When someone ask you about your lubrication program what is your response? Do you explain lubricant selection, storage and handling, lubrication or PM frequencies, execution procedures, personal performing the tasks, documentation, or personal training? All of these are important processes for any lubrication initiative that form your lubrication program. Once in place does it remain static or does it continuously improve with changing conditions.
Saying we have a lubrication program we are defining a plan of action aimed at accomplishing a clear business objective, with details on what work is to be done, by whom, when, and what means of resources will be used. When we consider executable actions from cost benefits, data analysis, root cause elimination, evaluations through metrics or data technology sources, and a collaborative effort for improvement we cross the threshold into the realm of continuous improvement. Defined, Continuous Improvement is a process that is an ongoing effort aimed at improving the current processes and develops a culture of innovation and constant improvement.
Lubrication initiatives will directly impact equipment operational effectiveness at any facility. A quest for reliability excellence will have effective lubrication as the cornerstone of this process which is constantly evolving. Once the fundamental understanding is developed that every component requiring lubrication needs the correct lubricant, applied in the correct manner, in the correct amount, at the correct time. When these four principles are adhered to, equipment will last almost indefinitely.
Consider our operation, we feel that lubrication is a constantly evolving process that requires a combination of technical improvements and employee engagement to yield successful results. Each facility has unique challenges to overcome and distinct approaches for resolution. One common process, we are all committed to maximizing the safe useful life of our equipment at the lowest operational cost.
I would like to give a brief overview of our operation and some of the challenges. We are an underground mining operation that utilize a room and pillar style of mining. The mine is 1800 feet deep and extends approximately 4 miles under Lake Erie. Our business is very dependent on Mother Nature since our primary product is deicing salt used for keeping the roadways and sidewalks ice free. We maintain a fleet of specialized mobile equipment that extracts the salt, which is loaded onto a conveyor belt system for transport to the milling operation which is also located underground. The milling operation crushes and screens the salt into a usable product where it is transported to the surface utilizing a Koepe style hoist. The surface areas maintain a shipping facilities that ship by truck, rail, and ship as well as a milling operation to make specialized products plus packaging facilities.
We have a vast array of both mobile equipment and rotating stationary equipment that requires us to refine our approach and understanding to minimize cost and maximize availability. Various methods can be employed to accomplish this goal but when technology is integrated into the equation such as oil analysis, thermography, and vibration analysis, are the results interpreted as the immediate failure for repair or is a root cause determined. One area that is often overlooked is the engagement of personal. This is of utmost importance to the success of any lubrication initiative and continuous improvement process. Involving the employees on deciding what product to use, how to construct facilities or to assist in diagnosing an issue will foster the feeling of involvement. When people see their ideas become a reality they develop ownership and continually evolve the process.
The actions we take before any failure for prevention will have a direct impact on failure frequency and severity. The question we must ask ourselves, have we actually resolved issues taking our reliability to the next level or have we improved our response to the same recurring issues. I would like to share a few examples of some of the situations that we encountered that were resolved using continuous improvements initiatives.
Having a solid foundation for lubrication initiatives is of the utmost importance. The best method to build and develop the foundation is increase the knowledge base of anyone handling, storing, or using lubricants. Part of this development was to have each maintenance person, storeroom personal and some operators attend a three day lubrication course that was conducted on site. This provided the necessary training to develop the fundamental understandings of lubrication principals and the direct effect their actions have.
You may wonder why train store room personal in lubrication practices. It’s ironic but they are the first line of defense in ensuring the correct oil is being put into a machine. Before the training, when someone requested oil, storeroom personal would fill their request. After the training the oil request was met with the question where are you going to be using that oil. If the oil requested did not meet the application the stores personal would tell them no, that’s the wrong oil, you need this product and send them on their way with the correct oil. This was a great start to control cross contamination and help educate people.
We looked at our underground lubrication inventory which was 3 pages of different lubricants, in excess of 60 products. Seeing from the inventory that several products were very similar we initiated a consolidation effort. With the assistance of our lubricant provider, we evaluated each application for correct product specifications. We were able to consolidate the three pages into 10 oil products and 2 grease products for mobile equipment plus an additional 6 oil products and 1 grease product to cover all rotating stationary equipment. This was followed by a product application sheet for mobile and rotating stationary equipment. This is a color coded one page sheet listing all mobile or stationary equipment that identifies what product to use in what application. This significantly reduced inventory, reduced cross contamination, and provided a quick easy reference for application. Without this consolidation effort being in place it would have been next to impossible to maintain a cost effective lubrication initiative.
