Tagged: lubrication

Types Of Antiwear Additives and How They Work

There are many types of antiwear additives, but they typically all fall under the category of polar materials such as fatty oils, acids, and esters, according to Pirro, Webster & Daschner, 2016. According to Mortier, Fox, & Orszulik, 2010, several compounds can form surface films to help protect against friction and wear.

These include:

Oxygen-containing organic compounds (with a polar head that can adsorb to surfaces). These can include alcohols, esters, and carboxylic acids.
Organic compounds containing nitrogen groups
Organic sulphur compounds which can form reacted films at surfaces
Organic phosphorus compounds which can form reacted films at surfaces
Organic boron compounds which may form reacted films at surfaces
Organic molybdenum compounds which can form MoS2 film on surfaces
ZDDPs, which can form polymeric films on surfaces

While this is an exhaustive list, the more popular ones are listed below. In this next part of the article, we will also dive into how they function.

Organic Oxygen Compounds

According to Mortier, Fox, & Orszulik, 2010, these compounds usually include esters, alcohols and acids. These are generally responsible for improving the “oiliness” or reducing the friction for most lubricants. However, how does this work?

Carboxylic acids form metallic soaps with the contacting surfaces. According to Mortier, Fox, & Orszulik, 2010, some evidence suggests that the upper limit of friction coincides with the melting point of the metal soap. As such, when the upper limit of friction is reached, the metallic soap melts, protecting the surface and performing its antiwear function.

Interestingly, there has been a debate concerning whether these long-chain surfactant friction modifiers reduce friction by forming adsorbed films of monolayer thickness or if they form thick films equivalent to several or many multilayers.

Again, as per Mortier, Fox, & Orszulik, 2010, after experimenting, it was concluded that some of these types of additives form thick boundary films while others do not.

The thick boundary films result from the formation of insoluble iron (II) oleate on the rubbing surfaces. For metal oleates, this will only occur for metals lower than iron in the electrochemical series.

Thus, when speaking about organic oxygen compounds, they help to reduce the friction in lubricants by forming layers on the contacting surfaces.

Organophosphorus Esters

These types of esters have long been used as antiwear additives, according to Mortier, Fox, & Orszulik, 2010. There are two different types of reaction films which are typically formed:

Films derived from tricresyl phosphate which form thin films (0.1-2nm) consisting of low shear strength FePO4 and FePo4.2H2O
Films consisting of iron (III) monoalkyl/aryl phosphate oligomers are thicker (approximately 100-300nm) and polymeric.

It is important to note that for the tricresyl phosphate (TCP) to be effective, the presence of oxygen, water, and other polar impurities is necessary to form the reaction film. Typically, the hydrolysis of the ester occurs initially, which releases phosphoric acid. This is then critical in the formation of the surface oxide film.

Another noteworthy function of the ester of phosphoric acid is that it helps ensure the solubility of the product in the oil. It can also aid in rust protection by hydrolysis to the phosphoric acid.

During the formation of the film, there is a loss of an alkyl group by hydrolysis, which generates two P-O ligands for coordination. This phosphate anion, which was formed, has reduced oil solubility, which allows for the boundary layer of oil covering the metal surface.

Eventually, as the polymer continues growing, the film moves from a soft, viscous liquid to that of a glass-like solid. This glass-like solid allows the surfaces to stay separated, thus reducing wear.

Essentially, organophosphorus esters form films that can either be very thin or thicker and glass-like, depending on their nature. While they act as antiwear additives, they can also perform the function of rust inhibition in the appropriate environments.

Molybdenum Sulfur

Coyle et al., Patent No. 4,995,996, 1991 recognize Molybdenum disulphide as a lubricant additive and discuss its origins. They mention that molybdic xanthine typically decomposes under particular conditions to form the molybdenum sulfide on protected materials. The use of thiosulfenyl xanthates has also been formulated for particular ashless lubricants.

As per Mortier, Fox, & Orszulik, 2010, compounds such as MoDTC (molybdenum dithiocarbamate) or MoDDP (molybdenum dithiophosphate) typically react with the surfaces to produce the famous molybdenum disulphide. In this compound, there is an ease of shearing, which leads to unusually low coefficients of friction.

A synergistic relationship exists between MoDTC and ZDDP. While MoDTC does not form low friction layers independently, these layers are only formed when ZDDP is present. The layer of MoS2 is only formed on top of the glass of ZDDP reaction products. The ZDDP layer acts as a source of sulphur, reduces the oxidation of MoS2 and limits the diffusion of sulphur from MoS2 into the ferrous substrate.

Interestingly, Molybdenum disulphide (also commonly known as “Moly”) is extremely popular in grease applications especially in the mining industry. “Moly” is known for being a solid additive to grease thickeners for specific applications.

As seen above, it may not exactly be “Moly” added to the lubricant, but rather, it is only created when its parent compound decomposes and is formed.

Zinc Dialkyldithiophosphates (ZDDP)

These are the most commonly used antiwear additives on the market and are known by their chemical abbreviation ZDDP. Originally, ZDDP was developed as an antioxidant additive. However, it has been used in many applications, such as engine, hydraulic, and even circulating oils, as both an antiwear and antioxidant additive.

