IntroductiontoPokaYoke

Poka-yokeandJidoka:

Continuousimprovement

toZeroQualityControl

QualityandHumanError

□"Toerrishuman../'...AlexanderPope

□Humanbeingsmakemistakes,humanbeingssometimesforget.

□Ifyourelyonahumanbeingtoproducequalityproductandnot

makeamistakeornotforgetsometimes

□Thenyoureallydonotcaretomakeaqualityproduct.

□ADDRESSQUALITYISSUESTHROUGHTHEPROCESS.

IntroductiontoPokaYoke

2022/11/2

EvolutionofKey"Lean"Concepts

=ConceptsrelatedtoPoka-yoke

ShigeoShingo

ZeroQualityControlconcept:197

"ZeroDefects^concept:1975

SMEDmethodologyformalized:196

spiredbyToyotaFoolproofingmeasures,developsmethodolo

toapplytechniquestosourceinspection:191965:Kanban,externalsuppliers

1962:Kanban,companywide,internal

ShigeoShingobeginsconsulting

1955:Waterspiderconcept

relationshipwithToyota:19

1953:/zSupermarket,/systems

1953:Workcellsin"U〃shapedlayouts

Set-upreduction:internal&external,195^Tbolproofingtechniquesandtheconceptof/zautonomation//(Poka?yoke)二

1ststagesofSMED:1951950:Andon,visualcontrol''

1950:Multi(3-4)machinehandling,rectangularor"LTshapedlayout

1948:Pull:Withrawalbysubsequentprocesses

1947:Dualmachinehandling,"〃shapedlayoutToyota&

1945:JustInTimeTaichiiOhno

IntroductiontoPokaYoke

2022/11/2

Contents

□IntroductiontoPoka-yokeandtypesof

inspectionsystems

□Poka-yokeSystems

口Poka-yokeMethods

口CommonMistakeProofingDevices

口Poka-yokeexercises

口ShingoQuiz

IntroductiontoPokaYoke

2022/11/24

Poka-yokeandJidoka:Simple&Clear

□Poka-yoke:Poka-yokepreventsdefectsfrombeingmade

□Jidoka:Preventsdefectsfrombeingpassedontothenextstepintheprocess

HumanInspectionHumanInterventionMistakeProofing

withmachineassist

Toll-gateIn-ProcessVisualInspectionPoka-yoke

InspectionInspection&EvolutiontowardZero

JidokaQualityControl-

atFinishedFinalInspectionmayThebeginningofOperatorTimededicated

Goodsdecrease,operatorsautonomation-toContinuous

ortheendofmaydorequiredsignificantdefectImprovement

mainprocessesprocessinspectionsreductions

IntroductiontoPokaYoke

2022/11/2

ThreeBasicTypesofInspection

□Therearethreebasictypesofinspectiontechniques

□JudgmentInspection

W川not-Human,visual,possiblymeasured

reducedefects-Onlydiscoversdefectsafterproduction

、□InformativeInspection

-StatisticalQualityControl:flowcharts,controlcharts

-Theoreticalsamplingtechniques

-Selfcheckinspection,SuccessiveInspection

-Inspectsproductstohelpcontroltheprocess

□SourceInspection

-Processfocused

-Tocorrectoperatingconditions

-Rootcausesareeliminatedorcorrected

一Beforeproductionoccurs

IntroductiontoPokaYoke

2022/11/2

AShortStory

YamadaElectric,Nagoya,Japan

ThePlantmanager:

“Oneoftheoperationswedoinvolvestheassemblyofanextremelysimplepush-

buttondevicethatwedelivertoourparentcompany,MatsushitaElectric.The

deviceiscomposedoftwobuttons,andonbuttonandanoffbutton,undereachof

whichwehavetoencloseasmallspring.Sometimes,though,oneofourworkers

forgetstoputinaspring.WhenMatsushitaelectricdiscoversaswitchwithoutaspring,

wehavetosendaninspectorallthewaytoKyushatocheckeveryswitchthatwas

delivered.

Thisisarealpainintheneck,sowheneverithappens,wetellworkerstobe

particularlycarefulandforawhilethingsimproveabit.Thesamethinghappens

againbeforelong,though,andthesechronicdefectsaregettingtobeanuisance.

Matsushitagetsmadatuseverytimeformakingmistakesinsuchasimpleoperation,

andIrecentlyhadtogotoKyushamyselftoapologize.Isthereanythingwecandoto

keepthesedefectsfromhappening?"7

IntroductiontoPokaYoke

2022/11/2

AShortStory

YamadaElectric,Nagoya,Japan

TheConsultantandthePlantManager:

C:“Whatdoesitmeanforahumanbeingto'forget'something?"

PM:Theplantmanagerlookedpuzzled..."To'forget'means...well...it

justmeansto'forget'something,doesn'tit?"

