15-第十五章短期調(diào)度

Short-TermSchedulingShort-TermSchedulingPrinciplesofOperationsManagement PrinciplesofOperationsManagement #第十五章短期調(diào)度主要內(nèi)容Outline短期調(diào)度的戰(zhàn)略重要性［TheStrategicImportaneeofShort-TermScheduling］［高效+高速+低庫存+準(zhǔn)確的交貨期］調(diào)度問題［SchedulingIssues］［能力計劃+綜合計劃+主生產(chǎn)計劃+短期調(diào)度］正向與逆向調(diào)度［定制［ForwardandBackwardScheduling調(diào)度準(zhǔn)則SchedulingCriteria［時間短+利用率高+庫存少+等待短］工藝專業(yè)化設(shè)施的調(diào)度［SchedulingProcess-FocusedFacilities］［計劃文件］作業(yè)分配［LoadingJobs］輸入輸出控制Input-OutputControl［固定在制品卡片］甘特圖GanttCharts分配方法AssignmentMethod［指派問題-匈牙利法］作業(yè)排序［SequencingJobs］派工的優(yōu)先規(guī)則PriorityRulesforDispatchingJobs［FCFS+SPT+EDD+LPT］關(guān)鍵比CriticalRatio［剩余交付時間/剩余作業(yè)時間］N項作業(yè)兩臺機器的排序問題：約翰遜規(guī)則 SequencingNJobsonTwoMachines: Johnson'sRule基于規(guī)則的作業(yè)派工系統(tǒng)的局限性 LimitationsofRule-BasedDispatchingSystems有限能力計劃［FiniteCapacityScheduling(FCS)］約束理論［TheoryofConstraints］瓶頸Bottlenecks鼓、緩沖、繩子Drum,Buffer,Rope［節(jié)拍+庫存+信號］I5.8重復(fù)性設(shè)施的調(diào)度［SchedulingRepetitiveFacilities］［物料平準(zhǔn)化］15.9服務(wù)業(yè)的調(diào)度［SchedulingServices］［24/7運作+需求管理+能力管理］用循環(huán)調(diào)度法編制服務(wù)人員的工作班次SchedulingServiceEmployeeswithCyclicalScheduling［循環(huán)調(diào)度］［案例］達美航空：天氣不佳時的飛行調(diào)度GlobalCompanyProfile:DeltaAirLines達美航空公司每年有近 10%的航班受到各種影響，其中一半是由于天氣原因引起 About10%ofDelta'sflightsaredisruptedperyear,halfbecauseofweather公司每年損失4.4億美元，包括收入損失、加班工資以及乘客的食宿費用 Costis$440millioninlostrevenue,overtimepay,foodandlodgingvouchers公司投入3千3百萬建立運營控制中心以適應(yīng)各種變化 ［通訊+除冰+及時通知乘客+變更航線］禾口保持航班準(zhǔn)確運行The$33millionOperationsControlCenteradjuststochangesandkeepsflightsflowing每年節(jié)約3千五百萬SavesDelta$35millionperyear15.1短期調(diào)度的戰(zhàn)略重要性 [TheStrategicImportaneeofShort-TermScheduling綜合計劃的落實]有效和高效的調(diào)度是企業(yè)的一個競爭優(yōu)勢 Effectiveandefficientschedulingcanbeacompetitiveadvantage高效的調(diào)度意味著商品或者服務(wù)更快的通過生產(chǎn)設(shè)施， 提高了資產(chǎn)的利用率， 從而降低了成本Fastermovementofgoodsthroughafacilitymeansbetteruseofassetsandlowercosts高效的調(diào)度意味更強的生產(chǎn)能力， 更快的吞吐速度以及生產(chǎn)柔性，意味著更快的交貨速度從而可以為顧客提供更好的服務(wù) Additionalcapacityresultingfromfasterthroughputimprovescustomerservicethroughfasterdelivery良好的調(diào)度意味著更可靠的交貨期 Goodschedulesresultinmoredependabledeliveries15.2調(diào)度問題［SchedulingIssues］-領(lǐng)導(dǎo)-指揮-戰(zhàn)爭戰(zhàn)役指揮員［給我沖+跟我沖］調(diào)度就是安排各項運作的時間 Schedulingdealswiththetimingofoperations調(diào)度的任務(wù)就是根據(jù)設(shè)備能力對需求 ［預(yù)測+訂單］進行分配并安排優(yōu)先級Thetaskistheallocationandprioritizationofdemand調(diào)度要考慮的問題Significantissuesare調(diào)度的類型，正向還是逆向的 Thetypeofscheduling,forwardorbackward］迎戰(zhàn)+進攻］調(diào)度準(zhǔn)則的優(yōu)先標(biāo)準(zhǔn) Thecriteriaforpriorities不同組織調(diào)度決策有不同內(nèi)容 ［SchedulingDecisions］［醫(yī)院、學(xué)校、制造商、餐廳及航空公司］組織Organization管理人員需要對以下內(nèi)容進行調(diào)度 ManagersMustScheduletheFollowing醫(yī)院ArnoldPalmerHospital手術(shù)室的使用Operatingroomuse病人收治Patientadmissions護理人員、安全人員以及設(shè)備護理人員Nursing,security,maintenancestaffs門診患者的治療Outpatienttreatments大學(xué)University ofMissouri教室和音響設(shè)備Classroomsandaudiovisualequipment學(xué)生和教師的課表 Studentandinstructorschedules本科生和研究生的課程 Graduateandundergraduatecourses工廠LockheedMartinfactory產(chǎn)品生產(chǎn)Productionofgoods物料采購Purchasesofmaterials工人Workers餐廳HardRockCafe廚師、服務(wù)員、吧臺侍者 Chef,waiters,bartenders新食物交付Deliveryoffreshfoods表演人員Entertainers餐廳營業(yè)時間Openingofdiningareas航空公司DeltaAirLines飛機維護Maintenanceofaircraft起飛時間表Departuretimetables航班機組人員、餐飲服務(wù)人員、登機口和檢票人員 Flightcrews,catering,gate,ticketingpersonnel

SchedulingDecisionsOrganization ManagersMustScheduletheFollowingArnoldPalmerHospitalUniversityofArnoldPalmerHospitalUniversityofMissouriLockheedMartinfactoryPatientadmissionsNursing,security,maintenancestaffsOutpatienttreatmentsClassroomsandaudiovisualequipmentStudentandinstructorschedulesGraduateandundergraduatecoursesProductionofgoodsPurchasesofmaterialsHardRockCafeDeltaAirLinesTable15.1 Chef,waiters,bartendersDeliveryoffreshfoodsEntertainersOpeningofdiningareasMaintenanceofaircraftDeparturetimetablesFlightcrews,catering,gate,ticketingpersonnel-調(diào)度工作計劃流程SchedulingFlow［把握組織的能力計劃+綜合計劃+HardRockCafeDeltaAirLinesTable15.1 Chef,waiters,bartendersDeliveryoffreshfoodsEntertainersOpeningofdiningareasMaintenanceofaircraftDeparturetimetablesFlightcrews,catering,gate,ticketingpersonnel-調(diào)度工作計劃流程SchedulingFlow［把握組織的能力計劃+綜合計劃+主生產(chǎn)計劃+短期調(diào)度的關(guān)系］能力計劃［長期，年］設(shè)備變更設(shè)備調(diào)整綜合計劃［中期，季度或月］設(shè)備利用率人員調(diào)整分包主生產(chǎn)計劃［中期，周］物料需求計劃分解綜合生產(chǎn)計劃短期調(diào)度［短期，天、小時或分鐘］工作中心負(fù)荷作業(yè)排序/分派SchedulingFlowJkggr?(|BlEHnnnlnH■wnn; armanl-lyj耳陽網(wǎng)ullnrl^rAirwrrqlEfirgpiSdbmynEinR比口W祕舊MMh1丄用"bqi.PraduclicnPlanifarAJIHilcaa(LkrtrnirrwpvwrmricrwteorttKTing□旺pste* 祠帕rrihfl抵4加巾9沖咖MmHfSctwMa口iiigp■書m pUnkltrftfi1i2J ■T1VndQlZSModal100W150VodalZQ100ica1D0100MafllarP*raducbcflBtahadl,AqfBliwMoeHhaaptdtytdiMhila]9hd-H盼盲.