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Lubrication fundamentals
The document provides an overview of lubrication fundamentals including tribology, lubrication functions, lubrication films and regimes, base oils, additives, greases, lubricant failures, and oil analysis basics. It discusses topics such as how lubricants are formulated using base oils and additives, common lubricant types, mineral and synthetic base oil properties, grease consistency, grease thickeners, and ways that lubricants can fail through contamination, oxidation, thermal degradation, and additive depletion.
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Lubrication fundamentals
- 2. • Introduction • BaseOil • Additives • Grease • Lubricants Failures • Viscosity • Grease Application Method • Oil Application Method • Handling, Storage and Management of Lubricants • Basics of Oil Analysis CONTENT
- 3. Introduction • Tr ib o l o g y. • L u b r i c a t i o n f u n c t i o n . • L u b r i c a t i o n f i l m a n d r e g i m e . • Fa c t o r s e f fe c t i n g o i l re g i m e .
- 4. Tribology Tribology: A studyof friction, wear and lubrication. • Friction: the resistance force between two bodies where one body moves to the surface of the other. • Wear: rubbing away of the material surface. • Abrasive wear (cutting wear): wear due to embedded of hard material into soft surface. • Adhesive wear (Galling or scuffing): wear due to sliding surfaces contact of one into another. • Fatigue wear: wear due to cyclic loading of a surface. • Lubrication: application of some oily or greasy substance in order to minimize friction. According to tribologist Ernest Rabinowicz (MIT)
- 5. Lubrication functions Friction control Wearcontrol Corrosion control Contamination control Temperature control Reduce heat generation and power consumption Reduce mechanical and corrosive wear Protects surfaces from corrosive substances Transports contaminants to filters Absorbs and transfer heat
- 6. Lubrication Films andLubrication Regime Viscosity Oil Film Suspended Oil Film Chemical Oil FilmLubrication Film Hydrodynamic Mixed BoundaryLubrication Regime Full speed condition Start, stop and shock load condition metal lubricant Anti-wear additive Film thickness > 5 & < 200 microns Film thickness < 1 micron
- 7. Factors effecting lubricantregimes • Speed • Load • Viscosity • Additives • Oil temperature Stribeck Curve
- 8. Base Oil • Ho w l u b r i c a n t s a r e fo r m u l a t e d . • C o m m o n l u b r i c a n t t y p e s . • B a s e o i l . • M i n e ra l o i l p ro p e r t i e s . • S y n t h e t i c l u b r i c a n t s a n d i t s p r o p e r t i e s . • W h e n t o s e l e c t s y n t h e t i c o i l ?
- 9. How Lubricants areFormulated B a s e O i l Mineral Synthetic Vegetable Enhance base oil properties
- 10. Common Lubricants TypesB a s e O i l Lubricant Description Application R&O Rust and oxidation inhibited oil Bearing oils AW Lubricating oil with anti-wear (AW) additive Hydraulic fluids EP Lubricating oil with extreme pressure (EP) additive Gear oils COMP Compounded oils containing synthetic fatty-acid agents Worm gear oils Motor Oil Anti-wear with detergents and dispersants Internal combustion engine oils • AW lubricant: lubricants that improve service life of elements operating in boundary lubricant regime. • EP lubricant: lubricants that impart to rubbing surfaces to carry greater loads to prevent excessive wear and damage. • Detergents and dispersant: additive that keeps insoluble materials in homogenous solution to prevent settle out and accumulate.
