facilities. objectives of facility layout minimize material handling costs minimize material...

FacilitiesFacilities

Objectives of Facility LayoutObjectives of Facility Layout Minimize material handling costsMinimize material handling costs Utilize space efficientlyUtilize space efficiently Utilize labor efficientlyUtilize labor efficiently Eliminate bottlenecksEliminate bottlenecks Facilitate communication and interaction Facilitate communication and interaction

between workers, between workers and between workers, between workers and their supervisors, or between workers and their supervisors, or between workers and customerscustomers

Reduce manufacturing cycle time or customer service time

Objectives of Facility LayoutObjectives of Facility Layout Eliminate waste or redundant movementEliminate waste or redundant movement Facilitate the entry, exit, and placement of Facilitate the entry, exit, and placement of

material, products, or peoplematerial, products, or people Incorporate safety and security measuresIncorporate safety and security measures Promote product and service qualityPromote product and service quality Encourage proper maintenance activitiesEncourage proper maintenance activities Provide a visual control of operations or Provide a visual control of operations or

activitiesactivities Provide flexibility to adapt to changing Provide flexibility to adapt to changing

conditionsconditions Increase capacityIncrease capacity

Process LayoutProcess Layout Machines grouped by process they performMachines grouped by process they perform

Product LayoutProduct Layout Linear arrangement of workstations to Linear arrangement of workstations to

produce a specific productproduce a specific product

Fixed Position LayoutFixed Position Layout Used in projects where the product cannot Used in projects where the product cannot

be movedbe moved

Basic Types of LayoutsBasic Types of Layouts

Manufacturing Process LayoutManufacturing Process Layout

L

L

L

L

L

L

L

L

L

LM

M

M

M

D

D

D

D

D

D

D

D

G

G

G

G

G

G

A A AReceiving andShipping Assembly

Painting Department

Lathe DepartmentMilling

Department Drilling Department

Grinding Department

P

P

A Product LayoutA Product Layout

InIn

OutOut

Comparison Of Product Comparison Of Product And Process LayoutsAnd Process Layouts

1.1. DescriptionDescription Sequential arrangementSequential arrangement Functional groupingFunctional grouping

of machinesof machines of machines of machines

2.2. Type of ProcessType of Process Continuous, mass Continuous, mass Intermittent, job Intermittent, job shopshop

production, mainlyproduction, mainly batch production, batch production,

assemblyassembly mainly fabrication mainly fabrication

3.3. ProductProduct StandardizedStandardized Varied,Varied,

made to stockmade to stock made to order made to order

4.4. DemandDemand StableStable FluctuatingFluctuating

5.5. VolumeVolume HighHigh LowLow

6.6. EquipmentEquipment Special purposeSpecial purpose General purposeGeneral purpose

7.7. WorkersWorkers Limited skillsLimited skills Varied skillsVaried skills

PRODUCT LAYOUTPRODUCT LAYOUT PROCESS LAYOUTPROCESS LAYOUT

Comparison Of Product Comparison Of Product And Process LayoutsAnd Process Layouts

8. 8. InventoryInventory Low in-process,Low in-process, High in-process,High in-process,

high finished goodshigh finished goods low finished low finished goodsgoods

9. Storage space9. Storage space SmallSmall LargeLarge

10. Material10. Material Fixed pathFixed path Variable pathVariable path

handlinghandling (conveyor) (conveyor) (forklift) (forklift)

11. Aisles11. Aisles NarrowNarrow WideWide

12. Scheduling12. Scheduling Part of balancingPart of balancing DynamicDynamic

13. Layout decision13. Layout decision Line balancingLine balancing Machine locationMachine location

14. 14. GoalGoal Equalize work atEqualize work at Minimize materialMinimize material

each stationeach station handling cost handling cost

15. Advantage15. Advantage EfficiencyEfficiency FlexibilityFlexibility

PRODUCT LAYOUTPRODUCT LAYOUT PROCESS LAYOUTPROCESS LAYOUT

Fixed-Position LayoutsFixed-Position Layouts

Typical of projectsTypical of projectsEquipment, workers, materials, other Equipment, workers, materials, other

resources brought to the siteresources brought to the siteHighly skilled laborHighly skilled laborOften low fixed Often low fixed Typically high variable costsTypically high variable costs

Designing Process LayoutsDesigning Process Layouts

Minimize material handling costsMinimize material handling costs Block DiagrammingBlock Diagramming

