![© 2006 Prentice Hall, Inc. 17 – 17
Effective ExampleEffective Example
A redundant process is installed to supportA redundant process is installed to support
the earlier example where Rthe earlier example where Rss = .713= .713
RR11
0.90
0.90
RR22
0.80
0.80
RR33
0.99
= [.9 + .9(1 - .9)] x [.8 + .8(1 - .8)] x .99= [.9 + .9(1 - .9)] x [.8 + .8(1 - .8)] x .99
= [.9 + (.9)(.1)] x [.8 + (.8)(.2)] x .99= [.9 + (.9)(.1)] x [.8 + (.8)(.2)] x .99
= .99 x .96 x .99 = .94= .99 x .96 x .99 = .94
Reliability hasReliability has
increasedincreased
fromfrom .713.713 toto .94.94](https://image.slidesharecdn.com/machinemaintenancepresentation-190407052942/85/Machine-maintenance-presentation-17-320.jpg)
Machine maintenance presentation
- 1. © 2006 Prentice Hall, Inc. 17 – 1 Operations Management Maintenance andMaintenance and ReliabilityReliability
- 2. © 2006 Prentice Hall, Inc. 17 – 2 SnapshotSnapshot 1. What is maintenance. 2. How it is classified. 3. Type of industrial cost. 4. Effect of maintenance on production cost. 5. Break even point. 6. Benefits of preventive maintenance. 7. Conclusion.
- 3. © 2006 Prentice Hall, Inc. 17 – 3 OutlineOutline Company Profile: PRAN Agro Limited.Company Profile: PRAN Agro Limited. The Strategic Importance ofThe Strategic Importance of Maintenance and ReliabilityMaintenance and Reliability ReliabilityReliability Improving Individual ComponentsImproving Individual Components Providing SurplusProviding Surplus
- 4. © 2006 Prentice Hall, Inc. 17 – 4 Outline – ContinuedOutline – Continued MaintenanceMaintenance Implementing PreventiveImplementing Preventive MaintenanceMaintenance Increasing Repair CapabilitiesIncreasing Repair Capabilities Total Productive MaintenanceTotal Productive Maintenance Techniques for EnhancingTechniques for Enhancing MaintenanceMaintenance
- 5. © 2006 Prentice Hall, Inc. 17 – 5 Learning ObjectivesLearning Objectives When you complete this chapter youWhen you complete this chapter you should be able to:should be able to: 1.1. Describe how to improve systemDescribe how to improve system reliabilityreliability 2.2. Determine system reliabilityDetermine system reliability 3.3. Determine mean time between failureDetermine mean time between failure (MTBF)(MTBF)
- 6. © 2006 Prentice Hall, Inc. 17 – 6 Learning ObjectivesLearning Objectives When you complete this chapter youWhen you complete this chapter you should be able to:should be able to: 3.3. Distinguish between preventive andDistinguish between preventive and breakdown maintenancebreakdown maintenance 4.4. Describe how to improve maintenanceDescribe how to improve maintenance 5.5. Compare preventive and breakdownCompare preventive and breakdown maintenance costsmaintenance costs
- 7. © 2006 Prentice Hall, Inc. 17 – 7 Strategic Importance ofStrategic Importance of Machine MaintenanceMachine Maintenance Failure has far reaching effects on aFailure has far reaching effects on a firm’sfirm’s OperationOperation ReputationReputation ProfitabilityProfitability Dissatisfied customersDissatisfied customers Idle employeesIdle employees Profits becoming lossesProfits becoming losses Reduced value of investment in plant andReduced value of investment in plant and equipmentequipment
- 8. © 2006 Prentice Hall, Inc. 17 – 8 Maintenance and ReliabilityMaintenance and Reliability The objective of maintenance andThe objective of maintenance and reliability is to maintain thereliability is to maintain the capability of the system whilecapability of the system while controlling costscontrolling costs Maintenance is all activities involvedMaintenance is all activities involved in keeping a system’s equipment inin keeping a system’s equipment in working orderworking order Reliability is the probability that aReliability is the probability that a machine will function properly for amachine will function properly for a specified timespecified time
- 9. © 2006 Prentice Hall, Inc. 17 – 9 Important TacticsImportant Tactics ReliabilityReliability 1.1. Improving individual componentsImproving individual components 2.2. Providing redundancyProviding redundancy MaintenanceMaintenance 1.1. Implementing or improvingImplementing or improving preventive maintenancepreventive maintenance 2.2. Increasing repair capability or speedIncreasing repair capability or speed