[Stwrl11rm; tnui斗QvnIvIndtigRnrkrz^httrftFigure15.115-15-1215.2.1正向調(diào)度與逆向調(diào)度15.2.1正向調(diào)度與逆向調(diào)度正向調(diào)度Forwardscheduling正向調(diào)度一旦需求已知，就開始調(diào)度 Forwardschedulingstartsassoonastherequirementsareknown產(chǎn)生一個可行的時間表，雖然它可能無法滿足交貨期Producesafeasibleschedulethoughitmaynotmeetduedates經(jīng)常導(dǎo)致在制品庫存積壓 Frequentlyresultsinbuildupofwork-in-processinventoryDate［案例］醫(yī)院、診所、餐廳和機床制造等 ［一般上班前準(zhǔn)備好］。逆向調(diào)度Backwardscheduling逆向調(diào)度從計劃交付期開始， 首先從最后一項作業(yè)開始調(diào)度 Backwardschedulingbeginswiththeduedateandschedulesthefinaloperationfirst對其他工序逆向依次進行調(diào)度 Scheduleisproducedbyworkingbackwardsthoughtheprocesses實現(xiàn)調(diào)度計劃所需資源可能出現(xiàn)匱乏 ResourcesmaynotbeavailabletoaccomplishthescheduleDateDate［案例］制造業(yè)企業(yè)+宴會+安排手術(shù)［有需求就準(zhǔn)備有時兩者結(jié)合效果更好[Oftentheseapproachesarecombinedtodevelopatrade-offbetweenafeasiblescheduleandcustomerduedates]15.2.2調(diào)度準(zhǔn)則[SchedulingCriteria]調(diào)度在于優(yōu)化資源滿足生產(chǎn)目標(biāo) Optimizetheuseofresourcessothatproductionobjectivesaremet完成時間最短[Minimizecompletiontime]利用率最高[Maximizeutilizationoffacilities]在制品庫存最少[Minimizework-in-process(WIP)inventory]顧客等待時間最短[Minimizecustomerwaitingtime]不同工藝流程的調(diào)度方法 DifferentProcesses/DifferentApproaches:工藝專業(yè)化設(shè)施[作業(yè)車間]+工作單元+重復(fù)性生產(chǎn)設(shè)施[裝配線]+連續(xù)性生產(chǎn)+大規(guī)模定制工藝專業(yè)化設(shè)施Process-focusedfacilities正向調(diào)度Forward-lookingschedulesMRPduedates

Finitecapacityscheduling工作單元Workcells正向調(diào)度Forward-lookingschedulesMRPduedatesDetailedscheduledoneusingworkcellpriorityrules重復(fù)性生產(chǎn)設(shè)施Repetitivefacilities正向調(diào)度Forward-lookingschedulewithabalaneedlinePulltechniquesforscheduling連續(xù)性生產(chǎn)Product-focusedfacilities正向調(diào)度Forward-lookingschedulewithstabledemandandfixedcapacityCapacity,set-up,andruntimesknownCapacitylimitedbyIong-termcapitalinvestment大規(guī)模定制MassCustomization逆向調(diào)度Backwardscheduling正向調(diào)度效率逆向調(diào)度響應(yīng)性DifferentProcesses/DifferentApproachesProcess-focusedfacilitiesWorkcellsRepetitivefacilitiesProduct-focusedfacilitiesTable15.22008PrenticeHall,Inc.Forward-lookingschedulesProcess-focusedfacilitiesWorkcellsRepetitivefacilitiesProduct-focusedfacilitiesTable15.22008PrenticeHall,Inc.Forward-lookingschedulesMRPduedatesFinitecapacityschedulingForward-lookingschedulesMRPduedatesDetailedscheduledoneusingworkcellpriorityrulesForward-lookingschedulewithabalaneedlinePulltechniquesforschedulingForward-lookingschedulewithstabledemandandfixedcapacityCapacity,set-up,andruntimesknownCapacitylimitedbylong-termcapitalinvestment15-16工藝專業(yè)化設(shè)施的調(diào)度［SchedulingProcess-FocusedFacilities］工藝專業(yè)化設(shè)施［間歇性設(shè)施/作業(yè)車間］的調(diào)度［多品種，小批量的生產(chǎn)系統(tǒng)］+［原料+加工順序+加工需求+加工時間+調(diào)整設(shè)備］安排訂單計劃不要超過的能力約束 Scheduleincomingorderswithoutviolatingcapacityconstraints發(fā)布一個訂單指令前 ，要檢查該部門可用的工具和材料 Checkavailabilityoftoolsandmaterialsbeforereleasinganorder為每個工作設(shè)置完成時間 ，并檢查生產(chǎn)進度 Establishduedatesforeachjobandcheckprogress檢查在制品情況Checkworkinprogress提供反饋Providefeedback提供工作效率統(tǒng)計和監(jiān)控操作人員的時間 Provideworkefficiencystatisticsandmonitortimes計劃文件［PlanningFiles］

零件主文件包括企業(yè)采購和生產(chǎn)的每個零部件的信息 Anitemmasterfilecontainsinformationabouteachcomponent工藝路線文件用于說明每個零部件在車間內(nèi)部的工藝流程 Aroutingfileindicateseachcomponent'sflowthroughtheshop工作中心主文件包括工作中心的各種信息 ［產(chǎn)能和效率］Awork-centermasterfilecontainsinformationabouttheworkcenter控制文件［ControlFiles］根據(jù)每項工作指令的計劃來跟蹤實際進度 Tracktheactualprogressmadeagainsttheplan作業(yè)分配［LoadingJobs］分配［Loading］是指將工作分配給工作中心和加工中心。作業(yè)分配設(shè)法將成本、 空閑、完成時間最小化Assignjobssothatcosts,idletime,orcompletiontimeareminimized分配的兩種形式Twoformsofloading能力導(dǎo)向Capacityoriented將作業(yè)分配給特定的工作中心 Assigningspecificjobstoworkcenters輸入-輸出控制［Input-OutputControl］識另U超負(fù)荷或負(fù)荷不足 Identifiesoverloadingandunderloadingconditions采取迅速管理行動來解決調(diào)度問題 Promptsmanagerialactiontoresolveschedulingproblems通過固定在制品卡片，對運營系統(tǒng)工作任務(wù)總量來進行控制 CanbemaintainedusingConWIP［constantworking-in-process固定在制品］cardsthatcontroltheschedulingofbatches運作人員可以從以下幾方面管理作業(yè)流程，實現(xiàn)有效調(diào)度 Optionsavailabletooperationspersonnelinclude:校正設(shè)備性能Correctingperformances提高產(chǎn)能Increasingcapacity增加或減少工作中心的輸入 IncreasingorreducinginputtotheworkcenterInput-OutputControlExamplePlannedOutput320320PlannedOutput320320320320ActualOutput270270270270CumulativeDeviation-50-100-50說00CumulativeChangeinBacklog0-0-10+5Figure15.2WorkCenterDNCMilling(instandardhours)WeekEnding6/66/136/206/277/47/11PlannedInput280280280280280ActualInput270250280285280CumulativeDeviation-0-0F0-3515-15-22［實際投入ActualInput+實際產(chǎn)出ActualOutput］1542甘特圖[GanttCharts]-調(diào)度的有效工具甘特圖，也稱為條狀圖(Barchart)，是1917年由亨利甘特開發(fā)的，其內(nèi)在思想簡單，基本是線條圖，橫軸表示時間，縱軸表示活動 (項目)，線條表示在整個期間上計劃和實際的活動完成情況。