质量控制与质量管理：Bv_08e Failure prevention

1、Dateiname: Bv_08e.ppt1/28lecture 88QM in the early phases focus: Failure Prevention8.1Introduction8.2Design Review8.3Quality Assessment8.4Fault tree analysis (FTA) and similar methods8.5FMEA - Failure Mode and effects analysis(Product and Process)Dateiname: Bv_08e.ppt2/288.1 ProblemWe reinvented the

2、 safety.The new A-Class.Dateiname: Bv_08e.ppt3/288.1 Design changes before job #1DevelopmentphaseManufacturingpreparationStage ofutilizationFrequency of the constructive changes to the product-24 months-3 months+3 monthsjob #1Legend:Japanese companiesU.S.- and European companies日本的企业在产品开发阶段更改较多最后的汽车

3、召回数量远少于欧美欧美是在制造阶段更改较多Dateiname: Bv_08e.ppt4/288.1 Methodologies and tools for the quality assurance before serial productionFault Tree AnalysisQuality AssessmentDesign of ExperimentsStatistical Tolerance AnalysisQuality Function DeploymentDevelopment-phaseManufacturing-phaseSystem FMEA ProductSystem

4、 FMEA ProcessMarketresearchDevelopment + DesignProcessplanningManufacturingreleasetimeDesign ReviewDateiname: Bv_08e.ppt5/288.1 Weird way TeamworkThis is a story about four people:Everybody, Somebody, Anybody and Nobody. There was an important job to be done and Everybody was asked to do it. Everybo

5、dy was sure Somebody would do it. Anybody could have done it, but Nobody did it. Somebody got angry about that because it was Everybodys job. Everybody thought Anybody could do it, but Nobody realized that Everybody wouldnt do it. It ended up that Everybody blamed Somebody when actually Nobody asked

6、 Anybody.Dateiname: Bv_08e.ppt6/288.1 Design Review - DRDefinition / Preliminary NotesDR is a method to formally check the accordance of a product development to its definition / to standards / its proceeding.DR can cover the whole Product Lifecycle Process.Besides DR, further similar methods like Q

7、uality Assessment (QA)are in use.Other methods like FMEA, FTA, QFD can be integrated into DR or be used to prepare a DR.Objectives:-Ensure that the product meets the customer requirements-Enhance product quality -Recognise faults at an early stage-Reduce the number of design changes-Decrease develop

8、ment timesDateiname: Bv_08e.ppt7/288.2 Design Review classification by the type of realizationDesign ReviewDocument ControlwrittenWalk throughoralCHECKLISTSDateiname: Bv_08e.ppt8/288.2 Phase model for the product development processLegend:Quality-Gate / MilestoneDRDesign ReviewCDR Critical DR PDR Pr

9、eliminary DRMDR Manufacturing DRSDR System DR FDR Finalfacturing DRFunctional spec.Lab-samplePrototypePilot lotDevelopment Finalize functional spec.QualificationDecision for a draftPreseries Release of prototypeSeriesRelease of seriesDefinition Project startUtili-sationDR:Item:PDRSDRCDRMDRFDRDateina

10、me: Bv_08e.ppt9/288.2 Procedure at the Design ReviewNominate project manager forDesign Review ConstituteDesign Review teamEstablishDesign Review planExecute reviewsPreparation:- Compose documents- Work sharingExecution:- Problem treatment- Problem formulation- Problem solution- Selection and assessm

11、ent- MeasuresPost processing:- Measures control- Allocation of status- DocumentationProcess planningProductionDesignQuality assuranceDevelopmentMarketingDateiname: Bv_08e.ppt10/288.2 Cut out of a Review checklist1Customer changes to the program since last review?2Speed test (180 km/h + 5%) passed?3N

12、o Aquaplaning at 80 km/h?4Wear behaviour ?5Dimensions in tolerance?6Maximum load adequate?7Tread suitable for heavy terrain?8Tread design made to customer demands?9Homologation process initiated and promising?10.Excellent Tyres Ltd.Review-ChecklistRevision: 04/2004Elaboration phaseObject:offroad tyr

13、eProduct: 4x4 rangerIdent.-Nr.: 1234Nr. Checkpointyes noRemarksDateiname: Bv_08e.ppt11/288.3 Process of the Quality Assessment (QA) in three stepsReasons for Quality Assessment (QA): New application for existing products Increased quality risk New development New materials or processes Use of parts

14、that are obliged to documentationReview item:ConceptActivity:Theoretical preview of function and safetyReview item:Development prototypeActivity:Test and trialReview item:Intermediate and first prototypeActivity:Test of ability for serial manufacturingQA 1:Concept selectionQA 2:Development prototype

