Grease basic knowledge_nk0906
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Grease basic knowledge_nk0906 Presentation Transcript

  • 1. HOME END Fuchs Indonesia Fuchs Indonesia 1
  • 2. HOME END Fuchs Indonesia Grease A solid to semi-fluid product of a thickening agent in a liquid lubricant. Other ingredients imparting general properties may be included 2
  • 3. HOME END Fuchs Indonesia Grease • Advantages • Disadvantages Convenience Low Cooling Rate Resistance Contamination Protection Performance Cleanliness Limitations 3
  • 4. HOME END Fuchs Indonesia Grease Composition Base Oil Thickener Additives 70 - 95% 10 - 20% 5 - 10% Grease 4
  • 5. HOME END Fuchs IndonesiaLubricating Greases - Basics and Applications 5
  • 6. HOME END Fuchs Indonesia Components Used in Grease FormulationBase oils Thickeners AdditivesMineral oils Sodium soap Anti-oxidantsSynthetic mineral oils Calcium soap Anti-wear additivesDi-esters Lithium soap EP additivesSilicones Aluminium soap Corrosion inhibitorsPhospate esters Barium soap Friction modifiersFluorocarbon Aluminium complex Metal deactivatorsFluorinated silicone Lithium complex VI improversChlorinated silicone Bentonite clay Pour-point depressants Silica Tackiness additives Carbon/graphite Water repellants Polyurea Dyes PTFE Structure modifiers Polyethylene Indanthrene dye Phthalocyanine dye 6
  • 7. HOME END Fuchs Indonesia Typical Oils Used in Lubricating Greases• Petroleum Paraffinic – good VI and thermal stability to 350oF max. temp. Naphthenic – good low temperature performance to –65oF min• Synthetic Nominal Serviceable Temp. Range. oF Diester - 100 to 400 Fluorosilicone - 50 to 450 Hydrocarbon - 80 to 350 Polyalkylene glycol - 40 to 350 Polyol ester - 50 to 400 Silicone - 100 to 450 7
  • 8. HOME END Fuchs Indonesia Base Oil For Grease • Depends on required characteristics of grease. Flow, viscosity, temp. range and speed. • Paraffinic and napthenic mineral oils • Synthetics used for special applications – very low/very high temp. • Base oil function is to lubricate 8
  • 9. HOME END Fuchs Indonesia Thickener Types •Metal soaps Lithium, calcium, sodium, barium, aluminium, etc Complex (I.e. Lithium complex, alumunium complex, Calcium complex) • Inorganics/non soap Clays, megalite, montmorilonite, hectorites, bentonites • Organics Polyurea • Fluoro Organic PTFE 9
  • 10. HOME END Fuchs Indonesia Thickener Influences • Act as a carrier To release fluid • Water Resistance 1. Washout Resistance - the ability of the lubricant to stay in the bearing while operating partially or fully submerged (ASTM D1264). 2. Water Absorption - the ability of the grease to deal with the presence of water by either absorbing or resisting the washing and diluting action of the water. 3. Spray Resistance - the ability of the grease to resist displacement from a direct impingement of the water on the greased surface (ASTM D4049). • Heat Resistance 10
  • 11. HOME END Fuchs Indonesia Grease Additives • Anti-Wear/Extreme Pressure Agents Zinc dialkyIdithiophosphates Dithiocarbamates (Zn, Sb, Pb) Phosphate esters Sulfurized fatty acids Sulfurized hydrocarbons Chlorinated hydrocarbons 11
  • 12. HOME END Fuchs Indonesia Grease Additives • Anti-oxidants Aryl amines Zinc dialkyldithiophosphates Hinderes phenols Zinc and amine dithiocarbamates 12
  • 13. HOME END Fuchs Indonesia Grease Additives • Rust and Corrosion Inhibitors Sulfonates (Ca, Ba, Li, Mg, Na, Pb, amine salts) Napthenates (Zn, Ba, Pb) Carboxylic acid derivatives Triazoles Sodium Nitrite 13
  • 14. HOME END Fuchs Indonesia Grease Additives • Friction Modifiers Molybdenum disulfide Graphite PTFE Powdered fluorocarbons 14
  • 15. HOME END Fuchs Indonesia Grease Additives • Adhesion Promoters Polyolefins and olefin copolymers 15
  • 16. HOME END Fuchs Indonesia PenetrationThe depth, in tenths of a millimeter, that a standard cone sinks into amaterial under prescribed conditions of weight, time and temperature.This depth is described as NLGI numbers. NLGI Number ASTM Worked Penetration 000 445-475 00 400-430 0 355-385 1 310-340 2 265-295 3 220-250 4 175-205 5 130-160 6 85-115 16
