
- Keep oil reservoirs clean and free of debris. Dirt, dust, and debris can create the effect of a thermal blanket and raise the temperature of the oil inside the reservoir.
- Ensure the integrity of shaft seals. Poor shaft seals lead to excessive lubricant leakage that can quickly result in an under-lubrication state.
- Implement a lubricant test-and-control process to ensure that incompatible lubricants are not mixed together in the same bearing space, something that can lead to a variety of detrimental conditions, including overheating.
- Where hydrocarbon-base lubricants are employed in cold-weather climates, use timed block heaters or blanket-wrap element heaters for reservoir and drum/pail heating. If a lubricant is to protect a bearing surface it must readily flow across the bearing. MT
Lubrication expert Ken Bannister is principal consultant with EngTech Industries, Innerkip, Ontario. 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 email@example.com.
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The types of analytic, forensic, and diagnostic methods leveraged by various crime-lab sleuths in a long-running television franchise also have value for maintenance organizations in real-world environments.
By Ken Bannister, MEch (UK), CMRP, MLE, Contributing Editor
Many maintenance professionals may be fans of the popular CBS television crime series “CSI (Crime Scene Investigation).” Modeled in the classic whodunit format popularized by Sir Arthur Conan Doyle’s Sherlock Holmes character, “CSI” has always used a mix of cutting-edge technology and common sense to quench our quixotic need to provide simple solutions and answers to what are most often complex problems—something that sounds much like conducting troubleshooting procedures in plants. The latest and, reportedly last, iteration of this franchise, “CSI: Cyber,” may be of particular interest to those involved in a site’s overall asset-management activities, given the show’s focus on computer networks and digital information. If you haven’t already, consider taking a page from this world of fiction in your efforts. It could pay great dividends.
Then and now
For decades, maintenance organizations have long prided themselves on their ability to swoop in at a moment’s notice and save the day whenever a breakdown occurred. The 1970s and 80s witnessed a wholesale change in industrial maintenance from a total reactive maintenance model to the commencement of a more preventive and proactive model—largely due to the introduction of computerized maintenance management software (CMMS), an improved understanding of how to prevent machine failure, and a lean approach to work that focused on waste elimination. Unfortunately, many of the maintenance-improvement approaches implemented to date have not evolved to meet the changing needs of today’s industrial environment.
To be sure, most companies have updated and/or changed their CMMS programs and added preventive-maintenance (PM) work orders to the system for new equipment purchases over time. Still, few have actually performed analytics on their CMMS set-up and operation data to determine its validity and ability to allow data-driven decision making.
Marcel Proust, a nineteenth-century novelist stated, “The real voyage of discovery consists not in making new landscapes but in having new eyes.” Analytics are the eyes that allow the compilation of meaningful data for communication purposes from which to make informed asset-management decisions.
A quick, two-part litmus-test procedure for a management system is to perform several basic queries (reports) on the data to see how well it can be mined.
The first test looks for a report on all of the data for the current year and the previous two years to determine what percentage of the maintenance spend was allocated to labor and what percentage to maintenance parts. This information can be further distilled to understand what percentages of the maintenance spend went to internal maintenance staff labor and parts versus outside contract staff labor and parts use.
The second test is to determine, over the same periods of time, the mean time between failure (MTBF) for all assets combined. These figures can then be trended on a simple graph to show the gross maintenance-spend relationship to overall asset reliability. These simple reports allow management to perform a validity test of maintenance spend versus reliability that can be more focused by performing similar reporting on smaller groups of assets, such as manufacturing (product) line, location, equipment type/group, and supervisor, to discover reduced levels of performance and determine key opportunities for improvement. This information can be scrutinized even further to determine if the PM task or schedule is valid. The ability to generate these simple performance reports allows the user to relate the outcome to maintenance processes and convert the data into actionable information.
Alas, many CMMS and enterprise asset management (EAM) systems in use today would have trouble passing this litmus test. Although they are likely charged full of data, such data are typically not relevant for reporting purposes or are difficult to access due to ineffective system code-management set-up. Other barriers to analytics can include work that’s performed but not captured on a work order or entered into the CMMS; and closed work orders that don’t contain vital information such as actual hours, parts used, tools used, and failure codes.
If your system can’t pass this basic two-part test or if you are unable to easily perform such a test on it, your CMMS or EAM is no longer a management system but rather a work-order system, and your data can be equated to MUD (meaningless unrelated data). MUD is difficult to navigate and extract meaning for informational purposes—information being compiled that can be used for effective management decision-making. (As many readers will recall, MUDA, ironically, is the Japanese word used for waste when implementing a lean approach to production and maintenance.)