Minimize nonadjacent loadsMinimize nonadjacent loads Use when quantitative data Use when quantitative data

is availableis available

Relationship DiagrammingRelationship Diagramming Based on location preference between areasBased on location preference between areas Use when quantitative data is not availableUse when quantitative data is not available

Block DiagrammingBlock DiagrammingCreate load summary chartCreate load summary chartCalculate composite (two way) Calculate composite (two way)

movementsmovementsDevelop trial layouts minimizing Develop trial layouts minimizing

number of nonadjacent loadsnumber of nonadjacent loads

Block DiagramsBlock Diagrams

3

2

5

1 4

(a) Initial block diagram(a) Initial block diagram

Block DiagramsBlock Diagrams

12

3

4

53

2

5

1 4

(a) Initial block diagram(a) Initial block diagram (b) Final block diagram(b) Final block diagram

Relationship DiagrammingRelationship Diagramming(Murther’s Grid)(Murther’s Grid)

Used when quantitative Used when quantitative data is not availabledata is not available

Muther’s grid displays Muther’s grid displays preferencespreferences

Denote location Denote location preferences with preferences with weighted linesweighted lines

Relationship Diagramming Relationship Diagramming ExampleExample

ProductionProduction

OfficesOffices

StockroomStockroom

Shipping and Shipping and receivingreceiving

Locker roomLocker room

ToolroomToolroom


AA AA

AA OO

OO

OOOO

OO

UU

UU UU

UU

EEXX

II


OfficesOffices

StockroomStockroom



ToolroomToolroom

AA Absolutely Absolutely necessarynecessaryEE Especially Especially importantimportantIIImportantImportantOO OkayOkayUUUnimportantUnimportantXXUndesirableUndesirable


AA A

A O

OO

OOOO

OO

UU

UU UU

UU

EXX

I


OfficesOffices

StockroomStockroom



ToolroomToolroom

AA Absolutely Absolutely necessarynecessaryEE Especially Especially importantimportantIIImportantImportantOO OkayOkayUUUnimportantUnimportantXXUndesirableUndesirable


11 11

11 44

44

4444

44

55

55 55

55

2266

33


OfficesOffices

StockroomStockroom



ToolroomToolroom

11 Absolutely Absolutely necessarynecessary22 Especially Especially importantimportant33 ImportantImportant44 OkayOkay55UnimportantUnimportant66UndesirableUndesirable

Service LayoutsService LayoutsUsually process layouts due to Usually process layouts due to

customers needscustomers needsMinimize flow of customers or Minimize flow of customers or

paperworkpaperworkRetailing tries to maximize customer Retailing tries to maximize customer

exposure to productsexposure to productsComputer programs consider shelf Computer programs consider shelf

space, demand, profitabilityspace, demand, profitabilityLayouts must be aesthetically pleasingLayouts must be aesthetically pleasing

Designing Product LayoutsDesigning Product Layouts

Product layouts or assembly linesProduct layouts or assembly linesDevelop precedence diagram of Develop precedence diagram of

taskstasksJobs divided into work elementsJobs divided into work elementsAssign work elements to Assign work elements to

workstationsworkstationsTry to balance the amount work of Try to balance the amount work of

each workstationeach workstation

Line BalancingLine BalancingPrecedence diagramPrecedence diagram

Network showing order Network showing order of tasks and restrictions of tasks and restrictions on their performanceon their performance

Cycle timeCycle time Maximum time product Maximum time product

spends at any one spends at any one workstationworkstation

Hybrid LayoutsHybrid LayoutsCellular layoutsCellular layouts

Group machines into machining cellsGroup machines into machining cells

Flexible manufacturing systemsFlexible manufacturing systems Automated machining & material Automated machining & material

handling systemshandling systems

Mixed-model assembly linesMixed-model assembly lines Produce variety of models on one lineProduce variety of models on one line

Cellular LayoutsCellular Layouts1.1. Identify families of parts with Identify families of parts with

similar flow pathssimilar flow paths

2.2. Group machines into cells Group machines into cells based on part familiesbased on part families

3.3. Arrange cells so material Arrange cells so material movement is minimizedmovement is minimized

4.4. Locate large shared machines Locate large shared machines at point of useat point of use

Advantages Of Advantages Of Cellular LayoutsCellular Layouts

Reduced material handling and transit timeReduced material handling and transit time Reduced setup timeReduced setup time Reduced work-in-process inventoryReduced work-in-process inventory Better use of human resourcesBetter use of human resources Easier to control - visibilityEasier to control - visibility Easier to automateEasier to automate

