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To start a lubrication program, you need to understand that there are several different substances that can be used to lubricate a surface. The most common are grease and oil. Grease is comprised of oil and a thickening agent. The thickening agent’s job is to retain the desired consistency, while the job of the oil is the actual lubrication.
The selection of the proper grease should be done with the utmost diligence to address all equipment needs. This leads to lubrication-based failures because once the oil separates, the grease loses its protective quality. I have seen organizations use extension hoses to make grease points easily accessible. This can be a machine killer depending on your grease.
You need to know the amount of time the grease will sit in the line based on the frequency of application and amount. The wrong grease will allow the oil to leach out of the thickening agent and all you will be providing the lubricated asset is the thickening agent, devoid of oil. What would appear to be a great idea to an uninformed organization could be a self-inflected wound.
Many of the manufacturers sell inferior grease, and the thickening agent and oil separate. The most widely used thickener is a lithium complex. Over 75% of thickeners in use are this type. The main reason lithium complex is so widely used, is because it is the easiest to make, little talent is required to produce it and it is cheap. Other thickeners provide superior performance but require the company making them to have significantly more advanced abilities.
The difference is the cost to buy. Lithium is cheaper to make so it is cheaper to buy. But you should never make a lubricant decision on cost to buy. The only important cost is the cost to use. The right premium lubricant will save you money because you will use less, and it will protect your equipment and provide reliability. I will repeatedly say “right premium lubricant” throughout this article. What I mean by this is not all premium lubricants are created equal. There are many determining factors to decide the right one. There are also a lot of misleading manufacturer’s in the market that label things premium.
So, the most important thing is to educate yourself or hire a third party to consult with you. Never trust the lubricant provider with this decision. A true leader makes decisions based on facts and never allows their emotions into the decision-making process. Friendship or a long-standing relationship is not a lubrication qualification. If these people genuinely care about your reliability, they will welcome an expert consult to prove they are providing you the best.
Oils come in three common varieties: vegetable, mineral-based, or synthetic. They can also be a combination of these as well. The application dictates which oil, referred to as the base oil, should be used. Synthetic oils are designed for extreme conditions while vegetable oil is used where there are environmental concerns.
Your decision on which to use needs to go beyond application and should consider your overall program. Resources will play into your decision as the different bases require different proactive approaches. If your organization plan includes in-the-field filtration instead of interval-based replacement, you need to understand the effects on your base and its additives.
Reliability leaders need to have experience with this, or you will leave this type of decision to a supplier who may be unqualified and most certainly does not have any “skin in the game.” In all my writing I will continue to warn you to never trust your lubrication program to the lubrication supplier. The vast majority lack any true experience running or maintaining a facility and their knowledge is mostly as a salesperson.
If they represent a fuel provider, like the top ten petroleum companies, the product they offer is likely inferior in every way to a lubricant provider that specializes in lubrication. To these providers lubricants are not an afterthought but their focus. I compare this to the medical profession. If you need heart surgery, you do not go to a general practitioner or worse a dentist. Your lubricants require the same attention and careful consideration. It is the life blood of your equipment.
Most organizations leave this important decision up to their supplier because they offer “free” advice. Is it truly “free” if your reliability suffers? Part of your justification for your program start-up is the real cost of “free” advice and its detriment to plant reliability. Suppliers have very little risk in providing free bad advice because if an organization is allowing them to give it, the organization lacks the ability to determine that it is bad and hold them accountable.
The answer is yes! If this is something new to you, then you need to research more about the lubricants you are using. For qualified lubrication professionals, this is a simple truth. First let us break this down into the different crudes.
West Texas Intermediate
Is an extremely high quality crude oil which is greatly valued for the fact that it is of such premium quality, more and better gasoline can be refined from a single barrel than from most other types of oil available on the market.
These combined qualities as well as location make WTI a prime crude oil to be refined in the United States, which is by far, the largest gasoline consuming country on the planet.
It is also slightly "sweeter" and "lighter" than Brent.
The vast majority of WTI crude oils are refined in the Midwest and Gulf Coast regions. This is 100% US product.
This Oil is a collective of seven different crude oils from Algeria, Saudi Arabia, Indonesia, Nigeria, Dubai, Venezuela and the Mexican Isthmus.
Organization of Petroleum-Exporting Countries.
The stated mission of the organization is to "coordinate and unify the petroleum policies of its member countries and ensure the stabilization of oil markets, in order to secure an efficient, economic and regular supply of petroleum to consumers, a steady income to producers, and a fair return on capital for those investing in the petroleum industry." The organization is also a significant provider of information about the international oil market. The current OPEC members are the following: Algeria, Angola, Equatorial Guinea, Gabon, Iran, Iraq, Kuwait, Libya, Nigeria, the Republic of the Congo, Saudi Arabia (the De facto leader), the United Arab Emirates and Venezuela. Former OPEC members are Ecuador, Indonesia and Qatar.
