Uranium Corporation of
India Ltd.
A CASE STUDY IN
PINAKI ROY
A BRIEF RE-CAP of
MAINTENANCE
MAINTENANCE is the act of maintaining
or the state of being maintained.
It denotes the work ...
Basics of Maintenance
Maintenance technology comprises of technical
knowledge plus experience and their application
in ide...
Two Keywords of
Maintenance
• CLEANING
&
• LUBRICATION
• CLEANING PHILOSOPHY:
• IF YOU CAN’T SEE IT,
• YOU CAN’T FIX IT
• ...
LUBRICATION
• Dictionary defines lubrication
as the application of some oily
or greasy substance in order to
diminish fric...
STATUS of GREASE
- General Perceptions
Isn’t it true that of all types of lubricants in use, only
Grease is looked down up...
Grease – A Case Study in
UCIL
• UCIL stands for Uranium Corporation of India Ltd, a modern
Indian Public Sector Undertakin...
TRAINING – The key to change
The analysis highlighted that most workmen (even
some engineers) hardly had any knowledge of
...
Evolutionary Change –
The Model Adopted
• A team of related engineers were selected & sent for a
lubrication training cour...
Evolutionary Change –
The Line of Action
• A list of personnel from various maintenance
sections was prepared by taking th...
Training Content
• In order to provide training relevant to the
Equipment in use & the grasping
power/education levels of ...
A Layman's DEFINITION of
LUBRICATION
““To make smooth or slipperyTo make smooth or slippery
with oil, or other matter towi...
TECHNICAL DEFINITION OF
LUBRICATION
• LubricationLubrication
– any procedure that reduces friction
between two moving surf...
FRICTION
• Always exists where there is sliding contact
between two surfaces
• Always consumes power
• Always produces hea...
TYPES OF FRICTION
SLIDING FRICTION
(most)
ROLLING FRICTION
FLUID FRICTION
(least)
LUBRICATION, FRICTION AND WEAR
SIMPLE REPRESENTATION
UNLUBRICATED
METAL SURFACES
PRESSURE AND
SLIDING MOTION
FRICTION AND
...
LUBRICATION, FRICTION AND WEAR
LUBRICATION: “MAKES SURFACES SLIPPERY”
LUBRICATED
METAL SURFACES
PRESSURE AND
SLIDING MOTIO...
FRICTION
• Always exists where there is sliding contact
between two surfaces
• Always consumes power
• Always produces hea...
THE LAWS OF FRICTION
There are two laws of physics that govern sliding
friction:
1. The friction between two solid bodies ...
Frictional Conditions CoF (µ)
Fluid Friction 0.001 - 0.005
Rolling Friction
• Ball 0.002
• Roller 0.004
Sliding Friction
•...
CONDITIONS LEADING TO
BOUNDARY LUBRICATION
• STATIC LOAD
• SLOW SPEEDS
• HIGH LOADS
• ROUGH SURFACE FINISH
• SMALL CLEARAN...
µ
µ
region of boundary lubrication
partial fluid film lubrication
full fluid film lubrication
TYPES OF OF FRICTIONTYPES OF...
• Modes of lubrication
• Hydrostatic
• Hydrodynamic
• Elasto-hydrodynamic
• Boundary
• Regime depends upon
• Design
• Spee...
A solid to semi-fluid product of
dispersion of a thickening agent in
a liquid lubricant.
Greases consist of the following:...
COMPONENTS OF GREASE
• LUBRICATING FLUID
• THICKNER SYSTEM
• ADDITIVES
LUBRICATING OIL(Pet./SYN. 4-20%)
+THICKNER(SOAP/NON...
Mineral Oils
( Paraffinic or Naphthenic Hydrocarbon Based)
Synthetic Oils
(Chemically Synthesised Oils and Esters)
Silicon...
Soap based thickener system
( Product of reaction between fats and
alkalis)
Non-soap thickener systems
THICKENING SYSTEMS
Anti-oxidants
Antirust
Antiwear
Extreme Pressure
Tackifiers
Solid Lubricants
Friction Modifiers
Structure Modifiers
Metal ...
