4. Layout planning - WordPress.com · PDF file04.04.2012 · Layout Planning Models, Al h d d lgorithms and computerized Layout Planning References 1. Tompikins et al., Facility Planning,3rd

Layout Planning Models, l h d d

Layout Planning Models, l h d d Algorithms and computerized

Layout PlanningAlgorithms and computerized

Layout PlanningLayout PlanningLayout Planning

ReferencesReferences1. Tompikins et al., Facility Planning, 3rd edition, John Wiley & Sons Ltd.,

i 2003Singapore,2003.

2. Richard L.Francis et al., Facility Layout and Location: an analyticalh 2 d diti P ti H ll f I di Ltd 2002

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approch, 2nd edition, Prentice Hall of India Ltd., 2002.

3. Dr-Ing. Daniel Kitaw, Industrial Management and Engineering Economy

Introduction Introduction

• The generation of layout alternatives is a critical step

i th f iliti l i i th l tin the facilities planning process, since the layout

selected will serve to establish the physical

relationships between activities.

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CONT’D CONT’D

• Which comes first, the material handling system or

the facility layout?the facility layout?

Centralized versus decentralized storage of worki (WIP) t li d liin process(WIP), tooling, and supplies

Fixed path versus variable path handling The degree of automation used in handling The type of level of inventory control physical

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The type of level of inventory control, physicalcontrol, and computer control of materials.

Layout proceduresLayout procedures

• A number of different procedures have been developed

t id th f iliti l i d i i l tto aid the facilities planner in designing layouts.

Construction type Construction type

Improvement type

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P th b si d t

Apples plant layout procedureApples plant layout procedureDetermine storage requirements• Procure the basic data

• Analyze the basic data• Design the productive process

• Determine storage requirements• Plan service and auxiliary

activitiesDesign the productive process• Plan the material flow pattern• Consider the general material

h dli l

• Determine space requirements• Allocate activities to total space

Consider building typehandling plan• Calculate equipment requirement• Plan individual workstations

• Consider building type• Construct master layout• Evaluate, adjust, and check thePlan nd v dual workstat ons

• Select specific material handlingequipmentC din t ps f l t d

, j ,layout with appropriate persons

• Obtain approvals• Install the layout

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• Coordinate groups of relatedoperations

• Design activity interrelationships

• Install the layout• Follow up on implementation of

the layout.

Reeds plant layout procedureReeds plant layout procedure• Analyze the product or products to be produced• Determine the process required to manufacture the product• Prepare layout planning charts• Determine workstations

l• Analyze storage area requirements• Establish minimum aisle widths

E t bli h ffi i t• Establish office requirement• Consider personnel facilities and services• Survey plant services

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• Survey plant services• Provide for future expansion

Cont’dCont’d• Layout planning chart is the most important single

phase of the entire layout process, it incorporates thef ll ifollowing: Flow process, including operations, transportation,

d i istorage and inspection Standard time for each operation Machine selection and balance Material handling equipment

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Material handling equipment

Cont’dCont’d

Layout planning chart

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Systematic Layout Planning(SLP) procedureSystematic Layout Planning(SLP) procedure

• Systematic Layout Planning (SLP) methodology was

developed by Richard Mutherdeveloped by Richard Muther.

• The framework is uses activity relationship diagram asy p g

a foundation activity.

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SLP cont’dSLP cont’d

• Based on the input data and anunderstanding of the roles and

l ti hi b t ti itirelationships between activities, amaterial flow analysis(from-to-chart )and an activity relationshipanalysis(activity relationship chart) areanalysis(activity relationship chart) areperformed.

• From the analysis performed, ay p ,relationship diagram is developed.

4 - 10SLP procedure

Cont’dCont’d

• The relationship diagram positions

activities spatially.p y

• Proximities are typically used to reflect

th l ti shi b t i s fthe relationship between pairs of

activities.

4 - 11Activity relationship chart

Cont’dCont’d

Relationship diagram Space relationship diagram

4 - 12Alternative block layouts

Algorithmic approachesAlgorithmic approaches

• Algorithmic approach is a formal procedure that can

h l th l t l t t d l i l thelp the layout analyst to develop or improve a layout,

and it provide objective criteria to facilitate the

evaluation of various layout alternatives that emerge

i th ssin the process.

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Most layout al orithms can be classified accordin to

Algorithm classificationAlgorithm classification• Most layout algorithms can be classified according to

the type of input data they requires.

Qualitative flow data(such as relationship chart)

Quantitative flow data(such as flow matrix

expressed as a from to chart)expressed as a from-to-chart)

Some algorithms accepts both relationship chart

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m g m p p

and from-to-chart

Cont’dCont’d

• Layout algorithms can also be classified according to

their objective functions.