Disadvantages Of Disadvantages Of Cellular LayoutsCellular Layouts

Inadequate part familiesInadequate part familiesPoorly balanced cellsPoorly balanced cellsExpanded training and scheduling Expanded training and scheduling

of workersof workers Increased capital investmentIncreased capital investment

Manufacturing Manufacturing CellCell

Key:Key:

SS = Saw= SawLL = Lathe= LatheHMHM = Horizontal milling = Horizontal milling

machinemachineVMVM = Vertical milling machine= Vertical milling machineGG = Grinder= Grinder

Paths of three Paths of three workers moving workers moving within cellwithin cell

Material Material movementmovement

InIn OutOutWorker 1Worker 1

Worker 2Worker 2

Worker 3Worker 3

Dir

ecti

on

of

par

t m

ove

men

t w

ith

in c

ell

Dir

ecti

on

of

par

t m

ove

men

t w

ith

in c

ell

S

L

HM

VM

G

VM

L

Final inspection

Finished part

Flexible Manufacturing Flexible Manufacturing SystemsSystems

Automated machining operationsAutomated machining operations Automated material handlingAutomated material handling Automated tool changersAutomated tool changers Computer controlled systemComputer controlled system Designed around size of parts processed Designed around size of parts processed

& average processing time for parts& average processing time for parts Can process wide variety of items quicklyCan process wide variety of items quickly

Mixed Model Mixed Model Assembly LinesAssembly Lines

Produce multiple models in any Produce multiple models in any order on one assembly lineorder on one assembly line

Harley, OpelHarley, Opel Issues in mixed model linesIssues in mixed model lines

Line balancingLine balancing U-shaped lineU-shaped line Flexible workforceFlexible workforce Model sequencingModel sequencing

Facility Location Facility Location ModelsModels

Types Of FacilitiesTypes Of Facilities

Heavy manufacturingHeavy manufacturingAuto plants, steel mills, chemical plantsAuto plants, steel mills, chemical plants

Light industryLight industrySmall components mfg, assemblySmall components mfg, assembly

Warehouse & distribution centersWarehouse & distribution centersRetail & serviceRetail & service

Factors in Heavy Factors in Heavy Manufacturing LocationManufacturing Location

Construction costsConstruction costsLand costsLand costsRaw material and finished goods Raw material and finished goods

shipment modesshipment modesProximity to raw materialsProximity to raw materialsUtilitiesUtilitiesLabor availabilityLabor availability

Factors in Light Factors in Light Industry LocationIndustry Location

Construction costsConstruction costsLand costsLand costsEasily accessible Easily accessible

geographic regiongeographic regionEducation & training capabilitiesEducation & training capabilities

Factors in Factors in Warehouse LocationWarehouse Location

Transportation costsTransportation costsProximity to markets (Customers)Proximity to markets (Customers)

Transportation and distribution industry--based on business and employment base providing transportation, distribution, warehousing and related services. Work force--geared to existing and available logistics-related workers in the area. Road infrastructure--measures factors like available lane miles per capita, interstate highway access, miles of paved roads etc. Road density, congestion and safety--ranks the city on traffic volumes and delays as well as accident statistics and other factors affecting the smooth flow of traffic. Road condition--draws on state performance and includes condition of highways and bridges among other measures. Interstate highway--includes access to interstate highways, spending on highway construction and maintenance. Taxes and fees--provides a measure of logistics-related costs, including highway and fuel taxes and related business activity taxes. Railroad--offers a state-based rank of access to Class 1 and other rail services and miles of track. Waterborne commerce--includes ocean port capacity as well as inland waterways. Air cargo--ranks the city on its access to cargo services, including wide-body passenger service by combination carriers, international and expedited services.

Source: Logistics Today, “The Logistics Quotient: Midwest

2007 Rating METROPOLITAN AREA

T&D Industry Metro Rank

Work Force Cost Metro Rank

Road Infra-structure Metro Rank

Road D/C/S Metro Rank

Road Condition State Rank

Interstate Highways Metro Rank

Taxes & Fees State Rank

Rail Road Metro Rank

Waterborne Commerce Metro Rank

Air Cargo Metro Rank

5-Star Champaign-Urbana, Ill.

