Project and Production Management Module 7 Facility Location and Layout Prof Arun Kanda & Prof S.G. Deshmukh, Department of Mechanical Engineering, Indian

Project and Production Management

Module 7

Facility Location and Layout

Prof Arun Kanda & Prof S.G. Deshmukh, Department of Mechanical Engineering,Indian Institute of Technology, Delhi

module 7: Facility Location and Layout

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MODULE 7: Facility Location and Layout

1. Issues in Location of Facilities

2. Mathematical Models for Facility Location

3. Layout Planning

4. Computerised Layout Planning

5. Product Layouts

6. Illustrative Examples

7. Self Evaluation Quiz

8. Problems for Practice

9. Further exploration


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1. Issues in location of Facilities


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A Case Study

A Decision Model for a Multiple Objective

Plant Location Problem

Prem Vrat And Arun Kanda

INTEGRATED MANAGEMENT, July 1976, Page 27-33



OBJECTIVE OF LOCATION

To set up a straw board plant (Packaging material) from industrial waste

Plant

Sources of Industrial waste

Industries needing packaging material



RELEVANT FACTORS FOR PLANT LOCATION

k..Notation

Factor

A Nearness to raw material source B Availability and dependability

of power

C Transport facilities D Labour supply E Employee facilities F Competition for the market

G Nearness to market H Govt. Incentives

I Cost of land



O b j e c t i v e s

W e i g h t a g e s t o v a r i o u s o b j e c t i v e s

O 1 ( W 1 )

O 2 ( W 2 )

… … … … . … … … … . O n

( W n )

M e a s u r e s o f e f f e c t i v e n e s s o f v a r i o u s a l t e r n a t i v e s

A 1 P 1 1 P 1 2 … … … … . P 1 n j

n

jj WPE

111

A 2 P 2 1 P 2 2 … … … … P 2 n

n

jjWjPE

122

AL

TE

RN

AT

IVE

S

. . . .

. . . .

… … … … … … … … … … … … … … … …

. . . .

A m P m 1 P m 2 … … … … p m n

n

jPmjWjEm

1



TRIANGULAR MATRIX

O2 O3 …….. On Scores

O1 O1 - 2 S1

O2 S2

O3 On Sn



APPLYING PARETO PRINCIPLE B C D E F G H I

A A-2 A-1 A-3 A-3 F-1 A-2 A-2 A-3

B C-1 B-1 B-3 F-2 G-2 H-2 I-1

C C-1 C-3 F-2 G-1 H-1 C-1

D D-3 F-3 G-2 H-2 I-2

E F-3 G-3 H-3 I-3

Major difference = 3 F F-1 F-1 F-1

Medium difference=2 G H-2 I-1

Minor difference = 1 H H-2



SUMMARYNotation Factor Total

Points weightage factor(%)

A Nearness to raw material source 16 23.0

B Availability and dependability of power

4 5.7

C Transport facilities 6 8.6 D Labour supply 3 4.3

E Employee facilities 0 0.0

F Competition for the market 14 20.0

G Nearness to market 8 11.4 H Govt. Incentives 12 17.0

I Cost of land 7 10.0

Total 10 100



DECISION MATRIX FOR ALTERNATIVE LOCATIONS

A B C D F G H I Total Points

Alternative Location

.230 .057 .086 .043 .200 .114 .170 .100

Panipat 90 80 100 50 100 50 90 90 86.01

Sonepat 80 100 80 70 100 85 80 85 85.98 Rohtak 100 80 90 70 100 60 100 100 *91.16

Meerut 90 50 80 90 80 60 70 60 75.05

Faridabad 50 60 90 100 50 100 50 50 61.87 Gurgaon 55 65 50 60 100 95 60 70 71.26 Ghaziabad 60 50 80 100 60 90 50 60 64.60

* Optimal Location.



NORMAILZATION I

80

P

20

Po

ints

Capital Cost

L C H



NORMALIZATION II

80

20

Po

ints

Capital Cost

L L’ H

D A

B

C1

C2



NORMALIZATION III

80

20

Po

ints

Labour Attitudes

| Restive | Satisfactory Cooperative |

60



NORMALIZATION IV

On

.

.

