Bài giảng Operations Management - Chapter 17: Maintenance and Reliability

Operations ManagementMaintenance and ReliabilityChapter 171OutlineGLOBAL COMPANY PROFILE: NASATHE STRATEGIC IMPORTANCE OF MAINTENANCE AND RELIABILITYRELIABILITYImproving Individual ComponentsProviding RedundancyMAINTENANCEImplementing Preventive MaintenanceIncreasing Repair CapabilityTOTAL PRODUCTIVE MAINTENANCETECHNIQUES FOR ESTABLISHING MAINTENANCE POLICIES2Learning ObjectivesWhen you complete this chapter, you should be able to :Identify or Define: MaintenanceMean time between failuresRedundancyPreventive maintenanceBreakdown maintenanceInfant mortality3Learning Objectives - continuedWhen you complete this chapter, you should be able to :Describe or Explain:How to measure system reliabilityHow to improve maintenanceHow to evaluate maintenance performance4NASAMaintenance of space shuttlesColumbia:86,000,000 miles on odometer3 engines each the size of a VWexpected to make dozens more launchesMaintenance requires600 computer generated maintenance jobs3-month turnaroundMore than 100 people5All activities involved in keeping a system’s equipment workingObjective: Maintain system capability & minimize total costs© 1995 Corel Corp.Maintenance Management6The Strategic Importance of Maintenance and ReliabilityFailure has far reaching effects on a firm’soperationreputationprofitabilitycustomersproductemployeesprofits7Maintenance ProceduresEmployee InvolvementMaintenance Performance© 1995 Corel Corp.© 1995 Corel Corp.Maintenance Performance8Good Maintenance & Reliability StrategyRequires:Employee involvementMaintenance and reliability proceduresTo yield:Reduced inventoryImproved qualityImproved capacityReputation for qualityContinuous improvement9Employee InvolvementInformation sharingSkill trainingReward systemPower sharing© 1995 Corel Corp.10Maintenance & Reliability ProceduresClean and lubricateMonitor and adjustMinor repairComputerized recordsMaintenance Procedures© 1995 Corel Corp.11Lower operating costsContinuous improvementFaster, more dependable throughputHigher productivityImproved qualityImproved capacityReduced inventoryMaintenanceMaintenance Benefits12 Tactics for Reliability and MaintenanceReliability Tacticsimproving individual componentsproviding redundancyMaintenance Tacticsimplementing preventive maintenanceincreasing repair capabilities13System Reliability - Components in SeriesAverage Reliability of all Components (Percent)Reliability of the System (Percent)100806040200100 99 98 97 96n=1n=10n=50n=100n=200n=300n=40014Reliability of Components in Series R = R1 * R2 * R3 * ...15ReliabilityProbability that an item will function for a given timeMean time between failures (MTBF)Average time between failures of a repairable itemFailure rateReciprocal of MTBFEvaluating Maintenance16Failure Rate (%) Number of failures FR(%) = * 100% Number of units tested 17Lifetime Failure RatesInfantmortalityandimproper usefailure“normal” failureWearoutfailureFailurerateLifetime18Failures Per Operating Hour Number of Failures FR(n) = Operating Time19Mean Time Between Failures 1 MTBF = FR(N)20Providing RedundancyProbability of first component workingProbability of second component working+Probability of needing second component*= P(R)21How much preventive & breakdown maintenanceWho performs maintenanceCentralized, decentralized, operator etc.Contract or in-houseWhen to replace or repairHow much to replaceIndividual or group replacementMaintenance Decisions22PreventiveBreakdownRoutine inspection & servicingPrevents failuresBases for doingTime: Every dayUsage: Every 300 piecesInspection: Control chart deviations Non-routine inspection & servicingRemedialBasis for doingEquipment failureTypes of Maintenance23Mean Time Between Failure and Preventive MaintenanceFrequencyof failureMean Time Between FailureCandidate for preventivemaintenance will havedistribution with lowvariability24Centralized maintenance departmentDoes all maintenance (PM & breakdown)Decentralized maintenance departmentUseful if different equipment used in different areas of companyContract maintenanceUsed if little equipment or expertiseOperator ownership approachOrganizing the Maintenance Function25Operator does preventive maintenance Equipment condition is their responsibilityLearns equipment betterIncreases worker’s prideReduces repair time & PM costsMaintenance department is backupHandles non-routine problemsProvides maintenance trainingHas plant-wide responsibilitiesOperator-Ownership Approach26A Computerized Maintenance System27Maintenance CommitmentCostPreventive Maintenance CostTotal Maintenance CostBreakdown CostOptimal Maintenance CostsTraditional View28Maintenance CostsFull Cost ViewMaintenance CommitmentCostOptimal Total costsFull cost of breakdownsPreventive maintenance costs29Contract for Preventive MaintenanceCompute the expected number of breakdowns without the service contractCompute the expected breakdown cost per month with no preventive maintenance contractCompute the cost of preventive maintenanceCompare the two options30Increasing Repair Capabilities:Features of A Good Maintenance FacilityWell-trained personnelAdequate resourcesAbility to establish a repair plan and prioritiesAbility and authority to do material planningAbility to identify the cause of breakdownsAbility to design ways to extend MTBF31Operations Manager Must Determine How Maintenance Will be PerformedOperatorMaintenance DepartmentManufacturer’s field serviceDepot Service (return equipment)Competence is higher as we more to the rightPreventive maintenance costs less and is faster as we move to the left32Total Productive MaintenanceAdditional requirements of:Designing machines that are reliable, easy to operate and easy to maintainEmphasizing total cost of ownership when purchasing machines, so that service and maintenance are included in the costDeveloping preventive maintenance plans that utilize the best practices of operators, maintenance departments, and depot servicesTraining workers to operate and maintain their own machines33A Key To SuccessHigh utilization of facilities, tight scheduling, low inventory and consistent quality demand reliability - total preventive maintenance is the key to reliability.34Techniques for Establishing Maintenance PoliciesSimulation - enables one to evaluate the impact of various maintenance policiesExpert systems - can be used by staff to help diagnose faults in machinery and equipment35