159 39 84 65 73 36 344 24 119 134

5-Star Charleston, W.Va. MSA

115 126 223 171 251 36 247 63 6 115

5-Star Chicago-Naperville-Joliet, Ill.-Ind.-Wis. MSA

2 26 103 348 87 2 294 1 5 5

5-Star Cincinnati-Middletown, Ohio-Ky.-Ind. MSA

23 45 222 209 189 15 149 34 24 20

5-Star Cleveland-Elyria-Mentor, Ohio MSA

25 18 146 150 192 5 208 17 14 44

5-Star Columbus, Ohio MSA

21 53 146 250 192 36 208 34 52 34

5-Star Davenport-Moline-Rock Island, Iowa-Ill. MSA

99 115 162 82 109 23 288 63 51 111

Source: Logistics Today, “The Logistics Quotient: Midwest

Layout ConsiderationsLayout Considerations• Cross docking• dock doors - how many• picking techniques• bulk storage• safety/backup stocks• product flow• conveyors?• Vehicle flow

Warehouse Size Warehouse Size ConsiderationsConsiderations

• Customer service level• layout• # of products (Stock Keeping Units - SKUs)• customer base• size of products• racks/shelving• demand variability• MHE requirements/aisle size• regulations - CAL OSHA - earthquake; safety; fire

Factors in Retail LocationFactors in Retail Location

Proximity to customersProximity to customersEase of customer entry and Ease of customer entry and

exitexitLocation is everythingLocation is everything

Global Location FactorsGlobal Location Factors

Government stabilityGovernment stability Government regulationsGovernment regulations Political and economic Political and economic

systemssystems Economic stability and Economic stability and

growthgrowth Exchange ratesExchange rates CultureCulture ClimateClimate Export import regulations, Export import regulations,

duties and tariffsduties and tariffs

Raw material availability Raw material availability Number and proximity of Number and proximity of

supplierssuppliers Transportation and Transportation and

distribution systemdistribution system Labor cost and educationLabor cost and education Available technologyAvailable technology Commercial travelCommercial travel Technical expertiseTechnical expertise Cross-border trade Cross-border trade

regulationsregulations Group trade agreementsGroup trade agreements

Regional Location FactorsRegional Location Factors Labor (availability, Labor (availability,

education, cost and education, cost and unions)unions)

Proximity of Proximity of customerscustomers

Number of customersNumber of customers Construction/leasing Construction/leasing

costscosts Land costsLand costs Modes and quality of Modes and quality of

transportationtransportation Transportation costsTransportation costs

Incentive packages Incentive packages Governmental Governmental

regulationsregulations Environmental Environmental

regulationsregulations Raw material Raw material

availabilityavailability Commercial travelCommercial travel ClimateClimate InfrastructureInfrastructure Quality of lifeQuality of life

Regional Location FactorsRegional Location Factors

Community Community governmentgovernment

Local business Local business regulationsregulations

Government servicesGovernment services Business climateBusiness climate Community servicesCommunity services TaxesTaxes

Availability of sitesAvailability of sites Financial ServicesFinancial Services Community Community

inducementsinducements Proximity of suppliersProximity of suppliers Education systemEducation system

Site Location FactorsSite Location Factors

Customer baseCustomer base Construction/ Construction/

leasing costleasing cost Land costLand cost Site sizeSite size TransportationTransportation UtilitiesUtilities

Zoning restrictionsZoning restrictions TrafficTraffic Safety/securitySafety/security CompetitionCompetition Area business Area business

climateclimate Income levelIncome level

Location IncentivesLocation Incentives

Tax credits Wal-Mart in WyandotteTax credits Wal-Mart in WyandotteRelaxed government regulationRelaxed government regulationJob trainingJob training Infrastructure improvementInfrastructure improvementMoneyMoney

Locate facility at center of geographic area Locate facility at center of geographic area Based on weight and distance traveledBased on weight and distance traveled Establish grid-map of areaEstablish grid-map of area Identify coordinates Identify coordinates

and weights shipped and weights shipped for each locationfor each location

Center-of-Gravity TechniqueCenter-of-Gravity Technique

Center of gravity

DataWeight X coord Y coord

Location 1 0.2 100 400Location 2 0.2 250 200Location 3 0.2 50 125Location 4 0.2 300 300Location 5 0.2 10 475

ResultsSum 1 710 1500Average 142 300Weighted Average 142 300

Distance tableX coord 100 250 50 300 10Y coord 400 200 125 300 475

X coord Y coord Location 1 Location 2 Location 3 Location 4 Location 5100 400 Location 1 0 250 279.5085 223.6068 117.1537250 200 Location 2 250 0 213.6001 111.8034 365