According to Bruce, 2012, The Ecole Centrale de Lyon / Shell Corporation collaboration made significant conclusions on ZDDP performance. This study shows that ZDDP produces a thin film of iron sulfide and zinc sulfide nearest to the metal surface. Next, there is a zinc polyphosphate layer, made up of long-chain zinc polyphosphates and then soluble alkylphosphates, closest to the oil layer.

According to Zhang & Spikes, 2016, at very high temperatures (above 150°C), ZDDP reacts slowly to form films on solid surfaces. This occurs despite the absence of rubbing and is called “thermal films .” However, at lower temperatures (below 25°C) in the presence of rubbing films in a ZDDP lubricant, these ZDDP films are generated more rapidly. These are called “tribofilms”. Based on analysis, it is suggested that both films have similar structures.

It has also been shown (through inelastic electron tunneling spectroscopy, IETS with Yamaguchi and Ryason) that secondary ZDDP is adsorbed much more readily than primary ZDDP. On the other hand, alkaryl ZDDP is hydrolyzed on adsorption onto aluminum oxide surfaces.

According to Mortier, Fox, & Orszulik, 2010, ZDDP reduces wear by forming relatively thick boundary lubrication films. These are usually 50-150nm thick and are based on a complex glass-like structure (as mentioned earlier). The figure below, taken from Mortier, Fox, & Orszulik, 2010, shows the structure of this ZDDP glass film.

Structure and composition of a ZDDP glass film (taken from Mortier, Fox, & Orszulik, 2010)

The strength of the ZDDP’s antiwear function lies in the structure of the alkyl groups. Chain branching and chain length have critical roles in this determination. Short-chain primary alkyl groups are more reactive than long primary alkyl groups.

As Mortier, Fox, & Orszulik, 2010, explain, the ZDDPs most efficient at antiwear film formation typically suffer depletion due to thermal effects. Under very high temperatures and/or long drain service, the most active ZDDP may not provide the best wear protection.

Want to read the entire article? Find it here in Precision Lubrication Magazine!

Oil Properties

What Are Antiwear Additives?

As the name suggests, antiwear additives help to prevent wear in one way or another. However, what makes them unique compared to other additives in lubricants? Why are they used more predominantly in specific applications than other applications? This article explores antiwear additives, why they are needed, and how they work.

What Are Antiwear Additives?

According to (Bloch, 2009), antiwear agents can also be called mild EP (Extreme Pressure) additives. In some cases, they may also act as antioxidant additives (depending on their chemical structure). In essence, antiwear additives protect against friction and wear when the surfaces experience moderate boundary conditions.

During moderate boundary conditions, the full film of the lubricant has not yet formed, and asperities on both surfaces can come into contact with each other. As such, antiwear additives can also be called boundary lubrication additives.

Usually, these antiwear additives react chemically with the metal to form a protective layer. This layer or coating will allow the two surfaces to slide over each other with low friction and minimal metal loss. As such, antiwear additives have also adopted the nickname “anti-scuff” additives.

According to Pirro, Webster, & Daschner, 2016, the adsorbed film on metal surfaces is formed from long-chain materials. In these cases, the polar ends of the molecules attach to the metal while the projecting ends of the molecules remain between the surfaces.

Under mild sliding conditions, wear is reduced; however, under severe conditions, molecules can be rubbed off such that the wear-reducing effect is lost. When this happens, it is evident in the oil analysis data with the presence of wear metals in large quantities.

In essence, antiwear additives help protect the oil while reducing friction, protecting the surfaces, and, in some cases, enhancing the oil to be more resistant to oxidation. While they can perform these functions, it must be noted that there are many different types of antiwear additives.

Want to read the entire article? Find it here in Precision Lubrication Magazine!

Oil Properties

Measuring Oil Viscosity

The viscosity of oil is one of its most essential characteristics. Thus, it is important to understand how this is measured and quantified. There are two main types of viscosity, dynamic (or absolute) and kinematic viscosity.

The dynamic viscosity measures the force required to overcome fluid friction in a film and is reported in centipoise (cP) or in SI units Pascal Seconds (Pa s) where 1 Pa s = 10 P (Poise). It can also be considered the internal friction of a fluid. This is usually used for calculating elastohydrodynamic lubrication related to rolling element bearings and gears.

On the other hand, the kinematic viscosity of a fluid is the relative flow of a fluid under the influence of gravity. Its unit of measure is centistokes (cSt) which in SI units is mm2/s, 1cSt = 1 mm2/s. (Mang & Dresel, 2007).

Kinematic Viscosity = Dynamic Viscosity / Density

Other units of measure for viscosity include; Saybolt, Redwood, and Engler, but these are less widely used than the cSt or cP, especially for lubricants.

Oil Viscosity Grades and Standards

One of the best-kept secrets about viscosity is that a particular grade often represents a range. When oils are classified, one may see an ISO 32 or ISO 220 and believe that the oil will have this exact viscosity (32 cSt or 220 cSt). However, this is not the case.

There are three general classifications where viscosity grades have particular ranges based on the fluid type. The fluid may behave differently in each application, hence the need for these three scales. However, there is a chart that allows users to convert the various scales into the one needed.