- 10. © 2006 Prentice Hall, Inc. 17 – 10 Maintenance StrategyMaintenance Strategy Employee InvolvementEmployee Involvement Information sharing Skill training Reward system Employee empowerment Maintenance and ReliabilityMaintenance and Reliability ProceduresProcedures Clean and lubricate Monitor and adjust Make minor repair Keep computerized records ResultsResults Reduced inventory Improved quality Improved capacity Reputation for quality Continuous improvement Reduced variability Figure 17.1Figure 17.1
- 11. © 2006 Prentice Hall, Inc. 17 – 11 ReliabilityReliability Improving individual componentsImproving individual components RRss = R= R11 x Rx R22 x Rx R33 x … x Rx … x Rnn wherewhere RR11 = reliability of component 1= reliability of component 1 RR22 = reliability of component 2= reliability of component 2 and so onand so on
- 12. © 2006 Prentice Hall, Inc. 17 – 12 Overall System ReliabilityOverall System ReliabilityReliabilityofthesystem(percent)Reliabilityofthesystem(percent) Average reliability of each component (percent)Average reliability of each component (percent) | | | | | | | | | 100100 9999 9898 9797 9696 100100 – 8080 – 6060 – 4040 – 2020 – 00 – n = 10 n = 1 n = 50n = 100n = 200n = 300 n = 400 Figure 17.2Figure 17.2
- 13. © 2006 Prentice Hall, Inc. 17 – 13 Product Failure Rate (FR)Product Failure Rate (FR) Basic unit of measure for reliabilityBasic unit of measure for reliability FRFR((%%)) = x= x 100%100% Number of failuresNumber of failures Number of units testedNumber of units tested FRFR((NN)) == Number of failuresNumber of failures Number of unit-hours of operating timeNumber of unit-hours of operating time Mean time between failuresMean time between failures MTBF =MTBF = 11 FRFR((NN))
- 14. © 2006 Prentice Hall, Inc. 17 – 14 Failure Rate ExampleFailure Rate Example 2020 air conditioning units designed for use inair conditioning units designed for use in NASA space shuttles operated forNASA space shuttles operated for 1,0001,000 hourshours One failed afterOne failed after 200200 hours and one afterhours and one after 600600 hourshours FRFR((%%)) = (100%) = 10%= (100%) = 10% 22 2020 FRFR((NN)) = = .000106= = .000106 failure/unit hrfailure/unit hr 22 20,000 - 1,20020,000 - 1,200 MTBFMTBF = = 9,434= = 9,434 hrshrs11 .000106.000106
- 15. © 2006 Prentice Hall, Inc. 17 – 15 Failure Rate ExampleFailure Rate Example 2020 air conditioning units designed for use inair conditioning units designed for use in NASA space shuttlesNASA space shuttles operated foroperated for 1,0001,000 hourshours One failed afterOne failed after 200200 hours and one afterhours and one after 600600 hourshours FRFR((%%)) = (100%) = 10%= (100%) = 10% 22 2020 FRFR((NN)) = = .000106= = .000106 failure/unit hrfailure/unit hr 22 20,000 - 1,20020,000 - 1,200 MTBFMTBF = = 9,434= = 9,434 hrhr11 .000106.000106 Failure rate per trip FR = FR(N)(24 hrs)(6 days/trip) FR = (.000106)(24)(6) FR = .153 failures per trip
- 16. © 2006 Prentice Hall, Inc. 17 – 16 Providing RedundancyProviding Redundancy Provide backup components toProvide backup components to increase reliabilityincrease reliability ++ xx ProbabilityProbability of firstof first componentcomponent workingworking ProbabilityProbability of needingof needing secondsecond componentcomponent ProbabilityProbability of secondof second componentcomponent workingworking (.8)(.8) ++ (.8)(.8) xx (1 - .8)(1 - .8) = .8= .8 ++ .16 = .96.16 = .96
- 17. © 2006 Prentice Hall, Inc. 17 – 17 Effective ExampleEffective Example A redundant process is installed to supportA redundant process is installed to support the earlier example where Rthe earlier example where Rss = .713= .713 RR11 0.90 0.90 RR22 0.80 0.80 RR33 0.99 = [.9 + .9(1 - .9)] x [.8 + .8(1 - .8)] x .99= [.9 + .9(1 - .9)] x [.8 + .8(1 - .8)] x .99 = [.9 + (.9)(.1)] x [.8 + (.8)(.2)] x .99= [.9 + (.9)(.1)] x [.8 + (.8)(.2)] x .99 = .99 x .96 x .99 = .94= .99 x .96 x .99 = .94 Reliability hasReliability has increasedincreased fromfrom .713.713 toto .94.94