它直觀地表明任務(wù)計劃在什么時候進行，及實際進展與計劃要求的對比。 Loadchartshowstheloadingandidletimesofdepartments,machines,orfacilities，Displaysrelativeworkloadsovertime，Schedulechartmonitorsjobsinprocess，AllGanttchartsneedtobeupdatedfrequentlytoaccountforchangesGanttLoadChartExampleWork****.^DayCenter^****-*^MondayWork****.^DayCenter^****-*^MondayTuesdayWednesdayThursdayFridayMetalworksJob349■-Job350Mechanical■ Job349 ■Job408ElectronicsJob408Job349PaintingJob295 .Job408Job349Centernotavailable口Processing□UnscheduledFigure15.315-15-2615.4.3任務(wù)分配方法[AssignmentMethod]-指派問題屬于線性規(guī)劃問題，按照資源分配任務(wù)或工作 Aspecialclassoflinearprogrammingmodelsthatassigntasksorjobstoresources目標(biāo)：成本和時間的最小化 Objectiveistominimizecostortime一項作業(yè)分配給一臺設(shè)備 Onlyonejob(orworker)isassignedtoonemachine(orproject)兩個緯度：任務(wù)-完成者

AssignmentExampleStep4-AssignmentsTypesetterATypesetterABCR-34$11$14$6S-66P$8$10$11T-50$9$12$7TypesetterABCR-34$3$4$0S-66$0$0$5T-50$0$1$0FromtheoriginalcosttableMinimumcost=$6+$10+$9=$252008PrenticeHall,Inc. 15-35作業(yè)分配是一種關(guān)注運作負(fù)荷的生產(chǎn)能力控制技術(shù)。作業(yè)排序［SequencingJobs］排序［Sequencing］規(guī)定各項作業(yè)被完成先后順序。派工的優(yōu)先規(guī)則［PriorityRulesforDispatchingJobs］-指導(dǎo)方針適用于工藝專業(yè)化設(shè)施確定工作的順序，即工作應(yīng)該那個工作中心先實施Specifiestheorderinwhichjobsshouldbeperformedatworkcenters優(yōu)先規(guī)則用于對工作進行分派和排序 Priorityrulesareusedtodispatchorsequeneejobs先到先服務(wù)FCFS:Firstcome,firstserved最短加工時間SPT:Shortestprocessingtime最早交貨時間EDD:Earliestduedate最長加工時間LPT:Longestprocessingtime

SequencingExampleApplythefourpopularsequencingrulestothesefivejobsJobJobWork(Processing)Time(Days)JobDueDate(Days)A68B26C818D315E92315-15-37[作業(yè)加工時間JobWork(Processing)Time(Days)+預(yù)定交貨時間JobDueDate(Days)]SequencingExampleSummaryofRulesRuleAverageCompletionTime(Days)Utilization(%)AverageNumberofJobsinSystemAverageLateness(Days)FCFS15.436.42.752.2SPT13.043.12.321.8EDD13.641.22.431.2LPT20.627.23.689.615-15-46規(guī)則Rule平均完成時間AverageCompletionTime(Days)利用率Utilization(%)系統(tǒng)中的平均作業(yè)數(shù)量 AverageNumberofJobsinSystem平均作業(yè)延遲AverageLateness(Days)醫(yī)院一般會采用先到先服務(wù)，但急診室有時候會例外。比較排隊規(guī)則ComparisonofSequencingRules