Engine Oil Classification (SAE J300)

As per the Society of Automotive Engineers (SAE), the SAE J300 standard classifies oils for use in automotive engines by viscosities determined at low shear rates and high temperature (100°C), high shear rate and high temperature (150°C) and both low and high shear rates at low temperature (-5°C to -40°C) (Pirro, Webster, & Daschner, 2016).

Engine manufacturers have widely used this system to aid in designing lubricants suited for these applications. As such, oil formulators also adhere to these classifications when engineering lubricants.

One will note the use of the suffix letter “W” in some of the grades below. These oils are intended for low ambient conditions, whereas those without the “W” are intended for oils that will not encounter low ambient conditions.

These are commonly described as multigrade (where the “W” is found between two numbers) and monograde oils (where the “W” is at the end or the grade is identified by a number only) in the table below.

The table shows that the viscosities must fall within a particular range to be classified. For instance, a 5W30 oil should meet the specifications of:

Low temperature, Cranking viscosity of 6600 cP at -30°C
Low temperature, Pumping Viscosity Max with No Yield Stress of 60,000 cP at -35°C
Low shear rate Kinematic viscosity at 100°C should be between 9.3 -12.5 cSt
High Shear rate viscosity at 150°C Max at 2.9 cP

One will notice the range of 9.3 to 12.5 cSt (at 100°C). This is where oils can be blended to either end of this scale but still achieve the classification of a 5w30 oil.

Axle and Manual Transmission Lubricant Viscosity Classification (SAE J306)

As per the SAE recommended practice J306, automotive manual transmissions and drive axles are classified by viscosity, measured at 100°C (212°F), and by the maximum temperature at which they reach the viscosity of 150,000 cP (150 Pa s) when cooled and measured in accordance to ASTM D2983 (Method of Test for Apparent Viscosity at Low Temperature Using Brookfield Viscometer). (Pirro, Webster, & Daschner, 2016).

The table below shows that for an SAE grade of 190, the kinematic viscosity must fall within the range of 13.5 to 18.5 cSt at 100°C. While most viscosities tend to fall mid-range of these values, it also indicates that if the lubricant achieves 18 cSt at 100°C, it can still be classified at an SAE grade 90.

The most common multigrade lubricants within this grade fall within the 80w90 or 75w140 classifications.

Another factor for these types of lubricants is API GL4 or GL5 ratings. It must be noted that a GL5 lubricant is recommended for hypoid gears operating under high-speed, high-load conditions.

On the other hand, a GL4 lubricant is usually recommended for the helical and spur gears in manual transmissions and transaxles operating under moderate speeds or loads. These should not be used interchangeably as the GL5 lubricants tend to adhere to the surfaces and may cause more damage in a GL4 application.

Figure 5: Automotive Gear Lubricant Viscosity Classification. Source: Lubrication Fundamentals, Third Edition Revised and Expanded by Pirro D. M., Webster M., and Daschner E. pg 52

Viscosity System for Industrial Fluid Lubricants

This classification was jointly developed by the ASTM and STLE (Society for Tribologists and Lubrication Engineers). Initially, the system was based on viscosities measured at 100°F but converted to viscosities measured at 40°C.

ASTM D2422 and ISO 3448 are the references for this system. In this system, it is clearer to see the variances in the ranges of viscosities. In this case, the mid-point of the range is used as the ISO viscosity. To determine the range of any ISO viscosity, one can calculate ±10% of the mid-point value to get the minimum and maximum values of the range.

Figure 6: Viscosity System for Industrial Fluid Lubricants. Source: Lubrication Fundamentals, Third Edition Revised and Expanded by Pirro D. M., Webster M., and Daschner E. pg 52

All of these systems can be represented in the figure below, where it is easy to calculate the oil viscosity using another system:

Figure 7: Various viscosity systems in one chart.

Want to read the entire article? Find it here in the Precision Lubrication Magazine!

Oil Properties

What is Oil Viscosity?

Oil viscosity is the internal friction within an oil that resists its flow. It measures the oil’s resistance to flow and is one of the most important factors in lubricants. Viscosity is also defined as the ratio of shear stress (pressure) to shear rate (flow rate).

Understanding Oil Viscosity

Imagine walking through a swimming pool filled with water. While walking through the pool, your body experiences some resistance from the water. Now imagine walking through the same swimming pool, filled with molasses this time!

It takes someone much longer to wade through a molasses-filled pool than one filled with water. In this case, the molasses is more viscous than the water. Thus, it has a higher viscosity than water.

You can also apply this to using a straw for drinking water from a glass. Pulling the liquid from the cup will be easy using a big straw. However, getting the same liquid to the person using the straw would take longer if a thinner straw were used.

Engine Oil Analogy

We can draw this analogy to car engines over the last 30-40 years. These engines had larger clearances for the oil to flow throughout the engine. As such, most of these engines used a 50-weight (or straight 50) oil.

As the technology evolved, the size of the engines got smaller. The clearances also got smaller, and the engine oil was now required to flow faster, control the transfer of heat and contaminants and keep the engine lubricated.

