Production Plant Layout (1)Production Plant Layout (1)

• Facility Layout Problem: design problemFacility Layout Problem: design problem– locations of activitieslocations of activities– dimensionsdimensions– configurationsconfigurations

• No overall algorithm existsNo overall algorithm exists

Design problem

Greenfield Location of one new machine

Production Plant Layout (2)Production Plant Layout (2)

• Reasons:Reasons:– new productsnew products– changes in demandchanges in demand– changes in product designchanges in product design– new machines new machines – bottlenecksbottlenecks– too large bufferstoo large buffers– too long transfer timestoo long transfer times

Production Plant Layout (2)Production Plant Layout (2)

DesignDesign

Layout

Product

Logistics Process

Production Plant Layout (3)Production Plant Layout (3)

• Goals (examples):Goals (examples):– minimal material handling costsminimal material handling costs– minimal investmentsminimal investments– minimal throughput timeminimal throughput time– flexibilityflexibility– efficient use of spaceefficient use of space

Production Plant Layout (4)Production Plant Layout (4)

• Restrictions:Restrictions:– legislation on employees working legislation on employees working

conditionsconditions– present building (columns/waterworks)present building (columns/waterworks)

• Methods:Methods:– Immer: The right equipment at the right Immer: The right equipment at the right

place to permit effective processingplace to permit effective processing– Apple: Short distances and short timesApple: Short distances and short times

Goals Production Plant LayoutGoals Production Plant Layout

• Plan for the preferred situation in the Plan for the preferred situation in the futurefuture

• Layout must support objectives of the facilityLayout must support objectives of the facility

• No accurate data No accurate data layout must be flexible layout must be flexible

Selection

Search

Analysis

Systematic Layout PlanningSystematic Layout Planning Muther (1961) Muther (1961)

0 Data gathering

10 Evaluation

4 Space requirements

5 Space available

6 Space relationship diagram

1 Flow 2 Activities

3 Relationship diagram

7 Reasons to modify

8 Restrictions9 Layout alternatives

0 - Data gathering (1)0 - Data gathering (1)• Source: product designSource: product design

– BOMBOM– drawingsdrawings– ““gozinto” (assembly) chart, see fig 2.10gozinto” (assembly) chart, see fig 2.10– redesign, standardization redesign, standardization simplifications simplifications

machines

product design

sequence of assembly operations

layout (assembly) line

0 - Data gathering (2)0 - Data gathering (2)

• Source: Process designSource: Process design– make/buymake/buy– equipment usedequipment used– process timesprocess times

operations process chart operations process chart (fig 2.12)(fig 2.12)

assembly chartassembly chart

operations operations precedence diagramprecedence diagram

(fig 2.13)(fig 2.13)

0 - Data gathering (3)0 - Data gathering (3)

• Source: Production schedule designSource: Production schedule design– logistics: where to produce, how much logistics: where to produce, how much

product mixproduct mix– marketing: demand forecast marketing: demand forecast

production rateproduction rate– types and number of machinestypes and number of machines– continuous/intermittentcontinuous/intermittent– layout layout schedule schedule

1/2 - Flow and Activity Analysis1/2 - Flow and Activity Analysis

• Flow analysis:Flow analysis:– Types of flow patternsTypes of flow patterns– Types of layoutTypes of layout

flow analysis approachesflow analysis approaches

• Activity relationship analysisActivity relationship analysis

1/2 - Flow analysis and activity 1/2 - Flow analysis and activity analysisanalysis

Flow analysisFlow analysis• quantitative measure of movements quantitative measure of movements

between departments:between departments:material handling costsmaterial handling costs

Activity analysisActivity analysis• qualitative factorsqualitative factors

Flow analysisFlow analysis

• Flow of materials, equipment and Flow of materials, equipment and personnelpersonnel

Raw material Finished product

layout facilitates this flowlayout facilitates this flow

Types of flow patternsTypes of flow patterns

P = receivingP = receivingS = shippingS = shipping

R S

R S

R

S

long line

• Horizontal transportHorizontal transport

LayoutLayout

volumes of productionvolumes of productionvariety of productsvariety of products

• volumes: what is the right measure of volumes: what is the right measure of volume from a layout perspective?volume from a layout perspective?