  • 17. HOME END Fuchs Indonesia Factors In Deciding NLGI Grades• Speed The higher the speed the harder the grease, so for high speeds use no. 3. The maximum outer race speed for grease- lubricated rolling bearings is about 15 m/s (3000 ft/min)• Bearing size Use a harder grease in a large bearing, No.3 or even no.4• Sealing If there is a particular need for effective sealing, use a harder grease, No.3 or No.4 17
  • 18. HOME END Fuchs Indonesia Factors In Deciding NLGI Grades• Shock loads or vibration Shock load or vibration tends to cause grease to slump into the moving components causing churning. A harder grease minimizes the problem, so use No.3 or No.4. (Note that normal steady loading does not strongly influence the grade)• Temperature 18
  • 19. HOME END Fuchs Indonesia Grease SelectionSome basic rules:Low speeds Greases with high base oil viscosityand high loads and EP and / or solid lubricants like Graphite or MoS2High speeds Greases with low base oil viscosityOscill. movement Greases with white solid lubricantsHigh or low Greases with synthetic base oilstemperatures 19
  • 20. HOME END Fuchs Indonesia Important factors on Grease selection 1. Bearing design 2. Bearing speed 3. Load 4. Temperature 5. Environmental conditions 20
  • 21. HOME END Fuchs Indonesia Grease Incompatibility 21
  • 22. HOME END Fuchs Indonesia Base fluid compatibility Mineralöl Polyalfa- Poly- Ester, Natives Öl Alkoxy- Silikonöl Öl- olefin glykol synth. fluoröl Typ Mineralöl + + - + + - - Polyalfa- olefin + + - + + - - Polyglykol - - + - - - - Ester, synth. + + - + + - - Natives Öl + + - + + - - Alkoxy- fluoröl - - - - - + - Silikonöl - - - - - - + 22
  • 23. HOME END Fuchs Indonesia Calculation of lubricant consumption Effective lubrication is the combination of a suitable lubricant, right re-lubrication intervals and the optimum re- lubrication quantity. „The more, the better“ is (nearly) always wrong. Over- lubrication leads to preliminary bearing failure and causes additional costs. Frequent re-lubrication with small quantities is better than seldom re-lubrication in huge quantities. Optimization is necessary, because frequent re-lubrication needs more time. 23
  • 24. HOME END Fuchs IndonesiaCalculation of lubricant consumption: When calculating the optimum grease quantity, the free volume in the bearing as well as free space in the housing has to be considered. First fill of bearing: Fill the bearing completely, fill free space in the housing only with a quantity which allows, that grease coming out of the bearing during operation can remain in the housing to avoid undesired heating of the grease and the bearing. Sometimes sealing discs can be helpful. 24
  • 25. HOME END Fuchs Indonesia Calculation of lubricant consumptionExceptions:very high speeds: fill bearing and housing only to one third to avoidineffective working of the greasevery low speeds: fill bearing and housing completely to ensurelubrication of all parts. In this case inner friction of thegrease can be neglected. 25
  • 26. HOME END Fuchs Indonesia Calculation of lubricant consumptionCalculation of the free bearing volume:Calculation can be done with the dimensions and weightsgiven by the suppliers of the bearings with the followingformula: V ≈ π/4 . B . (D² - d²) . 10-3 - G . 1000 / 7,8 [cm³]V - free bearing volume in cm³ d - Inner diameter in mmB - Bearing width in mm G - Weight in kgD - Outer diameter in mm 26
  • 27. HOME END Fuchs Indonesia Calculation of lubricant consumptionBasic quantities when using grease guns:One stroke with aconventional (DIN) orwithSYSTEM REINER-Grease Gun gives ca. 1,5- 2 ccm of grease. 27
  • 28. HOME END Fuchs Indonesia Calculation of lubricant consumption Re-lubrication quantities and -intervals depend very much on the real operating conditions. Therefore, exact calculation is extremely difficult. In the past data of practical applications were collected which were used as a data base for calculations for specific application fields. These calculations use factors for special operating conditions which were found by studying numerous similar applications. Difficulties arise from the determination of these correction factors as well as from the use of specialised greases with a performance being much higher than that of conventional Li-soap-mineral-oil greases. 28