- 11. Base Oil Ba s e O i l Derived from vegetable oils Man- made fluid Crude oil derivative Most lubricating oils come from petroleum (95%) Types of Base Oil
- 12. Common mineral oil: 1)Paraffinic 2) Naphthenic 3) Aromatic Mineral Oil Properties B a s e O i l PARAFFINIC NAPHTHENIC VISCOSITY INDEX 95-105 30-70 POUR POINT Wax pour point Lower than paraffinic FLASH POINT Higher than Naphthenic Lower than Paraffinic ADDITIVE SOLVENCY Poor to fail Good APPLICATION Crankcase oil, hydraulic oil, gear oil, and Bearings oil Refrigerant oils Compressor oils
- 13. Synthetic Lubricants Ba s e O i l Synthetic lubricants are man made lubricants using mineral oil or other raw materials as base fluid. • provides superior mechanical and chemical properties. • Made by polymerization. Common Synthetic Lubricants : Fluid Application Polyalphaolefins (PAO) Engine oil, gear oils, bearing oils and lube-for-life application Diesters and Polyol Easters Compressor oils, co-base stock with PAO, oil mist and jet engine oil. Phosphate Easters Fire resistance fluid used in: power plant, mining and aircraft. Polyalkylene Glycols Refrigeration compressor, H1 food grade etc. Silicones High temp fluid and lubricant contacting chemicals
- 14. Properties What doesit mean? Advantages Higher flash point Improved fire resistance and thermal stability Lower pour point Improved low temp pumpability Fire resistance Safe for high-risk hydraulic applications Thermal stability Oil doesn’t degrade at high temperatures Oxidation stability Resist sever application High viscosity index Function like multi-grade oil Lower friction Reduce energy consumption Natural detergency Keeps surface clean of deposits High shear strength No viscosity thinning Disadvantages High cost Synthetic lubricant costs 04 to 15 times more than mineral oil Toxicity Phosphate Easter may be a toxicity risk Seal compatibility Some seals may shrink or swell with synthetic oils and some incompatible with coating (paint) Hydrolytic stability Easter based synthetics may degrade in presence of water Mix ability Some are unmixable in other fluids Synthetic Lubricants Properties B a s e O i l
- 15. When to SelectSynthetic Oil B a s e O i l 1. When equipment performance demands exceed the capabilities of mineral oil. 2. Cost reduction. 3. Safety and environmental enhancement. High Oxidation Stability • High temperature application. • Longer lubricant life. • Low deposit forming Improved Lubricity • Reduce equipment wear. • Longer equipment life. • Lower maintenance cost. • Energy saving by reducing friction. High Viscosity Index and Low Pour Point • High temperature range operation. • Satisfy low temperature application Other Factors • Low volatility. • Anti-foaming. • Excellent demulsibility.
- 16. Additives • A dd i t i v e s d e f i n i t i o n . • Ro l e o f a d d i t i v e s . • A d d i t i v e s p o l a r i t y. • Ty p e s o f a d d i t i v e s .
- 17. Additives Definition Ad d i t i v e s 0.1% 30% Additives percentage in base oil 1% 5% 10% Gears & Hydraulic Oils Engine Oil Additive: a compound that added to base oil to enhance some properties.
- 18. Role of AdditivesA d d i t i v e s
- 19. Additives Polarity Additive polarity:The tendency of additive's molecules to react with other polar materials in contact with oil. A d d i t i v e s Polarmaterial Water Glass Metal Wood Non-Polarmaterial Teflon Mineral oil Wax Polar mechanism What happen? Additives Particle enveloping Additive clings to particle surface Metal deactivators, detergents and dispersant Water emulsifying Polar head of additive to droplets of moisture Emulsifying agent Metal wetting Additive anchors to metal surface Rust inhibitors, AW&EP additives, oiliness agent and corrosion inhibitors
- 20. Types of additives Additivetype Function Compound used Antioxidant/oxidation inhibitors Prevent the formation of acids, varnish, and sludge by Attacking oxidants like heat, water and air Zinc Dialkyldithiophosphate (ZDDP), Peroxide Decomposer Rust & corrosion inhibitors Protects surface from rust and corrosion Sulfonates, phosphoric, succinic acid and calcium phenol sulfides Dispersant Disperses engine soot particles in oil Succinimides and other organic compounds Detergents Scrubs engine surface of deposits and neutralize acids Organometallic soaps of barium, calcium and magnesium Anti-Wear & Extreme Pressure agents Protects surface from wear Zinc Dialkyldithiophosphate (ZDDP) AW Sulfur phosphorus EP VI improvers Improve VI of oil Radial Polyisoprene, Polyisobutylene, Polymethacrylates and Olefin co-polymer Defoamants/antifoam agents Retard the formation of stable foam on the surface of the oil Methyl silicone and organic polymers (polymethacrylate) Demulsifying agents Separate water from oil salt of an amphiphilic amine and an amphiphilic acid Pour point depressants (PPD) Control wax crystal formation poly alkyl methacrylates, Chlorinated wax polymethacrylates, polyacrylates A d d i t i v e s
- 21. Grease • L ub r i c a t i n g g r e a s e . • G r e a s e t h i c ke n e r • G r e a s e a d v a n t a g e s a n d d i s a d v a n t a g e s . • G re a s e c o n s i s t e n c y. • G r e a s e d r y - o u t .