50 125 Location 3 279.5085 213.6001 0 305.1639 352.2783300 300 Location 4 223.6068 111.8034 305.1639 0 338.7108

10 475 Location 5 117.1537 365 352.2783 338.7108 0Total 870.269 940.4035 1150.551 979.2849 1173.143Weighted Total 174.0538 188.0807 230.1102 195.857 234.6286

Location

0

100

200

300

400

500

0 100 200 300 400

Center of gravity

DataWeight X coord Y coord

Location 1 0.3 100 400Location 2 0.25 250 200Location 3 0.1 50 125Location 4 0.2 300 300Location 5 0.15 10 475

ResultsSum 1 710 1500Average 142 300Weighted Average 159 313.75

Distance tableX coord 100 250 50 300 10Y coord 400 200 125 300 475

X coord Y coord Location 1 Location 2 Location 3 Location 4 Location 5100 400 Location 1 0 250 279.5085 223.6068 117.1537250 200 Location 2 250 0 213.6001 111.8034 365

50 125 Location 3 279.5085 213.6001 0 305.1639 352.2783300 300 Location 4 223.6068 111.8034 305.1639 0 338.7108

10 475 Location 5 117.1537 365 352.2783 338.7108 0Total 870.269 940.4035 1150.551 979.2849 1173.143Weighted Total 152.7453 173.4707 251.1271 176.3559 229.3661

Location

0

100

200

300

400

500

0 100 200 300 400

Project ManagementProject Managementand Operationsand Operations

Project Project ManagementManagement

First Essay on Project Management:1697 – “An Essay Upon Projects”

1959 HBR Article – “The Project Manager

Air Force Manual 1964

Project ManagementProject ManagementProject management is the discipline of organizing and managing resources in such a way that these resources deliver all the work required to complete a project within defined scope, quality, time and cost constraints. A project is a temporary and one-time endeavor undertaken to create a unique product or service, that brings about beneficial change or added value. This property of being a temporary and a one-time undertaking contrasts with processes, or operations, which are permanent or semi-permanent ongoing functional work to create the same product or service over and over again. (wikipedia)

Project ManagementProject ManagementIn today’s global marketplace, complexity and speed are certainties. In such an environment, a good axiom for project management is, Do It, Do It Right, Do It Right Now. Creating clear direction, efficiency, timely response, and quality outcomes requires project managers who are agile -- adept at change. The associated disciplinary areas are clearly spelled out in the following PMI definition.

“Project management is the application of knowledge, skills, tools, and techniques to a broad range of activities in order to meet the requirements of a particular project. Project management is comprised of five Project Management Process Groups – Initiating Processes, Planning Processes, Executing Processes, Monitoring and Controlling Processes, and Closing Processes.

Source: Project Management Institute - http://www.pmi.org/info/PP_AboutProfessionOverview.asp?nav=0501

http://www.pmi.org/info/PP_AboutProfessionOverview.asp?nav=0501



Program management is the process of managing multiple ongoing inter-dependent projects. An example would be that of designing, manufacturing and providing support infrastructure for an automobile manufacturer. This requires hundreds, or even thousands, of separate projects. (wikipedia)

Program ManagementProgram Management

Elements of Project Elements of Project ManagementManagement

Project teamProject team Individuals from different departments within Individuals from different departments within

companycompany Matrix organizationMatrix organization

Team structure with members from different Team structure with members from different functional areas depending on skills neededfunctional areas depending on skills needed

Project manager - Leader of project teamProject manager - Leader of project team Project Charter – high level description of what is Project Charter – high level description of what is

to be accomplished in a project and delegates to be accomplished in a project and delegates authority to project manager to implement authority to project manager to implement actions to complete projectactions to complete project

Project PlanningProject PlanningStatement of workStatement of work

Written description of goals, work & Written description of goals, work & time frame of projecttime frame of project

Activities require labor, resources & Activities require labor, resources & timetime

Precedence relationship shows Precedence relationship shows sequential relationship of project sequential relationship of project activitiesactivities