Minimizing the sum of flows times distances Minimizing the sum of flows times distances

Maximizing an adjacency score Maximizing an adjacency score

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• Distance based objectiveCont’dCont’d

Distance based objective

m = the number of departmentsfij = the flow from department i to department j(unit

load/unit time)h f l d dcij = the cost of moving a unit load one distance unit

from department i to jd th di t f d t t i t j

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dij = the distance from department i to j

• Adjacency based objectiveCont’dCont’d

Adjacency based objective

m = the number of departmentsfij = the flow from department i to department j(unit

load/unit time)h d f d d h lxij = the adjacent of department i and j in the layout

• The adjacency score is helpful in comparing two orlt ti l t

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more alternative layouts

Cont’dCont’d

• According to the primary functions layout algorithms

can be classified as:can be classified as:

Improvement type: start with an initial layout andp yp y

seek to improve the objective function through

i t l hincremental change.

Construction type: develop a layout from scratch

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Construction type: develop a layout from scratch

• The overall modeling techniques and/orModeling techniques/methodsModeling techniques/methods

• The overall modeling techniques and/ormethods used in various layout algorithms; P i i h th d Pairwise exchange method A graph based method CRAFT BLOCPLAN MIP LOGIC

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LOGIC MULTIPLE

Graph-based methodGraph-based method

• The graph-based method is a construction-

type layout algorithmtype layout algorithm.

• Uses the adjacency based objectiveUses the adjacency based objective.

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Graph-based method-ConsiderationsGraph-based method-Considerations• The adjacency score does not account for distance• The adjacency score does not account for distance,

nor does it account for relationships other than thosebetween adjacent departments.between adjacent departments.

• Dimensional specifications of departments are notconsidered; the length of common boundaries betweenconsidered; the length of common boundaries betweenadjacent department are also not considered.

• The arcs do not intersect; this property of graphs is• The arcs do not intersect; this property of graphs iscalled planarity.

• The score is very sensitive to the assignment of

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• The score is very sensitive to the assignment ofnumerical weights in the relationship chart.

• Consider a company want to develop layout forGraph-based methodGraph-based method

• Consider a company want to develop layout for

its new five departments of equal sizes.p q

9

8

1

2 1 29

7

0

8

0

1012

13

720

3

2 1

3

5

2

4

12

1020 2

7

138

0

2

4

5

0

4 - 22Relationship chart Relationship diagram

ProcedureGraph-based methodGraph-based method

ProcedureStep 1: from the relationship chart select a department

pair with the largest weightpair with the largest weight.

91

8

0

1012

13

720

3

2

720

02

4

5

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• Departments 3 and 4 are selected to enter the graph.


ProcedureStep 2: Select the third department to enter, the third

department is selected based on the sum of thedepartment is selected based on the sum of theweights with respect to departments 3 and 4.

3 4 Total1 8 10 182 12 13 25(best)

21312

D t t 2 i h ith l f 25

2 12 13 25(best)5 0 2 2 3 4

20

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Department 2 is chosen with a value of 25.


ProcedureStep 3: Pick the fourth department to enter by

evaluating the value of adding one of theevaluating the value of adding one of theunassigned departments represented by a nodeon a face of the graph 2g p2 3 4 Total

1 9 8 10 27(Best)5 7 0 2 9

1312

1

9

5 7 0 2 9

3 420

1

8 10

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Department 1 is chosen with a value of 27. 20


ProcedureStep 4: Determine on which face to insert the last

departmentdepartment.1 2 3 4

5 0 7 0 2

2

75 0 7 0 21312 9

Faces Total 5

7

0

3 4

1

8 10

1-2-3 7

1-2-4 9(best)

1-3-4 2

02

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3 420

1-3-4 2

2-3-4 9(best)


ProcedureStep 5: Construct a corresponding block layout.

2 13

12

18

9

5

7

0

3

18

10

5

2

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420

Computerized Relative Allocation of Facility Technique(CRAFT)Computerized Relative Allocation of Facility Technique(CRAFT)

• Introduced in 1963 by Armour, Buffa, and Vollman.• CRAFT is a tool used to help improve the existing• CRAFT is a tool used to help improve the existing

layout of the facilities.The f cilit is impr ved b s itchin t r three• The facility is improved by switching two or threedepartments to help arrange the facility in an optimalfloor planfloor plan.

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• This procedure requires the following inputs:• This procedure requires the following inputs:o From-To Chart,o Cost Matrix,o Distances (determined for a given layout) and an( g y )

Initial layout.• Craft is used when the number of departments is soCraft is used when the number of departments is so

large that the computation by hand would be veryintensive and make the improvement not worth the

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time for many companies.