- 22. Lubricating Grease What isGrease: Grease is a solid to semi-fluid product of thickening agent in a liquid lubricant. G r e a s e Lubricating Grease Base oil 70 to 95% Thickener 3 to 30% Additive 0 to 10% National Lubricating Grease Institute is an international trade association that serves the grease and gear lubricant industry
- 23. Grease Thickener What isGrease Thickener: Grease thickener is a material that added to lubricant to produce the solid to semi- fluid structure. Types of grease thickener: 1. Simple soap thickener 2. Complex soap thickener 3. Non-Soap thickener G r e a s e Long-chain Fatty Acid Metal Hydroxide (Li,Na,Al,Ca) Metal Soap Long-chain Fatty Acid Short chain Fatty Acid Metal Hydroxide (Li,Na,Al,Ca) Complex Metal Salt Soap
- 24. Grease Advantages andDisadvantages Advantages Disadvantages Better stop-start performance (lower risk of dry starts) Tends to hold heat in place (reduced cooling/heat transfer) Less risk of leakage and starvation Limitation of bearing speed (to avoid heat generation of high viscosity grease) Seals out contaminants Poor compatibility of grease thickeners Less risk of product contamination (Due to its resistance to flow onto products) Lower resistance to oxidation Provide squeeze film under vertical loading Lower contamination control (particles in grease suspended permanently) Serves better in lubed-for-life applications Frequent occurrence of over and under greasing (difficult to control quantity) Insoluble solid additives remain suspended in grease Difficult to sample and analyze in-service grease G r e a s e
- 25. Grease Consistency Grease consistencyis the ability of grease to resist the deformation under mechanical force. Factors effecting grease consistency: • Viscosity of base oil. • Thickener type and concentration. • Temperature. • Agitation. • Pressure. • Contamination. G r e a s e Field condition NLGI # ASTM Worked penetration @ 25 ◦C Appearance (@ room temp) Food analogy 000 445-475 Fluid Cooking oil 00 400-430 Semi-fluid Apple sauce 0 355-385 Very soft Brown mustard 1 310-340 Soft Tomato paste 2 265-295 Normal Peanut butter 3 220-250 Firm Vegetable shortening 4 175-205 Very firm Frozen yogurt 5 130-160 Hard Smooth pate 6 85-115 Very hard Cheddar cheese Cone Penetrometer Used to measure grease consistency NLGI Consistency Number
- 26. Grease Dry-Out Gr e a s e Contamination • Dirt, dust, fly ash. • Incompatible grease. Oxidation • Heat. • Water. • Metals. Volatilization • High temperature. • Low flash point. Bleed • Vibration. • High temperature. • Low base oil viscosity. Grease Dry-Out
- 27. Lubricants Failures • Ho w l u b r i c a n t p r o p e r t i e s c h a n g e ? • H o w l u b r i c a n t s fa i l ? • C o n t a m i n a t i o n . • O i l d e g ra d a t i o n . • A d d i t i v e d e p l e t i o n .
