摩托罗拉六西格玛企业培训 PG 3.1 Analyze Potential Root Causes

1、Copyright 2002 Motorola. All rights reserved.Six Sigma Black Belt Program 3.1 Analyze Potential Root Causes3.1 - 1Six SigmaBlack Belt Program3.1 - AnalyzePotential Root CausesThese materials, including all attachments, are protected under the copyright laws of the United States and other countries a

2、san unpublished work. These materials contain information that is proprietary and confidential to Motorola University and are thesubject of a License and Nondisclosure Agreement. Under the terms of the License and Nondisclosure Agreement, thesematerials shall not be disclosed outsider the recipients

3、 company or duplicated, used or disclosed in whole or in part by therecipient for any purpose other than for the uses described in the License and Nondisclosure Agreement. Any other use ordisclosure of this information, in whole or in part, without the express written permission of Motorola Universi

4、ty is prohibited.Copyright 2002 Motorola. All rights reserved.3.1 Analyze Potential Root Causes3.1 - 23.1 Analyze Potential Root CausesObjectiveTo document and evaluate with data potentialroot causes of variation in our CTQs/CTPs.Key Topics Problem Solving Model Tools to Identify Potential Root Caus

5、es3.1AnalyzePotential RootCauses3.2ImplementComparativeMethods3.4Apply FailureModes andEffects Analysis(FMEA)3.3ConductSources ofVariation (SOV)Studies3.5CompleteCorrelation andRegressionAnalysisCopyright 2002 Motorola. All rights reserved.3.1 Analyze Potential Root Causes3.1 - 3Sources of Variation

6、 (SOV)Determine the Root Cause of the ProblemThe objective of sigma process improvement is to permanently eliminate the root cause ofdefects, which are the source of customers dissatisfaction and poor business results. Todo so requires analysis of both the process and data collected from the process

7、. We aretrying to find the inputs, x1, x2, x3, etc.Y = f (X) = X1 + X2 + X3 . . .Root cause analysis leads to the underlying source of the defect, so the team can designsolutions and change the process to permanently eliminate the defects.SuppliersProcess InputsBusiness ProcessesProcess OutputsCCRsD

8、efectsVariation in theoutput ofprocesses causesdefectsXsare activities or factors withinthe process that are the rootcause of variation in YY103102101100999897U1 U2 U3time: # 1 - unit103102101100999897U1 U2 U3tim e: # 2 - unit103102101100999897U1 U2 U3tim e: # 3 - unit1.401.201.000.800.600.400.200.0

9、0U1 U2 U3time : # 1 - unit1.401.201.000.800.600.400.200.00U1 U2 U3tim e: # 2 - unit1.401.201.000.800.600.400.200.00U1 U2 U3tim e: # 3 - unitFrequencyofDeliveryTimesMeasurementStandardDeviationCountCountCountCountroDintiultReReicukekeNo8NoDifDifer- er-18181616131414121210107rd rd86622220allalloloolos

10、 er ng r ble s er ble r ngilailard -lo rd -looooovarnrn-to-tongngavReReicutu lt s-t ro t- tu ult t-a ro s-tf ke W No fic No W keererrd rd18181616131414121210108855466222440er erononallallloabloabrdrdoooovava-c -o -l -co il -c -o -l il -co-to-tot-as-tt-as-trn ng rn ngroCopyright 2002 Motorola. All ri

11、ghts reserved.3.1 Analyze Potential Root Causes3.1 - 4Problem Solving & Variation ReductionType of CTQ/CTP?Focus onProblem SolvingFocus onVariation ReductionscretenuousCritical Customer CoRequirement = 10 daysDefects: Serviceunacceptable to customers = Variation or data spreadx = 7.7 days1 2 3 4 5 6

12、 7 8 9 10 11 12Delivery TimeExcessive Variation results in DiscreteDefects is our discrete CTQ/CTP linkedto a continuous variable?Sources of Variation (Multi-Vari)Tools to Identifyand Prioritize: Cause & EffectDiagram Cause & EffectMatrix 5 Whys FMEATools to Validate: ComparativeMethods18100% 100%90

