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Chapter 15Chapter 15

Lean ProductionLean ProductionLean ProductionLean Production

Operations Management 5th EditionOperations Management 5th EditionOperations Management - 5th EditionOperations Management - 5th Edition

Roberta Russell & Bernard W. Taylor, IIIRoberta Russell & Bernard W. Taylor, III

Copyright 2006 John Wiley & Sons, Inc.Copyright 2006 John Wiley & Sons, Inc.Beni AsllaniBeni Asllani

University of Tennessee at ChattanoogaUniversity of Tennessee at Chattanooga

L O liL O liLecture OutlineLecture Outline

Basic Elements of Lean ProductionBenefits of Lean ProductionImplementing Lean ProductionLean Services

Copyright 2006 John Wiley & Sons, Inc.Copyright 2006 John Wiley & Sons, Inc. 1515--22

L P d iLean Production

Doing more with less inventory, fewer workers, less spaceJ t i ti (JIT)Just-in-time (JIT)

smoothing the flow of material to arrive just as it is needed“JIT” and “Lean Production” are used interchangeably

Mudawaste, anything other than that which adds value to the product or service


W i O iW i O iWaste in OperationsWaste in Operations


W i O i ( )W i O i ( )Waste in Operations (cont.)Waste in Operations (cont.)


B i ElB i ElBasic ElementsBasic Elements

1. Flexible resources2. Cellular layouts3. Pull production system4. Kanban production control5. Small lot production6. Quick setups7. Uniform production levels8. Total productive

maintenance9. Supplier networks


Fl ibl RFlexible Resources

Multifunctional workersperform more than one jobgeneral-purpose machines perform several basic functions

Cycle timeytime required for the worker to complete one pass through the operations assignedg

Takt timepaces production to customer demand


Standard OperatingStandard Operating Routine for a Worker


C ll l LCellular Layouts

Manufacturing cellscomprised of dissimilar machines broughtcomprised of dissimilar machines brought together to manufacture a family of parts

Cycle time is adjusted to match takt timeCycle time is adjusted to match takt time by changing worker paths


C ll i h W k RCells with Worker Routes


Worker Routes Lengthen asWorker Routes Lengthen as Volume Decreases


P ll SPull System

Material is pulled through the system when Material is pulled through the system when neededneededReversal of traditional push system where Reversal of traditional push system where material is pushed according to a schedulematerial is pushed according to a scheduleForces cooperationForces cooperationForces cooperationForces cooperationPrevent over and underproductionPrevent over and underproductionWhile push systems rely on a predeterminedWhile push systems rely on a predetermined schedule, pull systems rely on customer requests


K bK bKanbansKanbans

Card which indicates standard quantity Card which indicates standard quantity of productionof productionof productionof productionDerived from twoDerived from two--bin inventory systembin inventory systemMaintain discipline of pull productionMaintain discipline of pull productionMaintain discipline of pull productionMaintain discipline of pull productionAuthorize production and movement of Authorize production and movement of goodsgoodsgoodsgoods


S l K bS l K bSample KanbanSample Kanban


O i i f K bO i i f K bOrigin of KanbanOrigin of Kanbana) Twoa) Two--bin inventory systembin inventory system b) Kanban inventory systemb) Kanban inventory system

Bin 1Bin 1KanbanKanban

Reorder Reorder cardcard

Bin 2Bin 2

Q - Rcardcard Q RRR

QQ = order quantity= order quantityRR = reorder point = reorder point -- demand during lead timedemand during lead time


T f K bT f K bTypes of KanbanTypes of Kanban

Production kanbanauthorizes production of

Signal kanbana triangular kanban

d t i lp

goodsWithdrawal kanban

authorizes movement of

used to signal production at the previous workstationauthorizes movement of

goodsKanban square

k d d i t d

Material kanbanused to order material in advance of a processa marked area designated

to hold itemsadvance of a process

Supplier kanbanrotates between the


rotates between the factory and suppliers

Determining Number ofDetermining Number ofDetermining Number of Determining Number of KanbansKanbans