• The major features of CRAFT are:The major features of CRAFT are:o Attempts to minimize transportation cost,

T i fl *di * iTransportation cost=flow*distance*unit costo CRAFT is a path-oriented method, the final layout is

dependent on the initial layout.o Requires an assumption that:q p

i. Move costs are independent of the equipmentutilization and

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ii. Move costs are linearly related to the length ofthe move


CRAFT i t• CRAFT requirements:o Initial layouto Flow datao Cost per unit distanceo Cost per unit distanceo Total number of departments

F d d d h lo Fixed departments and their locationo Area of departments

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Th d d t d f i CRAFT• The procedures adopted for using CRAFT are:o Determine department centroids.o Calculate rectilinear distance between centroids.o Calculate transportation cost for the layouto Calculate transportation cost for the layout.o Consider department exchanges of either equal area

departments or of departments sharing a commondepartments or of departments sharing a commonboarder.

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D t i t t ti t f h d t t lo Determine transportation cost of each departmentalinterchange.

l d l h d l ho Select and implement the departmental interchangethat offers the greatest reduction in transportationcostcost.

o Repeat the procedure for the new layout until noint h n is bl t d th t nsp t ti ninterchange is able to reduce the transportationcost.

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M j di d t f i CRAFT• Major disadvantages of using CRAFTo Because the basis is the cost of material handling,

l d d d d Nonly production departments are considered. Noservice departments are considered.

o An initial idea of the layout is required. Thereforethe technique is only applies to the modification ofn xistin l tan existing layout.

o The distances between the departments is taken ast i ht li h i ti t i

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straight lines whereas in practice movement isusually rectangular along ortagonal lines.


Example: consider the following layout problem with unitExample: consider the following layout problem with unit

cost matrix. Use Craft algorithm to obtain layout. The

initial layout and the flow matrix is shown below

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Initial layout Flow matrix

COmputerized RElationship LAyout Planning (CORELAP)COmputerized RElationship LAyout Planning (CORELAP)

D l d f i f t• Developed for main frame computers• Adjacency‐based method

o CORELAP uses A=4 E=3 I=2 O=1 U=0 and X=‐1o CORELAP uses A=4, E=3, I=2, O=1, U=0 and X=‐1values

• Selection of the departments to enter the layout isp ybased on Total Closeness Rating.

• Total Closeness Rating (TCR) for a department is thef h l l d h lsum of the numerical values assigned to the closeness

relationships between the department and all otherdepartments

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departments.

D t t l ti


Department selection1. The first department placed in the layout is the one

with the greatest TCR value If there is a tie thenwith the greatest TCR value. If there is a tie, thenchoose the one with more A’s (E’s, etc.).

2. If a department has an X relationship with the firstp pone, it is placed last in the layout. If a tie exists,choose the one with the smallest TCR value.

h d d h h3. The second department is the one with an Arelationship with the first one (or E, I, etc.). If a tieexists choose the one with the greatest TCR value

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exists, choose the one with the greatest TCR value.

4 If d t t h X l ti hi ith th d


4. If a department has an X relationship with the secondone, it is placed next‐to‐the‐last or last in the layout.If a tie exists choose the one with the smallest TCRIf a tie exists, choose the one with the smallest TCRvalue.

5. The third department is the one with most A (E, I,p ( , ,etc.) relationships with the already placeddepartments. If a tie exists, choose the one with the

lgreatest TCR value.6. The procedure continues until all departments have

been placed

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been placed.

D t t l t


Department placement• Placing rating(PR) is the sum of the weighted closeness

b h d h lratings between the department to enter the layoutand its neighbors.

• , where k-{departments already placed}

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Th l t f d t t i b d th


• The placement of departments is based on thefollowing steps:1 h f d l d l d h1. The first department selected is placed in the

middle.2. The placement of a department is determined by

evaluating PR for all possible locations around thent l t in nt l k is d b innincurrent layout in counterclockwise order beginning

at the “western edge”.3 Th d t t i l t d b d th

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3. The new department is located based on thegreatest PR value.

ExampleExample

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ALDEP ‐ Procedure• Department selection• Department selection

o Randomly selects the first departmento Out of those departments which have “A”o Out of those departments which have A

relationship with the first one (or “E”, “I”, etc. – minlevel of importance is determined by the user) itselects randomly the second department.

o If no such department exists it selects the secondn c mpl t l r nd mlone completely randomly

o The selection procedure is repeated until all thedepartments are selected

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departments are selected

Department placement• Starts from upper left corner and extends it

downward• Vertical sweep pattern• Sweep width is determined by the userSweep width is determined by the userAdjacency‐based evaluation• If minimum requirements met it prints out the layout• If minimum requirements met, it prints out the layout

and the scores• Repeats the procedure (max 20 layouts per run)

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p p (m y p )• User evaluation

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Documents

4. Layout planning - WordPress.com · PDF file04.04.2012 · Layout Planning Models, Al h d d lgorithms and computerized Layout Planning References 1. Tompikins et al., Facility Planning,3rd