- 28. How Lubricant PropertiesChange? Base oil Additive Thickener Mixed lubricant Incompatibility: • Sludge. • Varnish. • Viscosity change. • Oxidation stability. Incompatibility: • Neutralizer. • Sludge. • Varnish. Incompatibility: • Consistency change. • Separation. Contamination • Oxidation. • Physical properties. • Thermal degradation. • Radiation. • Oxidation. • Accelerated depletion. • Chemical reaction. Incompatibility: • Consistency change. • Separation. Mechanical shear • Oxidation. • Shear out of VI improver& depressant. • Consistency change. Storage - • Separation. • Insoluble additive. • Separation. In-Service Environment • Oxidation. • Thermal degradation. • Chemical reaction. • Filtration. • Separation. • Evaporation. • Centrifugal separation. • Thermal separation. L u b r i c a n t s Fa i l u r e
- 29. How lubricants Fail? Contamination Externalsource such as dirt, water and material Oil Degradation Oxidation High temperature Additive Depletion Decomposition Separation Adsorptive L u b r i c a n t s Fa i l u r e
- 30. Contamination Contaminant Change chemical properties ofoil Change physical properties of oil Attacks machine surface Solids dirt • Oxidation. • Additive depletion. • Viscosity effected. • Varnish. • Abrasion. • Surface fatigue. Water • Oxidation. • Additive depletion. • Viscosity effected. • Acidity destruction. • Rust. • Cavitation. • Scuffing. Fuel • Additive depletion. • Sulfur. • Lowers flash. • Lowers viscosity. • Increase vapor pressure. • Sulfuric acid corrosively. • Film strength loss. Air • Oxidation. • Oxidation. • Viscosity increases. • Foam. • Rust & corrosion. • Varnish. • Cavitation. Heat • Thermal degradation. • Oxidation. • Volatility. • Viscosity effected. • Varnish. • Acidity. • Film strength loss. L u b r i c a n t s Fa i l u r e
- 31. Oil Degradation Oxidation Degradation oflubricant by chemical reaction involving O2. Oxidation indicators: • Darkening. • Foul odor. • Acid no. increase. • Viscosity increase. • Oxidation. Thermal Breakdown High oil temperature accelerates oil degradation (for every 10 ◦C increases, oil life cut in half) Oxidation and high oil temperature leads to varnish and sludge. Varnish: film deposit occurring in interior parts. L u b r i c a n t s Fa i l u r e On Field On Lab
- 32. Additive Depletion Additive depletionmeans change in additive’s molecules irreversibly. L u b r i c a n t s Fa i l u r e Decomposition Neutralization Hydrolysis Oxidation Thermal degradation Shear down Separation Condensation setting Filtration Aggregate adsorption Evaporation Centrifugation Adsorptive Surface adsorption Rubbing contact Particles scrubbing Water wasting
- 33. Viscosity • V is c o s i t y a n d v i s c o s i t y i n d ex . • M e a s u r e m e n t o f v i s c o s i t y. • E n g i n e o i l v i s c o s i t y c l a s s i f i c a t i o n . • G e a r o i l v i s c o s i t y c l a s s i f i c a t i o n .
- 34. Viscosity Viscosity: measurement ofa fluid’s resistance to flow and shear. Viscosity influenced by: • Temperature. • Water. • Contaminants. • Pressure. • Chemical change. • shear (large molecules breaks to small pieces) Viscosity selection application: V i s c o s i t y Low viscosity application High viscosity application High speed Low speed Smooth surfaces High load EP additives Shock load Cold temperature Hot temperature Heat exchange used Abrasive in oil Higher viscosity
- 35. Viscosity Index Viscosity index:measure of a fluid’s viscosity changes with temperature. The higher viscosity index, the smaller the relative change in viscosity with temperature. Viscosity index is determined experimentally by taking its viscosity at 40 ◦C and 100 ◦C . V i s c o s i t y Viscosity/temperature chart VI value Oil type -20 to 0 Phosphate ester 0 to 60 Naphthenic mineral oil 60 to 100 Paraffinic mineral oil 100 to 200 Synthetic oil
- 36. Measurements of Viscosity AbsoluteViscosity (µ) • Unit: Centipoise (cP) • Formula: µ=ʋ* SG (mPa.s) • Measurement device: Rotary viscometer (Brookfield) SG= Ꝭoil/ꝬH2O SG: specific gravity Ꝭ: Density Kinematic Viscosity (ʋ) • Unit: Centistoke (cSt) • Formula: ʋ=µ/SG (mm2/s) • Measurement device: Capillary viscometer V i s c o s i t y
- 37. Engine Oil ViscosityClassification SAE J-300 Engine Oil V i s c o s i t y
- 38. Gear Oil ViscosityClassification V i s c o s i t y SAE J-306 Gear Oil
- 39. Grease Application Method •M a n u a l g r e a s i n g . • S i n g l e p o i n t l u b r i c a n t s . • C e n t ra l i ze d m u l t i - p o i n t l u b r i c a t i o n s y s t e m .