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

CCwherewhere

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 stock


CC = container size= container size

Determining Number of Determining Number of ggKanbans: ExampleKanbans: Example

dd = 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 5SS 0.10(150 x 0.5) 7.5 0.10(150 x 0.5) 7.5CC = 25 bottles= 25 bottles

dLdL SS (150 0 5) + 7 5(150 0 5) + 7 5NN = == =

= = 3.3 kanbans or containers= = 3.3 kanbans or containers

dLdL + + SSCC

(150 x 0.5) + 7.5(150 x 0.5) + 7.52525

75 + 7.575 + 7.52525

Round up to 4 (to allow some slack) or Round up to 4 (to allow some slack) or d t 3 (t f i t)d t 3 (t f i t)

2525


down to 3 (to force improvement)down to 3 (to force improvement)

S ll LS ll LSmall LotsSmall Lots

Require less space and capital Require less space and capital investmentinvestmentinvestmentinvestmentMove processes closer togetherMove processes closer togetherMake quality problems easier to Make quality problems easier to detectdetectMake processes more dependent Make processes more dependent on each otheron each other


o eac ot eo eac ot e

Inventory Hides ProblemsInventory Hides Problems


Less Inventory Exposes ProblemsLess Inventory Exposes Problems


C f L d TiC f L d TiComponents of Lead TimeComponents of Lead Time

Processing timeProcessing timeReduce number of items or improve efficiencyReduce number of items or improve efficiencyReduce number of items or improve efficiencyReduce number of items or improve efficiency

Move timeMove timeReduce distances, simplify movements, standardize Reduce distances, simplify movements, standardize routingsroutings

Waiting timeWaiting timeBetter scheduling sufficient capacityBetter scheduling sufficient capacityBetter scheduling, sufficient capacityBetter scheduling, sufficient capacity

Setup timeSetup timeGenerally the biggest bottleneckGenerally the biggest bottleneck


Generally the biggest bottleneckGenerally the biggest bottleneck

Q i k SQ i k SQuick SetupsQuick Setups

Internal setupInternal setupC b f dC b f d

SMED PrinciplesSMED PrinciplesSeparate internal setup from Separate internal setup from Can be performed Can be performed

only when a only when a process is stoppedprocess is stopped

E t l tE t l t

p pp pexternal setupexternal setupConvert internal setup to external Convert internal setup to external setupsetup

External setupExternal setupCan be performed Can be performed in advancein advance

ppStreamline all aspects of setupStreamline all aspects of setupPerform setup activities in Perform setup activities in parallel or eliminate them entirelyparallel or eliminate them entirelyparallel or eliminate them entirelyparallel or eliminate them entirely


Common Techniques for ReducingCommon Techniques for ReducingCommon Techniques for Reducing Common Techniques for Reducing Setup TimeSetup Time


Common Techniques for ReducingCommon Techniques for ReducingCommon Techniques for Reducing Common Techniques for Reducing Setup Time (cont.)Setup Time (cont.)


U if P d i L lUniform Production Levels

Result from smoothing production requirementsrequirementsKanban systems can handle +/Kanban systems can handle +/-- 10% 10% demand changesdemand changesggSmooth demand across planning Smooth demand across planning horizonhorizonMixedMixed--model assembly steadies model assembly steadies component productioncomponent production


MixedMixed--Model SequencingModel SequencingMixedMixed Model SequencingModel Sequencing


Q li h SQuality at the Source

Visual controlmakes problems visible

Jidokaauthority to stop the

Poka-yokesprevent defects from

production lineAndons

call lights that signal prevent defects from occurring

Kaizena system of continuous

g gquality problems

Under-capacity schedulinga system of continuous

improvement; “change for the good of all”

gleaves time for planning, problem solving, and maintenance


Examples of VisualExamples of VisualExamples of Visual Examples of Visual ControlControl


Examples of VisualExamples of VisualExamples of Visual Examples of Visual Control (cont.)Control (cont.)