- 18. © 2006 Prentice Hall, Inc. 17 – 18 MaintenanceMaintenance Two types of maintenanceTwo types of maintenance Preventive maintenance –Preventive maintenance – routine inspection and servicingroutine inspection and servicing to keep facilities in good repairto keep facilities in good repair Breakdown maintenance –Breakdown maintenance – emergency or priority repairs onemergency or priority repairs on failed equipmentfailed equipment
- 19. © 2006 Prentice Hall, Inc. 17 – 19 Implementing PreventiveImplementing Preventive MaintenanceMaintenance Need to know when a system requiresNeed to know when a system requires service or is likely to failservice or is likely to fail High initial failure rates are known asHigh initial failure rates are known as infant mortalityinfant mortality Once a product settles in, MTBFOnce a product settles in, MTBF generally follows a normal distributiongenerally follows a normal distribution Good reporting and record keeping canGood reporting and record keeping can aid the decision on when preventiveaid the decision on when preventive maintenance should be performedmaintenance should be performed
- 20. © 2006 Prentice Hall, Inc. 17 – 20 Computerized MaintenanceComputerized Maintenance SystemSystem Figure 17.3Figure 17.3 Output ReportsOutput Reports Inventory and purchasing reports Equipment parts list Equipment history reports Cost analysis (Actual vs. standard) Work orders – Preventive maintenance – Scheduled downtime – Emergency maintenance Data entry – Work requests – Purchase requests – Time reporting – Contract work Data FilesData Files Personnel data with skills, wages, etc. Equipment file with parts list Maintenance and work order schedule Inventory of spare parts Repair history file
- 21. © 2006 Prentice Hall, Inc. 17 – 21 Maintenance CostsMaintenance Costs The traditional view attempted toThe traditional view attempted to balance preventive and breakdownbalance preventive and breakdown maintenance costsmaintenance costs Typically this approach failed toTypically this approach failed to consider the true total cost ofconsider the true total cost of breakdownsbreakdowns InventoryInventory Employee moraleEmployee morale Schedule unreliabilitySchedule unreliability
- 22. © 2006 Prentice Hall, Inc. 17 – 22 Maintenance CostsMaintenance Costs Figure 17.4 (a)Figure 17.4 (a) TotalTotal costscosts BreakdownBreakdown maintenancemaintenance costscosts CostsCosts Maintenance commitmentMaintenance commitment Traditional ViewTraditional View PreventivePreventive maintenancemaintenance costscosts Optimal point (lowestOptimal point (lowest cost maintenance policy)cost maintenance policy)
- 23. © 2006 Prentice Hall, Inc. 17 – 23 Maintenance CostsMaintenance Costs Figure 17.4 (b)Figure 17.4 (b) CostsCosts Maintenance commitmentMaintenance commitment Full Cost ViewFull Cost View Optimal point (lowestOptimal point (lowest cost maintenance policy)cost maintenance policy) TotalTotal costscosts Full cost ofFull cost of breakdownsbreakdowns PreventivePreventive maintenancemaintenance costscosts
- 24. © 2006 Prentice Hall, Inc. 17 – 24 Maintenance Cost ExampleMaintenance Cost Example Should the firm contract for maintenanceShould the firm contract for maintenance on their printers?on their printers? Number ofNumber of BreakdownsBreakdowns Number of Months ThatNumber of Months That Breakdowns OccurredBreakdowns Occurred 00 22 11 88 22 66 33 4 Total:Total: 2020 Average cost of breakdownAverage cost of breakdown = $300= $300
- 25. © 2006 Prentice Hall, Inc. 17 – 25 Maintenance Cost ExampleMaintenance Cost Example 1.1. Compute the expected number ofCompute the expected number of breakdownsbreakdowns Number ofNumber of BreakdownsBreakdowns FrequencyFrequency Number ofNumber of BreakdownsBreakdowns FrequencyFrequency 00 2/20 = .12/20 = .1 22 6/20 = .36/20 = .3 11 8/20 = .48/20 = .4 33 4/20 = .24/20 = .2 ∑∑ Number ofNumber of breakdownsbreakdowns Expected numberExpected number of breakdownsof breakdowns CorrespondingCorresponding frequencyfrequency== xx = (0)(.1) + (1)(.4) + (2)(.3) + (3)(.2)= (0)(.1) + (1)(.4) + (2)(.3) + (3)(.2) = 1.6= 1.6 breakdowns per monthbreakdowns per month
- 26. © 2006 Prentice Hall, Inc. 17 – 26 Maintenance Cost ExampleMaintenance Cost Example 2.2. Compute the expected breakdown cost perCompute the expected breakdown cost per month with no preventive maintenancemonth with no preventive maintenance ExpectedExpected breakdown costbreakdown cost Expected numberExpected number of breakdownsof breakdowns Cost perCost per breakdownbreakdown== xx = (1.6)($300)= (1.6)($300) = $480= $480 per monthper month