- 40. Manual Grease Gun Advantages: •Lower cost. • Simple to use. • Low maintenance. Disadvantages: • High labor cost. • Over or under greasing risk. Manual Greasing Grease Application Methods Tips to use: • Purge a small amount of grease to flush away debris. • Measure grease weight per shot using scale. • Wipe fitting before dispensing. • Use grease cap after re- greasing. How much volume per re-greasing? SKF Formula: G= 0.005 DB Where: G: grease quantity in grams. D: bearing outside dia (mm) B: bearing width (mm)
- 41. Single Point Lubricants(SPL) Application: • Lubrication in remote or restricted access area. • Enabling continuous or periodic lube supply. • Increases machine reliability. Types: • Spring type grease cup. • Gas type SPL. • Pump type SPL. Grease Application Methods Spring type grease cup Pump type SPL Gas type SPL
- 42. Centralized Multi-point LubricationSystem Components: • Lubricant reservoir. • Pumping station. • Flow dividers. • Metering/controlling valve. • Lubricating nozzle. Lubricating system: • Parallel (non-progressive). • Series (progressive). Types: Grease Application Methods Single-line Parallel System Single-line Series System Dual-line Parallel
- 43. Oil Application Method •L u b r i c a t i n g o i l d e l i v e r y o p t i o n s . • M a n u a l l u b r i c a t i o n . • D r o p a n d w i c k fe e d c u p s . • C o n s t a n t l e v e l o i l . • O i l l i f t e r. • S p l a s h l u b r i c a t e d g e a r d r i v e . • P r e s s u r e s p ray l u b r i c a t i o n . • O i l m i s t l u b r i c a t i o n . • C o n t i n u o u s f o r c e d o i l c i rc u l a t i o n .
- 44. Lubricating Oil DeliveryOptions Manual: • Brush • Hand pad • Oil cans • Spray bottle Flood, Bath & Splash: • Bearings • Gears • Crankcase Gravity: • Drip feed • Wick feed • Constant level oilers • Oil cups Mist: • Pure mist • Purge mist • Air-line oiler Oil Lifters: • Rings • Collar • Slingers • Flingers • Paddle gears • Capillary Pressure: • Spray • Centralized system • Single point oilers Circulating: • Wet sump • Dry sump • Hydraulic Oil Application Methods
- 45. Manual Lubrication Advantages: • Lowercost. • Easy to apply. • Inspection can be performed. Disadvantages: • Require frequent re-lubrication. • High contamination risk. • High labor cost. • Difficult to apply during running condition Oil Application Methods
- 46. Drop and WickFeed Cups Advantages: • Simple and low cost. • Variable feed rate. • Oil level can be inspected easily. Disadvantages: • Dirt and water can restrict flow in wick. • Wick must be replaced frequently. • Flow rate need to be adjusted frequently. • High contamination risk during refilling. Oil Application Methods Drop feed oiler Wick feed oiler
- 47. Constant Level Oiler Advantages: •Low maintenance. • Oil level can be inspected easily. • Sealed against contamination. Disadvantages: • Contamination risk during refilling. • Gasket degradation. • Adjusting to wrong oil level. • Oil level can not be reduced. Oil Application Methods Mechanism When reservoir level drops, air will enter to the bottle and the oil will flow to maintain the constant level..
- 48. Oil Lifter Oil liftersutilizes rotating mechanisms to lift oil up to gears or bearings during running. Oil Application Methods
- 49. Splash-Lubricated Gear Drive Splashlubrication: splash oil by gear teeth, or any projection dip into the oil reservoir during running condition. Notes: • Channeling risk in cold-start conditions. • Speed/viscosity limitations. • Dry-start risk. • Correct oil level is critical. Oil Application Methods
- 50. Pressure Spray Lubrication Pressurespray systems use compressed air to spray the lubricant which delivered by pump on sliding parts. Components: • Oil pump. • Compressed air supply. • Ejectors. • Spar nozzles. Oil Application Methods
- 51. Oil Mist Lubrication Oilmist is the transport of an oil by air flow to machine surface to be lubricated. Advantages: • Lower wear rate. • Lower friction and energy consumption. • Lower maintenance cost. Disadvantages: • Viscosity limitation. • Risk of injectors clogging. Oil Application Methods Mechanism Oil is lifted by vacuum generated by high air velocity through Venturi, oil droplets then passes through piping to target machine surface being lubricated.