• variety variety high/low commonality high/low commonality

layout typelayout type

Types of layoutTypes of layout

• Fixed product layoutFixed product layout• Product layoutProduct layout• Group layoutGroup layout• Process layoutProcess layout

Fixed product layoutFixed product layout

• Processes Processes product (e.g. shipbuilding) product (e.g. shipbuilding)

Product layout (flow shop)Product layout (flow shop)

• Production line according to the Production line according to the processing sequence of the productprocessing sequence of the product

• High volume productionHigh volume production• Short distancesShort distances

Process layout (Job shop)Process layout (Job shop)

• All machines performing a particular All machines performing a particular process are grouped together in a process are grouped together in a processing departmentprocessing department

• Low production volumesLow production volumes• Rapid changes in the product mixRapid changes in the product mix• High interdepartmental flowHigh interdepartmental flow

Group layoutGroup layout

• Compromise between product layout Compromise between product layout and process layoutand process layout

• Product layouts for product families Product layouts for product families cells (cellular layout)cells (cellular layout)

• Group technologyGroup technology

Production volume and product variety Production volume and product variety determines type of layoutdetermines type of layout

group layout process layout

product variety

production volume

product layout

Layout determinesLayout determines• material handlingmaterial handling• utilization of space, equipment and utilization of space, equipment and

personnel (table 2.2)personnel (table 2.2)

Flow analysis techniquesFlow analysis techniques• Flow process charts Flow process charts product layout product layout• From-to-chart From-to-chart process layouts process layouts

Activity relationship analysis Activity relationship analysis

• Relationship chart (figure 2.24)Relationship chart (figure 2.24)• Qualitative factors (Qualitative factors (subjective!subjective!))• Closeness rating (A, E, I, O, U or X)Closeness rating (A, E, I, O, U or X)

3 - Relationship diagrams3 - Relationship diagrams

• Construction of relationships diagrams: Construction of relationships diagrams: diagrammingdiagramming

• Methods, amongst others: CORELAPMethods, amongst others: CORELAP

Relationship diagram (1)Relationship diagram (1)

• Spatial picture of the relationships Spatial picture of the relationships between departmentsbetween departments

• Constructing a relation diagram often Constructing a relation diagram often requires compromises. requires compromises. What is closeness? 10 or 50 meters?What is closeness? 10 or 50 meters?

• See figure 2.25See figure 2.25

Relationship diagram (2)Relationship diagram (2)

PremisePremise:: geographic geographic proximityproximity reflects the reflects therelationshipsrelationships

Sometimes other solutions:Sometimes other solutions:– e.g. X-rating because of noise e.g. X-rating because of noise acoustical acoustical

panels instead of distance separationpanels instead of distance separation– e.g. A rating because of communication e.g. A rating because of communication

requirement requirement computer network instead of proximitycomputer network instead of proximity

Graph theory based approachGraph theory based approach

• close close adjacent adjacent• department-nodedepartment-node• adjacent-edgeadjacent-edge• requirement: graph is planar requirement: graph is planar

(no intersections)(no intersections)• region-faceregion-face• adjacent faces: share a common edgeadjacent faces: share a common edge

graphgraph

Primal graph Primal graph dual graph dual graph

• Place a node in each face Place a node in each face • Two faces which share an edge – join Two faces which share an edge – join

the dual nodes by an edgethe dual nodes by an edge• Faces dual graph correspond to the Faces dual graph correspond to the

departments in primal graph departments in primal graph block layout (plan) e.g. figure 2.39block layout (plan) e.g. figure 2.39

Graph theoryGraph theory

• Primal graph planar Primal graph planar dual graph dual graph planarplanar

• Limitations to the use of graph theory: Limitations to the use of graph theory: it may be an aid to the layout designerit may be an aid to the layout designer

CORELAPCORELAP

• Construction “algorithm” Construction “algorithm” • Adjacency!Adjacency!• Total closeness rating = sum of Total closeness rating = sum of

absolute values for the relationships absolute values for the relationships with a particular department.with a particular department.

jiji rTCR

CORELAP - stepsCORELAP - steps

1.1. sequence of placements of sequence of placements of departmentsdepartments

2.2. location of departmentslocation of departments

CORELAP – step 1CORELAP – step 1

• First department: First department:

• Second department: Second department: – X-relation X-relation “last placed department” “last placed department”– A-relation with first. If noneA-relation with first. If none E-relation E-relation

with first, etceterawith first, etcetera

iiTCRmax

CORELAP – step 2CORELAP – step 2

• Weighted placement valueWeighted placement value

1st

8

1

2 3

7 6

5

4

2nd

4 - Space requirements4 - Space requirements

• Building geometry or building site Building geometry or building site space availablespace available

• Desired production rate, distinguish:Desired production rate, distinguish:– Engineer to order (ETO)Engineer to order (ETO)– Production to order (PTO)Production to order (PTO)– Production to stock (PTS)Production to stock (PTS)

marketing forecast marketing forecast productions quantities productions quantities