GREASE- CLASSIFICATION
THICKENERS
SOAP
SIMPLE SOAP COMPLEX SOAP
LITHIUM LITHIUM COMPLEX
CALCIUM CALCIUM COMPLEX
ALUMINIUM ...
 The interactions between thickenerThe interactions between thickener
and lubricant (Base oil +Additive)and lubricant (Ba...
PROPER GREASE SELECTIONPROPER GREASE SELECTION
 Due to the lack of specificity in most grease recommendations, it isDue t...
Additives and Base Oil TypeAdditives and Base Oil Type
 The additive and base oil types are otherThe additive and base oi...
Base Oil ViscosityBase Oil Viscosity
 The most important property of any lubricant is viscosity.The most important proper...
Grease Consistency andGrease Consistency and
Thickener TypeThickener Type
Now for that extra step:
• The consistency of gr...
Greases stay put
Greases seal out contaminants
Greases do not need circulation systems
Greases decrease dripping, splatter...
• REMAINS AT APPLICATION POINT & ADHERES TO SURFACE
• LESS FREQUENT APPLICATION NEEDED
• SEALS OUT CONTAMINANTS
• REDUCES ...
 Greases may not reach all placesGreases may not reach all places
in need of lubricationin need of lubrication
 Greases ...
• Viscosity - Know the viscosity of each grease and
the machine requirements
• Grease base - Which greases are compatible ...
 Removal
 Clean Area
 Inspection of New
Bearings
 Alignment
 Never assume the manufacturer has properlyNever assume the manufacturer has properly
lubricated the bearing from factory...
• Scoop or Paddle from a Container
• Tube Refills
• Refilling from a Storage Container using
Mechanical or Hydraulic Pumps
FAQ’s
In spite of covering most areas, there
were always plenty of questions.
The common ones were:
How much grease to pum...
HOW MUCH GREASE
TO PUMP
Pumping grease into a well-sealed bearing until
you see the grease leaving at the seal often
compr...
In Grease,what actually
lubricates?
It is the oil within grease that does the
lubricating, not the thickener. The
thickene...
How to Prevent Mixing Greases "Is
there a color and shape code used to
distinguish between different
greases?”
Use tags to...
IMPROPER SELECTION AND APPLICATION OF
GREASE
Grease lubricated
failures fall in 4 categories
• The selection and
applicati...
IN CONCLUSION….
• So the next time you hear
someone cursing this
semi solid slimy lubricant
please take a few minutes
and ...
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Grease presentation

  1. 1. Uranium Corporation of India Ltd. A CASE STUDY IN PINAKI ROY
  2. 2. A BRIEF RE-CAP of MAINTENANCE MAINTENANCE is the act of maintaining or the state of being maintained. It denotes the work undertaken for keeping something in proper condition i.e. upkeep. It can be machines, household goods or even yourself !!
  3. 3. Basics of Maintenance Maintenance technology comprises of technical knowledge plus experience and their application in identifying and implementing the best possible maintenance and repair techniques for all maintainable items, in line with organizational policy. • It provides a means to maintain the plant and equipment in a high state of operating efficiency and enhance its productivity.
  4. 4. Two Keywords of Maintenance • CLEANING & • LUBRICATION • CLEANING PHILOSOPHY: • IF YOU CAN’T SEE IT, • YOU CAN’T FIX IT • So use: • High pressure water jets • Anti-Rust & Grease removal compounds • Scrape, clean & re-paint regularly
  5. 5. LUBRICATION • Dictionary defines lubrication as the application of some oily or greasy substance in order to diminish friction. Though a valid definition, it fails to realize all that lubrication actually achieves. • Many different substances can be used to lubricate a surface. Oil and grease are the most common. Grease is composed of oil and a thickening agent to obtain its consistency, while the oil is what actually lubricates. The application determines which oil, commonly referred to as the base oil, should be used.
