just in-time and lean production
TRANSCRIPT
BA 320 Operations Management
Chapter 11Chapter 11
Just-In-Time and Just-In-Time and Lean ProductionLean Production
BA 320 Operations Management
Producing only what is needed, Producing only what is needed, when it is neededwhen it is needed
A philosophy A philosophy An integrated management systemAn integrated management systemJIT’s mandate: JIT’s mandate:
Eliminate all wasteEliminate all waste
What is JIT ?What is JIT ?
BA 320 Operations Management
Basic Elements of JITBasic Elements of JIT1.1. Flexible resourcesFlexible resources2.2. Cellular layoutsCellular layouts3.3. Pull production systemPull production system4.4. Kanban production controlKanban production control5.5. Small-lot productionSmall-lot production6.6. Quick setupsQuick setups7.7. Uniform production levelsUniform production levels8.8. Quality at the sourceQuality at the source9.9. Total productive maintenanceTotal productive maintenance10.10. Supplier networksSupplier networks
BA 320 Operations Management
Figure 11.1Figure 11.1
Waste in OperationsWaste in Operations
BA 320 Operations Management
Figure 11.1Figure 11.1
Waste in OperationsWaste in Operations
BA 320 Operations Management
Figure 11.1Figure 11.1
Waste in OperationsWaste in Operations
BA 320 Operations Management
Flexible ResourcesFlexible Resources
Multifunctional workersMultifunctional workersGeneral purpose machinesGeneral purpose machinesStudy operators & improve Study operators & improve
operationsoperations
BA 320 Operations Management
Standard Operating Routine Standard Operating Routine for a Workerfor a Worker
Standard Operating RoutineSheet 1
Worker: RussellCycle Time: 2 min
Order of Operations timeOperations :10 :20 :30 :40 :50 1:00 1:10 1:20 1:30 1:40 1:50 2:00
Pick up material
Unload/load machine 1
Unload/load machine 2
Unload/load machine 3
Inspect/pack
Figure 11.2Figure 11.2
BA 320 Operations Management
Cellular LayoutsCellular LayoutsGroup dissimilar machines in Group dissimilar machines in
manufacturing cell to produce manufacturing cell to produce family of partsfamily of parts
Work flows in one direction Work flows in one direction through cellthrough cell
Cycle time adjusted by changing Cycle time adjusted by changing worker pathsworker paths
BA 320 Operations Management
Manufacturing Cell with Manufacturing Cell with Worker RoutesWorker Routes
Worker Worker 11
Worker Worker 22
Worker Worker 33
Cell 1Cell 1
Figure 11.3Figure 11.3
BA 320 Operations Management
Worker Routes Lengthened Worker Routes Lengthened as Volume Decreasesas Volume Decreases
Cell 5Cell 5
Worker Worker 22
Cell 2Cell 2
Worker Worker 11
Cell 1Cell 1
Worker Worker 33
Cell 3Cell 3 Cell 4Cell 4
Figure 11.4Figure 11.4
BA 320 Operations Management
The Pull SystemThe Pull SystemMaterial is pulled through the system Material is pulled through the system
when neededwhen neededReversal of traditional push system Reversal of traditional push system
where material is pushed according where material is pushed according to a scheduleto a schedule
Forces cooperationForces cooperationPrevent over and underproductionPrevent over and underproduction
BA 320 Operations Management
Kanban Production Kanban Production Control SystemControl System
Kanban card indicates standard quantity Kanban card indicates standard quantity of productionof production
Derived from two-bin inventory systemDerived from two-bin inventory system Kanban maintains discipline of pull Kanban maintains discipline of pull
productionproduction Production kanban authorizes productionProduction kanban authorizes production Withdrawal kanban authorizes movement Withdrawal kanban authorizes movement
of goodsof goods
BA 320 Operations Management
A Sample KanbanA Sample Kanban
BA 320 Operations Management
The Origin of KanbanThe Origin of Kanbana) Two-bin inventory systema) Two-bin inventory system b) Kanban inventory systemb) Kanban inventory system
Reorder Reorder cardcard
Bin 1Bin 1
Bin 2Bin 2
Q - R
KanbanKanban
RR
QQ = order quantity = order quantity
RR = reorder point - demand during lead time = reorder point - demand during lead time
Figure 11.5Figure 11.5
BA 320 Operations Management
Types of KanbansTypes of Kanbans
Figure 11.6Figure 11.6
BA 320 Operations Management
Types of KanbansTypes of Kanbans