A straight 50 oil could not pass through the smaller straw at the speed it should. This would be equivalent to the user using a smaller straw for drinking molasses. It could take a while!

However, if a lighter weight (or less viscous) engine oil was used (such as a 0w20 or 10w30), then this is like someone trying to drink water (0w20) with a smaller straw.

It will flow much faster than molasses (straight 50) with the same straw! The lighter-weight oil would also transfer heat and flow much faster than the heavier-weight (more viscous) oil.

Future Developments and Research in Oil Viscosity

As explained at the beginning of this article, the changes in technology (such as smaller engines) will demand more from lubricants, especially in viscosity. Thirty years ago, a 0w16 engine oil was unfathomable, but today, it is being integrated into our newer model vehicles.

Some of the concepts which will continue in the future can include:

Reducing viscosity – as seen in the examples above, with most pieces of equipment getting smaller, the need for lighter weight (lower viscosity) oils will continue as OEMs constantly evolve and push the boundaries of their equipment.
Measuring viscosity – traditionally, viscometers have always been used where the difference in the height of the liquid at particular temperatures (or under certain conditions) is measured. Given the advancements in technology, this may be subject to change very shortly into a more reliable and even more accurate method.
Viscosity-dependent parameters – temperature and pressure have the most significant impacts on the oil’s viscosity. However, some of these challenges can be overcome with the advent of viscosity index improvers. With enhancements in the formulation of viscosity index improvers, one can expect oils of varying viscosities to be used in parameters they could not have used in the past.
Alternative oils – more sustainable options are constantly being explored. Whether this lies in using plant-based oils or other alternative bio-based oils, these may introduce new ways or conditions under which different viscosities can exist.

Overall, viscosity is one of the most important characteristics of a lubricant. It can easily influence the impact of the oil on the internal surfaces of the equipment and its overall energy efficiency.

It is important to remember that oil viscosity should be determined by the application in which it is being used. Parameters such as temperature, pressure, and shear rate should all be considered when selecting the lubricant’s viscosity.

Want to read the entire article? Find it here in the Precision Lubrication Magazine!

Lubricant Degradation

Can Lube Oil Varnish be Eliminated?

Varnish can be likened to cholesterol in the human body. It can build up in our arteries and eventually clog those, causing restrictions in blood flow to our heart which may lead to a heart attack.

Humans cannot simply change their blood to remove the cholesterol build-up. However, cholesterol is controlled through proper diet, exercise, and with some condition monitoring in the form of blood tests to help gauge the presence of it in the bloodstream. Similarly, a couple of approaches can be used to reduce the varnish build-up or eliminate it.

As per Livingstone et al. (2011), the lifecycle of varnish is critical. Particular attention should be paid to the double arrows between the stages of Solubility to Varnish formation in the figure below.

This means that even after varnish has been deposited, it can be solubilized back into the oil. This can only occur if conditions are met per Hansen’s Solubility principles where the solvent and degradation products meet using the three parameters of Polarity, Hydrogen Bonding, and Dispersive Forces as discussed in “The Hansen Solubility Principles and Its Relation to Varnish” (2022).

The Varnish Lifecycle as per Livingstone et al. (2011)

Varnish exists in various forms and can consist of differing compositions. Hence, it is essential to understand the characteristics of the varnish being formed in a system before attempting to eliminate it.

There are certain technologies, such as solubility enhancers or specifically engineered filtration media, which can be effective at removing lube oil varnish. However, this technology is heavily reliant on the type of varnish being formed and can be customized as per the system accordingly.

Solubility enhancers can solubilize the varnish back into the oil solution. When these deposits are reintroduced into the oil, they can be removed using resin-based filtration. In this method, the media is specifically designed to allow for the adsorption and removal of the varnish which presently exists in the oil.

When these methods are used together, they can prove quite effective and prevent manufacturing plants from experiencing unwanted downtime.

To summarize, it is of utmost importance to first understand the characteristics of the varnish being produced in your equipment before attempting to remove it from your system.

There is no cookie-cutter method to eliminate varnish from a system as it is a complex deposit. Similar to practices we observe with our bodies in the instances of cholesterol build-up, we can employ methods of dissolving the varnish and removing it while monitoring for possible recurrences in the future.

Want to read the entire article? Find it here on Precision Lubrication Magazine!

References:

Livingstone, Ameye, & Wooton. (2015.). Antioxidant Monitoring as Part of Lubricant Diagnostics – A Luxury or a Necessity? OilDoc, Rosenheim, Germany.

Livingstone, Overgaag, & Ameye. (2011). Advanced removal Techniques for Turbine oil Degradation Products. Powergen Milan.

Mathura, S. (2020). Lubrication Degradation Mechanisms (CRC Press Focus Shortform Book Program) (1st ed.). CRC Press.

The Hansen Solubility Principles and its Relation to Varnish. (2022, July 31). Fluitec International. https://www.fluitec.com/the-hansen-solubility-principles-and-its-relation-to-varnish/

Certifications

Obtaining my MLT I & II certifications

The MLT (Machinery Lubrication Technician) exams are developed by ICML (International Council for Machinery Lubrication) and is seen as the entry level certification for those who are working in the field of lubrication. When I entered the reliability field (years ago!), it was one of the credentials I was told that I should obtain to allow others to take me seriously since I was a young female entering a male dominated world. Back then, the training for these exams usually took place as a week-long intensive course in the US followed by the exam. For me, this would have meant travelling to the US, studying for the exam, catching up on work, balancing some jet lag and then writing the exam. This approach didn’t work for me.