Once people are trained and know what lubricants to use where there must be a functional schedule of what needs lubrication, how often it, how much, by who, and when. All of these areas may be combined to what some may refer to as a Lubrication PM or an operational round. No matter what you call it, this is critical to be maintained in a disciplined manner to ensure the equipments healthy performance.
Once these items are all accomplished and being executed we have a lubrication program aimed at maintaining the current health of our equipment. Your journey from this point will be defined by the dynamics of your continuous improvement process. The gains realized could be take several forms from extending current equipment usable life by identifying impending failures addressing the issue in a proactive manner, analyzing failures to prevent the reoccurrence, or simply ensure the correct lubricants are being utilized in the correct place to prevent cross contamination and meet the design criteria.
Consider our one page lubricant application sheet that is posted at all lubrication dispensing point. This includes all working sections, PM facility, maintenance shop, lubrication trucks, and storeroom. When new equipment is installed, is the sheet revised to include the new requirements? It is important to keep the lubricant use sheet as a living document to prevent cross contamination which can have disastrous effects. Who decides what lubricant to use and how much? Our approach is to have the site lubrication team evaluate the new equipment requirements. This team is comprised of mechanics, maintenance apprentices, lubrication technicians, and stores personal. They consider the manufactures requirements then evaluate to products that are already in stock for acceptability. This is not always an easy task since at times products are only listed by the equipment suppliers branded name. The group will enlist the assistance of our lubricant supplier to unravel the mystery to gain the proper product selection. Once the sheet is updated it must be posted at all locations and the old sheets discarded to be useful and complete the process.
Who better to evaluate the equipment requirements than the people that are directly impacted. This direct involvement in the decision making process develops a sense of ownership in the process, execution, and outcome. This fosters employee engagement to promote successful results.
One of the questions we have to ask ourselves does everyone lubricating equipment know the fill location for each lubricant and location of the grease fittings. Even the most experienced person can need a reference to jog their memory especially if they do not see specific equipment on a regular basis. The addition of a machine specific lubrication manual onboard the machine provides that quick reference when needed to both the new operator and the seasoned veteran. This is more in-depth than a lubrication chart. It is a pictorial manual that shows where the lubrication point is located, what lubricant is applied, how much lubricant is applied, and the frequency. This provides the quick necessary reference required to eliminate missing points or applying the incorrect lubricant. Unfortunately, this type of information is rarely supplied by the manufacturer and must be developed by the site. The benefits realized by ensuring all points are receiving proper lubrication to maximize life outweigh the effort required in developing these manuals.
We have many reciprocating air compressors throughout the facility that use quality mineral base compressor oil. One of these compressors used in the underground milling operation experienced a catastrophic failure. The mechanic that was investigating the failure made a point to mention that the oil was very dark and smelled burnt. That one statement was enough information to bring to the lubrication team and ask why. After some discussion it was discovered the operational use of this compressor had recently changed. Normally because of their intermittent use these compressors at most have 600 operational run time hours per year. The PM calls to change the oil on an annual basis that is well within the 1000 operational hour rating of the oil.
The team discovered that the compressor was now running 1000 hours in a 3 to 4 month period. The team saw two options to eliminate this failure in the future. We could either increase the frequency of the PM to once every 3 months or upgrade to an oil with a longer run time. After they completed a cost benefit evaluation it was concluded that the cost of one additional PM was more expensive than upgrading the oil to an 8000 hour synthetic.
Now this one compressor would be unique using different oil than the other 24 similar units in the facility. The team evaluated the the risk of the incorrect oil being used in this one compressor and the benefits of maintaining the past consolidation efforts. Their decision was to upgrade all reciprocating compressors to the synthetic oil and eliminate the prior product. This was only a slight cost increase that avoids another $5000 compressor replacement. In addition the team recommended oil analysis to detect abnormal wear that is now being conducted. This entire sequence of events was triggered by one engaged mechanic making a point to mention “the oil looked dark and smelled burnt”.