  • 29. HOME END Fuchs Indonesia Calculation of lubricant consumption Correction factors for re-lubrication intervals f1 - Dust and moisture (0.1 ... 0.9) f2 - Shocks, vibrations (0.1 ... 0.9) f3 - Temperature higher than 70°C (0.1 ... 0.9) f4 - High load (0.1 ... 1.0) f5 - Air flow through the bearing (0.1 ... 0.7) The reduced re-lubrication interval is then calculated by multiplying all these single factors: tfq = f1 . f2 . f3 . f4 . f5 . tf 29
  • 30. HOME END Fuchs Indonesia ASTM Grease Tests 30
  • 31. HOME END Fuchs IndonesiaMechanical dynamic testing of lubricating greasesFE 8-bearings Timken-machine with specimen FBT-balls Emcor-machines 31
  • 32. HOME END Fuchs Indonesia ClassificationLubricating GreasesProperties: Consistency (NLGI-grade) Temperature range EP-properties Classification (DIN 51502): Base oil viscosity and type e.g. K P F 2 K -20 Thickener Solid lubricants 32
  • 33. HOME END Fuchs Indonesia Grease Troubleshooting Guide Application Symptom Possible Cause Check For Bearings Rolling Noise Condition of bearing Worn or brinelled bearing contact High bearing temp. Over greasing Too frequent application Bearing packed too full Excessive grease charge Starvation Insufficient application frequency Incorrect product Wrong base oil viscosity Excessive leakage Seals Mechanical damage Incorrect installation Over greasing Too frequent application Excessive amount applied Incorrect product Too soft for application or softening in service Incompatibility of grease Admixture of grease 33
  • 34. HOME END Fuchs Indonesia Grease Troubleshooting Guide Application Symptom Possible Cause Check For Bearings Rolling Frequent bearing Excessive wear Deficient load carrying (EP) contact replacement Starvation Contamination (dirt,dust) Bearing life exceeded Improper installation Grease too stiff (channeling) High temperature High operating temperature Misalignment Correct alignment Bearings Plain Overheating Improper distribution Grease too stiff Incorrect grooving Starvation Infrequent application Defective lubricator Incorrect grease Mechanical stability Excessive wear Starvation Infrequent application Defective lubricator Incorrect grease Load carrying (EP) Temperature range 34
  • 35. HOME END Fuchs Indonesia Grease Troubleshooting GuideApplication Symptom Possible Cause Check ForGears Enclosed Excessive leakage Grease too soft Product penetration Milling down of product Incompatibility of greases Admixture of greases Noisy gearbox Lack of lubrication Improper lubricant level Grease to stiff Overheating Lack of lubrication Improper lubricant level Grease too stiff Churning High grease level Grease too stiff Tooth breakage Not usually lubricant related Pitting Mostly poor design and fatigue related While not generally lubricant related, a heavier grease or base oil may retard progression of pitting Wear and scoring Lack of lubrication Improper lubricant level Grease too stiff Incorrect product used Consistency, EP, quality and base oil viscosity Abbrasive wear Lubricant contamination Alignment Not lubricant related 35
  • 36. HOME END Fuchs Indonesia Grease Troubleshooting GuideApplication Symptom Possible Cause Check ForGears Open Gear wear Lack of lubrication Incorrect lubricant Incorrect application frequency Build up on gears or in roots Excessive lubricant Application frequency Lubricant type Airborne dirtSliding Surfaces Non-uniform motion Lack of lubrication Application frequency Proper grease typeUniversal Joints Excessive wear Insufficient lubrication Lubricant EP, temperature quality Application frequency Grease slumpabilityElectric Motors Electric malfunction Excessive grease leakage Application frequency and quantity High temperatureCouplings Dry coupling Excessive grease leakage Damaged seals Grease consistency Keyway openings Initial fill 36
  • 37. HOME END Fuchs Indonesia Thank you 37