I may have taken the unconventional route and written my first book, “Lubrication Degradation Mechanisms – A Complete Guide” published by CRC Press and obtained my MLE (Machinery Lubrication Engineer) certification before thinking of these exams. After achieving my MLE and becoming the first person (and still the only female) in the Caribbean, I went on to secure the Varnish badges from ICML. These are the VIM (Varnish and Deposit Identification Mechanisms) & VPR (Varnish and Deposit Prevention and Removal) badges from ICML. I was the first female in the world to achieve these and to date, still the only female with these badges. I pursued all of these courses via On demand sessions from the master himself, Michael Holloway of 5^th Order Industry.

Everything at the right time

At the end of 2020, Mike approached me to write a guide book for the MLT Level I & II exams. My first question to him was, “How can I write the book for these exams if I don’t have these certifications?”. He assured me that the MLE content covered the topics in MLT I & II and then a lot more. We decided to work on writing the book and get the certification before the book was published. Surely enough after we submitted the pages to the publishing house, I began my preparation for the exam using Mike’s On Demand videos and the book we had just developed for these exams! I was preparing myself to take the MLT I first and then the MLT II right afterwards. Plus, Mike had a really good deal on the course content! How could I refuse?!

Unfortunately, life happened, or in this case death. In November, one of my parents contracted COVID and did not survive. While taking care of them, we also contracted COVID, the one with the long haul effects. Needless to say during the following months, I could not retain any information nor sit an exam. One of the side effects from COVID was brain fog and even after a couple of months this did not clear up to the point where I felt that I was ready to retain any information. I had forgotten basic info which would have been at the forefront of my memory and really struggled for some time to come to terms with everything that had happened and the new journey which lay before us. Our lives were changed forever.

Exam preparation

In May, I finally began to feel a bit better and restarted my MLT Journey with Mike’s videos and our certification book as our guide. This time, I had a physical copy of the book on my desk as it was already published (maybe things do work out in their own special timings). Getting back into study mode while running the business and dealing with never ending paperwork and legalities which surround a death was tricky. I was so grateful for the on demand courses to allow me to study on my own time, at my own pace, when I was truly ready. Also being able to book the exam and complete it virtually from my own space was terrific! The time and anxiety associated with taking an exam is enough, we don’t need to include traffic, getting to a physical location and the environmental conditions of the exam room into the mix!

If you’re preparing for the MLT exam, you have to complete Level I first. There is no skipping ahead to Level II as during the sign up process for MLT II, you have to include your MLT I ID#. My advice for scheduling the exams would be to schedule one on the Monday and the other by Friday of the same week.

Exam scheduling

Here are some tips on scheduling your exam:

When you sign up and pay for the exam you should allow 1-2 business days for processing.
Once you have been approved, then you can set your exam date. You will be notified via email with instructions on the next steps.
MLT I & II are both 3 hours, so choose your timeslot carefully.
Exam results take 2-3 days to process. You will receive an email with your results and grades in the various areas of the BoK.
Once you have passed MLT I and gotten your ID#, you should sign up for the MLT II exam immediately, if you intend to pursue it afterwards.
This will then take 1-2 days to process again. You will receive another email letting you know that you can choose your exam date.
Then, it’s on to schedule your exam date.
After the exam, you will have to wait for 2-3 business days to get your results.

Ideally, one should schedule a 2 week window for taking both the MLT I & II exams and receiving the results. You cannot take both exams in one day (just yet!).

Exam day

Once you enter the Examity portal, you will be asked to suggest a couple of security questions. Please choose these wisely and remember your answers as they will be asked on the day of the exam by the proctor. My advice would be to check the exam portal one day before your exam to familiarize yourself with the questions and answers as these are blocked out on the day of the exam. You should try to log on to the portal 30 minutes before the actual exam just to make sure you can get in and everything works. You will not be able to enter the “exam room” until 15 minutes before your appointed time. Afterwards, the Proctor will do their checks and balances with you where they ask to see your government issued identification (be sure your picture and expiry date are on the same side of this identification). They will also ask to see a 360 view of the room in which you are sitting to ensure it is clear.

During the exam, you can flag questions which you are not sure about and always go back to those afterwards. When you get to the last question, the button turns to submit but you don’t have to use this button until you are ready. Use your time to go back to your flagged questions, decipher the best suited answer and then press forward with your exam. Once you have finished and clicked the “Done” button, you should notify your proctor that you have finished the exam. They also have to close off the session on their side, so this is important to remember. You will see a page which comes up saying exam results, don’t panic! These are not your actual results, just a statement of the time you took. You will get your actual results within the next few days.