15、 contractQA 3:Release of series productionSeries manufacturingDateiname: Bv_08e.ppt12/288.3 Checklist for the Quality Assessment (QA)Symbols: Non problematical Probably non problematical Probably problematical Very problematical Indices: 1 - Theoretical View 2 - Function sample 3 - Trial sample 4 -

16、First sample 5 - Own trialEvaluationI Function e.g. Statutory instructions, standards e.g. Customer requirementsII Reliability e.g. Static and dynamic strength e.g. permanent(operation) behaviourIII Typical features e.g. maintenance e.g. Ease of RepairIV Quality preview Prognosis of the failure quot

17、es in the field according to the % of delivery advised - during warranty period - after warranty periodV Total evaluation Product complies with requirements - in all scope - with restriction - insufficientQA 1(concept)QA 2(concept prototype)QA 3(start serial production)+-0.04%0.09%0.02%0.04%+ 1 1+ 1

18、 / 3+ 1 / 3+ 1+ 5+ 5 5 5 5 1 1-+ 5+ 5+ 3+ 3 1 1+-+Dateiname: Bv_08e.ppt13/288.4 Fault tree analysis, FTAFehlerbaumanalyse (engl: Fault Tree Analysis, FTA)Definition / Preliminary NotesFTA is a method to determine all logical combinations ofcomponent or system faults, that lead to an unwanted event.O

19、bjectives:-Recognise faults at an early stage-Calculate system reliability characteristics -avoid failure causesLogical Combinations of Inputs / Outputs (Boolean Logic)Starting from the unwanted event (TOP), all potential causes are listed up (Top-Down).Quantitative, objektive calculation of system

20、reliability characteristicsPreventive and retrospective insertion possibleDateiname: Bv_08e.ppt14/288.4 Fault tree analysis processDetermination of measures8Calculation and Interpretation of fault tree data7Evaluation of the inputs of fault treewith failure rate, time of failure, etc.6Creation of fa

21、ult tree5Determination of the types of failureof the components4Definition of relevant reliabilityparameters and time intervalsP in3000 h3System analysis1Definition of unwanted events andfailure criteria 2Bang!对失效模式确定一个准则（什么叫做失效）定义，比如桌子腿的承重定义什么是决定失效的关键参数参数对应一个失效数Dateiname: Bv_08e.ppt15/288.4 System

22、analysis processSystem analysisComponentoriented view“Determination of system functionsSystem as “Black Box”-I/O-behavior-Performance aim-Tolerable variations-Operation phaseDetermining environmental condExamine resourcesIdentify components-Coaction of components-Environmental influences-Reaction to

23、 failuresIterationfor allcomponentsholistic view“Components treeOrganization andbehaviour-Description-Input-Output-Performancepurpose-Operation phaseDateiname: Bv_08e.ppt16/288.4 Symbols to represent a fault treeStandard signs for fault tree analysisAND-combinationTogether to lead to Up-level eventT

24、ransfer In- and OutputCommentEventOI2&I1Standard-Input(Primary fault)Basic eventNOT-combinationI to O under certain conditionsOr otherwise not occurOR-combinationAny leads to up-levelevent OIOI2 1I1Logical Combinations of Inputs / Outputs (Boolean Logic)Secondary-Input(Secondary fault)Incomplete

25、 eventLegend: I = Input; O = OutputDateiname: Bv_08e.ppt17/288.4 Example for a Component treeComponent treeThe pressure System will be started by pressing switchS2. Relay K1 works as self abiding relay. K2 is closing.Thereby the motor started. If the maximum pressure isreached, pressure switch P is

26、opening and K2 relapses.Whereby the motor stops. Compressed air systemPneumaticsElectrics- Safety valve- Manometer- Discharging- Pressure Tank- Compressor- Motor M1- Switch S2- Relay K1- Relay K2- Pressure Switch P- .- . Technical SystemSafety valveManometerDischar-gingPressuretankDrainage valveRF1F

27、2S1K2S2K1M1MpPCompressorDateiname: Bv_08e.ppt18/288.4 Example for a fault treeTechnical SystemFault treeThe Pressure System will be startedby pressing switch S2. Relay K1 worksas self abiding relay. K2 is closing.Thereby the motor started. If themaximum pressure is reached,pressure switch P is openi

28、ngand K2 relapses.Whereby the motor stops.Bursting of pressure tankPressure tankfailureOperation con-ditions exceededOverpressureNon-acceptableconditionsSafety valve do not openFill up tohighest pressureSafety valuemal-functionWrongvalue-setupP-switchdo not openCompressoris working1& X1&11X2

29、X3RF1F2S1K2S2K1M1MpPSafety valveManometerDischar-cingPressuretankDrainage valveCompressorDateiname: Bv_08e.ppt19/28Example of automobile braking systemWC1BP1WC2BP2WC3BP3WC4BP4MCMmaster cylinder Ccable system WCwheel cylinder BPbraking pad Dateiname: Bv_08e.ppt20/28Fault tree for the automotive braki

