JIT推式与拉式系统

1、及時化生產系統1及時化(just in time，JIT)概述提出者：豐田汽車副社長，大野耐一(Taiichi Ohno)。意義將需要的物品在必須的時間供應必須的品質與數量到需要的地點。目的消除混亂使系統彈性化降低籌置與前置時間存量最小化消除浪費及時化生產系統2JIT目標和建築架構的歸納 產品設計流程設計人員因素製造規劃避免中斷使系統有彈性排除浪費平衡迅速的流程最終目標支援目標建築架構及時化生產系統3常見的資源浪費1超額生產(overproduction)等候時間(waiting time)不必要的運送(unnecessary transporting)存貨(inventory)加工浪費(pr

2、ocessing waste)不必要的生產步驟產出瑕疵品及時化生產系統4常見的資源浪費2無效的工作方法(inefficient work method)不佳的佈置和物料搬運模式，增加在製品存貨產品不良再製成本消費者不滿意造成銷售損失及時化生產系統5Waste in Operations及時化生產系統6Waste in Operations及時化生產系統7Waste in Operations及時化生產系統8The Principles of the TOYOTA Production System (TPS)1All work must be completely specified as t

3、o content, sequence, timing, and outcome.Every customer-supplier connection must be direct, unambiguously specifying the people involved, the form and quantity of the services or goods to be provided, the way the requests are made by each customer, and the expected time in which the requests will be

4、 met.及時化生產系統9The Principles of the TOYOTA Production System (TPS)2The pathway for every service and product must be simple and direct.Any improvement to the system must be made in accordance with the scientific method, under the guidance of a teacher, at the lowest possible organizational level.及時化生

5、產系統10Basic Elements of JIT1標準的零件(產品設計)模組化設計(產品設計)高產能的系統(產品設計)可同時生產(產品設計)將員工視為資產(人員/組織的要素)訓練員工，使其變成多能工(人員/組織的要素)持續改善(人員/組織的要素)成本會計(人員/組織的要素)領導與專案管理(人員/組織的要素)及時化生產系統11Basic Elements of JIT2Cellular layouts (製程設計Pull production system(製造規劃與控制)Flexible resources (製程設計)Kanban production control(製造規劃與控制)S

6、mall-lot production(製程設計)Quick setups (製程設計)Uniform production levels (製造規劃與控制)Quality at the source(製程設計)Total productive maintenance (製造規劃與控制)Supplier networks(製造規劃與控制)及時化生產系統12Flexible ResourcesMultifunctional workers (多能工)Perform more than one jobGeneral purpose machines (通用設備)Perform several ba

7、sic functionsStudy operators & improve operations及時化生產系統13Cellular LayoutsGroup dissimilar machines in manufacturing cell to produce family of partsWork flows in one direction through cellCycle time adjusted by changing worker paths及時化生產系統14Manufacturing Cell with Worker RoutesWorker 1Worker 2Worker

8、 3Cell 1及時化生產系統15Worker Routes Lengthened as Volume DecreasesCell 5Worker 2Cell 2Worker 1Cell 1Worker 3Cell 3Cell 4及時化生產系統16推式與拉式系統推式系統(push system)(例如，MPR)當工作在某工作站完成時，產出就被推往下一站。拉式系統(pull system)(例如，JIT)工作移動的控制落於下一站;每一工作站從前一站拉拔所需產出。及時化生產系統17Kanban Production Control System(看板生產管制系統)Kanban card indic

9、ates standard quantity of productionDerived from two-bin inventory system(雙倉制)Kanban maintains discipline of pull productionProduction kanban(生產看板) authorizes productionWithdrawal kanban(提領看板) authorizes movement of goods及時化生產系統18A Sample Kanban及時化生產系統19The Origin of Kanbana) Two-bin inventory syste

10、mb) Kanban inventory systemReorder cardBin 1Bin 2Q - RKanbanRRQ = order quantityR = reorder point - demand during lead time及時化生產系統20Types of Kanbans Dual kanbans及時化生產系統21Single-Card Kanban SystemReceiving postKanban card for product 1Kanban card for product 2Fabrication cellO1O2O3O2Storage areaEmpty