4 - Space requirements4 - Space requirements

Equipment requirements:Equipment requirements:• Production rate Production rate number of machines number of machines

requiredrequired• Employee requirementsEmployee requirements

rate

machine operators

machines employees

assembly

Space determinationSpace determination

Methods:Methods:1. Production center1. Production center2. Converting2. Converting4. Standards4. Standards5. Projection5. Projection

4 - Space determination (1)4 - Space determination (1)

1. Production center1. Production center• for manufacturing areasfor manufacturing areas• machinemachinespace requirementsspace requirements

2. Converting2. Converting• e.g. for storage arease.g. for storage areas• present space requirement present space requirement space space

requirementsrequirements• non-linear function of production quantitiynon-linear function of production quantitiy

# machines per operator

# assembly operatorsSpace requirements

4 - Space determination (2)4 - Space determination (2)

4.4. Space standardsSpace standards– standardsstandards

5.5. Ratio trend and projectionRatio trend and projection– e.g. direct labour hour, unit producede.g. direct labour hour, unit produced

– Not accurate!Not accurate!– Include space for: Include space for:

packaging, storage, maintenance, offices, aisles, packaging, storage, maintenance, offices, aisles, inspection, receiving and shipping, canteen, tool inspection, receiving and shipping, canteen, tool rooms, lavatories, offices, parkingrooms, lavatories, offices, parking

factorspace

Deterministic approach (1)Deterministic approach (1)

• n’ = # machines per operator (non-integer)n’ = # machines per operator (non-integer)• a = concurrent activity timea = concurrent activity time• t = machine activity timet = machine activity time• b= operatorb= operator

batan

'

Deterministic approach (2)Deterministic approach (2)

bamta

Tc

• TTcc = cycle time = cycle time• a = concurrent activity timea = concurrent activity time• t = machine activity timet = machine activity time• b = operator activity timeb = operator activity time• m = # machines per operatorm = # machines per operator

Deterministic approach (3)Deterministic approach (3)

mTmCCmTC c

21)(

• TC(m) = cost per unit produced as a function of mTC(m) = cost per unit produced as a function of m• CC11 = cost per operator-hour = cost per operator-hour• CC22 = cost per machine-hour = cost per machine-hour

• Compare TC(n) and TC(n+1) for n < n’ < n+1Compare TC(n) and TC(n+1) for n < n’ < n+1

Designing the layout (1)Designing the layout (1)

• Search phaseSearch phase• Alternative layoutsAlternative layouts• Design process includesDesign process includes

– Space relationship diagramSpace relationship diagram– Block planBlock plan– Detailed layoutDetailed layout– Flexible layoutsFlexible layouts– Material handling systemMaterial handling system– PresentationPresentation

Designing the layout (2)Designing the layout (2)

• Relationship diagram + space Relationship diagram + space space relationship diagram space relationship diagram (see fig 2.56)(see fig 2.56)

• Different shapesDifferent shapes

9 – Layout alternatives9 – Layout alternatives

• Alternative layouts by shifting the Alternative layouts by shifting the departments to other locations departments to other locations

block plan, also shows e.g. columns block plan, also shows e.g. columns and positions of machines and positions of machines (see fig 2.57)(see fig 2.57)

selection

detailed design

detailed design

selectionor

Flexible layoutsFlexible layouts

• Future Future • Anticipate changesAnticipate changes• 2 types of expansion: 2 types of expansion:

1.1. sizessizes2.2. number of activitiesnumber of activities

Material handling systemMaterial handling system

• Design in parallel with layoutDesign in parallel with layout• PresentationPresentation

– CAD templates 2 or 3 dimensionalCAD templates 2 or 3 dimensional– simulationssimulations– ““selling” the layout (+ evaluation)selling” the layout (+ evaluation)

10 Evalution (1)10 Evalution (1)

Selection and implementationSelection and implementation• best layoutbest layout

– cost of installation + operating costcost of installation + operating cost– compare compare futurefuture costs for both the new and the old costs for both the new and the old

layoutlayout• other considerationsother considerations

– selling the layoutselling the layout– assess and reduce resistanceassess and reduce resistance

• anticipate amount of resistance for each alternativeanticipate amount of resistance for each alternative

10 Evalution (2)10 Evalution (2)

• Causes of resistance:Causes of resistance:– inertiainertia– uncertaintyuncertainty– loss of job contentloss of job content– ……

• Minimize resistance byMinimize resistance by– participationparticipation– stagesstages