Figure 11.6Figure 11.6
BA 320 Operations Management
Types of KanbansTypes of Kanbans
Figure 11.6Figure 11.6
BA 320 Operations Management
Types of KanbansTypes of Kanbans Kanban SquareKanban Square
Marked area designed to hold itemsMarked area designed to hold items Signal KanbanSignal Kanban
Triangular kanban used to signal Triangular kanban used to signal production at the previous workstationproduction at the previous workstation
Material KanbanMaterial KanbanUsed to order material in advance of a Used to order material in advance of a
processprocess Supplier KanbansSupplier Kanbans
Rotate between the factory and suppliersRotate between the factory and suppliers
BA 320 Operations Management
Determining Number of Determining Number of KanbansKanbans
wherewhere
NN = number of kanbans or containers= number of kanbans or containersdd = average demand over some time period= average demand over some time periodLL = lead time to replenish an order= lead time to replenish an orderSS = safety stock= safety stockCC = container size= container size
No. of Kanbans =No. of Kanbans =average demand during lead time + safety stockaverage demand during lead time + safety stock
container sizecontainer size
NN = =dLdL + + SS
CC
BA 320 Operations Management
Determining the Number Determining the Number of Kanbansof Kanbansdd = 150 bottles per hour= 150 bottles per hourLL = 30 minutes = 0.5 hours= 30 minutes = 0.5 hoursSS = 0.10(150 x 0.5) = 7.5= 0.10(150 x 0.5) = 7.5CC = 25 bottles= 25 bottles
Round up to 4 (to allow some slack) or Round up to 4 (to allow some slack) or down to 3 (to force improvement)down to 3 (to force improvement)
NN = == =
= = 3.3 kanbans or containers= = 3.3 kanbans or containers
dLdL + + SSCC
(150 x 0.5) + 7.5(150 x 0.5) + 7.5
252575 + 7.575 + 7.5
2525
Example 11.1Example 11.1
BA 320 Operations Management
Small-Lot ProductionSmall-Lot Production
Requires less space & capital Requires less space & capital investmentinvestment
Moves processes closer togetherMoves processes closer togetherMakes quality problems easier to Makes quality problems easier to
detectdetectMakes processes more dependent Makes processes more dependent
on each otheron each other
BA 320 Operations Management
Inventory Hides ProblemsInventory Hides Problems
BA 320 Operations Management
Lower Levels of Inventory Lower Levels of Inventory Expose ProblemsExpose Problems
BA 320 Operations Management
Components of Lead TimeComponents of Lead TimeProcessing timeProcessing time
Reduce number of items or improve Reduce number of items or improve efficiencyefficiency
Move timeMove time Reduce distances, simplify Reduce distances, simplify
movements, standardizemovements, standardize routingsroutingsWaiting timeWaiting time
Better scheduling, sufficient capacityBetter scheduling, sufficient capacitySetup timeSetup time
Generally the biggest bottleneckGenerally the biggest bottleneck
BA 320 Operations Management
SMED PrinciplesSMED Principles
1.1. Separate internal setup from Separate internal setup from external setupexternal setup
2.2. Convert internal setup to external Convert internal setup to external setupsetup
3.3. Streamline all aspects of setupStreamline all aspects of setup
4.4. Perform setup activities in Perform setup activities in parallel or eliminate them entirelyparallel or eliminate them entirely
BA 320 Operations Management
Common Techniques for Common Techniques for Reducing Setup TimeReducing Setup Time
Figure 11.8Figure 11.8
BA 320 Operations Management
Common Techniques for Common Techniques for Reducing Setup TimeReducing Setup Time
Figure 11.8Figure 11.8
BA 320 Operations Management
Common Techniques for Common Techniques for Reducing Setup TimeReducing Setup Time
Figure 11.8Figure 11.8
BA 320 Operations Management
Uniform ProductionUniform ProductionResults from smoothing production Results from smoothing production
requirementsrequirementsKanban systems can handle +/- 10% Kanban systems can handle +/- 10%
demand changesdemand changesSmooths demand across planning Smooths demand across planning
horizonhorizonMixed-model assembly steadies Mixed-model assembly steadies
component productioncomponent production
BA 320 Operations Management
Mixed-Model SequencingMixed-Model Sequencing
Example 11.2Example 11.2