When the word forensics is used in a maintenance context, it implies the use of science and technology in combination with the legal system. Forensics is most often brought into play when a maintenance failure resulting in serious consequence or harm to person(s), property, and/or the environment is considered capable of occurring—or has occurred. Mitigating responsibility requires a systematic, due-diligence approach to all machine failures, as part of an organized strategy in preventing, predicting, trending, documenting, and analyzing for potential and actual failures.
Physical parts that have failed can be sent to a forensic laboratory to understand metallurgical failure, and documented through a failure-mode effects and analysis (FMEA) or root-cause analysis of failure (RCAF) investigation. Where due diligence is an issue, a full documentation trail is essential. This will require documenting processes and procedures and a full work-order audit trail within the CMMS. All documents should be capable of undergoing a questioned document examination (QDE)—the forensic science of documents that can be challenged in court.
The standardization of crime-scene photography hasn’t changed much since its introduction in 1888 by French police officer Alphonse Bertillon. Interestingly, television’s “CSI’s” sleuths begin each investigation with a photo essay of the crime scene in an identical manner to the way Alphonse Bertillon did so long ago. Real-world problem-solvers in plants and facilities should do likewise.
With the communication devices and cameras in use today, there is no excuse not to photograph a failure scene. Each time a piece of equipment or component fails, it leaves behind an evidence trail that will lead not only to the failure cause, but also deliver a strategy to understand and/or predict and prevent future failure events.
Accordingly, if we are to reduce levels of maintenance while increasing availability and reliability in our operations, it behooves maintenance professionals to develop a systematic approach (see sidebar) to diagnosing a failure scene that follows the “CSI” lead, i.e., commencing with photography and documentation of all contextual aspects of the failure scene, and not destroying the scene by contaminating or throwing out evidence in our haste to “save the day.” The generated investigation documents, in turn, are essential for forensic and failure analysis and planning and scheduling use.
In short, adopting a “CSI”-inspired approach to failure-diagnostic investigations is sure to enhance your operation’s maintenance and reliability efforts and help meet your overall asset-management goals. MT
Ken Bannister is managing partner and principal consultant for EngTech Industries Inc., an asset-management consulting firm in Innerkip, Ontario. He can be reached at firstname.lastname@example.org.
Follow the “CSI” Lead: 8 Simple Steps To Failure Diagnosis
- Secure the scene. Work with operations to perform a quality evaluation of the failure scene before commencing repairs and/or restarting the equipment.
- Photograph the scene. The old adage “a picture is worth a 1,000 words” could not be truer in a failure investigation. Photos allow the failure scene to be revisited well after the equipment is back up and running, and act as good training materials for preventing future failures.
- Perform on-scene forensics. Maintenance and reliability personnel can perform many technical diagnostics at a failure scene, i.e., infrared signatures, oil-analysis signatures, and metallurgy.
- Bag and tag all physical evidence of failure or tampering. Once all local physical evidence of tampering and breakage has been photographed, tagged, and bagged, the actual failed components can be dismantled and replaced. Any parts for repair must be photographed and any parts requiring replacement must also be bagged and tagged.
- Interview witnesses. Operators can describe any abnormal sound, smell, or vibration emanating from the equipment prior to failure.
- Perform laboratory forensics. Examine all past failure records and vibration readings, performing any necessary metallurgical and oil testing.
- Analyze findings and write up a FMEA or RCAF report. Include recommendations and update preventive strategy(ies), as required.
- Code the failure on the work order. Complete the work order with a report of the findings, making sure to include failure-symptom codes.
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While this account of one plant’s extremely costly, catastrophic experience is a tough read, rest assured that the situation was avoidable.
By Ken Bannister, MEch Eng (UK)CMRP, MLE, Contributing Editor
Maintenance departments may perform their own purchasing/expediting of MRO (maintenance/repair operations) materials or, conversely, rely on a formal relationship with the corporate purchasing department to perform that task. In either case, it behooves a maintenance department to have processes and procedures in place to ensure the exact lubricants required are successfully ordered and received—every time.
This case study involves a catastrophic event at an automotive assembly plant located somewhere in North America. At the time of this lubrication-related failure, the plant was operating with three continual shifts, 24/7, to accommodate a four-week running backlog of vehicle orders. With an average unit selling price of $35,000 and a line speed averaging 60 units/hour, downtime losses were unrecoverable at the rate of more than $2 million in sales losses/hour.
Despite its successful order book, the company had engaged in a corporate efficiency program that required its purchasing staff to individually review every purchase request and seek out less expensive alternatives wherever possible. In exchange, the company would extend a bonus based on the percentage of all accumulated savings. As a result, all purchases—including those associated with critical lubrication activities—slowed as agents in this motivated department immersed themselves in the role of price-cutting negotiator. The situation only served to reduce the level of service to the maintenance department and upset its regular group of suppliers.