Total ProductiveTotal ProductiveTotal Productive Total Productive Maintenance (TPM)Maintenance (TPM)

Breakdown maintenanceBreakdown maintenanceR i t k f il d hi ti lR i t k f il d hi ti lRepairs to make failed machine operationalRepairs to make failed machine operational

Preventive maintenancePreventive maintenanceSystem of periodic inspection and System of periodic inspection and maintenance to keep machines operatingmaintenance to keep machines operating

TPM combines preventive maintenance TPM combines preventive maintenance and total quality conceptsand total quality concepts


TPM R iTPM R iTPM RequirementsTPM Requirements

Design products that can be easily produced Design products that can be easily produced on existing machineson existing machinesDesign machines for easier operation, Design machines for easier operation, changeover, maintenancechangeover, maintenanceTrain and retrain workers to operate machinesTrain and retrain workers to operate machinesTrain and retrain workers to operate machinesTrain and retrain workers to operate machinesPurchase machines that maximize productive Purchase machines that maximize productive potentialpotentialDesign preventive maintenance plan spanning Design preventive maintenance plan spanning life of machinelife of machine


5S Scan Goal Eliminate or CorrectUnneeded equipment, tools, furniture; unneeded items on walls, bulletins; items blocking aisles or stacked in corners; unneeded inventory, supplies, parts; safety

Keep only what you need

Seiri(sort)

y pp p yhazardsItems not in their correct places; correct places not obvious; aisles, workstations, & equipment locations not indicated; items not

A place for everything and everything in its Seiton

( t i d )q p

put away immediately after useFloors, walls, stairs, equipment, & surfaces not lines, clean; cleaning materials not easily accessible; labels, signs broken or unclean;

y gplace Cleaning, and looking for ways to keep clean and

(set in order)

Seisou(shine) g

other cleaning problemsNecessary information not visible; standards not known; checklists missing; quantities and limits not easily recognizable; items can’t be

porganized

Maintaining and monitoring the first

(shine)

Seiketsu(standardi e)

y glocated within 30 secondsNumber of workers without 5S training; number of daily 5S inspections not performed; number of personal items not stored; number

gthree categoriesSticking to the rules

(standardize)

Shisuke(sustain)


of times job aids not available or up-to-date( )

S li N kSupplier Networks

Long-term supplier contractsSynchronized productionSynchronized productionSupplier certificationMixed loads and frequent deliveriesMixed loads and frequent deliveriesPrecise delivery schedulesSt d di d d d liStandardized, sequenced deliveryLocating in close proximity to the customer


Benefits of LeanBenefits of Lean Production

Reduced inventoryImproved qualityImproved qualityLower costsReduced space requirementsReduced space requirementsShorter lead timeIncreased productivityIncreased productivity


Benefits of LeanBenefits of Lean Production (cont.)

Greater flexibilityBetter relations with suppliersBetter relations with suppliersSimplified scheduling and control activitiesIncreased capacityIncreased capacityBetter use of human resourcesMore product varietyMore product variety


I l i L P d iImplementing Lean Production

Use lean production to finely tune anUse lean production to finely tune anUse lean production to finely tune an Use lean production to finely tune an operating systemoperating systemSomewhat different in USA than JapanSomewhat different in USA than JapanSomewhat different in USA than JapanSomewhat different in USA than JapanLean production is still evolvingLean production is still evolvingLean production isn’t for everyoneLean production isn’t for everyone


L S iL S iLean ServicesLean Services

Basic elements of lean Basic elements of lean production apply equally toproduction apply equally toproduction apply equally to production apply equally to servicesservicesM t l t li tiMost prevalent applications

lean retailinglean bankinglean health care


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