ImplementationImplementation

• InstallationInstallation– planningplanning

• Periodic checks after installationPeriodic checks after installation

Systematic Layout PlanningSystematic Layout Planning0 Data gathering

10 Evaluation

Analysis

Search

Selection

4 Space requirements

5 Space available

6 Space relationship diagram

1 Flow 2 Activities

3 Relationship diagram

7 Reasons to modify

8 Restrictions9 Layout alternatives

Systematic Layout PlanningSystematic Layout Planning0 Data gathering

10 Evaluation

Analysis

Search

Selection

4 Space requirements

5 Space available

6a Space relationship diagram

1 Flow 2 Activities

3 Relationship diagram

7 Reasons to modify

8 Restrictions9 Layout alternatives

6b Analytical analyses

Automatic Guided Vehicles (AGV’s)Automatic Guided Vehicles (AGV’s)

• Unmanned vehicle for in-plant transportation on Unmanned vehicle for in-plant transportation on manufacturing and assembly areasmanufacturing and assembly areas

• Two types of guidanceTwo types of guidance– free rangingfree ranging

• dead reckoning + lasers or transpondersdead reckoning + lasers or transponders– path restrictedpath restricted

• induction wires in the floorinduction wires in the floor

• AGV AGV fork lift truck with RF-communicationfork lift truck with RF-communication

Design and operational control of an Design and operational control of an AGV systemAGV system

• AGV systemAGV system– track layouttrack layout– number of AGVsnumber of AGVs– operational controloperational control

• Traffic control: zonesTraffic control: zones

max. throughput max. throughput capacitycapacity

Track layoutTrack layout• infrastructureinfrastructure• location of pick-up and drop-off stationslocation of pick-up and drop-off stations• buffer sizesbuffer sizes

– congestion/blockingcongestion/blocking• tandem configurationtandem configuration

Determination of number of AGVsDetermination of number of AGVs

h

timetravelemptytotaltvAGVs i j

ijij

)min(#

5 x

6 x

4 x LP-problem(i.e. a classical TP)

Operational transportation controlOperational transportation control

Job controlJob control(routing and scheduling of transportation tasks)(routing and scheduling of transportation tasks)

Traffic controlTraffic controlTraffic rulesTraffic rules• Goal: minimize empty travel + waiting timeGoal: minimize empty travel + waiting time

• Single load:Single load: Performance indicators:Performance indicators:- Throughput- Throughput- Throughput times- Throughput times

Operational controlOperational control

• production control production control transportation controltransportation control– flow shopflow shop– job shopjob shop

• centralized controlcentralized control– all tasks are concurrently consideredall tasks are concurrently considered

• or decentralized controlor decentralized control– FEFS: AGV looks for work (suited for tandem configuration)FEFS: AGV looks for work (suited for tandem configuration)

• think-aheadthink-ahead– combine tasks to routescombine tasks to routes

• or no think-aheador no think-ahead

Relations between the issuesRelations between the issues

Combination 1 Combination 1 Separated/no think-aheadSeparated/no think-ahead

• centralized controlcentralized control• on-line priority rules:on-line priority rules:

1.1. transportation task assignmenttransportation task assignmenttasks wait, ortasks wait, or

2.2. idle vehicle assignmentidle vehicle assignmentidle vehicles waitidle vehicles wait

Ad 1: push/pull (JIT), e.g. FCFS, MOQRSAd 1: push/pull (JIT), e.g. FCFS, MOQRS Push Push sometimes “shop locking” sometimes “shop locking”

Ad 2: NV, LIVAd 2: NV, LIV

Combination 3 Combination 3 Separated/think-ahead (1)Separated/think-ahead (1)

• Centralized controlCentralized controla. without time windowsa. without time windows

– Only routingOnly routing– Minimize empty travel time by simulated annealing:Minimize empty travel time by simulated annealing:

– 2 options:2 options:• determine optimal route each time a new task determine optimal route each time a new task

arrivesarrivesproblem: a task may stay at the end of the routeproblem: a task may stay at the end of the route

• Periodic controlPeriodic controltime horizon (length?)time horizon (length?)

Combination 3 Combination 3 Separated/think-ahead (2)Separated/think-ahead (2)

• Centralized controlCentralized controlb. with time horizonsb. with time horizons

– Simulated annealingSimulated annealingmachine 1

machine 2

machine 3

machine 1

machine 2

machine 3

machine 1

machine 2

machine 3

loaded tripempty trip

loaded tripempty trip

loaded tripempty trip

Combination 4 Combination 4 Integrated/think-aheadIntegrated/think-ahead

AGV’s ~ parallel machinesAGV’s ~ parallel machinesempty travel time ~ change-over timeempty travel time ~ change-over timetransportation time ~ machine timetransportation time ~ machine time

Shop-floor schedulingShop-floor scheduling

Basic conceptBasic concept

Case studyCase study