The MLT I & II Body of Knowledge

Here’s a look at the BoK for MLT I and MLT II. You will realize that the MLT II builds on the content covered in MLT I. Depending on where you are on your journey to machine lubrication, you can opt to take the both tests (one after the other of course) or simply start with the MLT I and then work up to the MLT II exam. In our certification guide, we used a Unique 5 Step process for learning:

Familiarize
Find Socrates
Be the Exam
Practice Exam
Explore

This unconventional method has proven to be exceptionally effective, not for only passing the exam, but to truly retaining the knowledge and becoming an expert in the content you’re studying. Certification requirements are discussed throughout the work, making this the ideal resource for prospective MLT I and/or MLT II certification candidates.

Here’s a quick overview of the content covered in the book:

Notes Outline: For the reader to complete. Aids in organizing ideas and thoughts.
Guided Cooperative Argument: A dialogue between authors concerning the topics. Helps answer questions that are asked on the job.
Statements of Truth and Exam Development: From the recommended Body of Knowledge, with space to develop your multiple-choice questions. Develops critical thinking process and understanding of how the exam questions are structured.
Body of Knowledge Outline: Works as a reference to help answer any questions that may arise.
Practice Exam: A mock exam designed to familiarize the reader with taking a multiple-choice test that is similar in structure and content to the real one.
Glossary & Appendices: List of common terms, charts, and tables with which all certification candidates need to be familiar.

I hope this helps anyone on their journey towards achieving their ICML MLT certifications. Good luck to those who are getting ready to take these exams.

Certifications / Lubricant Degradation / Reliability

Varnish Badges of Honour

Varnish is widely known as a primary culprit of equipment failure. This sticky enemy effectively finds its way into most of our equipment and causes operators, maintenance personnel and plant managers a series of nightmares. From unplanned shutdowns costing millions of dollars to sticking of servo valves on startup, or increases in bearing temperature, varnish usually announces its arrival. Once it has been found, there is typically a cause for panic but perhaps it just needs to be understood rather than feared?

The ICML VPR & VIM Badges

Recently (August, 2021), the International Council for Machinery Lubrication launched two new badges. These badges are, VIM (Varnish & Deposit Identification and Measurement) & VPR (Varnish & Deposit Prevention & Removal). These were created after the culmination of 3 years of work from the global varnish test development committee. It has been designed for those involved in all aspects of managing or advising lubricant programs especially those with the responsibility of recommending, selling or installing appropriate deposit control equipment or other mitigation strategies.

Most of the readers will already be familiar with my enthusiasm for understanding lubricant degradation. Thus, when these badges came out, I knew I had to secure them! While the requirements for taking the test suggest the possession of the MLT I or MLA I certification or 1 year of experience, I figured that my MLE certification would be an asset (as I haven’t gotten my MLT I certification yet, it’s on the list!). However, I wanted to make sure that I covered all of the elements in the BoK for both the VIM & VPR badges, so naturally I turned to the varnish guru himself, Greg Livingstone!

Fluid Learning – All the way!

1604954736_Fluid Learning Splash 2020-01

Greg is the CIO at Fluitec but he’s also the facilitator for the ICML VPR & VIM badges. What a treat! If you’ve never heard the name Greg Livingstone then you’re obviously not in the lubrication field. Greg has penned hundreds of papers on varnish and can be thought of as the varnish guru since he has extensive experience in this area. It’s a no brainer that I chose Fluid Learning to get me up to speed on what I needed to know for these exams!

Greg was an amazing facilitator and not only covered information relevant to the BoK for the exams but gave students a full overview about everything you needed to know about varnish. These on demand sessions kept me scribbling notes and nodding to myself and saying, “Oh that’s what really happens!” He presents the information clearly and adds some much needed humour into the sessions. It was an absolute privilege having him as my tutor for these badges.

VPR & VIM- What you need to know!

VPR - Varnish & Deposit Prevention and Removal

The VPR badge ensures that candidates understand proactive methods and technologies which can be employed to reduce the degree of degradation. It is also designed to confirm that they can sufficiently evaluate combinations of technologies to prevent and remove varnish including the proper steps to set up and implement an effective varnish removal system.

The topics covered in the VPR include:

Problems associated with Varnish & Deposits (20%)
Factors affecting Breakdown (28%)
Proactive Methods that can be used to minimize oil breakdown (16%)
Methods / Technologies that can be used to remove oil breakdown products and/or prevent deposits (36%)

The complete BoK for the VPR badge can be found here.

VIM (Varnish & Deposit Identification & Measurement)

The VIM badge on the other hand is more ideally suited for personnel responsible for recommending suitable oil analysis tests and mitigation efforts related to the deposit tendencies of various in-service fluids (application dependent). They would also be responsible for monitoring and adjusting these strategies accordingly.

The topics covered in VIM include:

Problems associated with Varnish and Deposits (20%)
Varnish and Deposit Composition (24%)
How Breakdown Products / Contaminants become Deposits (24%)
Oil Analysis Techniques that can be used to gauge Breakdown and Propensity towards Deposit Formation (32%)

The complete BoK for the VIM badge can be found here.

Exam tips!

The actual exams for both the VPR & VIM are set at 45 minutes with 25 multiple choice questions. Candidates must achieve 70% grade to attain the badges. Currently, the fee for the exam is USD75. Since there were overlaps of the content and the exam durations weren’t that long, I decided to sit both exams in one day. I will only advise this for those who are comfortable with doing this as exam anxiety and all that comes along with it can be stressful!