11、 containersFull containersAssembly line 1Assembly line 2及時化生產系統22Storage areaEmpty containersFull containersSingle-Card Kanban SystemReceiving postKanban card for product 1Kanban card for product 2Fabrication cellO1O2O3O2Assembly line 1Assembly line 2及時化生產系統23Storage areaEmpty containersFull contain

12、ersSingle-Card Kanban SystemReceiving postKanban card for product 1Kanban card for product 2Fabrication cellO1O2O3O2Assembly line 1Assembly line 2及時化生產系統24Storage areaEmpty containersFull containersSingle-Card Kanban SystemReceiving postKanban card for product 1Kanban card for product 2Fabrication c

13、ellO1O2O3O2Assembly line 1Assembly line 2及時化生產系統25Storage areaEmpty containersFull containersSingle-Card Kanban SystemReceiving postKanban card for product 1Kanban card for product 2Fabrication cellO1O2O3O2Assembly line 1Assembly line 2及時化生產系統26Storage areaEmpty containersFull containersSingle-Card

14、Kanban SystemReceiving postKanban card for product 1Kanban card for product 2Fabrication cellO1O2O3O2Assembly line 1Assembly line 2及時化生產系統27Storage areaEmpty containersFull containersSingle-Card Kanban SystemReceiving postKanban card for product 1Kanban card for product 2Fabrication cellO1O2O3O2Asse

15、mbly line 1Assembly line 2及時化生產系統28看板系統 single kanban及時化生產系統29Dual kanban vs. single kanbanDual kanbanIs used when material is not necessarily moving between two consecutive processes, or when there is more than one input to a process and the inputs are dispersed throughout the facility.Single kanba

16、nIs used when the processes are tightly linked.及時化生產系統30Types of KanbansKanban SquareMarked area designed to hold itemsSignal KanbanTriangular kanban used to signal production at the previous workstationMaterial KanbanUsed to order material in advance of a processSupplier KanbansRotate between the f

17、actory and suppliers及時化生產系統31Types of Kanbans kanban square and kanban racks及時化生產系統32Types of Kanbans signal kanbans及時化生產系統33看板管理系統之規則不要把不良品交給後製程。由後製程到前製程來領取零件。前製程僅生產將被後製程領用去的數量。生產必須平衡。看板只做為微調整的手段，其張數必須減到最少。製程必須安定化、合理化。及時化生產系統34Single-Card Kanban SystemKANBANPart Number:1234567ZLocation:Aisle 5Bin 4

18、7Lot Quantity:6Supplier:WS 83Customer:WS 116Each container must have a cardAssembly always withdraws from fabrication (pull system)Containers cannot be moved without a kanbanContainers should contain the same number of partsOnly good parts are passed alongProduction should not exceed authorization及時

19、化生產系統35看板(容器)數量之決定1K=容器數量。d=工作中心之計劃使用率(預期每日需求) 。p=每箱容器零件之平均加工時間。W=在生產過程中之平均等候時間，加上每箱物料的搬運時間。C=標準容器之零件容量。X=政策變數。反應生產系統的效率(10%以內)及時化生產系統36看板(容器)數量之決定2k=在前置時間期間的平均需求+安全庫存每箱內的單位數量=d(w+p)(1+x)c及時化生產系統37看板(容器)數量之決定3whereN = number of kanbans or containersd = average demand over some time periodL = lead ti

20、me to replenish an orderS = safety stockC = container sizeNo. of Kanbans =average demand during lead time + safety stockcontainer sizeN =dL + SC及時化生產系統38容器數量決定範例某汽車零件公司生產4輪傳動車的方向盤及暫停系統中的搖桿手臂組合。一般1箱零件在製造週期中需要0.02天的加工及0.08天的物料處理和等候時間。零件每日的需求為2000個單位。管理部門認為搖桿手臂組合的需求不確定，所以其安全庫存為需求量的10%。若每箱內各有22個零件，則應授權的

21、箱子數量為多少。及時化生產系統39小批量 (Small-lot production) 的效益降低在製品存貨減少因品質發生問題時所產生的檢驗和重加工成本減少儲存空間問題更容易顯現增加生產彈性易於進行作業平衡及時化生產系統40Inventory Hides Problems及時化生產系統41Lower Levels of Inventory Expose Problems及時化生產系統42Components of Lead Time(前置時間的元素)Processing timeReduce number of items or improve efficiencyMove timeReduc