Using technology to identify issues can allow a proactive approach to correct a condition before a failure occurs. This does not always mean that because an abnormal condition is detected something must be replaced, based on the condition and severity the possibility exists to extend the usable life. Using vibration analysis we were able to identify a bearing looseness condition on our most critical asset our production hoist. This is what transports our salt from underground to the surface with any outage being a very costly proposition. The bearings rotate at 62 RPM are lubricated daily with EP2 grease that contains 220 viscosity base oil and has been in service to this point for 30 years. Replacement of the three main bearings on a single shaft would cost approximately $100K for the bearings, a two week outage, and be very labor intensive.
We could see looseness in the vibration spectrum but did not know the cause. We first examined the mechanical options like loose mountings and hardware and found nothing. We have to open the bearings for a closer inspection. The bearing looked in very good condition with a clearance of .007” Being a taper lock bearing that is set with a reduction clearance there was no way to know if it was correct. While the bearing was open a grease sample was taken for analysis. The analysis showed nothing abnormal for a 30 year old bearing. Discussing the issue with the bearing manufacture they agreed that the clearance seemed a little excessive but also recommended not to try and readjust after 30 years since more damage could result than benefit gained.
Now knowing the looseness was coming from the bearing rollers hitting the races, we were quickly running out of options. Knowing that at 62 RPM the bearings were constantly in a boundary lubrication regime and never achieved enough speed to establish elastohydrodynamic lubrication. Our lubricant supplier lubrication engineer was consulted to assist in the evaluation to determine if we had any other options available. His recommendation was switch from the EP2 220 grease to low friction synthetic EP2 460 grease. His thought process was that the 460 base oil grease added additional depth to the lubrication layer and would not adversely affect performance because the bearings always experience boundary lubrication.
We switched grease and very quickly the looseness issue disappeared. That was 5 years ago with no issues, now these bearings have been in continuous service for over 35 years. Someday they will need replaced we are depending on vibration analysis to identify the onset of new issues to tell us when that time is approaching.
I mentioned that we grease these bearings daily, because of the criticality of the hoist we want someone to physically touching and looking at it daily. This cannot be achieved with automatic lubrication systems. This does not eliminate the human error factor so we also monitor the hoist with a continuous vibration monitor system. After a holiday weekend, New Years to be exact, we noticed a significant increase in vibration on one of the hoist bearings. Evaluation of the spectrum determined that lack of lubrication could be an issue.
A mechanic was dispatched to grease the bearing showing the issue and all the other hoist bearings as well. Shortly after greasing the vibration levels returned to normal. Coming back from a long holiday the person that normally greased the hoist bearings was off. No one including the supervisor even gave it a thought that the person that normally greased the bearings was not there and someone needed to cover this task. We usually consider vibration analysis to identify defects requiring replacement, but it can also be a window into establishing insufficient lubrication conditions.
Oil analysis is invaluable when taking a proactive approach to issue identification. When looking for fuel dilution in engine oil, simply looking at the percent fuel content will not always revile the full story. We use a B50 Biodiesel blend of fuel for our underground equipment because it produces the cleanest exhaust emissions. Typically when engine oil is run beyond its normal change interval soot loading will become an issue and the viscosity increases. Using biodiesel the engine oil viscosity will decrease over time. Using normal oil lab testing procedures for percent volume of fuel in the engine oil the result is always zero even when biodiesel is present.
When we receive an engine oil analysis report showing a low engine oil viscosity we have to consider fuel dilution as a possibility. The question becomes is the dilution from an extended run time, a fuel leak into the engine, or another source. One case a work order was written to investigate and correct the cause. During the investigation the mechanic found a fuel injection line that was under the valve cover leaking into the engine oil. With some of the newer diesel engines having the injectors and lines totally enclosed oil analysis is the most effective method to discover this type of problem before engine damage occurs. The line was repaired, oil and filter replaced, and the machine was released for service with a follow up engine oil sample schedule to ensure the repairs were effective.
Where do you go when no obvious cause is identified by a visual inspection? One possibility is the use of IR spectrometry to graph the absorption of various wavelengths. When using this technology it is very important to have a known reference sample of each component for a comparison. In this case we have a reference sample of our new engine oil and of the B50 Biodiesel. The greatest variations appear to occur in the frequency region of approximately 1200 cm-1 to 1800 cm-1 with some also at the 3000 cm-1 region. All these graph areas have characteristics of the biodiesel graph while the sample is actually of engine oil. Our conclusion can be that there is actually biodiesel fuel contained in the engine oil. Since there are no obvious leaks a systematic process of determining possible causes and testing are required to locate and correct the issue.