WhentheConsultantaskedthePlantManagertoexplain,hewasunabletoanswer.

Sohesuggestedtohimthattherewerereallytwokindsofforgetting.Thefirstinvolves

simplyforgettingsomething.Sincepeoplearenotperfect,theywill,onrareoccasions,

simplyforgetsomething.Itisnotintentional,itjusthappens.

Question:Haveyou

everforgottenC:"Thesecondtypeofforgetting,involvesforgettingthatonehasforgotten.We

anything?areallfamiliarwiththiskindofforgetting.Itisthereason,forexample,thatwemake

checklistsforourselves.Youcanapplythesamethingtothisoperation,ratherthan

thinkingthatyourpeopleshouldassembleswitchesperfectly,everytime,youshould

recognizethatbeinghuman,theywill,onrareoccasionsforgetthings.Whynottake

theideaofthechecklistandincorporateitintoyourprocess/"

IntroductiontoPokaYoke

2022/11/2

AShortStory

YamadaElectric,Nagoya,Japan

TheCurrentState:

Theoperatorassemblestwoswitchesatatime,placesthe

finishedswitchesintoaboxthatholdsonehundred.

Beforeshipping,aQCinspectorpullsasampleoutofeverybox.

TheSolutions:

1.Theoperatorassemblestwoswitchesatatime,placesthefinished

switchesintoarackthatholdonlysix,aftercompletingsix,pusheseach

buttononeachofthesixtochecktoseeifthespringisthere.After

pushingthebuttons,theoperatorpacksintothebox.

IntroductiontoPokaYoke

2022/11/2

AShortStory

YamadaElectric,Nagoya,Japan

TheSolutions:

2.Inthefirstmotion,anoperatorinsertstwospringsintheswitchthen

Boxwithmovesthemtooperatortwo.

Springs

LLEButtonsOperatortwoinspectsthatthespringisinplace,then

niniplacesthecoverontheswitch,placesthefinished

switchesintoaboxthatholdsonehundred.

Beforeshipping,aQCinspectorpullsasampleoutofeverybox.

3.Theoperatorhasasmallbowlinfrontofher.

Inherfirstmotionshetakestwospringsfromthebox,placesthemina

dish.

□□□Inhersecondmotion,sheinsertsthespringandthenthebuttonsare

annaniuinstalled.

niIfanyspringremainedonthedishafterassembly,theworkerrealized

thataspringhadbeenleftout,andtheassemblywascorrected.

2022/11/2

AShortStory

YamadaElectric,Nagoya,Japan

TheSolutions:

Thebuttonisdesignedsothatitcannotbeinstalledunlessthespring

ispresentintheswitch.

Operatorinstallstwosprings.

Operatorplacesbuttononswitch.

Operatorpacks.

Boxisreadyforshipment.

2022/11/2

SevenGuidelinesforPoka-yoke*

□QualityProcesses-Design“Robust"qualityprocessestoachievezerodefects.

□utilizeaTeamEnvironment-leveragetheteamsknowledge,experiencetoenhancethe

improvementefforts.

」EliminationofErrors-Utilizearobustproblemsolvingmethodologytodrivedefectstowardszero.

^Eliminatethe“RootCause"ofTheErrors-Usethe5Why'sand2H'sapproach

」D。ItRightTheFirstTime-Utilizingresourcestoperformfunctionscorrectlythe“first"time.

^EliminateNon-ValueAddedDecisions-Don/tmakeexcuses-justdoit!

口ImplementanIncrementalContinualImprovementApproach

□implementimprovementactionsimmediately

□focusonincrementalimprovements

□effortsdonothavetoresultina100%improvementimmediately.

IntroductiontoPokaYoke

2022/11/2

Source:Superfactory,2003.Module6,FundamentalsofManufacturingExcellence12

>12

Pokayoke

口Poke-yokeandPointofOriginInspections(ProactiveApproach):

口AfullyimplementedzerodefectsystemrequiresPokayokeusageator

beforetheinspectionpointsduringtheprocess.

口Pokayokewillcatchtheerrors

口beforeadefectivepartismanufactured

口100%ofthetime.

Source:2022/1l/25uperfactory,CX)3.Module6,FundamentalsofManufacturingExcellenceIntroductiontoPokaYoke

co

A

Jidoka

JidokaandInformativelnspection(ReactiveApproach):

□Checkoccursimmediatelyaftertheprocessstep.

□100%foolproofchecking(nointerpretationbyoperatorincontrol

/checking...)

□100%ofTime

^AlthoughnotaseffectiveastheSourceinspectionapproach,this

methodologyisEffectiveinpreventingdefectsfrombeingpassed

tonextprocess.

口Itismoreeffectivethanstatisticalsamplinganddoesprovidefeedbackin

reducingdefects.

*Source:Superfactory,2003.