  6. 6. STATUS of GREASE - General Perceptions Isn’t it true that of all types of lubricants in use, only Grease is looked down upon & treated with disdain. While pouring engine oil in your car is considered normal, greasing is generally given to the mechanic or his assistant, as its supposed to be a menial & dirty job. LETS UNDERSTAND GREASE & GIVE ITS DUE
  7. 7. Grease – A Case Study in UCIL • UCIL stands for Uranium Corporation of India Ltd, a modern Indian Public Sector Undertaking, involved in mining & processing of Uranium Ore. A few years back, a sudden spurt in equipment breakdowns made us go in for a detailed root cause analysis to study the failures. Many factors surfaced but what was shocking was that in most cases the lack or improper method of greasing was the culprit. • This presentation highlights the steps taken to address the problem and also makes an effort to educate the viewers on the importance of Greasing by explaining its various facets.
  8. 8. TRAINING – The key to change The analysis highlighted that most workmen (even some engineers) hardly had any knowledge of lubrication and greasing. So the first challenge was to impart training in this domain. While this challenge involved imparting technical awareness regarding Lubrication, it was also an exercise in changing sleepy and often rigid Mind Sets.
  9. 9. Evolutionary Change – The Model Adopted • A team of related engineers were selected & sent for a lubrication training course which involved both theoretical and practical training. On return they were assigned the following responsibilities: • Create a broad based site specific pictorial awareness manual on lubrication in english and the local language as a handbook for the workforce • Evolve a mechanism to train identified personnel • Demonstrate and bring pride to the persons involved in lubrication and greasing
  10. 10. Evolutionary Change – The Line of Action • A list of personnel from various maintenance sections was prepared by taking their education, age & experience. • A short objective test of such personnel was conducted in order to asses their basic I.Q. & grasping potential. • The top eight were short listed & trained in house on the basics of lubrication by theoretical and practical on equipment coaching and thereafter assigned exclusive lubrication responsibilities
  11. 11. Training Content • In order to provide training relevant to the Equipment in use & the grasping power/education levels of those persons, course material was formulated. • A broad scheme of the training material which became the foundation for understanding lubrication in general & grease in particular, is given in thefollowing slides:
  12. 12. A Layman's DEFINITION of LUBRICATION ““To make smooth or slipperyTo make smooth or slippery with oil, or other matter towith oil, or other matter to overcome friction”.overcome friction”.
  13. 13. TECHNICAL DEFINITION OF LUBRICATION • LubricationLubrication – any procedure that reduces friction between two moving surfaces. • LubricantLubricant – Any material that reduces friction. – The main function of a lubricant is to separate two moving surfaces and make their relative movement easier. – Liquids used as lubricants achieve this by substituting low fluid friction in place of high solid-to-solid friction.
  14. 14. FRICTION • Always exists where there is sliding contact between two surfaces • Always consumes power • Always produces heat • Is independent of contact area and sliding speed • Is dependent on surface roughness and contact pressure • Represented by COEFFICIENT OF FRICTION
  15. 15. TYPES OF FRICTION SLIDING FRICTION (most) ROLLING FRICTION FLUID FRICTION (least)
  16. 16. LUBRICATION, FRICTION AND WEAR SIMPLE REPRESENTATION UNLUBRICATED METAL SURFACES PRESSURE AND SLIDING MOTION FRICTION AND HEAT (ENERGY LOSS) CATASTROPHIC FAILURE SEIZURE
