工业工程Chapter-2

Chapter2WorkStudy,Unit1MethodStudyUnit2TimestudyUnit3TimeMeasurementMethodsUnit4WorkSampling,Unit1MethodsStudy,TheDefinitionandContentofMethodsStudyStepsofMethodsStudyTheClassificationsofMethodsStudyPrinciplesofMotionEconomy,IntroductiontoWorkStudy,2.StepsofMethodsStudy,Selectingtheworktobestudied&boundariestobedefined.Recordingtherelevantfactsaboutthejobtoberecorded.Examininganddevelopingthewaythejobtobeperformed.SixquestioningtechniquesAnalysiswith“ECRS”principles,3.ClassificationsofMethodsStudy,Therearethreemainclassesofmethodsstudy:processanalysisoperationanalysismotionanalysis.,ProcessAnalysis,Processanalysisisoneofthemaincontentsofmethodsstudy,bywhichresearcherscancompletelyobserveandrecordthewholeproductionprocessesandcarryoutintegratedanalysisfromamacroscopicviewpoint.,OperationAnalysis,Man-machineOperationAnalysisConstructionoftheMan-machineChartTwo-handProcessAnalysis,MotionAnalysis,4.PrinciplesofMotionEconomy,IPrinciplesrelatedtotheuseofhumanbodyIIPrinciplesrelatedtothearrangementofworkplacePrinciplesrelatedtotoolsandequipment,Unit2Timestudy,Whatistimestudy?ThemethodsofdeterminingtimestandardsThesignificanceandpurposesoftimestudyRequirementsoftimestudyToolsoftimestudyProcessofTimeStudy,Whatistimestudy,TimestudyisoneoftheworkmeasurementtechniquesTimestudyisastructuredprocessofdirectlyobservingandmeasuringhumanworkinordertoestablishthetimerequiredforcompletionoftheworkbyaqualifiedworkerwhenworkingatadefinedlevelofperformance,Themethodsofdeterminingtimestandards,Estimateshistoricalrecordsworkmeasurementprocedures,Thesignificanceoftimestudy,AccuratelyestablishedtimestandardshelpincreasetheefficiencyoftheequipmentandtheoperatingpersonnelSoundstandardswillmeanthedifferencebetweenthesuccessorfailureofabusiness,Purposesoftimestudy,Todeterminethetimestandardsandcontrollaborcosts.Tosetupthestandardtimesandtakethemasthebaseofpayroll.Todecidetheworkscheduleandworkplan.Todeterminethestandardcostandtakeitastheevidenceofstandardbudget.Todeterminetheutilizationefficiencyofmachinesandtosolvetheproblemsonbalanceofproductionlines.,Requirementsoftimestudy,Theoperatorshouldbethoroughlyacquaintedwiththenewtechniquebeforetheoperationisstudiedthemethodmustbestandardizedatallpointswhereitistobeused,beforethestudybeginsResearchersoftimestudyshouldtellallrelatedpeoplethatthejobistobestudied,Toolsoftimestudy,Stopwatch,ADecimalMinuteWatch,AnElectronicStopwatch,AComputer-assistedElectronicStopwatch,Toolsoftimestudy,VideotapeCamerasTimeStudyBoardTimeStudyForms,ProcessofTimeStudy,SelectingtheoperatorAnalyzingthejobBreakingitdownintoelementsRecordingtheelapsedelementalvaluesPerformanceratingtheoperatorAssigningappropriateallowances,Thestandardtime,Definition:thetimerequiredforafullyqualified,trainedoperator,workingatastandardpaceandexertingaverageeffortThestandardtimeiscalculatedbythefollowingequations:NT=OTR/100ST=NT+NTAllowance=NT(1+Allowance),Unit3TimeMeasurementMethods,DirectTimeStudyamethodofusingtimemeasurementtodeterminethestandardtime.Whenrecordingthewatchreadings,noteonlythenecessarydigitsandomitthedecimalpoint,thusgivingasmuchtimeaspossibletoobservingtheperformanceoftheoperator,Twotechniquesusedforrecordingtheelementaltimes,1.ThecontinuoustimingmethodPresentsacompleterecordoftheentireobservationperiodBebetteradaptedtomeasuringandrecordingveryshortelementsMoreclericalworkisinvolved,Twotechniquesusedforrecordingtheelementaltimes,2.ThesnapbacktechniqueNoclericaltimeisneededDelaysarenotrecordedEncouragestheremovalofindividualelementsfromtheoperation,ComparisonofTwoMethods,Sometimestudyresearchersusebothmethods,believingthatstudiesofpredominantlylongelementsaremoreadaptedtosnapbackreadings,whileshort-cyclestudiesarebettersuitedtothecontinuousmethod,CyclesinStudy,DetermininghowmanycyclestostudytoarriveatanequitablestandardisasubjectthathascausedconsiderablediscussionTheactivityofthejobanditscycletimedirectlyinfluencesthenumberofcyclesthatcanbestudiedfromaneconomicstandpoint,PerformanceRating,Thebasicprincipleofperformanceratingistoadjustthemeanobservedtime(OT)foreachelementperformedduringthestudytothenormaltime(NT)thatwouldberequiredbythequalifiedoperatortoperformthesamework,AddingAllowances,Nooperatorcanmaintainastandardpaceeveryminuteoftheworkingday.AllowancesmustbeaddedtothestandardtimeTheallowanceistypicallygivenasafractionofnormaltimeandisusedasamultiplierequalto1+allowanceST=NT+NTAllowance=NT(1+Allowance)ST=NT/(1-Allowance),Anexampletocomputethestandardtime,Inaunit,theobservedtimeis0.8min.,R=110,allowance=5%NT=OTR/100=0.8110/100=0.88min.ST=NT(1+Allowance)=0.88(1+5%)=0.924min.,IntroductiontoPredeterminedTimeSystems,FrankB.Gilbrethistheinventorofmotionstudy.HeclassifiedthebasicmotionsintowhathecalledTherbligsthatisthebaseofpredeterminedtimesystems.Since1945,therehasbeenagrowinginterestintheuseofthebasicmotiontimeasamethodestablishingratesquicklyandaccuratelywithoutusingthedirecttimestudy.,TheCharacteristicsofPredeterminedTimeSystems,Determinethestandardtimeinadvanceandobjectivelyinworkmeasurementswithouttheperformancerating.Recordtheoperationalwaysindetailsandobtaintheelapsedtimeofeachbasicmotion.Determinethestandardtimebeforetheworkbeingdonewithoutusingthestopwatch.Whentheoperationalwaysupdate,thestandardtimevaluesmustbealtered.However,thebaseofsettingupthestandardtime,predeterminedtimesystems,remainthesame.Itisthebestwaytobalancetheproductionlineswithpredeterminedtimesystems.,TheMethodofWorkFactors,Themethodofworkfactorsisthebasiconeofpredeterminedtimesystems.Itdeterminesworktimebasedonthemotionfeaturesandconditionsthroughthespecifiedtimevaluesinadvance.,Fourvariablesinflectingmotiontime,whenmotion,whichportionofbodyisworkingthemotiondistancethegravitationorresistanceovercomewhenmotionadjustmentbyhumanbeings(includingstop,guidanceofdirection,speciallycareof,anddirectionchange),MethodsTimeMeasurement(MTM),Definition:Aprocedurewhichanalyzesanymanualoperationormethodintothebasicmotionsrequiredtoperformit,andassignseachmotionapre-determinedtimestandardwhichisdeterminedbythenatureofthemotionandtheconditionsunderwhichitismade,TheSystemofMethodsTimeMeasurement,InMTM,MTM-1isthebasicmethod.MTM-1dataaretheresultofframe-by-frameanalysesofmotion-picturefilmsofdiversifiedareasofwork.ThedatatakenfromthevariousfilmsareratedbytheWestinghousetechniques,tabulated,andanalyzedtodeterminethedegreeofdifficultycausedbyvariablecharacteristics.MTM-1,MTM-2,MTM-3,MTM-C,MTM-V,MTM-M,MTM-TE,andsoforthconstitutedthesystemofMTM,ModularArrangementofPredeterminedMotionTimeStandard(MOD),MODisthelatestdevelopmentofpredeterminedtimesystems.MODclassifiesoperationalmotionsintoupperlimbbasicmotionsandothermotions.UsingMODneitherneedsmeasuringtimenortheperformancerate.,Unit4WorkSampling,Worksamplingisalsocalledtheinstantobservationmethod.Itgetstherequiredresultsthroughobservinginstantly,systematicanalysisanddealingwiththeobservationdatatotheoperatorduringalongerperiod.,Stopwatchtimestudy,Thereare18minutesvacancyand42minutesworking.Workratio=worktime/totalobservationtime=42/60=70%Vacancyratio=vacancytime/totalobservationtime=18/60=30%,TheResulto