22、e distances, simplify movements, standardize routingsWaiting timeBetter scheduling, sufficient capacitySetup timeGenerally the biggest bottleneck及時化生產系統43快速籌置 (Quick setups)Single-digit setupThe goal of having a setup time of less than 10 minutes.快速換模又稱一分鐘換模術 (single-minute exchange of dies, SMED)及時

23、化生產系統44快速籌置的實施步驟1. 將換模作業流程劃分外部整備作業與內部整備作業。2. 儘可能把內部整備作業改變成外部整備作業。3. 消除內部整備所需的調整作業。4. 外部整備作業的標準化。5. 推動平行作業。6. 利用機械提高換模效率。7. 其他管理部門的充分配合。及時化生產系統45Common Techniques for Reducing Setup Time1及時化生產系統46Common Techniques for Reducing Setup Time2及時化生產系統47Common Techniques for Reducing Setup Time3及時化生產系統48平準化

24、生產 (Uniform Production)Results from smoothing production requirementsKanban systems can handle +/- 10% demand changesThe way to reduce variability in productionSmooths demand across planning horizonMixed-model assembly steadies component production及時化生產系統49平準化範例1The APP of TOYOTA: 4500 vehicles per

25、week. Two full shifts, five days per week 450 per shift (480 minutes)Three models are produced: Camry (C), Avalon (A), and Sienna (S).200 Camry, 150 Avalons, and 100 Siennas per shiftCycle time: 480/450=1.067 (min)及時化生產系統50平準化範例2First 200 Cs 150 As 100SsHigh average cycle inventory levelLumpy requir

26、ementsSecond4 Cs 3 As 2Ss The cycle =9(1.067)=9.60 (50 times per shift)及時化生產系統51平準化範例3ThirdC S C A C A C S AThe setup times must be very short.Component requirements is steadyCapacity requirements are smoothed及時化生產系統52Quality at the Source1Jidoka (自働化) 在生產過程中自動偵測缺點Andon (安童) 在每個工作站裝置燈號系統，以指示問題及落後狀態。

27、Undercapacity scheduling allows for planning, problem solving & maintenance及時化生產系統53Quality at the Source2防呆裝置日文發音為POKAYOKE ，是指在模具，工具，機器設備上設計防止錯誤(不良)發生的裝置，一旦作業員做錯或需要作業上的警示時，防呆裝置可以預防或使機器停下來，確保不產生不良品。目視管理系統 (visual control)： 係透過顯示板之顯示得以快速且明顯地發現異常、浪費、故障、斷料等現場不順暢之情形，而達到能速謀對策的一種管理系統。及時化生產系統54Visual Contr

28、ol及時化生產系統55Visual Control及時化生產系統56Visual Control及時化生產系統57Kaizen (改善)Continuous improvementRequires total employment involvementEssence of JIT is willingness of workers toSpot quality problemsHalt production when necessaryGenerate ideas for improvementAnalyze problemsPerform different functions及時化生產系

29、統58Total Productive Maintenance (TPM)Breakdown maintenanceRepairs to make failed machine operationalPreventive maintenanceSystem of periodic inspection & maintenance to keep machines operatingTPM combines preventive maintenance & total quality concepts及時化生產系統59TPM Requires Management to:Design produ

30、cts that can be easily produced on existing machinesDesign machines for easier operation, changeover, maintenanceTrain & retrain workers to operate machinesPurchase machines that maximize productive potentialDesign preventive maintenance plan spanning life of machine及時化生產系統60導入JIT的基礎5S運動定義功能整理 (seir

31、i, organization)把東西分成必要與不必要，將不必要的東西撤走。排除資源空間的浪費。整頓 (seiton, tidiness)需要的東西排放整齊以便取用。排除尋找，縮短作業或產品線切換、準備時間。清掃 (seiso, cleanliness)把工作場所掃除清潔，去除雜物及灰塵。提升效率，排除隱藏的工業災害與品質不良。清潔 (seiketsu, maintenance) 保持整理、整頓、清掃所建立之成果。確保作業安全，延長設備壽命，提升產品品質。修養 (shitsuke, discipline)對於規定的事項確實遵守並養成習慣。加強小團體之自主性活動。及時化生產系統61Supplier Policies1Locate near to the customerUse small, side loaded trucks and ship mixed loadsConsider establishing small warehouses near to the customer or consolidating