While oil analysis is an excellent predictive technology that can reveal a wealth of information always consider other technologies that are use on any piece of equipment to complement each other. We conduct exhaust emission testing referred to as DPM (Diesel Particulate Matter) tests to determine engine health. In this case referencing the last DPM test showed a higher than normal amount of CO indicating incomplete combustion. This narrowed our focus to testing the injectors for possible leakage. Testing the injectors reviled that one injector was in fact leaking, the injector was replaced and both the oil sample and DPM tests returned to normal. The consequences for not discovering the leakage and rectifying the cause would have been a very expensive engine replacement.
While oil analysis can identify problems it is also important to take annual reference sample for analysis. These reference samples are taken from new as delivered oil from sealed containers. This serves as a base line when comparing sample data to known state. Additive package changes made by the oil supplier can be identified that may result in questions that need clarification. Knowing the cleanliness level of new oil provides information on the amount of filtration required to meet your equipment requirements. You can be alerted by additive depletion to change oil or adjust PM frequencies. One very important component is the ability to identify additives that are not supposed to be present.
We use the same model transmission on several pieces of equipment that are lubricated with industrial transmission oil while the hydraulic system uses fire resistant hydraulic oil that is a group V synthetic hydraulic oil. The hydraulic pumps are mounted directly to the transmission case meaning when a pump seal leaks on the pressure side, that leakage enters directly into the transmission. When we conducted some investigations we found that our group V synthetic had an adverse reaction with lead and copper. Transmission clutch plates are composed of lead and copper, this attack shortened transmission life considerably. When we compare the reference samples between the transmission and hydraulic system we found tin is present in the hydraulic oil but not the transmission oil.
Normally seeing small amounts of Tin in the transmission sample we would assume we were getting a little bearing cage wear but no real issue. With the new knowledge provided with the reference sample, when we see Tin in the transmission sample we know we have a cross contamination issue that needs attention. We stock one spare transmission on site. This spare was continuously being rebuilt and at times would have equipment waiting for the spare to return to eliminate poor performance from a failing transmission. Now that we are using the oil analysis results compared to reference samples we change approximately one transmission per year due to normal wear, not premature failure.
During a journey of continuous improvement not every issue has a clear charted course to follow. There are times when you feel that everything was done properly and failures still occur. One person may not have all the answers but several people each having one answer may solve the problem. When faced with this issue it is worth considering another methodology approach by assembling a cross functional team to conduct a cause and effect analysis or root cause analysis.
We use Megatex’s that are suspended rotating screens to separate and size the salt each capable of handling about 200 tons per hour. The unit is basically a totally enclosed square box rotated on an eccentric shaft with a bearing on each end of the shaft. The box is rotated around the shaft on the eccentric with no access to the bearings to take any vibration readings or any visual inspection. We used the manufactures specifications for grease volume and frequency yet we were experiencing bearing failures. In an effort to be proactive we did install a tri-axial vibration sensor on the bearing housing and wired it to a collection box mounted in an area with safe axis to collect data. This was a unique installation since the inner bearing race was stationary on the shaft and the vibration sensor was moving around with the housing. The first data collection reviled some peaks related to the inner race but we really were not sure if it was bearing or the material in the Megatex since this was all a new venture.
Two weeks after the sensor was installed the bearing failed. Examining the failed bearing when it was removed the most probable cause of failure was lack of lubrication. There were many questions arising that had no easy answers.
The best course of action was to assemble the cross functional team of mechanics, operators, and supervisor to perform a Root Cause Analysis or RCA. The RCA took less than one shift to complete with a wealth of information being reveled. Discovered was the Megatex was in fact making noise for 3 weeks but it was intermittent, the operator thought it was a loose screen opened and did repair a loose screen mount. The bearing was generating heat and the PM called for .45 oz of grease every week that was done on midnight shift when it was not running. Double checking the re-lubrication volume for a severe duty application the amount changed to 2.3 oz per week. Several areas on installation of the failed bearing were investigated where the findings reveled that proper installation procedures were followed.