  17. 17. LUBRICATION, FRICTION AND WEAR LUBRICATION: “MAKES SURFACES SLIPPERY” LUBRICATED METAL SURFACES PRESSURE AND SLIDING MOTION OIL FILM PREVENTS CONTACT FLUID VISCOSITY: “RESISTANCE TO FLOW”FLUID VISCOSITY: “RESISTANCE TO FLOW” or “INTERNAL FRICTION”or “INTERNAL FRICTION” FULL FILM, orFULL FILM, or HYDRODYNAMICHYDRODYNAMIC LUBRICATIONLUBRICATION
  18. 18. FRICTION • Always exists where there is sliding contact between two surfaces • Always consumes power • Always produces heat • Is independent of contact area and sliding speed • Is dependent on surface roughness and contact pressure Represented by COEFFICIENT OF FRICTION
  19. 19. THE LAWS OF FRICTION There are two laws of physics that govern sliding friction: 1. The friction between two solid bodies is independent of the area of contact. 2. The friction between two solid surfaces is proportional to the load by one surface on another. COEFFICIENT OF FRICTION µ = F / W where F = frictional force opposing motion And W = the load
  20. 20. Frictional Conditions CoF (µ) Fluid Friction 0.001 - 0.005 Rolling Friction • Ball 0.002 • Roller 0.004 Sliding Friction • Mixed Film 0.02 - 0.08 • Boundary 0.08 - 0.10 • Dry 0.15 - 0.40 LUBRICATION CONDITIONSLUBRICATION CONDITIONS
  21. 21. CONDITIONS LEADING TO BOUNDARY LUBRICATION • STATIC LOAD • SLOW SPEEDS • HIGH LOADS • ROUGH SURFACE FINISH • SMALL CLEARANCES • SHOCK LOADING
  22. 22. µ µ region of boundary lubrication partial fluid film lubrication full fluid film lubrication TYPES OF OF FRICTIONTYPES OF OF FRICTION
  23. 23. • Modes of lubrication • Hydrostatic • Hydrodynamic • Elasto-hydrodynamic • Boundary • Regime depends upon • Design • Speed • Load • Materials • Viscosity • Operating conditions etc. LUBRICATION CONDITIONSLUBRICATION CONDITIONS
  24. 24. A solid to semi-fluid product of dispersion of a thickening agent in a liquid lubricant. Greases consist of the following: 1. Additives 2. Thickener 3. Base oils
  25. 25. COMPONENTS OF GREASE • LUBRICATING FLUID • THICKNER SYSTEM • ADDITIVES LUBRICATING OIL(Pet./SYN. 4-20%) +THICKNER(SOAP/NON-SOAP 75-96%) +ADDITIVES(0-5%) = GREASE
  26. 26. Mineral Oils ( Paraffinic or Naphthenic Hydrocarbon Based) Synthetic Oils (Chemically Synthesised Oils and Esters) Silicone Oils (Polymerised product of Silicon Oxide) LUBRICATING FLUIDS
  27. 27. Soap based thickener system ( Product of reaction between fats and alkalis) Non-soap thickener systems THICKENING SYSTEMS
  28. 28. Anti-oxidants Antirust Antiwear Extreme Pressure Tackifiers Solid Lubricants Friction Modifiers Structure Modifiers Metal Deactivators ADDITIVES
  29. 29. GREASE- CLASSIFICATION THICKENERS SOAP SIMPLE SOAP COMPLEX SOAP LITHIUM LITHIUM COMPLEX CALCIUM CALCIUM COMPLEX ALUMINIUM ALUMINIUM COMPLEX BARIUM BARIUM COMPLEX SODIUM TITANIUM COMPLEX STRONTIUM MIXED SOAP NON SOAP INORGANIC ORGANIC ORGANOPHYLIC CLAY POLY UREA, etc Silica Based, etc
  30. 30.  The interactions between thickenerThe interactions between thickener and lubricant (Base oil +Additive)and lubricant (Base oil +Additive) together with the manufacturingtogether with the manufacturing process constitute the major part ofprocess constitute the major part of grease performancegrease performance
  31. 31. PROPER GREASE SELECTIONPROPER GREASE SELECTION  Due to the lack of specificity in most grease recommendations, it isDue to the lack of specificity in most grease recommendations, it is important to learn how to properly select greases for eachimportant to learn how to properly select greases for each application in the plant or equipment.application in the plant or equipment.  Proper grease specification requires all the components of oilProper grease specification requires all the components of oil selection and more. Other special considerations for greaseselection and more. Other special considerations for grease selection include thickener type and concentration, consistency,selection include thickener type and concentration, consistency, dropping point and operating temperature range, worked stability,dropping point and operating temperature range, worked stability, oxidation stability, wear resistance, etc.oxidation stability, wear resistance, etc.  