5Why 解决问题工具.docx
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5Why解决问题工具
U.S.StandardRailroadGauge
TheU.S.standardrailroadgauge(widthbetweenthetworails)is4feet,8.5inches.Onemightsaythat'sanexceedinglyoddnumber.
Whywasthatgaugeused?
Becausethat'sthewaytheybuilttheminEngland,andEnglishexpatriatesbuilttheUSrailroads.
WhydidtheEnglishbuildthemlikethat?
Becausethefirstraillineswerebuiltbythesamepeoplewhobuiltthepre-railroadtramways,andthat'sthegaugetheyused.
Whywasthatgaugeused?
Becausethepeoplewhobuiltthetramwaysusedthesamejigsandtoolsthattheyusedforbuildingwagons,whichusedthatwheelspacing.
Whydidthewagonshavethatparticularoddwheelspacing?
Well,iftheytriedtouseanyotherspacing,thewagonwheelswouldbreakonsomeoftheold,longdistanceroadsinEngland,becausethat'sthespacingofthewheelruts.Whobuiltthoseoldruttedroads?
ImperialRomebuiltthefirstlongdistanceroadsinEurope(includingEngland)fortheLegions.Theroadshavebeenusedeversince.Whatdoweknowabouttherutsintheroads?
Romanwarchariotsformedtheinitialruts,whicheveryoneelsehadtomatchforfearofdestroyingtheirwagonwheels.Sincethechariotsweremadefor(orby)ImperialRome,theywereallalikeinthematterofwheelspacing.
Thereyouhaveit!
TheUnitedStatesstandardrailroadgaugeof4feet,8.5inchesderivesfromtheoriginalspecificationforanImperialRomanwarchariot.Specificationsandbureaucraciesliveforever.Sothenexttimeyouarehandedaspecificationandwonderwhathorse'srearcameupwithit,youmaybeexactlyright,becausetheImperialRomanwarchariotsweremadejustwideenoughtoaccommodatethebackendsoftwowarhorses.
There'saninterestingextensiontothestoryaboutrailroadgaugesandhorses'behinds.WhenweseeSpaceShuttleColumbiasittingonitslaunchpad,therearetwobigboosterrocketsattachedtothesidesofthemainfueltank.Thesearesolidrocketboosters,or"SRB's".ThiokolmakestheSRB’sattheirfactoryatUtah.TheengineerswhodesignedtheSRB'smighthavepreferredtomakethemabitfatter,buttheSRB'shadtobeshippedbytrainfromthefactorytothelaunchsitebecauseoftheirsizeandweight.Therailroadlinefromthefactoryhastorunthroughatunnelinthemountains,andtheSRB'shadtofitthroughthattunnel.Thetunnelisslightlywiderthantherailroadtrack,andtherailroadtrackisaboutaswideastwohorses'behinds.
So,themajordesignfeatureofwhatisarguablytheworld'smostadvancedtransportationsystemwasdeterminedovertwothousandyearsagobythewidthofahorse'srearend!
PRACTICALPROBLEMSOLVING
Introduction
IntheDelphiorganization,acommon5-whyproblemsolvingprocessisusedtoanalyzeandsolvequalityproblems.
Therearefourmajorpartsoftheprocess:
∙UnderstandtheSituation
∙CauseInvestigation
∙ProblemCorrection
∙PreventionthroughErrorProofing
♦UnderstandtheSituation
Duringthefirstpartoftheprocess,you:
∙IdentifytheProblem
∙ClarifytheProblem
∙BreakdowntheProblem
∙LocatethePointofCause(PoC)
∙Graspthesignificanceoftheproblem
♦CauseInvestigation
Inthesecondpartoftheprocess,you:
∙Conducta“5-Why”investigationtoidentifytherootcause
▪forthespecificproblem
▪forwhytheproblemwasnotdetected
▪forwhythe“system”allowedtheproblemtooccur
♦ProblemCorrection
Inthethirdpartoftheprocess,you:
∙Takespecificactiontocorrecttheproblem(s).Ataminimum,short-termtemporarymeasuresarerequiredtoprotectthecustomer.
♦PreventionThroughErrorProofing
Inthefourthpartoftheprocess,you:
∙Takespecificactiontomakesuretheproblemcannotrecur,typicallythrougherrorproofing
∙CaptureandcommunicateLessonsLearned
PRACTICALPROBLEMSOLVINGMODEL
5WhyFunnel
BASICSTEPSOF
PRACTICALPROBLEMSOLVING
PartI–UnderstandtheSituation
♦Step1:
IdentifytheProblem
Inthefirststepoftheprocess,youbecomeawareofaproblemthatmaybelarge,vague,orcomplicated.Youhavesomeinformation,butdonothavedetailedfacts.Ask:
▪WhatdoIknow?
♦Step2:
ClarifytheProblem
Thenextstepintheprocessistoclarifytheproblem.Togainamoreclearunderstanding,ask:
▪Whatisactuallyhappening?
▪Whatshouldbehappening?
♦Step3:
BreakDowntheProblem
Atthispoint,breaktheproblemdownintosmaller,individualelements,ifnecessary.
▪WhatelsedoIknowabouttheproblem?
▪Arethereothersub-problems?
♦Step4:
LocatethePointofCause(PoC)
Now,thefocusisonlocatingtheactualpointofcauseoftheproblem.Whereintheprocessistheproblemoccurring?
Youneedtotrackbacktoseethepointofcausefirst-hand.Ask:
▪WheredoIneedtogo?
▪WhatdoIneedtosee?
▪Whomighthaveinformationabouttheproblem?
♦Step5:
GrasptheSignificanceoftheProblem
Tograspthesignificanceoftheproblem,ask:
▪When?
