5 whys.docx

5 whys.docx

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5whys

PRACTICALPROBLEMSOLVING

Introduction

IntheDelphiorganization,acommonproblemsolvingprocessisusedtoanalyzeandsolvequalityproblems.

Therearefourmajorpartsoftheprocess:

∙

GrasptheSituation

∙CauseInvestigation

∙ProblemCorrection

∙PreventionthroughErrorproofing

♦GrasptheSituation

Duringthefirstpartoftheprocess,you:

∙IdentifytheProblem

∙ClarifytheProblem

∙LocatethePointofCause（PoC）

♦CauseInvestigation

Inthesecondpartoftheprocess,you:

∙Conducta“5-Why”investigationtoidentifytherootcause

▪forthespecificproblem

▪forwhytheproblemwasnotdetected

▪forwhythe“system”allowedtheproblemtooccur

♦ProblemCorrection

Inthethirdpartoftheprocess,you:

∙Takespecificactiontocorrecttheproblem.Ataminimum,short-termtemporarymeasuresarerequiredtoprotectthecustomer.

♦PreventionThruErrorproofing

Inthefourthpartoftheprocess,you:

∙Takespecificactiontomakesuretheproblemcannotrecur,typicallythrougherrorproofing

∙CaptureLessonsLearned

PRACTICALPROBLEMSOLVINGMODEL

5WhyFunnel

BASICSTEPSOF

PRACTICALPROBLEMSOLVING

PartI–GrasptheSituation

♦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.Youneedtotrackbacktoseethepointofcausefirst-hand.Ask:

▪WheredoIneedtogo?

▪WhatdoIneedtosee?

▪Whomighthaveinformationabouttheproblem?

♦Step5:

GrasptheTendencyoftheProblem

Tograspthetendencyoftheproblem,ask:

▪Who?

▪Which?

▪When?

▪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:

▪Whydidwehavetheproblem?

▪Whydidtheproblemgettothecustomer?

▪Whydidour“system”allowittooccur?

5WHYCAUSEINVESTIGATION

AbnormalOccurrence

Why?

（cause/effectrelationship）

C

C

C

C

DirectCause

Why?

Why?

Why?

Why?

Therefore

Test

RootCause

Cause

Cause

Cause

（cause/effectrelationship）

（cause/effectrelationship）

（cause/effectrelationship）

C

C

C

C

C

C

C

C

C

C

C

C

C

Step8:

TakeSpecificActiontoAddresstheProblem

Usetemporarymeasurestoeliminatetheabnormaloccurrenceuntiltherootcausecanbeaddressed.Ask:

▪Doesitcontaintheproblemuntilapermanentsolutioncanbeimplemented?

Implementcorrectiveactionstoaddresstherootcausetopreventrecurrence.Ask:

▪Doesitpreventtheproblem?

Follow-upandcheckresults.Ask:

▪Isthesolutionworking?

▪HowdoIknow?

PRACTICALPROBLEMSOLVINGCHECKLIST

Tobesureyouhavefollowedtheproblemsolvingmodel,usethischecklistasyoucompletetheproblemsolvingprocess.

Graspthesituation

___Pick-uptheproblem.

___Clarifytheproblem.

___Breakdowntheproblem.

___LocatethePointofCause（PoC）.

___Graspthetendencyoftheproblem.

CauseInvestigation

___Identify/confirmthedirectcause.

___Ask5Why'stoidentifytherootcause.

___Ask5Why'sfor“Whytheproblemwasnotdetectedandreachedthecustomer?

”

___Ask5Why'sfor“Whydidthesystemallowtheproblemtooccur?

”

ProblemCorrection

___Implementcorrectiveaction;ataminimum,implementtemporarymeasures

Prevention

___Errorprooftherootcause.

___CaptureLessonsLearned.

ACTIVITY:

FLEXINDUSTRIESCASESTUDY

Directions:

▪UsetheDelphiProblemSolvingProcesstoevaluatetheFlexIndustriesCaseStudybelowandonthefollowingpages.Reviewthe5-WhyInvestigationresultsonPage11.

▪UsetheworksheetsonPages13and14torecordyourwork.

▪Useonlytheinformationprovided.

▪Donottrytore-engineertherivetsorsolvethetechnicalproblemsinthecasestudy.ThepurposeofthisactivityistousetheProblemSolvingmodeltoorganizethegivendata.