- 52. Continuous Forced OilCirculation Oil Application Methods The lubricant is pumped to parts to be lubricated and returned to reservoir by gravity passed through filters and coolers. Components: • Oi reservoir/tank. • Oil pump. • Filters. • Coolers. • Piping.
- 53. Handling, Storage and Managementof Lubricants • L u b r i c a n t s u p p l y o p t i o n s . • L u b r i c a n t s t o r e r o o m . • L u b e r o o m s a fe t y c o n s i d e ra t i o n . • P r o d u c t s t o ra g e l i fe . • M a i n t a i n w e l l l a b e l e d i nv e n t o r y.
- 54. Lubricant Supply Options BULKSTEEL DRUM PLASTIC DRUM RACK-MOUNT STATION PORTABLE TRANSFER EQUIPMENT Handling, storage and management of lubricants
- 55. Lubricant Store Room Properlubricant storage room, HOW IT IS LOOK? Handling, storage and management of lubricants
- 56. Lube Room SafetyConsideration Safety consideration: • Fire extinguisher should be available and inspected regularly. • All spills should be cleaned. Use solvent if still. • Avoid oil contact with skin. • Clean hand with warm water if comes in contact with oil. • Read MSDS for each oil. • “No Smoking” signs should be posted. • Proper air ventilation. • Proper lighting. • Earthing/grounding to be used. Handling, storage and management of lubricants
- 57. Product Storage Life •Don’t use products that have been stored for long time unless verified with oil analysis. • Cold temperature storing environment is risky for motor and gear oils • Consult lubricant supplier regarding shelf life. Handling, storage and management of lubricants Product Max. recommended storage time (months) Lithium Grease 12 Calcium Complex Grease 6 Lubricating Oils 12 Soluble Oils 6 Wax Emulsions 6
- 58. Maintain Well LabeledInventory Inventory label / tag should include: Color code tags: • Reduce possibility of errors. • Ease of knowing oil type. • Reduce confusion associating with switching suppliers. Handling, storage and management of lubricants • Lubricant name: • Lubricant viscosity grade: • Date of purchase: • Lubricant application: • Inventory code: • Expiry date:
- 59. Basics of oilanalysis • W h a t o i l a n a l y s i s c a n t e l l ? • W h a t t o c o n s i d e r fo r r i g h t o i l a n a l y s i s . • Ty p e s o f o i l a n a l y s i s . • F T I R S p e c t ro s c o p y. • R P VO t e s t .
- 60. What oil analysiscan tell? What oil analysis can tell? • When something is occurring that can lead to failure? • When in early stage fault exists. • Nature of problem (background). • How severe is the condition? • Expected oil life-time. • Corrective actions needed. • What cause the machine to fail? Basics of Oil Analysis
- 61. What to considerfor right oil analysis What to consider for right oil analysis? • Right machine to sample. • Correct sampling location. • Correct sampling frequency. • Right sampling procedure. • Proper lab selection. • Proper test to perform. Basics of Oil Analysis
- 62. Types of oilanalysis Sensors are attached to machine Unattended Portable instrument are used at machine without bottle sampling Portable Bottles are sent to lab Laboratory Basics of Oil Analysis
- 63. Fourier Transform InfraredSpectroscopy • Fourier transform infrared (FTIR) spectroscopy is a versatile tool used to detect common contaminants, lube degradation byproducts and additives within lubricating oils • FTIIR is a rapid way to monitor multiple oil parameters. • This test method is relatively quick to perform and is capable of simultaneously detecting multiple parameters. Basics of Oil Analysis
- 64. Rotating Pressure VesselOxidation Test • The Rotating Pressure Vessel Oxidation Test (RPVOT) is a test that determines the oxidation stability of an oil. • The test is very expensive to perform routinely and is usually performed annually on very large oil reservoirs such as a steam turbine where volumes exceed 10,000 gallons Applications Mainly used for lubricants with antioxidant additive packages to help monitor fluid health and provide an estimate of remaining life. Basics of Oil Analysis
- 65.