▪Where?
▪Which?
▪Howoften?
▪Howmuch?
Itisimportanttoaskthesequestionsbeforeasking“Why?
”
PartII:
CauseInvestigation
♦Step6:
Identifyandconfirmthedirectcauseoftheabnormaloccurrence.
Ifthecauseisvisible,verifyit.Ifthecauseisnotvisible,considerpotentialcausesandcheckthemostlikelycauses.Confirmthedirectcausebasedonfact.Ask:
▪Whyistheproblemoccurring?
▪CanIseethedirectcauseoftheproblem?
▪Ifnot,whatdoIsuspectaspotentialcauses?
▪HowcanIcheckthemostlikelypotentialcauses?
▪HowcanIconfirmthedirectcause?
♦Step7:
Use5-Whyinvestigationtobuildachainofcause/effectrelationshipsthatleadtotherootcause.Ask:
▪Willaddressingthedirectcausepreventrecurrence?
▪Ifnot,canIseethenextlevelofcause?
▪Ifnot,whatdoIsuspectasthenextlevelofcause?
▪HowcanIcheckandconfirmthenextlevelofcause?
▪Willaddressingthislevelofcausepreventrecurrence?
Ifnot,continueasking“Why?
”untilyoufindtherootcause.
Stopatthecausethatmustbeaddressedtopreventrecurrence.Ask:
▪HaveIfoundtherootcauseoftheproblem?
▪CanIpreventrecurrencebyaddressingthiscause?
▪Isthiscauselinkedtotheproblembyachainofcause/effectrelationshipsthatarebasedonfact?
▪Doesthechainpassthe“therefore”test?
▪IfIask“Why?
”again,willIbeintoanotherproblem?
Besureyouhaveused5-WhyInvestigationtoanswerthesequestions:
▪Whydidwehavethespecificproblem?
▪Whydidtheproblemgettothecustomer?
▪Whydidour“system”allowtheproblemtooccur?
5WHYCAUSEINVESTIGATION
Step8:
ProblemCorrection
TakeSpecificActiontoAddresstheProblem
Usetemporarymeasurestoeliminatetheabnormaloccurrenceuntiltherootcausecanbeaddressed.Ask:
▪Doesitcontaintheproblemuntilapermanentsolutioncanbeimplemented?
Step9:
PreventionthroughErrorProofing
Implementcorrectiveactionstoaddresstherootcause:
-Forthespecificproblem
-Forwhytheproblemwasnotdetected
-Forwhythe“system”allowedtheproblemtooccur
Ask:
▪Doesitpreventtheproblemfromhappeningagain?
Follow-upandcheckresults.Ask:
▪Isthesolutionworking?
▪HowdoIknow?
Captureandcommunicatelessonslearned.
PRACTICALPROBLEMSOLVINGCHECKLIST
Tobesureyouhavefollowedtheproblemsolvingmodel,usethischecklistasyoucompletetheproblemsolvingprocess.
Understandthesituation
___Identifytheproblem.
___Clarifytheproblem.
___Breakdowntheproblem.
___LocatethePointofCause(PoC).
___Graspthesignificanceoftheproblem.
CauseInvestigation
___Identify/confirmthedirectcause.
___Ask5Why'stoidentifytherootcause.
___Ask5Why'sfor“Whytheproblemwasnotdetectedandreachedthecustomer?
”
___Ask5Why'sfor“Whythesystemallowtheproblemtooccur?
”
ProblemCorrection
___Implementcorrectiveaction;ataminimum,implementtemporarymeasures
ProblemPrevention
___ErrorProoftherootcause.
___Verifyforeffectiveness.
___CaptureLessonsLearned.
ACTIVITY:
FLEXINDUSTRIESCASESTUDY
Directions:
▪UsetheDelphi5-WhyProblemSolvingProcesstoevaluatetheFlexIndustriesCaseStudybelowandonthefollowingpages.Reviewthe5-Whyanalysistemplateonpage12torecordyourinformation.
▪Useonlytheinformationprovidedinthecasestudytocompletethe5-Why.
▪Donottrytore-engineertherivetsorsolvethetechnicalproblemsinthecasestudy.Thepurposeofthisactivityistousethe5-whyProblemSolvingtemplatetoorganizethegivendataanduncoverthetruerootcause(s).
FLEXINDUSTRIESCASESTUDY
KeyPlayers
JakeQualityManager
JanetCSE,WindingRiverPlant
SamTeamLeader,EastLine
JudyQAAuditor,EastLine
BenMachineOperator
Background
JakeRyanistheQualityManageratFlexIndustries.Flexisacomponentsupplierthatmanufacturesmetalstampingsandlightassemblyproducts.Thecompanyhasareputationforsupplyinghighqualitypartsonaconsistentbasis.Seldomhastherebeenacustomercomplaint.FlexhasQualityrepresentativescalledCustomerSupportEngineers(CSE’s)ateverycustomerassemblyplant.TheCSE’sreportanyproblemstoJakeforinvestigationandfollow-up.
At7:
00a.m.thismorning,JakereceivedacallfromJanet,CSEattheWindingRiverAssemblyPlant.Janetinformedhimthatthecustomerhadfoundfivedefectivestabilizingbracketsonsecondshiftlastnight.Shecheckedtheremaininginventoryandtherewerenodefectsintheremaining326pieces.Themanufacturingstickeronthebackofthebracketsindicatedthattheyweremadebythesecondshiftoperator.Normally,thestabilizingbracketisfastenedtotheregulatormotorwiththreerivets.Thefivedefectivebracketshadonlytworivetsinthem.Thelowersetofrive