- 27. © 2006 Prentice Hall, Inc. 17 – 27 Maintenance Cost ExampleMaintenance Cost Example 3.3. Compute the cost of preventiveCompute the cost of preventive maintenancemaintenance PreventivePreventive maintenance costmaintenance cost Cost of expectedCost of expected breakdowns if servicebreakdowns if service contract signedcontract signed Cost ofCost of service contractservice contract == ++ = (1= (1 breakdown/monthbreakdown/month)($300) + $150)($300) + $150/month/month = $450= $450 per monthper month Hire the service firm; it is less expensive
- 28. © 2006 Prentice Hall, Inc. 17 – 28 Increasing RepairIncreasing Repair CapabilitiesCapabilities 1.1. Well-trained personnelWell-trained personnel 2.2. Adequate resourcesAdequate resources 3.3. Ability to establish repair plan andAbility to establish repair plan and prioritiespriorities 4.4. Ability and authority to do materialAbility and authority to do material planningplanning 5.5. Ability to identify the cause ofAbility to identify the cause of breakdownsbreakdowns 6.6. Ability to design ways to extend MTBFAbility to design ways to extend MTBF
- 29. © 2006 Prentice Hall, Inc. 17 – 29 How Maintenance isHow Maintenance is PerformedPerformed Figure 17.5Figure 17.5 OperatorOperator MaintenanceMaintenance departmentdepartment Manufacturer’sManufacturer’s field servicefield service Depot serviceDepot service (return equipment)(return equipment) Preventive maintenance costs less and is faster the more we move to the left Competence is higher as we move to the right
- 30. © 2006 Prentice Hall, Inc. 17 – 30 Total ProductiveTotal Productive Maintenance (TPM)Maintenance (TPM) Designing machines that are reliable, easy toDesigning machines that are reliable, easy to operate, and easy to maintainoperate, and easy to maintain Emphasizing total cost of ownership whenEmphasizing total cost of ownership when purchasing machines, so that service andpurchasing machines, so that service and maintenance are included in the costmaintenance are included in the cost Developing preventive maintenance plans thatDeveloping preventive maintenance plans that utilize the best practices of operators,utilize the best practices of operators, maintenance departments, and depot servicemaintenance departments, and depot service Training workers to operate and maintain theirTraining workers to operate and maintain their own machinesown machines
- 31. © 2006 Prentice Hall, Inc. 17 – 31 Establishing MaintenanceEstablishing Maintenance PoliciesPolicies SimulationSimulation Computer analysis of complexComputer analysis of complex situationssituations Model maintenance programs beforeModel maintenance programs before they are implementedthey are implemented Physical models can also be usedPhysical models can also be used Expert systemsExpert systems Computers help users identifyComputers help users identify problems and select course of actionproblems and select course of action
- 32. © 2006 Prentice Hall, Inc. 17 – 32 CONCLUSIONCONCLUSION • Maintenance is the hart of theMaintenance is the hart of the industry. Its always improves theindustry. Its always improves the machine efficiency and reduce themachine efficiency and reduce the production cost.production cost. • Proper maintenance will increaseProper maintenance will increase machine life cycle.machine life cycle.
- 33. © 2006 Prentice Hall, Inc. 17 – 33 QUESTION & ANSWERQUESTION & ANSWER
- 34. © 2006 Prentice Hall, Inc. 17 – 34 Graphic Depiction ofGraphic Depiction of BreakevenBreakeven $ Units Sold
- 35. © 2006 Prentice Hall, Inc. 17 – 35 Graphic Depiction ofGraphic Depiction of BreakevenBreakeven $ Units Sold
- 36. © 2006 Prentice Hall, Inc. 17 – 36
Editor's Notes
- #35: Activity Step 3 Identify key variables in the breakeven equation. Identify the lines on the graph. The Point at which Total Cost and Revenue intersect (are equal) is the point at which profit = zero
- #36: Activity Step 3 Identify key variables in the breakeven equation. Identify the lines on the graph. Revenue below the breakeven point results in loss (represented by the red shaded area)