沒有哪個規(guī)則在所有方面都好 Noonesequencingruleexcelsonallcriteria［最短加工時間-加工時間短］SPTdoeswellonminimizingflowtimeandnumberofjobsinthesystem,ButSPTmoveslongjobstotheendwhichmayresultindissatisfiedcustomers［先到先服務(wù)-公平］FCFSdoesnotdoespeciallywell(orpoorly)onanycriteriabutisperceivedasfairbycustomers［最早交貨時間-延遲最短］EDDminimizeslateness關(guān)鍵比［CriticalRatio］關(guān)鍵比是一個數(shù)值指標(biāo)，可以用距預(yù)訂交貨期限的剩余時間與剩余工作時間的比值來表示Anindexnumberfoundbydividingthetimeremaininguntiltheduedatebytheworktimeremainingonthejob作業(yè)的關(guān)鍵比較低［比值低于1］說明其已落后于計劃，大于 1的關(guān)鍵比意味著該作業(yè)超前于計戈UJobswithlowcriticalratiosarescheduledaheadofjobswithhighercriticalratios與優(yōu)先規(guī)則不同，關(guān)鍵比是動態(tài)的，易于進行更新PerformswellonaveragejoblatenesscriteriaCriticalRatio(CR)AnindexnumberfoundbydividingthetimeremaininguntiltheduedatebytheworktimeremainingonthejobJobswithlowcriticalratiosarescheduledaheadofjobswithhighercriticalratiosPerformswellonaveragejoblatenesscriteriaTimeremainingCR=TimeremainingCR= —WorkdaysremainingDuedate-Today'dateWork(lead)timeremaining15-15-48CriticalRatioExampleCurrentlyDayDue25WorkdaysRemainingCriticalRatioPriorityOrderJobDateA304(30-25)/4=1.253B285(28-25)/5=.601C272(27-25)/2=1.002WithCR<1,JobBislate.JobCisjustonscheduleandJobAhassomeslacktime.?2008PrenticeHall,Inc. 15-49關(guān)鍵比的作用CriticalRatioTechnique確定某項作業(yè)的進度情況 Helpsdeterminethestatusofspecificjobs確定各項作業(yè)之間的相對優(yōu)先順序 Establishesrelativeprioritiesamongjobsonacommonbasis將備貨生產(chǎn)和訂貨生產(chǎn)聯(lián)系起來Relatesbothstockandmake-to-orderjobsonacommonbasis自動調(diào)整優(yōu)先順序(修改進度計劃) ，根據(jù)需求和作業(yè)進度的變化情況 Adjustsprioritiesautomaticallyforchangesinbothdemandandjobprogress對作業(yè)進度情況實行動態(tài)跟蹤 DynamicallytracksjobprogressN項作業(yè)2臺機器的排序：約翰遜規(guī)則[SequencingNJobsonTwoMachines: Johnson'sRule]適用于兩個或兩個以上的工作 ，任務(wù)通過兩臺機器或工作中心的排序問題 Workswithtwoormorejobsthatpassthroughthesametwomachinesorworkcenters最小化加工時間，最小化空閑時間 Minimizestotalproductiontimeandidletime約翰遜規(guī)則Johnson'sRule第一步：從零件在兩臺設(shè)備的加工時間中，找出最小值， 若有兩個或幾個相同的最小值，任取一個。Listalljobsandtimesforeachworkcenter ，Choosethejobwiththeshortestactivitytime.第二步：若最小值出現(xiàn)在前一設(shè)備上，則該零件應(yīng)最先加工， 若出現(xiàn)在后一設(shè)備上，則該零件應(yīng)最后加工。 Ifthattimeisinthefirstworkcenter,schedulethejobfirst.Ifitisinthesecondworkcenter,schedulethejoblast.第三步：將已排加工順序的零件除去，再重復(fù)第一、第二步，照此思路，直到把所有零件排Onceajobisscheduled,itiseliminatedfromthelist，Repeatsteps2and3workingtowardthecenterofthesequenee