Module6,Fundamentalsof

ManufacturingExcellence

2022/11/2

IntroductiontoPokaYoke

□>a14

PokayokeSystemsGoverntheProcess

口TwoPokaYokeSystemapproachesareutilizedinmanufacturingwhichleadto

successfulzerodefectsystems:

1.ControlApproach

□Shutsdowntheprocesswhenanerroroccurs.

□Keepsthe/zsuspect,/partinplacewhenanoperationisincomplete.

2.WarningApproach

□Signalstheoperatortostoptheprocessandcorrecttheproblem.

IntroductiontoPokaYoke

TS

Source:2022/ll/2Superfactory,OOB.Module6,FundamentalsofManufacturingExcellence>,15

ControlversusWarning

I-'CONTROLAPPROACHI-'WARNINGAPPROACH

Takeshumanelementoutoftheequation;Sometimesanautomaticshutoffsystemis

doesnotdependonanoperatorornotanoption.

assembler.

口Awarningoralarmsystemcanbeusedtogetan

口Hasahighcapabilityofachievingzerodefects.operatorsattention.

口Machinestopswhenanirregularityis?Belowleftisanexampleofanalarmsystem

detectedusingdials,lightsandsoundstobringattention

totheproblem.

口Colorcodingisalsoaneffectivenon

automaticoption.

2022/11/2

IntroductiontoPokaYoke

國(guó)L

Poka-yokeandJidoka

InspectionMethodSettingFunctionRegulativeFunction

SourceInspectionContactMethod

Poka-yoke-ProactiveControlMethod

StopstheProcess

InformativeInspectionConstantValueMethod

(self)

Countspartsoroperationsteps.

Jidoka-Reactive

〃*-o..WarningMethod

InformativeInspectionMotion-SequenceMethod52

(successive)AlarmorLighttellsoperatorto

Jidoka-Reactivetakeaction(eg:stopmachine)

2022/11/2IntroductiontoPokaYoke

17

47-

CommonMistakeproofingDevices

□GuidePins

口Blinkinglightsandalarms

口Limitswitches

口Proximityswitches

口C—ount.ers

口Checklists

IntroductiontoPokaYoke

Source:2022/1l/2Superfactory,003.Module6,FundamentalsofManufacturingExcellence

MethodsforUsingPokayoke

□pokayokesystemsconsistofthreeprimarymethods:

1.Contact

2.Counting

3.Motion-Sequence

口Eachmethodcanbeusedinacontrolsystemorawarningsystem.

口Eachmethodusesadifferentprocesspreventionapproachfordealing

withirregularities.

*Source:Superfactory,2003.

Module6,Fundamentalsof

ManufacturingExcellence

2022/11/2

IntroductiontoPokaYoke

ContactMethod

口Acontactmethodfunctionsbydetectingwhetherasensingdevicemakescontactwitha

partorobjectwithintheprocess.

Missingcylinder;pistonfully□Anexampleofaphysicalcontactmethodislimitswitchesthatarepressed

extended,alarmsoundswhencylindersaredrivenintoapiston.Theswitchesareconnectedtopistons

thatholdthepartinplace.Inthisexample,acylinderismissingandthepartis

Cylinderpresentnotreleasedtothenextprocess.

Ab

Cannotproceedtonext

step.

ContactMethodusinglimitswitchesidentifies

missingcylinder.

并由6dHe灰）RtoPokaYoke

2022/11/2

Source:Superfactory,2003.Module6,FundamentalsofManufacturingExcellence

PhysicalContactDevices

ToggleSwitches

LimitSwitches

IntroductiontoPokaYoke

EnergyContactDevices

Photoelectricswitchescanbeusedwithobjects

thataretranslucentortransparentdependingupon

theneed.

Transmissionmethod:twounits,onetotransmit

light,theothertoreceive.

TransmitterReceiverReflectingmethod:PEsensorrespondstolightreflected

fromobjecttodetectpresence.

Ifobjectbreaksthetransmission,themachineissignaled

toshutdown.

Object

*Source:

2022/1l/2Superfactory,003.Module

6,FundamentalsofManufacturing

Excellence

IntroductiontoPokaYoke

ContactDevice

Anexampleofacontactdevice

usingalimitswitch.Inthiscase

theswitchmakescontactwitha

metalbarbsensingit'spresence.If

nocontactismadetheprocesswill

shutdown.

Source:2022/ll/2Superfactory,003.Module6,FundamentalsofManufacturingExcellence

23

ContactMethods

□DOrothavetobehi^htech!

Passivedevicesaresometimesthebestmethod.Thesecanbeassimple

asguidepinsorblocksthatdonotallowpartstobeseatedinthewrong

positionpriortoprocessing

□lakeadvantageofpartsdesignedwitharunevenshape!