The RCA generated action item that have been executed such as change lubrication PM from weekly to daily, corrected PM to show 10 pumps of grease daily, reassign lubrication duties to operator and train the operator in the task. Now we had an installation to form a base line to use as a comparison for future reference.
This exercise did identify and implement several issues that did improve the reliability of the Megatex bearing, but there was much more accomplished. The operators, mechanics, and supervisor sitting down in the same room having an open discussion about the failure issue without assigning blame, a bond start forming among the group. They now had a common goal they became engaged in the process and engaged in determining a beneficial outcome because it impacted them directly. Did it really have an effect on the people, I firmly believe that it did. Prior to this I would never hear this operator talking to the mechanics or minimal problem identification to his supervisor. Now I hear the operator telling the mechanics directly when he hears something unusual and what he has already checked. This interaction is crucial to early problem identification, who knows the machine better that the person that spends all day with it, the operator.
When a bearing is having issues and in immanent failure stage some of the first comments are it’s hot, or it’s too hot to touch, or it’s glowing red, or I can smell it cooking. The very next comment is, get some grease in that bearing. Well I hate to be the one to tell them but it’s way too late for that, it actually can be dangerous. Pumping grease into a bearing that is glowing red the grease can and will catch on fire. Depending on your industry and process, that may be a larger issue than the bearing being bad.
Here we are talking about a bearing that encountered a large amount of heating to detect a problem. What if we could detect an issue when there was only a minor amount of heating, before damage occurred? Fortunately we can, using mechanical IR thermography we can detect the minor increases in bearing temperature that indicate lubrication issues. These can be from insufficient lubricant, overloading for the lubricant, or an automatic lubrication delivery system where the lubricant is not reaching the bearing.
Having many miles of belt underground and on the surface I cannot even venture a guess at how many bearings we actually have. Once I know the base line temperature of the bearing I can use that information for a comparison when viewed with IR. The belt pulleys are turning at approximately 120 RPM and I know that all the bearings on the beltlines normally run under 100 degrees F. When viewed with IR and a temperature is seen over 100 F action is required. This may be simply greasing the bearing, the auto lubricator is not functioning, the grease channels in the bearing are not clear and caked with hardened material. All cases if the condition is corrected before sever heating occurs failure will not occur. This is a simple and cost effective method to increase reliability.
All failures are comprised of three phases with our response to each of these phases defining our future, Problem Identification, Repair execution, and Future Prevention. Problem identification is the method we choose to utilize in determine that an issue is present. We may use our physical senses or employ advanced technology, like oil analysis, vibration analysis, or IR Thermorgraphy or choose a run to failure strategy. All are valid methods or strategies once the application is analyzed. Repair execution is how we choose to implement the repairs.
During the repair do we use precision maintenance skills, have acceptance criteria established, or do we put it together the best we can make it last to the weekend. Again both could be valid under the correct set of circumstances. Future prevention is something that we are going to do different so the issue is not repeated. How we determine the bases for our decision and the course we choose to do something differently will affect the future. As Einstein stated “We can’t solve problems with the same kind of thinking we used to create them” Using a strategy of detecting a problem, executing replacement without finding a cause is the same kind of thinking. Mitigating the future failure by determining the root cause and executing corrections to prevent reoccurrence is that different kind of thinking that leads to reliability excellence.
We have reviewed examples of several specific issues that we employed different strategies for issue elimination. Each one of these was establishing a new process building on the previous success. The one common underlying theme that connects all the successes that is not obvious is the direct effect our engaged workforce have on these results. They are highly skilled individuals that know how to work as a cohesive team to foster successful results. Having the most technologically advanced systems will not necessarily gain improvements without a workforce taking ownership and pride in their accomplishments. Our mining systems are very labor intensive with automation technology not a viable option in our operation, we must rely on people. People who know the operation, the consequences their action have to the operation, and that can use their minds to overcome challenges.
We have evolved our lubrication program into a managed process of continuous improvement through lubrication, by developing a culture of innovation and employee involvement. We have taken significant steps in maintaining our equipment in the safest most reliable condition, and still have undiscovered improvements to make. This is an ongoing exercise that is a team effort in our quest for reliability excellence.
This article was previously published in the Reliable Plant 2013 Conference Proceedings.
By Ted Melencheck, Cargill Deicing Technology
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