Understanding the need and the methods for appropriate greaseUnderstanding the need and the methods for appropriate grease selection will go a long way toward improving lubrication programsselection will go a long way toward improving lubrication programs and the reliability of lubricated machinery.and the reliability of lubricated machinery.  Let’s go through the grease selection process step by step, startingLet’s go through the grease selection process step by step, starting with the most importantwith the most important
  32. 32. Additives and Base Oil TypeAdditives and Base Oil Type  The additive and base oil types are otherThe additive and base oil types are other components of grease that should be selected incomponents of grease that should be selected in a fashion similar to that used for oil-lubricateda fashion similar to that used for oil-lubricated applications.applications.  Most performance-enhancing additives found inMost performance-enhancing additives found in lubricating oils are also used in greaselubricating oils are also used in grease formulation and should be chosen according toformulation and should be chosen according to the demands of the application. However, therethe demands of the application. However, there are applications that might benefit from the useare applications that might benefit from the use of a synthetic base oil. Such applications includeof a synthetic base oil. Such applications include high or low operating temperatures, a widehigh or low operating temperatures, a wide ambient temperature range, or any applicationambient temperature range, or any application where extended re-lubrication intervals arewhere extended re-lubrication intervals are desired.desired.
  33. 33. Base Oil ViscosityBase Oil Viscosity  The most important property of any lubricant is viscosity.The most important property of any lubricant is viscosity.  A common mistake when selecting a grease is to confuseA common mistake when selecting a grease is to confuse the grease consistency with the base oil viscosity.the grease consistency with the base oil viscosity.  The majority of grease-lubricated applications are elementThe majority of grease-lubricated applications are element bearings, one should consider viscosity selection for thosebearings, one should consider viscosity selection for those applications.applications.  There are several common methods for determiningThere are several common methods for determining minimum and optimum viscosity requirements for elementminimum and optimum viscosity requirements for element bearings, most of which use speed factors, commonlybearings, most of which use speed factors, commonly denoted as DN or NDm.denoted as DN or NDm.  Speed factors account for the surface speed of the bearingSpeed factors account for the surface speed of the bearing elements and are determined by the following formulas:elements and are determined by the following formulas:  DN = (rpm) * (bearing bore)DN = (rpm) * (bearing bore) NDm =rpm * (bearing bore + outside diameter)/2)NDm =rpm * (bearing bore + outside diameter)/2)
  34. 34. Grease Consistency andGrease Consistency and Thickener TypeThickener Type Now for that extra step: • The consistency of grease is controlled by the thickener concentration, thickener type and the viscosity of the base oil. Even though base oil viscosity affects consistency, it is important to note that a grease can have a high consistency and a low base oil viscosity or vice versa. • Higher speed factors require higher consistency greases. Grade based on speed factor and operating temperature.
