Beni Asllani University of Tennessee at Chattanooga
Published byModified over 5 years ago
Presentation on theme: "Beni Asllani University of Tennessee at Chattanooga"— Presentation transcript:
1 Beni Asllani University of Tennessee at Chattanooga Chapter 15Lean ProductionOperations Management - 5th EditionRoberta Russell & Bernard W. Taylor, IIIBeni Asllani University of Tennessee at ChattanoogaCopyright 2006 John Wiley & Sons, Inc.
2 Lecture Outline Introduction Objective of lean production A comparison of attitudesBenefits of Lean ProductionBasic Elements of Lean ProductionImplementing Lean ProductionLean ServicesCopyright 2006 John Wiley & Sons, Inc.
3 Objective of Lean Production To eliminate wasteby:producing the needed items, at the right time, and the exact quantityCopyright 2006 John Wiley & Sons, Inc.
4 Benefits of JIT Reduced inventory (up to 90%) Reduced lead time (up to 90%)Reduced labor cost (up to 30%)Reduced manufacturing & storage space (up to 50%)Improvement of quality (up to 90%)Increased flexibility and adaptability to changesIncreased productivityCopyright 2006 John Wiley & Sons, Inc.
5 A Comparison of Attitudes Conventional AttitudesLarge lots are efficientJIT attitudesIdeal lot size is oneFaster production is more efficientBalanced production is more efficientInventory smoothes productionSafety stock is wasteInventory provides safetyINVENTORY IS THE ROOT OF ALL EVILCopyright 2006 John Wiley & Sons, Inc.
6 Inventory Hides Problems Copyright 2006 John Wiley & Sons, Inc.
7 Less Inventory Exposes Problems Copyright 2006 John Wiley & Sons, Inc.
8 Lean ProductionDoing more with less inventory, fewer workers, less spaceJust-in-time (JIT)smoothing the flow of material to arrive just as it is needed“JIT” and “Lean Production” are used interchangeablyMudawaste, anything other than that which adds value to the product or serviceCopyright 2006 John Wiley & Sons, Inc.
9 Basic Elements Pull production system Kanban production control Uniform production levelsSmall lotsQuick setupsFlexible resourcesCellular layoutsQuality at the sourceTotal productive maintenanceSupplier networksCopyright 2006 John Wiley & Sons, Inc.
10 LEVELED ASSEMBLY INSTRUCTIONS Pull SystemLEVELED ASSEMBLY INSTRUCTIONSPRODUCTION SCHEDULECBAFABFABVENDORBASUBFABFABVENDORFINAL ASSEMBLYFABFABSUBVENDORFABFABVENDORVENDORFABCopyright 2006 John Wiley & Sons, Inc.
11 Pull System Material is pulled through the system when needed Reversal of traditional push system where material is pushed according to a scheduleForces cooperationPrevent over and underproductionWhile push systems rely on a predetermined schedule, pull systems rely on customer requestsCopyright 2006 John Wiley & Sons, Inc.
12 Kanbans Card which indicates standard quantity of production Derived from two-bin inventory systemMaintain discipline of pull productionAuthorize production and movement of goodsCopyright 2006 John Wiley & Sons, Inc.
13 Sample KanbanCopyright 2006 John Wiley & Sons, Inc.
14 Origin of Kanbana) Two-bin inventory system b) Kanban inventory systemReordercardBin 1Bin 2Q - RKanbanRQ = order quantityR = reorder point - demand during lead timeCopyright 2006 John Wiley & Sons, Inc.
15 Types of Kanban Signal kanban Production kanban Withdrawal kanban a triangular kanban used to signal production at the previous workstationMaterial kanbanused to order material in advance of a processSupplier kanbanrotates between the factory and suppliersProduction kanbanauthorizes production of goodsWithdrawal kanbanauthorizes movement of goodsKanban squarea marked area designated to hold itemsCopyright 2006 John Wiley & Sons, Inc.
17 Uniform Production Levels Result from smoothing production requirementsKanban systems can handle +/- 10% demand changesSmooth demand across planning horizonMixed-model assembly steadies component productionCopyright 2006 John Wiley & Sons, Inc.
20 Small Lots Require less space and capital investment Move processes closer togetherMake quality problems easier to detectMake processes more dependent on each otherCopyright 2006 John Wiley & Sons, Inc.
21 HOOD & FENDER SETUP COMPARISON (800 TON PRESS) ToyotaU.S.A.SwedenGermanySetup Time10 min6 hr.4 hr.Setups/Day31-1/2Lot Size1 day*10 days1 month* For low demand items (less than 1000/month)Up to 7 daysCopyright 2006 John Wiley & Sons, Inc.
22 Components of Lead Time Processing timeReduce number of items or improve efficiencyMove timeReduce distances, simplify movements, standardize routingsWaiting timeBetter scheduling, sufficient capacitySetup timeGenerally the biggest bottleneckCopyright 2006 John Wiley & Sons, Inc.
23 Quick Setups SMED Principles Internal setup External setup Separate internal setup from external setupConvert internal setup to external setupStreamline all aspects of setupPerform setup activities in parallel or eliminate them entirelyInternal setupCan be performed only when a process is stoppedExternal setupCan be performed in advanceCopyright 2006 John Wiley & Sons, Inc.
24 Flexible Resources Multifunctional workers Cycle time Takt time perform more than one jobgeneral-purpose machines perform several basic functionsCycle timetime required for the worker to complete one pass through the operations assignedTakt timepaces production to customer demandCopyright 2006 John Wiley & Sons, Inc.
25 Cellular Layouts Manufacturing cells comprised of dissimilar machines brought together to manufacture a family of partsCycle time is adjusted to match takt time by changing worker pathsCopyright 2006 John Wiley & Sons, Inc.
26 Cells with Worker Routes Copyright 2006 John Wiley & Sons, Inc.
27 Worker Routes Lengthen as Volume Decreases Copyright 2006 John Wiley & Sons, Inc.
28 Quality at the Source Visual control Poka-yokes Kaizen Jidoka Andons makes problems visiblePoka-yokesprevent defects from occurringKaizena system of continuous improvement; “change for the good of all”Jidokaauthority to stop the production lineAndonscall lights that signal quality problemsUnder-capacity schedulingleaves time for planning, problem solving, and maintenanceCopyright 2006 John Wiley & Sons, Inc.
29 Examples of Visual Control Copyright 2006 John Wiley & Sons, Inc.
30 Total Productive Maintenance (TPM) Breakdown maintenanceRepairs to make failed machine operationalPreventive maintenanceSystem of periodic inspection and maintenance to keep machines operatingTPM combines preventive maintenance and total quality conceptsCopyright 2006 John Wiley & Sons, Inc.
31 TPM RequirementsDesign products that can be easily produced on existing machinesDesign machines for easier operation, changeover, maintenanceTrain and retrain workers to operate machinesPurchase machines that maximize productive potentialDesign preventive maintenance plan spanning life of machineCopyright 2006 John Wiley & Sons, Inc.
32 Supplier Networks Long-term supplier contracts Synchronized production Supplier certificationMixed loads and frequent deliveriesPrecise delivery schedulesStandardized, sequenced deliveryLocating in close proximity to the customerCopyright 2006 John Wiley & Sons, Inc.
33 Implementing Lean Production Use lean production to finely tune an operating systemSomewhat different in USA than JapanLean production is still evolvingLean production isn’t for everyoneCopyright 2006 John Wiley & Sons, Inc.
34 Lean ServicesBasic elements of lean production apply equally to servicesMost prevalent applicationslean retailinglean bankinglean health careCopyright 2006 John Wiley & Sons, Inc.