For those entering the field, what is the most difficult part of tribology science or lubrication engineering to understand?
TLT Sounding Board March 2014
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As a multidisciplinary science, tribology poses many challenges for the novice. TLT readers responding to this month’s survey said the most difficult aspects for newcomers to understand include the Stribeck curve, the role of additives, lubrication regimes, viscosity, just about everything relating to grease and even viscosity, the primary and most important characteristic of a lubricant. Many readers said the difference between book learning and real-world application can be vast for neophytes. For veterans of the field, challenges often come in the form of staying current on emerging products and processes and remaining open to new ideas and ways of thinking. All survey respondents noted that when it comes to tribology and lubrication engineering, the learning never stops. Said one respondent: “When we think we have all the answers, it is time to either check our pride and hit the books or retire.”
The most important part is the addition of lubricant to that very specific part of the machine deemed most important for the output.
Lubricant chemistry/additives, interaction and mechanism.
Major differences between elastohydrodynamic and boundary lubrication are very confusing and often discourage new researchers to investigate the details of tribological or lubrication issues.
The Stribeck curve, the concepts and properties of lube films in contacts, the changes that alter in-service lubes and everything about grease.
Reducing friction baffles them.
The vast differences between book learning and long-term practical experience.
Failure analysis.
The chemistry of it.
Friction is difficult to understand because its origin is still under extensive study.
EHL calculations.
Adhesive wear hydrostatic lubrication.
The boundary lubrication, hydrodynamic.
The science of what happens at l-s interfaces dynamically and being able to translate information into a lubricant might be an area. If a person is in a field where they are responsible for lubrication in many different environments, it might take them awhile to get a breadth of knowledge to cover all the areas.
Basic consideration in designs of an additive package.
Lubrication regimes and possibly rheology. Advanced oil analysis techniques and how they relate to other test data.
Fluid mechanics versus hardware.
Engineering design is the most difficult. Second, what are the characteristics common to additives that are designed for a particular application?
Formulation can be difficult because, in addition to learning about the industrial application, one must transition from the world of reagent-grade chemicals and simple systems to commercial industrial chemicals, complex mixtures and proprietary packages, while learning how to deal with complex systems including huge numbers of possible interactions.
Understanding grease tribology and filtering out the myths.
Straight oil applications are much easier to understand. Emulsion application systems and emulsion behavior are the most difficult.
Chemistry and physics of what is happening in a solid lubricated sliding contact.
Formal training requires real world experience to become truly effective. Students of tribology need good summer internship experiences.
The concept of chemical wear and extreme pressure protection as opposed to physical boundary protection.
Understanding the Stribeck curve.
How laminar shear fluid works in viscosity and how friction affects this process.
For engineers it is the chemistry, but for organic chemists it is the materials science and all the possible applications from metalworking to pumps, even engine oil.
Heat transfer.
The sheer magnitude of the applications.
It’s difficult to understand the breadth of the field since it involves analysis, experiment, chemistry, topology, physics, measurement, etc.
Seeing the actual mechanical components that the lubricant is performing in.
Integrating laboratory results with field studies—knowing how the lab results may or may not apply in the real world.
As a chemist, the most difficult concepts for me to grasp were mechanical. Things like automotive clutches and differential gears are foreign concepts to a young chemist.
Grease. Everything about grease.
I think this is highly dependent upon your background. A mechanical engineer has a very different perspective than a chemist or a material scientist. So perhaps it is the diversity of knowledge that is needed that can be overwhelming for someone new to the field.
Different forms and depictions of lubrication and how it is influenced and affected.
How important it is for workers on the floor taking care of the equipment to have some knowledge about lubrication and the impact that it can have if they are not properly trained.
That is truly dependent upon their entry point into this industry. My entry was as a laboratory technician in an oil analysis lab, and I had no idea what tribology actually involved. Nine years later, I manage a laboratory dealing in condition monitoring of in-service lubes. My biggest barrier into this industry was my own lack of education, which I overcame with questions, training and experience.
Differences in kinematic and dynamic viscosity measurements.
Having an open mind and embracing the past, as well as current and future opportunities.
Elastohydrodynamics.
The acronyms. Once you have that language down, you can understand the conversations much faster.
The theoretical aspect of how various frictions influence Newton’s second law of motion. After a few years, I am now somewhat comfortable with this aspect, but as a chemist entering the field it was quite difficult for me to grasp. Nevertheless, I started from scratch, deriving any equations I encountered and finally I became comfortable with it.
Molecular structure of lubricants and fuels.
Much like organic chemistry, you have to try and understand principles that you most often cannot see and have to visualize conceptually.
Fluid film strength as it relates to viscosity and additive chemistry’s influence on lubrication regimes.
Solid lubricants.
Basics of lubrication. Viscosity kinematic and dynamic.
Learning that no one has all the answers. You’re better off putting your pride aside and asking questions of your mentors. Only with a humble attitude will experience bring true knowledge.
The relationship that tribology has on wear phenomena.
The hydrodynamic lubrication regime. Understanding that too much oil might cause problems.
Fluid film thickness scales.
“Tri” means you have to try harder. Three sciences encompass tribology: chemistry, physics and mechanical engineering. I have met very few who truly understand organic chemistry.
Most specifications are written to minimum performance standards, not optimum or higher performance.
Information is presented in such a vast arena that the message often gets diluted. Need to start with the core building blocks that work out. Many start with a data sheet and either get lost or fall asleep.
Used oil analysis.
How lubrication and tribology are connected. I have no clear definition of tribology.