Aworkpiecewithaholeabumporanunevenendisaperfect

candidateforapassivejig.Thismethodsignalstotheoperatorright

awaythatthepartisnotinproperposition.

*Source:Superfactory,2022/11/22003.

Module6,FundamentalsofManufacturing

Excellence

IntroductiontoPokaYoke

Qa24

CountingMethod

'Usedwhenafixednumberofoperationsarerequiredwithinaprocess,orwhenaproduct

hasafixednumberofpartsthatareattachedtoit.

口Asensorcountsthenumberoftimesapartisusedoraprocessiscompletedand

releasesthepartonlywhentherightcountisreached.

Anotherapproachistocountthenumberofpartsorcomponents

requiredtocompleteanoperationinadvance.Ifoperatorsfind

partsleftoverusingthismethod,theywillknowthatsomething

hasbeenomittedfromtheprocess.

IntfodttetiontoPokaYoke

Source:Superfactory,2022/11/22003.Module6,FundamentalsofManufacturingExcellencenm

A

Motion-SequenceMethod

Thethirdpokayokemethodusessensorstodetermineifamotionorastep

inaprocesshasoccurred.Ifthestephasnotoccurredorhasoccurredoutof

sequence,thesensorsignalsatimerorotherdevicetostopthemachineand

signaltheoperator.

0Thismethodusessensorsandphoto-

electricdevicesconnectedtoatimer.If

movementdoesnotoccurwhen

required,theswitchsignalstostopthe

processorwarntheoperator.

IntroductiontoPokaYoke

Source:Superfactory,2UZ27Tl/22003.Module6,FundamentalsofManufacturingExcellence2?

>

m26

1.什么是傳統(tǒng)機(jī)械按鍵設(shè)計(jì)?

傳統(tǒng)的機(jī)械按鍵設(shè)計(jì)是需要手動(dòng)按壓按鍵觸動(dòng)PCBA上的開(kāi)關(guān)按鍵來(lái)實(shí)現(xiàn)功能的一種設(shè)計(jì)方式。

傳統(tǒng)機(jī)械按鍵結(jié)構(gòu)層圖:

傳統(tǒng)機(jī)械按鍵設(shè)計(jì)要點(diǎn)：

1.合理的選擇按鍵的類型，盡量選擇平頭類的按

鍵，以防按鍵下陷。

按鍵PCBA

2.開(kāi)關(guān)按鍵和塑膠按鍵設(shè)計(jì)間隙建議留

0.05~0.1mm,以防按鍵死鍵。

3.要考慮成型工藝，合理計(jì)算累積公差，以防按

鍵手感不良。

IntroductiontoPokaYoke

27

Motion-SequenceMethod

Inordertohelpoperatorsselecttherightpartsfortherightstepinaprocessthe

“sequencing“aspectofthemotion-stepmethodisused.Thisisespeciallyhelpfulwhen

usingmultiplepartsthataresimilarinsizeandshape.

□Inthisexample,eachstepofthemachinecycleiswiredtoanindicatorboardanda

timer.Ifeachcycleofthemachineisnotperformedwithintherequired"time"and

“sequence”,theindicatorlightthatstepwillbeturnedonandthemachinewillstop.

MachineIndicatorBoard

IntroductiontoPokaYoke

Source:Superfactory,2022/11/22003.Module6,FundamentalsofManufacturingExcellence

TypesofSensingDevices

口Sensingdevicesthataretraditionallyusedinpokayokesystemscanbedividedinto

threecategories:

1.Physicalcontactdevices

2.Energysensingdevices

3.WarningSensors

口Eachcategoryofsensorsincludesabroadrangeofdevicesthatcanbeused

dependingontheprocess.

Source:2022/1l/2superfactory,003.Module6,FundamentalsofManufacturingExcellencenn

A

*Source:Superfactory,2003.

Module6,Fundamentalsof

Devices:PhysicalContactSensorsManufacturingExcellence

Thesedevicesworkbyphysically

touchingsomething.Thiscanbea

machinepartoranactualpiece

beingmanufactured.

Inmostcasesthesedevicessend

anelectronicsignalwhentheyare

touched.Dependingonthe

process,thissignalcanshutdown

theoperationorgiveanoperator

awarningsignal.

2022/11/2

IntroductiontoPokaYoke

Qa30

Device:TouchSwitch

Method:Contact

口Usedtophysicallydetectthepresenceorabsenceofanobjectoritem-prevents

missingparts.

□llsedtophysicallydetecttheheightofapartordimension.

IntroductiontoPokaYoke

Source:2022/1l/2superfactory,2003.Module6,FundamentalsofManufacturingExcellence31

A

Devices:EnergySensors

口Thesedevicesworkbyusingenergytodetectwhetherornotandefecthas

occurred.

&FORCE

Fiberoptic

Vibration

Photoelectric