13、% 90%80% 80%70% 70%60% 60%50% 50%40% 40%30% 3 30%4 20% 4 1 20%2 10% 2 10%0 0% 0 0%-c -o -c a -c -o -cDif -ta Dif -taO OMajor-Complaint - Size of Customer: Large - Product Type: Major-Complaint - Size of Customer: Small - Product Type:Consumer Consumer100% 16 100%90% 90%80% 80%70% 70%60% 60%50% 50%40

14、% 40%30% 30%20% 1 20%2 10% 2 10%0 0% 0 0%s g r le s g le rtu lt tuf ta W fic ta WO OMajor-Complaint - Size of Customer: Large - Product Type: Major-Complaint - Size of Customer: Small - Product Type:Manufacturer ManufacturerStratification (Pareto Analysis)RootCauseAnalysisID XsDominantSourcesofVaria

15、tionID XsObstaclesGuidelines for Surmounting Them1. Root causes are not easy to find Challenge initial assumptions. Be persistent. Seek input from as many sources as possible.2. Pressure for quick solutions(managers, customers,stakeholders, etc.) Be patient. Do not jump to conclusions. Do not overlo

16、ok easy opportunities. Communicate interim results to outsiders.3. Preconceived notions for causes Let data reveal the true picture problems. Bring out and explore dissenting views. Use analytical tools.4. Resistance to collecting moredata Look for data that is already available. Collect data intell

17、igently. Look foropportunities to collect cause data during initialdata collection efforts. Distribute the workload evenly among all teammembers. Plan data collection. Use good checksheets andcollect the right data the first time.Copyright 2002 Motorola. All rights reserved.3.1 Analyze Potential Roo

18、t Causes3.1 - 5Searching for the Sources of Variation“Permanent defect reduction is the aim of Six Sigma Process Improvement”Copyright 2002 Motorola. All rights reserved.3.1 Analyze Potential Root Causes3.1 - 6Problem Solving Model Based upon the Scientific Method Focus on using data to make decisio

19、ns Often used for Discrete CTQs/CTPs Other models-Ford 8DStepProblem Solving Memory JoggerDMAIC1Describe the ProblemD2Describe the Current ProcessD/M3Identify and Verify Root CausesA4Develop a Solution and ActionPlanI5Implement the SolutionI6Review and EvaluateC7Reflect and Act on LearningsCCopyrigh

20、t 2002 Motorola. All rights reserved.3.1 Analyze Potential Root Causes3.1 - 7Problem Solving Model: StepsCopyright 2002 Motorola. All rights reserved.3.1 Analyze Potential Root Causes3.1 - 8Review Tools Week One Cause and Effect Diagram Cause and Effect Matrix Pareto ChartsCopyright 2002 Motorola. A

21、ll rights reserved.3.1 Analyze Potential Root Causes3.1 - 9Ishikawa DiagramCause and Effect DiagramPerhaps the most useful tool for identifying root causes is the cause and effect diagram. It goes byseveral names (Ishikawa, fishbone, etc.) and there are a variety of ways to use it. The cause andeffe

22、ct diagram is primarily a tool for organizing information to establish and clarify therelationships between an effect and its main causes.The cause and effect diagram identifies the root cause(s) of the problem so that collective actionscan be taken to eliminate their recurrence.The cause and effect

23、 diagram develops a picture composed of words and lines designed to showthe relationship between the effect and its causes.The cause and effect diagram assists in reaching a common understanding of the problem andexposes the potential drivers of the problem.CAUSESProblemStatementEFFECTSalespeopl eRe

24、ceipt proces sAnalyses wer eunable to verify40% of JanuaryreceiptsRushed salespeopleHourly completionrequiredRushedToo many salesNot enough salescoverage at peak timesoto-Lt-tLobe.-Tueq-toFrbepeTuWimttoBoifeilLncStecyenCoistnsCopyright 2002 Motorola. All rights reserved.3.1 Analyze Potential Root Ca