Because OPEC oil has a much higher percentage of sulfur within its natural make-up and therefore is not nearly as “sweet” as WTI or even Brent Blend and since it is also not naturally as “light” as well, the prices of OPEC oil are normally consistently lower than either Brent Blend or WTI.
If you know the basic information above, where do you think the best base oils would come from? However, the big fuel companies make their profits on gas not lubricants. So, they buy crude based on price, for their maximum profits, and not lubricant quality. Lubricants are a by-product that if they did not sell, they would have to dispose of and that would cost them profits.
Their focus is to make as much money at the expense of those who are not qualified to know the difference. Most organizations are buying their lubricants because they recognize the name on the label. They leave this critical aspect of their reliability program to a multinational conglomerate that cares nothing for their reliability. Their entire focus is on their profits.
With this little bit of information, you can plainly see that using a name brand fuel company’s product to protect your equipment is likely a bad decision.
In addition to determining the correct base oil, the selection of additives will enhance, add, or suppress properties within the base, and the lubricant’s performance. The additive package is determined by the type of base oil and the application that it will be used in. An example would be engine oil with a dispersant added. The dispersant keeps insoluble matter conglomerated together so it can be captured by the filter during circulation.
Additives can improve anti-wear and extreme pressure performance. It can enhance seal performance and reduce or eliminate start-up wear. Allowing the supplier to dictate such an important decision should never happen. Again, this seemingly “free” advice is costing you thousands or even tens of thousands of dollars in unreliability caused by premature failure of your lubricated assets. Educating yourself on machinery lubrication is vital to the selection of the proper lubricants, as is selecting a lubrication partner who has the same goals you have - plant reliability, not their profits.
In an application that experiences extreme temperature, from hot to cold, a viscosity index (VI) additive would be used. The molecular construction of these additives has long, organic molecules that stay together in cold conditions, but they unravel in hot environments. This allows the oil to change its viscosity and flow better when it is cold while maintaining its high-temperature properties.
The main concern most organizations should have with additives is that they can be depleted, requiring the oil to be changed to restore them to required levels. This was the “old school,” or supplier-preferred approach. In reality, you can re-infuse additives without a complete oil change. Working with a lubricant partner, you can determine what portion of transfusion is required to return the additives to desired levels.
The combination of in-the-field filtration, base oil, and infusion is another cost savings that can be leveraged to fund other reliability efforts. Most supplier representatives are not qualified to assist you in this decision so they will focus their efforts on sales and not your performance or cost savings. This is another aspect of reliability where you can save money to fund other reliability efforts.
The key objective of lubrication is to reduce friction, but it has a lot of other benefits. The lubricating film helps to prevent corrosion by shielding the metal surfaces from water and other substances. It also has a role in controlling contamination within the system. It serves as a conduit to move the contaminants to the filter for removal.
Another aspect of lubrication is that it aids in controlling the temperature by absorbing heat and transferring it to where it can be dissipated. Accordingly, the selection of your lubricants needs to align with your reliability strategy and is key to its success. Selecting your supplier cannot be left to purchasing agents and supply chain managers.
They are not qualified to make this decision. Selling the importance of lubrication is the job of Reliability Managers, and they can only do so if they have the experience and education to communicate this at all levels of the organization. Do not entrust this solely to your supplier; educate yourself in machinery lubrication so you can instruct your suppliers and not just hope they get it right.
Lubrication has three different types: boundary, mixed, and full film. Each of these is different, and they rely on both the lubricant and the additives to protect against wear.
There are two forms of full-film lubrication: hydrodynamic and electrohydrodynamic. Hydrodynamic is when two surfaces, relative to each other, in a sliding motion, are completely (fully) separated by a fluid film. Electrohydrodynamic differs from hydrodynamic in that the surfaces, relative to each other, are in a rolling motion.
An additional difference between the two is that while electrohydrodynamic has a much thinner film layer, the pressure on the film is much greater. This is called electrohydrodynamic because the film elastically deforms the rolling surface to properly lubricate it. If you want to test your supplier, ask a basic question about this and see if they can answer it.
No matter how polished or smooth the surface appears, there are always irregularities present. At a microscopic level, they jut out from the surface like peaks and valleys. The peaks and valleys are called asperities. It is the peaks of these asperities that carry the load. To achieve a full film condition, the lubricating film must be thicker than the asperities. This type of lubrication is the most desired and protects the surfaces most effectively. By filling in the peaks and valleys, you can spread the load across the entire surface area, reducing friction.
In applications where there are shock loading and frequent starts and stops, boundary lubrication is preferred. Additives like extreme pressure (EP) or anti-wear (AW) protect surfaces where a full film cannot be accomplished because of load, speed, or other factors. These additives form sacrificial layers of protection by clinging to the surfaces, preventing wear. When surfaces are contacting in such a way that only an EP or AW layer will protect them, boundary lubrication must be used. However, this is not the ideal situation because of high heat, friction, and other undesirable effects.