Elements of Elements of Project PlanningProject Planning

Define project objective(s)Define project objective(s) Identify activitiesIdentify activitiesEstablish precedence relationshipsEstablish precedence relationshipsMake time estimatesMake time estimatesDetermine project completion timeDetermine project completion timeCompare project schedule objectivesCompare project schedule objectivesDetermine resource requirements to Determine resource requirements to

meet objectivemeet objective

Work Breakdown Work Breakdown StructureStructure

Hierarchical organization of work to Hierarchical organization of work to be done on a projectbe done on a project

Project broken down into modulesProject broken down into modules Modules subdivided into Modules subdivided into

subcomponents, activities, and taskssubcomponents, activities, and tasks Identifies individual tasks, workloads, Identifies individual tasks, workloads,

and resource requirementsand resource requirements

Project ControlProject ControlAll activities identified and includedAll activities identified and includedCompleted in proper sequenceCompleted in proper sequenceResource needs identifiedResource needs identifiedSchedule adjustedSchedule adjustedMaintain schedule and Maintain schedule and

budgetbudgetComplete on timeComplete on time

A Gantt ChartA Gantt Chart

Popular tool for project schedulingPopular tool for project schedulingGraph with bar for representing the Graph with bar for representing the

time for each tasktime for each taskProvides visual display of project Provides visual display of project

schedulescheduleAlso shows slack for activitiesAlso shows slack for activities

Amount of time activity can be Amount of time activity can be delayed without delaying projectdelayed without delaying project

Around since 1914

Gantt ChartsGantt Charts

Gantt charts were employed on major infrastructure projects including the Hoover Dam and Interstate highway system and still are an important tool in project management.

Gantt described two principles for his charts:

1. measure activities by the amount of time needed to complete them

2. the space on the chart can be used the represent the amount of the activity that should have been done in that time.

A Gantt ChartA Gantt Chart| | | | |

Activity

Design house and obtain financing

Lay foundation

Order and receive materials

Build house

Select paint

Select carpet

Finish work

00 22 44 66 88 1010MonthMonth

MonthMonth11 33 55 77 99

Figure 6.2Figure 6.2

Example of Gantt Chart Example of Gantt Chart Problem Problem

6.8

Project Management

DataTime Precedence 1Precedence 2Precedence 3Precedence 4Precedence 5Precedence 6Precedence 7

a 3b 3 ac 5 ad 4 a ce 3 cf 2 d e

Results

Task Early StartEarly Finish Late Start

Late Finish Slack

a 0 3 0 3 0b 3 6 11 14 8c 3 8 3 8 0d 8 12 8 12 0e 8 11 9 12 1f 12 14 12 14 0

Project 14

Gantt Chart

0 5 10 15

a

c

e

Activ

ity

Time

CPM/PERTCPM/PERTCritical Path Method (CPM)Critical Path Method (CPM)

DuPont & Remington-Rand (1956)DuPont & Remington-Rand (1956) Deterministic task timesDeterministic task times

Project Eval. & Review Technique Project Eval. & Review Technique (PERT)(PERT)

US Navy, LockheedUS Navy, Lockheed Multiple task time estimatesMultiple task time estimates

PERT/CPMPERT/CPM

Program Evaluation and Review Technique (PERT): developed in conjunction with the development of the Polaris missile program for submarines – developed by the US Navy with Lockheed as the lead contractor

Critical Path Method (CPM): developed through a joint venture between the DuPont Corporation and the Remington Rand Corporation – the original purpose was to monitor and evaluate plant maintenance management projects.

Project Network for a HouseProject Network for a House

3322 00

11

33

11 1111

1 2 4 6 7

3

5

Lay Lay foundationfoundation

Design house Design house and obtain and obtain financingfinancing

Order and Order and receive receive materialsmaterials

DummyDummy

Finish Finish workwork

Select Select carpetcarpet

Select Select paintpaint

Build Build househouse

Figure 6.4Figure 6.4

Critical PathCritical Path A path is a sequence of connected A path is a sequence of connected

activities running from start to end activities running from start to end node in networknode in network

The critical path is the The critical path is the path with the longest path with the longest duration in the networkduration in the network

Project cannot be Project cannot be completed in less than completed in less than the time of the critical the time of the critical pathpath

The Critical The Critical PathPath

A:A: 1-2-3-4-6-71-2-3-4-6-73 + 2 + 0 + 3 + 1 = 93 + 2 + 0 + 3 + 1 = 9 months months

B:B: 1-2-3-4-5-6-71-2-3-4-5-6-73 + 2 + 0 + 1 + 1 + 1 = 83 + 2 + 0 + 1 + 1 + 1 = 8 months months