25、uses3.1 - 10Example: Surface Mount Technology (SMT) Fishbone DiagramScreen PrintingProcessPERSONNELMACHINEVOLUMESqueegee SpeedSlow SnapoffPumphead/BladeDown StopSnapoff SpeedSqueegee PressureVARIATION INSOLDER PASTEViscosityVariabilityManufacturing ProcessSupplierMATERIALAuto Dispense ConsistencyWet

26、tabilityReflow Profile SensitivitySlumpTactMETHODFULLY AUTOMATED!Why ar einvoiceslate?SystemSystemManualProcessReorganizationCopyright 2002 Motorola. All rights reserved.3.1 Analyze Potential Root Causes3.1 - 11Staf fFinanc ePolicyDocumentatio nExcessDemandAccess LimitationsLow PrioritySortDowntimeN

27、ewExcess MaintenanceDemand ContractorExample: Invoice ProcessingCost-Reduction ProgramOlder SystemOne Pick-Up DailyWorkspaceEquipmentLost/Misplaced MailTurnoverForward Payments Weekly Missing DocumentationCentralizedPayment Manual CrowdedAuthorization Files SpaceBranch OfficesResignedof Purchase Org

28、. No Limit ManagerInexperienced StaffAudit Recommendationfor Tighter ControlMissingPurchase OrdersTurnoverHiringFreezeOvertimeReducedAccess LimitationsMaximize CashLow PriorityMorale PaymentPaycuts DelaysProductivity DeadlinesIncreased WorkloadCopyright 2002 Motorola. All rights reserved.3.1 Analyze

29、 Potential Root Causes3.1 - 12Cause and Effect Matrix A tool that can help with the prioritization of KeyInput and Process Indicators (Xs) by evaluatingthe strength of their relationship to OutputIndicators (Ys). Useful when no data exists to establishcorrelations. Most effective in a team consensus

30、 environment.Copyright 2002 Motorola. All rights reserved.3.1 Analyze Potential Root Causes3.1 - 14Process for Creating Cause and EffectMatrix List across the top the Key Output Indicators. Assign a priority number for each Output (scale from 1 to 10). List vertically in 1st column all potential Inp

31、ut/Process Indicatorsthat may affect any of the Outputs. Rate the effect or correlation of each Input to Output (see samplescale below). Multiply each rating by the priority and sum across. The Input/Process Indicators can be prioritized by the results.Sample Scale (ratings):0 = No correlation1 = Li

32、ttle Correlation3 = Moderate Correlation9 = Strong CorrelationNumberofDefectsIncorrectSettingsComponentMissingOtherMountedWrong3Copyright 2002 Motorola. All rights reserved.3.1 Analyze Potential Root Causes3.1 - 15Pareto AnalysisPareto Charts A Way to Stratify DataPareto analysis is used to organize

33、 data to show which major factors make up the subject beinganalyzed. Frequently it is referred to as “the search for significance.”The Pareto chart is arranged with its bars descending in order, beginning from the left.The basis for building a Pareto is the 80/20 rule. Typically, approximately 80% o

34、f the problem(s) resultfrom approximately 20% of the causes.Defects FoundArranging data on a Pareto charthighlights “the vital few,”providing focus for constructingthe problem statement andconducting further analysis todetermine root cause.Incorrect setting8 = 50%16Component Missing8 + 3 = 69%16Moun

35、ted Wrong8 + 3 + 2 = 81%16Other8 + 3 + 2 + 3 = 100%162n = 1650%869%81%100%75%50%25%0%1614121086423Type of DefectCumulativePercentInstallationShippingDeliveryClericalMisc.NumberofComplaintsNumberofComplaintsMoistureCrushedWrongQuantityMisc.CumulativePercentCopyright 2002 Motorola. All rights reserved

36、.3.1 Analyze Potential Root Causes3.1 - 16Pareto StratificationLinking or stratifying Pareto charts canalso focus on the primary causes ofdefects as shown below.Field ServiceCustomer ComplaintShipping ComplaintsA two-levelPareto120110100908070605040302010025050751006055504540353025201510507550250100