  35. 35. Greases stay put Greases seal out contaminants Greases do not need circulation systems Greases decrease dripping, splattering and leakage Greases suspend solid additives easily Greases are suitable for intermittent operations Greases work under extreme operating conditions Greases seal for life Greases reduce noise Greased machinery tends to need less power
  36. 36. • REMAINS AT APPLICATION POINT & ADHERES TO SURFACE • LESS FREQUENT APPLICATION NEEDED • SEALS OUT CONTAMINANTS • REDUCES NOISE AND VIBRATION • MAINTENANCE COSTS REDUCED • OPERATES OVER WIDE TEMP. RANGE • WATER RESISTANT • MORE EFFECTIVE FOR EXTREME CONDITIONS SUCH AS SHOCK LOADING, REVERSING OPERATIONS, LOW SPEED & HIGH SPEEDS HOWEVER BECAUSE OF THE SEMI-SOLID NATURE OF GREASES, THE COOLING AND CLEANING FUNCTIONS OF A FLUID LUBRICANT ARE NOT PERFORMED. ADVANTAGES OF LUB. GREASE OVER OIL
  37. 37.  Greases may not reach all placesGreases may not reach all places in need of lubricationin need of lubrication  Greases do not have any cleaningGreases do not have any cleaning effecteffect  Greases do not work as coolingGreases do not work as cooling agentagent  Greases cannot be used at asGreases cannot be used at as high speeds as liquidshigh speeds as liquids
  38. 38. • Viscosity - Know the viscosity of each grease and the machine requirements • Grease base - Which greases are compatible with bearing requirements • Is heat a problem - Grease life is halved for every 15 degrees C over 70 deg. C • Question the grease supplied in new equipment . Standardize with existing equipment • Location of grease fittings e.g. Center of pillow block for a W33 style bearing • Grease path - Does the housing design allow grease to easily enter the bearing
  39. 39.  Removal  Clean Area  Inspection of New Bearings  Alignment
  40. 40.  Never assume the manufacturer has properlyNever assume the manufacturer has properly lubricated the bearing from factory. The newlubricated the bearing from factory. The new bearing may have been shipped with a limitedbearing may have been shipped with a limited amount of lubrication inside. This level may notamount of lubrication inside. This level may not be enough to form the necessary film betweenbe enough to form the necessary film between the inner race and rolling elementsthe inner race and rolling elements..  Determine lubrication level by using soundDetermine lubrication level by using sound analysis or vibration monitoring methods.analysis or vibration monitoring methods. Remember, a “dry” or under-lubricated bearingRemember, a “dry” or under-lubricated bearing will sound louder or “scratchier” than a “quiet” orwill sound louder or “scratchier” than a “quiet” or “smooth” sounding properly lubricated bearing.“smooth” sounding properly lubricated bearing.
  41. 41. • Scoop or Paddle from a Container • Tube Refills • Refilling from a Storage Container using Mechanical or Hydraulic Pumps
  42. 42. FAQ’s In spite of covering most areas, there were always plenty of questions. The common ones were: How much grease to pump? In Grease, what actually lubricates? What to do if a grease drum is not labeled?
  43. 43. HOW MUCH GREASE TO PUMP Pumping grease into a well-sealed bearing until you see the grease leaving at the seal often compromises the seal and assures that you have too much grease in the bearing. A reasonable volume model to use is: V = D*B*.114, where V = Ounces per cycle, D = Bearing OD” and B = Bearing width”.
  44. 44. In Grease,what actually lubricates? It is the oil within grease that does the lubricating, not the thickener. The thickener is an agent that holds oil like a reservoir. In many applications it also allows oil to release slowly as it becomes required in bearings and frictional machine surfaces
  45. 45. How to Prevent Mixing Greases "Is there a color and shape code used to distinguish between different greases?” Use tags to identify product type, quantity and interval. Colors and shapes can be used to tag grease guns and transfer containers. Standardize lubricants. Instead of using a poly-urea and a lithium-based EM grease, consolidate so that all similar machines receive the same lubricant. Use different grease fittings for different greases. This is an effective way of reducing cross contamination. Training. Training is a most important component in proper lubrication.
  46. 46. IMPROPER SELECTION AND APPLICATION OF GREASE Grease lubricated failures fall in 4 categories • The selection and application of the wrong type of grease • Incompatibility resulting in excessive softening • Contamination resulting in excessive wear • Too much or too little grease applied Points to remember • Do not mix greases of different thickener types. • Keep similar thickeners in the same application • Lack of grease can cause failure, but too much grease is the primary cause of failure since the excess lubricant causes high temperatures, which in turn oxidizes the grease
  47. 47. IN CONCLUSION…. • So the next time you hear someone cursing this semi solid slimy lubricant please take a few minutes and tell him the true story of Grease. • Whether he understands it or not is a different matter but in future he’ll think twice before ‘greasing any palms’!
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