If the original supplier didn’t lower its price, the purchasing agent would look for an alternative source based on the order specification. If the specification wasn’t exacting, he/she could seek out a “similar” product. As detailed here, this purchasing-efficiency approach fueled a very expensive lubrication failure.
Brewing a perfect storm
The maintenance purchase requisition simply stated “two totes of ISO 22 air-tool oil.” The automaker’s lubrication program had recently completed lube-consolidation activities that reduced the site’s different lubricant types/SKUs by half (to single digits)—leading to six-figure savings. As a result, lubricating oils were to be purchased in bulk totes from a reputable manufacturer through a reputable local supplier.
The lubrication program also ensured that lubricants were to be stored separately in a lubrication crib, and that they be adequately spill protected with a concrete berm and drain system. In addition to oils and greases, several release chemical agents were also stored in the lubrication crib.
To accommodate safe lubricant transfer, the maintenance department requested multiple “pogo-style” pneumatic drum pumps to move product to smaller containers. At the time of the failure, the lubrication crib had only one of these lube pumps to use with all lubricants and chemical fluids. (Questioned later, purchasing staff would admit that, to save money, they had made a conscious decision to only purchase one such pump.)
With no purchasing confines in place, only the lubricant viscosity specification to go on, and financially incentivized, enthusiastic purchasing staffers who had little understanding of or experience with lubricants, lubrication processes, or lubrication equipment, this plant put itself in a difficult place. It was the eye of a perfect storm.
Saving money in the wrong places
Looking back, the day of the catastrophe started out as a productive one for the site’s lubrication personnel. They had just received a new shipment of ISO 22-grade viscosity air-tool oil that appeared to have new SKU numbers and markings on the tote.
Thinking nothing of those new designations, the unsuspecting technicians went about their tasks of dispensing a number of release chemicals and filling corresponding reservoirs. Next, they dispensed ISO 220 gearbox oil and filled the corresponding gearbox reservoirs around the plant. A second crew then diligently used the same pogo transfer pump to dispense the new air-tool oil and also filled up air-tool FRL (filter, regulator, lubrication) units.
An automotive assembly plant uses a significant numbers of tools, which, to work properly, require clean, lubricated air. Within hours of the lube teams’ busy morning, assembly stations across the facility began shutting down as, one by one, their air-tools failed.
Throughout the plant, maintenance personnel were shocked to find all air-tools, lines, and fittings coated in a gummy plaque that couldn’t be flushed or cleaned without mechanical assistance. The assembly line ground to a complete halt and, due to the enormity of the situation, the second shift was sent home.
For its part, the third shift was told to stay home as engineers and maintenance staff frantically worked together to put in place a series of rented air compressors, new tools, and flexible hose that could get the assembly stations back up and working and the line started. Although the teams accomplished this feat in time for the third shift, the plant still suffered the loss of approximately one and a half unrecoverable production shifts. Additional costs were absorbed in the dismantling and cleaning of the original air-oil system and interim equipment-rental expenses.
A root-cause failure-analysis investigation found that the combination of the new and, evidently, economical air-tool oil-additive chemistry—purchased from a recycled oil blender—was different from the original air-tool oil. Combined with the gearbox oil and release chemicals during the day’s lube-transfer processes, it acted as a catalyst that caused the resultant fluid to become highly viscous and gummy. This manifestation, in turn, caused the plant’s air-tool bearings to overheat, degrade, and rapidly fail.
Yes, the company’s purchasing agents had managed to save thousands of dollars in lubricant and lube-pump costs. In the process, however, their decisions had inadvertently cost the corporation tens of millions of dollars. MT
Lubrication expert Ken Bannister is principal consultant with EngTech Industries, Innerkip, Ontario. The author of Lubrication for Industry and the Lubrication Section of the 28th Edition of Machinery’s Handbook (both Industrial Press, South Norwalk, CT), he can be reached at email@example.com.
Note: This article was updated October 14, 2015.
- Since many lubricants are not compatible with one another or other chemical fluids, always perform a compatibility test prior to changing out lubricants for a different manufacturers’ product.
- With engineered products and processes in place, always insist on “like for like” replacement/replenishment.
- When developing lubricant purchase specifications, do not rely on viscosity alone; spell out the manufacturer and full lubricant specification on the purchase request and accept no alternatives without a lubricant trial.
- When a lubrication-management program is in place, accept no new lubricants in the plant without them having gone through a lubricant-trial exercise to see how they perform. This requires your facility personnel to develop a lubricant-trial process designed to determine where and why a new product is needed, what it will replace, and how the new product will benefit the department.
- Always employ dedicated transfer equipment for each lubricant
- Never store chemicals and lubricants in the same immediate area, or allow their effluents to mix.