37、40%65%80%90%NumberofDefectsNumberofDefectsCopyright 2002 Motorola. All rights reserved.3.1 Analyze Potential Root Causes3.1 - 17Example: Problem Statement IdentificationTop three complaint categories comprise80% of problem.Other teams are working on 1 & 2. Yourteam is tasked with cabin-relatedcompla

38、ints.Cabin accommodations generated mostcomplaints related to aircraft cabins; mostcomplaints were about room for carry-onbaggage.In the last year, 65% of airline passenger complaints about aircraft cabin interior baggage accommodationsconcerned insufficient stowage in overhead bins for carry-on lug

39、gage. In all fare categories, passengers of bothsexes complained in equivalent proportions about this problem.OvhdBinUnder Garment OtherSeat RackBag Accommodations(Storage)65%Cabin PhysicalAccommodationsBagRoomLugRoomSeatWidthHeadRoomRestRoomOther80%50%Cabin-relatedComplaintsAccom.FoodBevsEntSoundOt

40、her80%50%ComplaintsCostSchedCabinBagsRgsTixEtc.Copyright 2002 Motorola. All rights reserved.3.1 Analyze Potential Root Causes3.1 - 18Other Tools and Approaches FMEA IS/IS NOT Ask WHY 5 TimesCopyright 2002 Motorola. All rights reserved.3.1 Analyze Potential Root Causes3.1 - 19Sources of VariationSupp

41、liersProcess InputsBusiness ProcessesProcess OutputsCCRsDefectsVariation in theoutput ofprocesses causesdefectsXsare activities or factors withinthe process that are the rootcause of variation in Y First we need to recognize that there are two primary sources ofvariation: Process variability. Measur

42、ement system variability. In Section 3.3 we will provide more analytical methods for measuringthese two sources of variation.YCopyright 2002 Motorola. All rights reserved.3.1 Analyze Potential Root Causes3.1 - 20Searching for the Sources of VariationProblem Investigation Identify events that occurre

43、d “What happened?” Identify conditions that exist now or before failure. Keep in mind “What changed?” Trace a single case walk through failure/event. Investigate location of defect. Environment Position Investigate the defect type. Material Differences in products Investigate symptom.Clues to solvin

44、g the problem lie in the problem itselfSome of the information/knowledge obtained in the field can not be put intodata form but works as a catalyst in a chemical reaction and gives us new hintsfor solving the problem during the “thinking” process for probable root causes.Copyright 2002 Motorola. All

45、 rights reserved.3.1 Analyze Potential Root Causes3.1 - 21 Why is this failure mode active?Potential Root CausesUsing the Cause and Effect diagram with the major categories, beginwith the “most likely” the questioning of “why.” Why does this occur? Why does the condition exist?Root Cause Most Basic

46、Reason a Problem Has or Could Occur1. Ask “Why” 3-5 times.Progressively becomes more difficult and a morethought provoking assignment.Why did thishappen?Symptom 1“why”Symptom 2“why”Early questions are usually superficial, obvious;the later ones more substantive.Symptom 3“why”Symptom 4And more “whys”

47、Probable Root CauseCopyright 2002 Motorola. All rights reserved.3.1 Analyze Potential Root Causes3.1 - 22Potential Root Causes(continued)2. Get to something “Actionable.” Something can be done that will, if fixed, prevent problem from existingor recurring. You or your department can do something abo

48、ut the probable rootcause. (Do you have control over the probable root cause?) Revisit each sub-bone for additional causes move back to symptom 3 andask again, why does this symptom occur? Next, why does symptom 2 occur?Continue asking why back to the major bone (category). Complete the entire cause

49、 and effect diagram using this same methodology. Identify the most likely root causes and circle or cloud them the lastelement in the chain you identified. (Hint: sometimes the causes mostrepeated are a good place to start.) Verify the potential root causes using data. Remember its not enough thatthe