FLEXINDUSTRIESCASESTUDY

Background

JakeRyanistheQualityManageratFlexIndustries.Flexisacomponentsupplierthatmanufacturesmetalstampingsandlightassemblyproducts.Thecompanyhasareputationforsupplyinghighqualitypartsonaconsistentbasis.Seldomhastherebeenacustomercomplaint.FlexhasQualityrepresentativescalledCustomerSupportEngineers（CSE’s）ateverycustomerassemblyplant.TheCSE’sreportanyproblemstoJakeforinvestigationandfollow-up.

At7:

00a.m.thismorning,JakereceivedacallfromJanet,CSEattheWindingRiverAssemblyPlant.Janetinformedhimthatthecustomerhadfoundfivedefectivestabilizingbracketsonsecondshiftlastnight.Shecheckedtheremaininginventoryandtherewerenodefectsintheremaining326pieces.Themanufacturingstickeronthebackofthebracketsindicatedthattheyweremadebythesecondshiftoperator.Normally,thestabilizingbracketisfastenedtotheregulatormotorwiththreerivets.Thefivedefectivebracketshadonlytworivetsinthem.Thelowersetofrivetsonallfivebracketswasmissingarivet.Thiswasthefirsttimethattheproblemoccurred.

GOODBAD

Jakeset-upcontainmentproceduresattheplantwarehousetosortfordiscrepantmaterials.Asofthismorning,twomoredefectivebracketshadbeenfoundintheremaining2019piecesofinventoryatFlex.

CauseInvestigation

Jakewentouttothefloortotalkwiththeteamleaderofthetworivetlines（EastandWest）andtheareaqualityassuranceauditor.HeinformedSam（theteamleader）ofthequalityproblemandaskedhimtoidentifythelinewhichrunsthestabilizingbracketassembly.SamdirectedJaketotheEastlinewhichrunsWindingRiverassemblybracketsonly.

AttheEastLine,hespokewithJudy（theQAAuditorforthearea）andaskedtoseethequalitylogsheets.JakeandJudyreviewedtheNov.11thlogsheetandcouldnotfindanythingoutoftheordinary.Heaskedhertoset-upin-housecontainmentprocedurestosortforanydiscrepantmaterialinthefinishedgoodsarea.

Next,Jaketriedtolocatethesecondshiftoperatorwhoseclocknumberwasonthedefectiveparts.Sincethatoperatorwasgone,Jakespokewiththecurrentmachineoperator（Ben）.HeaskedBenaboutanyrecentdifficultieswiththerivetmachine.Bensaidthathehadn’tnoticedanythingoutoftheordinary.Benalsomentioned,however,thattherehadneverbeenanyqualitybulletinspostedinthetwoyearsthatthisparticularparthasbeenrunning.

Jakedecidedtostayintheareatowatchthemachinerunforawhile.Afterabout15minutes,hewatchedBendumprivetsintothefeederbowltoprepareforthenextrun.

Shortlyafterrestartingrivetoperations,Benwalkedovertoanotherriveterandcamebackwithasteelrod.Benpokedaroundtherivetchuteandthencontinuedworking.JakeapproachedBenandaskedhimaboutthesteelrod.Benrepliedthatfromtimetotimethechutegetsjammedandhehastoclearitout.Thishappenstwoorthreetimesduringashift.Hedidn’tmentionthisinhisearlierconversationwithJakebecausetheproblemhasexistedeversincehestartedworkingwiththismachine.Thepreviousoperatorshowedhimhowtoclearthechute.Alltherivetmachinesarelikethis.

JakecalledtheMachineRepairDepartmentandaskedthatsomeonelookattherivettrack.Aslightgapinthetrackwasfoundandremoved,andBencontinuedtowork.

Twohourslater,JakegotacallfromBensayingthatthetrackwasstilljamming.AsfarasJakecouldsee,onlyrivetswereinthebowl.Next,Jakelookedintotherivetsuppliercontainers.Therewassomeforeignmaterialinthebluecontainer,butnoneintheredcontainer.ThelabelonthebluecontainershowedthatitwasfromAjaxRivet,Inc.,andthelabelontheredcontainerindicatedthatitwasfromFrank’sFasteners.Obviously,theforeignmaterialwasenteringtherivetfeederbowlandjammingthetrack.

JakecalledMaintenanceandrequestedthatthebowlbecleaned.Healsoaddedthecleaningopera