C:C: 1-2-4-6-71-2-4-6-73 + 1 + 3 + 1 = 83 + 1 + 3 + 1 = 8 months months

D:D: 1-2-4-5-6-71-2-4-5-6-73 + 1 + 1 + 1 + 1 = 73 + 1 + 1 + 1 + 1 = 7 months months

33

22 00

11

33

11 11

111 2 4 6 7

3

5




DummyDummy





The Critical The Critical PathPath

33

22 00

11

33

11 11

111 2 4 6 7

3

5




DummyDummy





1 2 4 6 7

3

5

3

2 0

1

3

1 1

Start at 3 months

Start at 5 months

1

Finish at 9 months

Start at 8 months

Figure 6.6

Activity Start Times

Early Early TimesTimes

ESES - earliest time activity can start - earliest time activity can start Forward pass starts at beginning of Forward pass starts at beginning of

CPM/PERT network to determine CPM/PERT network to determine ESES times times EF = ESEF = ES + activity time + activity time

ESESijij == maximum (EFmaximum (EFii))

EFEFijij == ESESijij - - ttijij ESES1212 == 00

EFEF1212 == ESES1212 -- t t1212

== 0 + 3 = 30 + 3 = 3 monthsmonths

33

22 00

11

33

11 11

111 2 4 6 7

3

5




DummyDummy





Why is this important?

Late TimesLate Times

LSLS - latest time activity can start & - latest time activity can start & not delay projectnot delay project

Backward pass starts at end of Backward pass starts at end of CPM/PERT network to determine CPM/PERT network to determine LSLS timestimes

LF = LS + LF = LS + activity timeactivity timeLSLSijij == LFLFijij -- ttijijLFLFijij = minimum (LS= minimum (LSjj))

Who Cares? Why is this Important?

Activity Slack Activity Slack DataData

33

22 00

11

33

11 11

111 2 4 6 7

3

5




DummyDummy





ActivityActivity LSLS ESES LFLF EFEF SlacksSlacks

*1-2*1-2 00 00 33 33 00*2-3*2-3 33 33 55 55 002-42-4 44 33 55 44 11

*3-4*3-4 55 55 55 55 004-54-5 66 55 77 66 11

*4-6*4-6 55 55 88 88 005-65-6 77 66 88 77 11

*6-7*6-7 88 88 99 99 00* Critical path* Critical path

Activity Slack Activity Slack DataData

33

22 00

11

33

11 11

111 2 4 6 7

3

5




DummyDummy





ActivityActivity LSLS ESES LFLF EFEF SlacksSlacks

*1-2*1-2 00 00 33 33 00*2-3*2-3 33 33 55 55 002-42-4 44 33 55 44 11

*3-4*3-4 55 55 55 55 004-54-5 66 55 77 66 11

*4-6*4-6 55 55 88 88 005-65-6 77 66 88 77 11

*6-7*6-7 88 88 99 99 00* Critical path* Critical path

1 2 4 6 7

3

5

3

2 0

1

3

1 1

1

Figure 6.10

Activity Slack

S = 0

S = 1S = 1

S = 1

S = 0 S = 0

S = 0

S = 0

Project CrashingProject CrashingCrashing is reducing project time Crashing is reducing project time

by expending additional resourcesby expending additional resourcesCrash time is an amount of time an Crash time is an amount of time an

activity is reducedactivity is reducedCrash cost is the cost of reducing Crash cost is the cost of reducing

the activity timethe activity timeGoal is to reduce project duration Goal is to reduce project duration

at minimum costat minimum cost

Crashing costs increase as project Crashing costs increase as project duration decreasesduration decreases

Indirect costs increase as project Indirect costs increase as project duration increasesduration increases

Reduce project length Reduce project length as long as crashing as long as crashing costs are less than costs are less than indirect costsindirect costs

Time-Cost Relationship Time-Cost Relationship

Life Cycle ManagementLife Cycle Management

• Long term view of projects to guide decision making – solutions that provide life time success vice short term

• Acquisition; development; production; introduction; sustainment; disposal

• Links system costs to big picture; better use of resources; minimize total cost of ownership

What’s Next What’s Next

• Mid Term

• Chapters 10, 11

facilities. objectives of facility layout minimize material handling costs minimize material...

Documents

process layouts1

quantitative data

placement of material

activitiesprovide flexibility

job shop production

visual control of operations

availablemuthers grid

mass intermittent