BA 320 Operations Management
Quality at the SourceQuality at the SourceJidoka is authority to stop production Jidoka is authority to stop production
linelineAndon lights signal quality problemsAndon lights signal quality problemsUndercapacity scheduling allows for Undercapacity scheduling allows for
planning, problem solving & planning, problem solving & maintenancemaintenance
Visual control makes problems visibleVisual control makes problems visiblePoka-yoke prevents defectsPoka-yoke prevents defects
BA 320 Operations Management
Visual ControlVisual Control
Figure 11.9Figure 11.9
BA 320 Operations Management
Visual ControlVisual Control
Figure 11.9Figure 11.9
BA 320 Operations Management
Visual ControlVisual Control
Figure 11.9Figure 11.9
BA 320 Operations Management
KaizenKaizenContinuous improvementContinuous improvementRequires total employment Requires total employment
involvementinvolvementEssence of JIT is willingness of Essence of JIT is willingness of
workers toworkers toSpot quality problemsSpot quality problemsHalt production when necessaryHalt production when necessaryGenerate ideas for improvementGenerate ideas for improvementAnalyze problemsAnalyze problemsPerform different functionsPerform different functions
BA 320 Operations Management
Total Productive Total Productive Maintenance (TPM)Maintenance (TPM)
Breakdown maintenanceBreakdown maintenance Repairs to make failed machine operationalRepairs to make failed machine operational
Preventive maintenancePreventive maintenance System of periodic inspection & maintenance System of periodic inspection & maintenance
to keep machines operatingto keep machines operating
TPM combines preventive maintenance & TPM combines preventive maintenance & total quality conceptstotal quality concepts
BA 320 Operations Management
TPM Requires TPM Requires Management to:Management to:
Design products that can be easily produced Design products that can be easily produced on existing machineson existing machines
Design machines for easier operation, Design machines for easier operation, changeover, maintenancechangeover, maintenance
Train & retrain workers to operate machinesTrain & retrain workers to operate machines Purchase machines that maximize Purchase machines that maximize
productive potentialproductive potential Design preventive maintenance plan Design preventive maintenance plan
spanning life of machinespanning life of machine
BA 320 Operations Management
Supplier PoliciesSupplier Policies1. Locate near to the customer2. Use small, side loaded trucks and ship
mixed loads3. Consider establishing small warehouses
near to the customer or consolidating warehouses with other suppliers
4. Use standardized containers and make deliveries according to a precise delivery schedule
5. Become a certified supplier and accept payment at regular intervals rather than upon delivery
BA 320 Operations Management
Benefits of JITBenefits of JIT1.1. Reduced Reduced
inventoryinventory2.2. Improved qualityImproved quality3.3. Lower costsLower costs4.4. Reduced space Reduced space
requirementsrequirements5.5. Shorter lead timeShorter lead time6.6. Increased Increased
productivityproductivity7.7. Greater flexibilityGreater flexibility
8.8. Better relations Better relations with supplierswith suppliers
9.9. Simplified Simplified scheduling and scheduling and control activitiescontrol activities
10.10. Increased capacityIncreased capacity11.11. Better use of Better use of
human resourceshuman resources12.12. More product More product
varietyvariety
BA 320 Operations Management
Use JIT to finely tune an Use JIT to finely tune an operating systemoperating system
Somewhat different in Somewhat different in USA than JapanUSA than Japan
JIT is still evolvingJIT is still evolvingJIT isn’t for everyoneJIT isn’t for everyone
JIT ImplementationJIT Implementation
BA 320 Operations Management
JIT In ServicesJIT In ServicesCompetition on speed & qualityCompetition on speed & qualityMultifunctional department store Multifunctional department store
workersworkersWork cells at fast-food restaurantsWork cells at fast-food restaurantsJust-in-time publishing for Just-in-time publishing for
textbookstextbooksConstruction firms receiving Construction firms receiving
material just as neededmaterial just as needed