Johnson'RuleExampleWorkCenter1 WorkCenter2Job(DrillPress) (Lathe)BEDCAC 8D 10E 7647BEDCAC 8D 10E 764712WC1BEDCAWC2B1EDCAime〔J3 5 / 910II12 13 1/ 1921222325 2/ 29 313335Time--基于規(guī)則的作業(yè)派工系統(tǒng)的局限性 [LimitationsofRule-BasedDispatchingSystems]調(diào)度是動態(tài)的，各種規(guī)則需隨著訂單、工藝、設(shè)備、產(chǎn)品作相應(yīng)的調(diào)整 Schedulingisdynamicandrulesneedtoberevisedtoadjusttochanges各種規(guī)則沒有顧及生產(chǎn)流程上下游的變化 Rulesdonotlookupstreamordownstream各種規(guī)則沒有顧及預(yù)訂交付期之外的因素 [庫存+訂單]Rulesdonotlookbeyondduedates有限能力計劃[FiniteCapacityScheduling(FCS)]通過為調(diào)度人員提供交互式計算機圖形系統(tǒng)輸出，克服了基于規(guī)則的排隊系統(tǒng)的缺陷Overcomesdisadvantagesofrule-basedsystemsbyprovidinganinteractive,computer-basedgraphicalsystem除使用優(yōu)先規(guī)則外、甘特圖、還使用專家系統(tǒng)或仿真允許實時響應(yīng)系統(tǒng)的變化 Mayincluderulesandexpertsystemsorsimulationtoallowreal-timeresponsetosystemchanges初始數(shù)據(jù)經(jīng)常來自于 MRP系統(tǒng)InitialdataoftenfromanMRPsystem可以根據(jù)生產(chǎn)效率對需求交付進行動態(tài)平衡 FCSallowsthebalancingofdeliveryneedsandefficiencyFiniteCapacitySchedulingMRPData?Master?InventoryPriorityrulesToolingandotherresourcesSetupsandruntimeschedule?BOM?Expertsystems?Simulationmodels?Routingfiles?WorkcenterinformationInteractiveFiniteCapacitySchedulingMRPData?Master?InventoryPriorityrulesToolingandotherresourcesSetupsandruntimeschedule?BOM?Expertsystems?Simulationmodels?Routingfiles?WorkcenterinformationInteractiveFiniteCapacitySchedulingFigure15.5約束理論[TheoryofConstraints]約束理論(TheoryofConstraints,TOC)是以色列物理學(xué)家、 企業(yè)管理顧問戈德拉特博士(Dr.EliyahuM.Goldratt)在他開創(chuàng)的優(yōu)化生產(chǎn)技術(shù)(OptimizedProductionTechnology,OPT)基礎(chǔ)上發(fā)展起來的管理哲理，該理論提出了在制造業(yè)經(jīng)營生產(chǎn)活動中定義和消除制約因素的一些規(guī)范化方法，以支持連續(xù)改進(ContinuousImprovement)。產(chǎn)銷量指的是企業(yè)生產(chǎn)并銷售出去的產(chǎn)品數(shù)量。[Throughputisthenumberofunitsprocessedthroughthefacilityandsold]

企業(yè)日標(biāo)j財務(wù)目標(biāo)?作業(yè)目標(biāo):現(xiàn)在利將來都能曬桂企業(yè)日標(biāo)j財務(wù)目標(biāo)?作業(yè)目標(biāo):現(xiàn)在利將來都能曬桂嚴(yán)(7)\ 庫存柑)] 遠(yuǎn)廿費fa〉制譴周期?1作業(yè)指標(biāo)*財蠶掏標(biāo)與制造周期的關(guān)毎約束理論是一個知識體系，用于處理任何限制組織實現(xiàn)目標(biāo)的能力問題[TOCdealswiththelimitsanorganizationfacesinachievingitsgoals]通過五步來識別并管理這些限制條件識另U約束Identifytheconstraints制定計劃來克服已識另U的約束 Developaplanforovercomingtheconstraints集中資源來完成計戈U Focusresourcesonaccomplishingtheplan通過減少負(fù)荷或擴大能力來減少約束的影響 Reducetheeffectsofconstraintsbyoff-loadingworkorincreasingcapacity克服舊約束，識另U新約束 Oncesuccessful,returntostep1andidentifynewconstraints瓶頸[Bottlenecks]瓶頸是工作中心的一種約束，限制了生產(chǎn)的產(chǎn)出 