Here are a couple tips for taking these exams:

Log into the system 30 minutes prior to your scheduled exam time. This allows you to clear your mind, settle yourself and gives you an extra 15 minutes to figure out where the email is with your credentials! If you can’t remember your password to login to the system, this also gives you enough time to get that reset and sorted before the actual exam time.
The session only opens 15 minutes before the appointed time. During this time, you will converse with the moderator as they do the checks of the room and your National Identification. The moderators will engage with you and ensure that you are sitting the correct exam.
Ensure you have your National Identification on hand (your passport can be used as well). As long as it has your picture and the expiration date on the same side, it will be acceptable. For the Trinidadians, do not use your National ID card as we have our pictures on the front with the information on the back (I used my Driver’s permit).
Candidates have the option of “Flagging” questions to come back to them later. This is a great tool to help you to mark those questions you want to return to or double check.
There is a timer in the screen layout which helps you to keep track of your time. 45 minutes passes very quickly when you’re running through the questions!
Exam results for these badges come back very quickly as much as within a few hours or one day depending on the time of your exam.

Why do you need these badges?

As long as you work within the lubrication sector or interface with machines requiring lubrication, then you need to get these badges! Oil degradation occurs throughout the life of the lubricant whether it’s a small or large operation. By understanding how it degrades and ways to mitigate that degradation, you can save your equipment and avoid unwanted downtime. These badges were designed for the personnel in the field to allow them to make decisions regarding the lubricant and to empower them in taking steps to avoid degradation or mitigate it should the need arise. Consider it as getting your passport stamped by the ICML!

The courses offered by Fluid Learning are perfect for those seeking to understand lubrication deposits, what causes them and how they can be mitigated. While the content covered during these sessions align with the ICML VPR & VIM badges, they also add to a more holistic approach to varnish and deposits. Fluid Learning is an official ICML Training Partner and is currently the only one (of which I am aware) offering training prep for these badges. I highly recommend them for anyone seeking to learn more about or avoid sticky varnish situations.

At the moment of writing this article, there are only 8 people globally who have acquired these badges from ICML. I am the first female in the world to attain these badges but I will not be the only female for very long. Varnish is an issue which affects us all and we need to understand it, so we can prevent it and keep our equipment safe. I hope to see many more candidates with these badges in the near future!

Industrial / Strategic Tips

Food Grade Lubricants

Q: What are the classifications for Food grade lubricants?

If you’ve ever dealt with food grade lubricants in the past, you would have noticed that not all food grade lubricants are made to the same standard. When we think about it from a manufacturing standpoint, we can understand the need for varying specifications.

For instance, in a facility there are components that will come into contact directly with the food while there are others that will never make contact with the product being produced for consumption. As with all specifications, the prices of the lubricants created for regular non-food grade usage will differ from those that are specifically designed for food grade usage.

NSF Standards

NSF International is the body responsible for protecting and improving global human health. They also facilitate the development of public health standards and provide certifications that help protect food, water, consumer products and the environment.

Here are the different specifications for each of the food grades (used in most countries)¹:

NSF H1 – General or Incidental Contact

NSF H2 – General – no contact

NSF H3 – Soluble oils

NSF HX-1 – Ingredients for use in H1 lubricants (incidental contact) [usually additives]

NSF HX-2 – Ingredients for use in H2 lubricants (no contact) [usually additives]

NSF HX-3 – Ingredients for use in H3 lubricants (soluble contact) [usually additives]

Usually using a NSF certified lubricant goes hand in hand with an HACCP based food safety program (Hazard Analysis and Critical Control Points).

Here's a bit more info on the Categories and where they should be used³:

H1 - food grade lubricants used in food processing environments where there is a possibility of incidental contact.
H2 - non-food grade lubricants used on equipment and machine parts where there is no possibility of contact
H3 - food grade lubricants which are edible oils used to prevent rust on hooks trolleys and similar equipment.

ISO standards

There are ISO standards that govern food safety. These are;

ISO 22000 – developed to certify food safety systems of companies in the food chain that process or manufacture animal products, products with long shelf life and other food ingredients such as additives, vitamins and biocultures².

ISO 21469 – specifies the hygiene requirements for the formulation, manufacture and use of lubricants that may come into contact with products during manufacturing².

References:

Quick Reference Guide to Categories, NSF USDA. https://info.nsf.org/USDA/categories.html#H1
International Regulations for Food Grade Lubricants. Richard Beercheck. Lubes N Greases Europe- Middle East-Africa. June 2014. https://d2evkimvhatqav.cloudfront.net/documents/nfc_int_regulations_food_grade_lubricants.pdf?mtime=20200420102000&focal=none
Chemistry and the Technology of Lubricants Third Edition by Roy M. Mortier, Malcom F. Fox, Stefan T. Orszuilk (Editors), Chapter 8 Industrial Lubricants, C. Kajdas et al. Springer Dordrecht Heidelberg London New York. DOI 10.1023/b105569

Industrial / Strategic Tips

FZG Ratings

Q: What does FZG mean and why do gear oils have a rating?