30、ng systemFailure to stopDateiname: Bv_08e.ppt21/288.5 Failure Mode and Effects Analysis（FMEA）Fehlerbaumanalyse (engl: Fault Tree Analysis, FTA)Definition / Preliminary NotesFMEA is a method to determine the effects and causes of potentialfailures of products or processesObjectives :-Recognise faults

31、 at an early stage-prioritisation of risks-avoid failure causes by implementing appropriate measuresModern QM-standards like ISO TS 16949 do explicitly mention FMEA as the state-of-the-art method for fault preventionFMEA is the most frequently used Quality Management method in industryDateiname: Bv_

32、08e.ppt22/288.5 Task area of the FMEAFailure Mode and Effects Analysisin teamwork-Determination of potential failures-Determination of possible failure causes and their effects-EValuation of potential mistakes-Use and Evaluation ofactionsInput informationsMethodologyOutput informationsMechanical dra

33、wingWorking planProduct dataWeak points:failures, risks .Actions:modifications, optimizations .Inspection features.Dateiname: Bv_08e.ppt23/288.5 Success factors of FMEA: Preventive Applicationmanufacturingproduct in usedesignfailuresprocessfailuresprocess-planningplanning datadesigndesign dataSystem

34、 FMEAproductSystem FMEAprocessDateiname: Bv_08e.ppt24/288.5 History of FMEA1986:Revision of the method by the VDA/DGQ-team Assurance of quality before job Nr.1“Early 60sDevelopment of theFMEA by the NASAEarly 70sApplication in aerospace industry1980:Standardization in Germany under the name of failu

35、re effects analysis“1990:- further dissemination of the method- computer-aided systems (form-based)since 2000:Usage ofdatabases 19601970198019902000since 1985:Application in theautomobile industry1996:- Revision by VDA- System FMEA Product- System FMEA Processsince 2000:ISO TS 16949Dateiname: Bv_08e

36、.ppt25/288.5 Failure Mode and Effects AnalysisS = Severity evaluation grade1 (no S.) - 10 (paramount S.)D = Detection grade1 (probable) - 10 (improbable)O = Occurrence evaluation grade1 (improbable) - 10 (probable)Legend:Excellent Tyres Ltd.Failure Mode and effects analysisFMEA-No:Page: System FMEA

37、Product System FMEA ProcessType/model/manufacture/batch:Offroad Ranger 4x4Subject No.:90 HFResponsibility:M. SchmidtDept.:DevelopmentStatus:A/369 437/KCCompany:ET Ltd.Date:28.04.2004System no./System element:SteelbeltSubject No.:Responsibility:Dept.Function/Task:Status:Company:DateNo Possible Effect

38、RnS Poss. FailurePoss.CausesRemedial MeasuresRnO Detection MeasuresRnDRPNResp./ Due dateX01Belt breaks02 03 04 05Belt too stiffTyre explodes9 9 9 9No assembly onrim possible6Belt diameter too small (dimensioning)Belt diameter too small (supplier)Material strengthtoo lowFatigue of materialBelt diamet

39、er too big (dimensioning)Stress simulation3Supplier audit5Stress simulation3Fatigue calculation3Assembly trial2Design review5135 D. Beckham17.05.2004Incoming Inspection 4180 T. Edison10.05.2004Recalculatedemensioning381H. NewtonDone 30.04.2004Fatigue test254J. Watt31.05.2004Design review560D. Beckha

40、m17.05.2004Dateiname: Bv_08e.ppt26/28Tool,fixing,etc.GrindingfailureWrong diameterconcent/processValvejarnsThrottlevalve doesnot openThrottle breakingpower lacksEnginebreakingpower is too lowEnginebreakdownVehiclebreakdownCalibration,disturbancevariableGrindingDiameter of the valveValveThrottleThrot

41、tle-breaking-systemEngine-breaking-systemEngineVehicleStruktur-ebeneExampleFailure-characteristicsProcess-para-meterProcess-stepFeaturePartModuleSubcom-ponentCompo-nentMaincompo-nentSystemSystem- FMEAProduct Legend: F= Failure FC = Failure Causes FE = Failure EffectFEFFCLevel I FEFFCLevel IIFEFEFFCF

42、FCFEFFCLevel IIILevel IVLevel VIIFFFFCSystem- FMEAProcessConnection System-FMEAProduct/Process8.5 Classification of types of FMEA in the product structureDateiname: Bv_08e.ppt27/288.5 Teamwork FMEATask of the Moderator- Project planning and -organisation- Documentation, evaluation- Assure methodological correctness- Moderation of conversationSystem FMEA ProductSystem FMEA Process FMEA-level System/ComponentFMEA-levelComponentFMEA-levelProcessresponsibleconstantlyinvolvedtemporaryinvolvedDevelopmentModeratorProcurem