Metalworking fluids.
That the coefficient of friction is not a constant.
Going from theory to reality.
Fundamentals of lubrication must be fully understood to become an expert in the field.
Learning to set aside the fear: “I can’t do this.”
Lubrication fundamentals.
Viscosity. With all the different units that have been used over the years, it can become a challenge.
Principle of friction, wear and lubrication in the macro- and micro-scale.
Lubricant applications and proper lubricant selection, especially when you go beyond the automotive lubricant to the industrial field.
The change in performance between laboratory conditions and the real world.
For me it has been different types of greases and additives.
Names of products continue to change. What specs do they cover?
Bearings.
The difference between Group I, II, III and IV basestocks and how this affects the end formulation.
That there could be so many fields with discoveries yet to be made and that they could be so focused.
The kinetics of corrosion.
Tribology’s overall importance.
How many days a year do you estimate you spend expanding your knowledge of tribology science or lubrication engineering?
0 days
2%
1-10 days
27%
11-20 days
22%
21-30 days
20%
>30 days
29%
Based on responses sent to 13,000 TLT readers.
What is the most difficult part of tribology science or lubrication engineering to understand, even for industry veterans?
Flushing/cleaning a large industrial circulation system, especially thermal oil system in OSB mills (often more than 250,000 liters of oil circulating).
Explaining the reasons and causes of tribological or lubricant issues always remains the most challenging. Should that be material hardness, surface texturing, lubricant starvation, accidental overloads, etc.? It is usually very easy to start heading in the wrong direction and failing to find a solution to the problem.
Bridging the gulf between the engineering approach (bench test and math models of bearings and gears) and the lube approach (chemistry, formulation and lab/analytical chemistry tests).
Understanding the resistance to flow.
I’d say the many marketing claims versus the actual long-term testimonial experiences with given lubes.
Biological control of water-containing fluids.
Failure analysis. Cleanliness. Chemistry.
Tribochemical reaction is an elusive and complex subject, even for long-time veterans.
Interpretation of the tribological tests because of the multiple connections with chemistry, physics, material sciences, etc. Diagnosis of wear mechanisms testing to validate computational models.
Bearings and gear lubrication.
I believe the biggest problem I run into is understanding the most current problems my clients face and identifying new solutions to new problems or updating old solutions to old problems.
Pressure-viscosity relationships of lubricants.
Bench test designs and development in performance evaluation of lubricants.
The designers should be proficient with not only the bench test machines but also the correlating real world operations, in addition to a strong tribology and lubricants background.
For me it is when you get a challenge that you don’t normally handle and trying to remember the details to help the customer.
Understanding grease tribology and filtering out the myths.
Viscosity of lubricants.
Generally, the corporate vision of perpetual improvement is only a motto.
Troubleshooting at an end-user plant requires noticing factors outside one’s specific discipline and understanding a total system.
Emulsion application systems and emulsion behavior.
Heat transfer.
Root cause analysis of equipment or surface failure. No matter how much you know, the real-world equipment failures show there is still much to learn. I think veterans try too much to shoehorn their previous experience/thinking into new scenarios.
Being forced to use certain materials because of customer insistence instead of the best available technology.
Interactions between various additives in lubricants.
The interaction between chemistry and mechanics.
Understanding the relationship between friction and lubrication.
The ever-changing landscape of raw materials, both changing and being available.
Assessing the practical value of new materials.
Practical problem-solving. It is often difficult to post facto determine why a system failed.
The amount of constraints acting on industrial applications and the right and dedicated choice of lubricant properties. The amount of dedicated and high-performance lubricants and the lack of diffusion of knowledge on these fields.
Long-time veterans sometimes have a hard time adapting to advances in technology. Buying into change can be difficult. If it has worked for so many years, why change...?
New ways of testing and understanding new protocol. So many dynamics are changing in the field of lubrication that it is a constant education process!
Developing tests that mimic field conditions.
I think the biggest hurdle for veterans of the field is keeping up with regulatory and formulary changes that are constantly occurring. The toolbox is always changing, and those time-tested formulary tools can be restricted by the changing demands of regulators and OEMs.
I think the details of the surface chemistry taking place during sliding and wear events are some of the most challenging parts of tribology, even for veterans.
Durability of lubricants.
Viscometrics over pressures and flows.
Keeping performance levels the same or improving them while making the products more environmentally friendly, renewable and safer for use. And, of course, all at the same price.
Lubrication calculations for proper lubrication of greased bearings.
The importance of keeping focus on the micron-size range and not just what can be seen with the human eye. It requires a change in culture and the way lubrication is thought of.
Dealing with the rig test or engine test variability (uncertainties) changing with time has been the biggest problem I face in my career.
Keeping pace with the ever-changing technological landscape. Once we have experience, we think we have knowledge and begin to apply what we know. This brings some successes, and we get busy. Next thing we know, while we’re applying daily what we learned years ago, time has passed us up again. We must always be alert to those areas of weakness. The learning never stops. When we think we have all the answers, it is time to either check our pride and hit the books or retire.
If your organization did not support your study of tribology science or lubrication engineering, would you seek to expand your knowledge on your own?
Yes
84%
No
16%
Based on responses sent to 13,000 TLT readers.
Editor’s Note: Sounding Board is based on an e-mail survey of 13,000 TLT readers. Views expressed are those of the respondents and do not reflect the opinions of the Society of Tribologists and Lubrication Engineers. STLE does not vouch for the technical accuracy of opinions expressed in Sounding Board, nor does inclusion of a comment represent an endorsement of the technology by STLE.