FZG stands for “Forschungsstelle für Zahnräder und Getriebebau”, Technische Universität München (Gear Research Centre, Technical University, Munich), Boltzmannstraße 15, D-85748 Garching, Germany.

There are several FZG tests and these vary to establish different things. We will explore the two most common tests and what they mean.

The FZG tests were designed to accurately determine the types of gear failures that were influenced by scuffing, low speed wear, micropitting and pitting¹. While there are load other tests for gear oils (such as Timken OK test) these do not accurately identify the actual failure stages that gears experience.

FZG A/8.3/90

One of the most commonly used FZG test is the FZG A/8.3/90 according to DIN ISO 14635-1. This is mainly used for evaluating the scuffing properties of industrial gear oils². What do the numbers in the test mean?

The “A” represents an A-type gear with Pinion face width = 20mm, center distance = 91.5mm, number of teeth (pinion) = 16, number of teeth (gear) = 24. These are used in the test and are loaded stepwise in 12 load stages between Hertzian stress of pC= 150 to 1800N/mm².

The “8.3” represents the pitch line velocity of 8.3m/s in which the gears are operated for 15 minutes at each load stage.

The “90” indicates the starting temperature of the oil (90°C) in each load stage under conditions of dip lubrication without cooling.

After each load, the gear flanks are inspected for scuffing marks. However, the fail load stage is determined when the faces of all pinion teeth show a summed total width of damaged areas which is equal or exceeds one tooth width. In the gravimetric test, the gears are dismounted and weighed to determine their weight loss.

FZG A10/16.6R/90

The FZG A10/16.6R/90 on the other hand is used for automotive gear oils (GL4). It is the standard FZG gear rig test but the speed, load, load application and sense of rotation have been slightly altered.

The “A” represents an A-type gear however, these now have a reduced pinion face width to 10mm (from 20mm above).

The “16.6R” represents the increased speed of the pitch line velocity of 16.6m/s in which the gears are operated for 15 minutes at each load stage in a reversed sense of rotation.

The “90” indicates the starting temperature of the oil (90°C) in each load stage under conditions of dip lubrication without cooling.

FZG S-A10/16.6R/90

However, the FZG S-A10/16.6R/90 is the shock level test done for the GL5 oils. In this test the gears are directly loaded in the expected load stage and a PASS or FAIL is issued.

References:

ISO 14635-1:2000 Gears- FZG test procedures- Part 1: FZG test method A/8,3/90 for relative scuffing load carrying capacity of oils.
Test methods for Gear lubricants. Bernd-Robert Hoehn, Peter Oster, Thomas Tobie, Klaus Michaelis. ISSN 0350-350X GOMABN 47, 2,129-152 Stručni rad/Professional paper UDK 620.22.05 : 621.892.094 : 620.1.05

Industrial / Strategic Tips

Flender Specs

Q: Why should I use a Flender spec oil?

A lot of users ask about the need to use a Flender approved lubricant for their equipment! For a gear oil to be Flender approved¹ in one of its units, the oil must be of CLP* quality according to DIN 51517-3 and motor oils must meet and ACEA Classification E2, API CF/SF. Additionally, it must meet the minimum requirements as per their specified “Proofs of performance / minimum requirements table” where the lubricants are tested at approved laboratories.

*CLP (according to DIN 51517-3)² refers to an oil that contains additives which protect from corrosion, oxidation and wear in the mixed friction zone.

The manufacturer must also guarantee performance of the lubricant both for new oil and used oil up to a permissible range as per the following:

Mineral oils (API I & II and ester oils) shall be 10,000 operating hours (2 years max)
Mineral (API III) and Synthetic (PAO & PAG) oils shall operate for 20,000 operating hours (4 years max)
All oil must produce the minimum requirements with an average operating temperature of 80°C

The following are a list of tests required by Flender which must produce specified minimum results:

FZG Scuffing test in accordance with DIN ISO 14635-1 (A/8.3/90)
FE8 rolling bearing test in accordance with DIN 51819-3 (D-7, 5/80-80)
FVA micropitting test FV A 54 VII
Flender oil Foam test in accordance with ISO 12152
Compatibility with internal coating
Compatibility with outer coating
Filterability test FFT 7300 Rev.3
Compatibility with liquid sealing component

Flender specifies the viscosity in the series to be tested for the minimum requirements.¹

The Flender approval process ensures that the lubricant being used has been tested and can withstand some degree of micropitting, scuffing, foaming and is compatible with the surfaces in which it comes into contact. Thus, this makes the Flender approved lubricant more desirable for systems which place emphasis on the compatibility of all materials in the equipment (such as elastomers, paints etc). In conclusion, if you do have a Flender gearbox or equipment, it would be wise to use the Flender approved lubricant as they have gone the extra mile to ensure that the lubricant can protect your equipment.

Users can access a listing of approved Flender lubricants here: https://www.flender.com/en/lubricants

References:

Specification for the gear oil approval for FLENDER Gear units (AS 7300) link
Trends in Industrial Gear Oils by Jean Van Rensselar (STLE, Tribology & Lubrication Technology Magazine February, 2013) link