Bottleneckworkcentersareconstraintsthatlimitoutput生產(chǎn)的變化弓丨起瓶頸產(chǎn)生 Commonoccurreneeduetofrequentchanges處理瓶頸的方法Managementtechniquesinclude:提高瓶頸環(huán)節(jié)的能力 Increasingthecapacityoftheconstraint交叉培訓(xùn)員工和加強設(shè)備維護 Cross-trainedemployeesandmaintenance改變工藝路線、加工過程或?qū)で蠓职?Alternativeroutings,procedures,orsubcontractors將檢查和測試移到瓶頸環(huán)節(jié)的緊前位置 Movinginspectionandtest調(diào)整產(chǎn)銷計劃、使其與瓶頸環(huán)節(jié)相匹配 Schedulingthroughputtomatchbottleneckcapacity鼓、緩沖、繩子[Drum,Buffer,Rope]鼓是指系統(tǒng)的--節(jié)拍，提供作業(yè)計劃 決定系統(tǒng)生產(chǎn)率Thedrumisthebeatofthesystemandprovidesthescheduleorpaceofproduction緩沖指的是系統(tǒng)資源庫存Thebufferistheinventorynecessarytokeepconstraintsoperatingatcapacity繩子可以被認(rèn)為是看板 --信號Theropeprovidesthesynchronizationnecessarytopullunitsthroughthesystem重復(fù)性設(shè)施的調(diào)度[SchedulingRepetitiveFacilities]重復(fù)性生產(chǎn)企業(yè)希望滿足顧客需求、 降低在制品資金投入、減少批量規(guī)模、充分利用設(shè)備和工藝流程Levelmaterialusecanhelprepetitivefacilities:Bettersatisfycustomerdemand,Lowerinventoryinvestment,Reducebatchsize,Betterutilizeequipmentandfacilities調(diào)度重點在于實現(xiàn)物料平準(zhǔn)化， 其是按照準(zhǔn)時制要求，實行頻繁的、高質(zhì)量的小批量生產(chǎn)模式。這正是世界級生產(chǎn)企業(yè)的管理實踐平準(zhǔn)化的優(yōu)勢Advantagesinclude:

降低庫存水平Lowerinventorylevels加快產(chǎn)出速度Fasterproductthroughput提高零部件質(zhì)量Improvedcomponentquality減少占地面積需要Reducedfloor-spacerequirements改善員工溝通Improvedcommunications使生產(chǎn)過程更順暢Smootherproductionprocess服務(wù)業(yè)的調(diào)度[SchedulingServices]服務(wù)系統(tǒng)和制造系統(tǒng)的差異 Servicesystemsdifferfrommanufacturing制造業(yè)調(diào)度Manufacturing服務(wù)業(yè)調(diào)度Services機器和原料Schedulesmachinesandmaterials人員Schedulestaff使用庫存平滑需求 Inventoriesusedtosmoothdemand很少維持庫存Seldommaintaininventories機器密集型和需求可以平滑Machine-intensiveanddemandmaybesmooth勞動密集型服務(wù)需求是變化的Labor-intensiveanddemandmaybevariable調(diào)度受到工會協(xié)議的限制 Schedulingmaybeboundbyunioncontracts法律因素限制靈活的調(diào)度 Legalissuesmayconstrainflexiblescheduling較少社會和行為問題Fewsocialorbehavioralissues社會和行為問題比較重要SocialandbehavioralissuesmaybequiteimportantSchedulingServicesServicesystemsdifferfrommanufacturing ManufacturingSchedulesmachinesandmaterials ManufacturingSchedulesmachinesandmaterialsInventoriesusedtosmoothdemandMachine-intensiveanddemandmaybesmoothSchedulingmaybeboundbyunioncontractsFewsocialorbehavioralissues2008PrenticeHall,Inc.Schedulestaff