In applications where you need both boundary and hydrodynamic lubrication, you can employ mixed lubrication. In this application, most of the surfaces are separated by a lubricating layer but the asperities will still come in contact. Because of this, you will need to employ additives.
Select several of your hottest running gearboxes. Mark the location of where you take the temperature readings and document the temperature. Take the readings at the exact same time of day to ensure quality results. Be mindful of equipment downtime because of the inferior lubricants to get an accurate reading.
Do this over several weeks and trend to identify the average temperature. Next change the oil and replace it with a premium (non-fuel company) lubricant and monitor the temperature in the exact same manner. If you have done your homework and selected the right premium lubricant, you will see a noticeable drop in the operating temperature. Remember the Arrhenius Rule, for every 10 degrees Celsius you will see doubling of the life of the lubricant.
Another thing to watch during the test is if your gear box leaks and you replace lubricants frequently, measure the amount of lubricants you are losing but document the replacement amount. Once you replace the lubricants, document the replacement frequency and amount of the premium lubricants. There are a couple of factors here to note. If you select the right premium lubricant, you will probably see it has a better viscosity index (VI).
The viscosity index measures the change in viscosity caused by temperature change. Cheap fuel company lubricants have a low VI and as the equipment heats up, the oil thins and leaks. The thinning also reduces the oils ability to separate the surfaces and protect your equipment. Additional considerations are that if you buy the right premium lubricants you must replace them less and this saves money on lubricant costs and frees up manpower to perform other tasks. All of us know that we are doing more with a lot less people, so saving manpower hours is another advantage of the right premium lubricants.
How do you see your grease performance? There are three opportunities to inspect the state of in-service grease. One is by disassembly (such as by removing the bearing cap), the second is by sampling the grease using a probe (ASTM D7718), and the third is by examining the purge discharge. The purge discharge is the grease that is extruded from exhaust ports, seals and other openings during relubrication or machine operation.
Not all grease-lubricated machines have a purge stream, but many do. Machines (mostly bearings) that purge grease provide a valuable opportunity for inspection. The opportunity is significant because of the frequency and simplicity of the inspection. Machines that purge are generally “total loss” systems, meaning the grease is not recovered for reuse but instead is discharged to a catch-pan, trap, grease thief, exterior surface or straight to the floor.
Starting with premium base oils and the right additives will prevent component lifecycle loss due to friction. Doing your own testing of these components to determine their performance under load and in adverse conditions will provide you the facts necessary to make an informed decision. Allowing the lubricant provider to provide you their data or some sales materials is not fact based. Nothing replaces the experience and visual confirmation for those responsible for reliability and those who will have to make the repairs if the product fails.
Outside of the best base oil and right additives, a couple of big physical attributes you need your grease to have is reversibility and waterproof. What is reversibility? When the grease is working, the thickener releases the base oil to lubricate the components. This is caused by the heat and load placed on the component.
The reversibility is the ability of the thickener to absorb the base oil back into itself for reuse when called upon once the heat and load are reduced and the grease is not asked to lubricate. Reversibility is a property of the thickener. Since the most used thickeners is lithium complex, reversibility is not available. The purge discharge is the grease that is extruded from exhaust ports, seals and other openings during relubrication or machine operation and is indicative of the grease reversibility. There is a difference between waterproof and water resistant.
Water resistant still allows severe moisture levels to be present in oil, the oil becomes cloudy or separates into a free water phase. These high water levels in oils contribute to corrosion, loss of lubricating film strength and impeded function of vital additives. Waterproof does not allow this to happen. So, reversibility and waterproof are significant attributes necessary for the grease you select. Jim Fitch, from Noria, pointed out in a recent Machinery Lubrication article, “... it takes only a small amount of water (less than 500 parts per million) to substantially shorten the service life of rolling-element bearings.”
Only with an understanding of the process will it be easy to determine which lubricants to use. The determination is between separating the surfaces or protecting them from friction, heat, wear, and other issues. Using oils, grease, gas, or other fluids will accomplish this. Next time you change the oil in your car, understand that there is a lot more going on than meets the eye.
My next article will focus on how to determine the impact of your lubrication program on reliability and pulling together a business case to educate your company’s leadership team. I can share with you over 30 years of running reliability programs and specifically lubrication programs that proactively support reliability for major corporations (unlike the lubrication salespeople who mislead you into thinking they are experts). I have thousands of side by side tests of fuel company lubricants and their failure compared to the right premium lubrications. If you do nothing else, get your lubrication program right. Feel free to drop me a note or call if there is a topic you would like to see, if you have questions, or would just like to chat.