.O2

O1

Po

ints

X1 X2 - - - - - - Xn



2. Mathematical Models for Facility Location



SINGLE FACILITY LOCATION

New lathe in a job shopTool crib in a factoryNew warehouseHospital, fire station, police stationNew classroom building on a college campus

New airfield for a number of bases

Component in an electrical network

New appliance in a kitchen

Copying machine in a library

New component on a control panel



PROBLEM STATEMENTm existing facilities at locations P1(a1,b1), P2(a2,b2) … Pm(am,bm)New facility is to be located at point X (x,y)d(X,Pi) = appropriately defined distance between X and Pi Euclidean, Rectilinear, Squared Euclidean Generalized distance, Network

The objective is to determine the location X so as to minimize transportation related costsSum (i=1,n) wi d(X,Pi), where wi is the weight associated with the ith existing facility (product of Cost/distance & the expected number of annual trips between X and Pi)



SINGLE FACILITY LOCATION

P1 (w1)

P2 (w2)

P3 (w3)

Pn-1 (wn-1)

Pn (wn)

Xd(X,P1)

d(X,P2)

d(X,P3)

d(X,P n-1)

d(X,Pn)



COMMONLY USED DISTANCES

Rectilinear: | (x-ai) | +| (y-bi)|

Euclidean : [ (x-ai)2 + (y-bi)2]1/2

Squared Euclidean: [(x-ai)2 +(y-ai)2 ]

Other , Network

X (x,y)

Pi (ai,bi)

X (x,y)

Pi (ai,bi)

X (x,y)

Pi(ai,bi)



RECTILINEAR DISTANCES

Z = Total cost

= Sum (i =1,n) [ wi | (x-ai) + (y-bi)|]

= Sum (i=1,n) [wi |(x-ai)| + wi |(y-bi)| ]

= Sum (i=1,n) wi |(x-ai)| +

Sum (i=1,n) wi |(y-bi)|

= f1(x) + f2(y)

Thus to minimize Z we need to minimize f1(x) and f2(y) independently.



EXAMPLE 1(RECTILINEAR DISTANCE

CASE)A service facility to serve five offices located at (0,0), (3,16),(18,2) (8,18) and (20,2) is to be set up. The number of cars transported per day between the new service facility and the offices equal 5, 22, 41, 60 and 34 respectively.

What location for the service facility will minimize the distance cars are transported per day?



SOLUTION (X-COORDINATE)

Existing facility

x-coordinate value

Weight Cumulative weight

1 0 5 5

2 3 22 27< 81

4 8 60 87> 81

3 18 41 128

5 20 34 162

x* = 8



SOLUTION (Y- COORDINATE)

Existing facility

y-coordinate value

Weight Cumulative weight

1 0 5 5

3,5 2 41+34 80< 81

2 16 22 102>81

4 18 60 162

y* = 16



EXAMPLE 2SQUARED EUCLIDEAN

CASE CENTROID LOCATION

x* = Σ wi ai /Σ wi =( 0 x5 + 3x22 + 18x41 + 8x60 + 20x34)/162

= 12.12

y* = Σ wibi/Σ wi = (0x5 + 16x22 + 2x41 + 18x60 + 2x34)/162

= 9.77

(Compare with the median location of (8,16)



R2

R1

Rm

M1

M2

Mn

1

2

m

m+1

m+2

m+n

P

Solution to theeuclidean distancelocation problem



MINIMAX PROBLEMS

*

For the location ofemergency facilitiesour objective wouldbe to minimize the maximum distance



COST CONTOURSIncreasing Cost

Cost Contourshelp identify alternativefeasible locations



SUMMARY

Decision Matrix approach to handle multiple objectives in Plant Location

(problem of choosing the best from options)

Single Facility Location Models Rectilinear distance Squared Euclidean Euclidean distance (to generate the best from infinite options)



SUMAARY(CONTD)

Notion of Minisum and Minimax problem

(Objective depending on the context)

Use of Cost Contours to accommodate practical constraints

(Moving from ideal to a feasible solution)



Location decisions are STRATEGIC

LIABLE TO AFFECT THE ENTIRE ORGANIZATION

OPERATIVE OVER LONG TIME SPANS

DIFFICULT TO REVERSE

CAPITAL INTENSIVE



HIERARCHY OF LOCATION PROBLEMS

Location of ‘Plant’

Plant Layout ( Location of ‘Depts’)

Physical Arrangements of M/cs

Work Place Layout ( Location of ‘tools’ or ‘raw materials’)



The term ‘FACILITY LOCATION’

emphasizes the generalized

approach that handles the variety

of above mentioned problems.



LOCATION DECISIONS ARE DYNAMIC

Owing to changing technology, competition,

change of consumer tastes, decisions like NEW PLANTS

EXPANSION

DECENTRALIZATION

PLANT SHUTDOWN

ARE CONSTANTLY UNDER REVIEW



IMPORTANT FACTORS IN LOCATION

MARKETRAW MATERIALSTRANSPORTATIONPOWERCLIMATE AND FUELLABOUR AND WAGESLAWS AND TAXATIONCOMMUNITY SERVICESWATER AND WASTEGOVT. INCENTIVES



ANNUAL OPERATION EXPENSES

CONSIST OF MATERIALS TRANSPORTATION REAL ESTATE TAXES FUEL COSTS SUNDRY STATE TAXES ELECTRIC POWER WATER



FIXED & VARIABLE COST

Annual Cost

Volume of Production

Location

B

Location

A



MECHANICAL ANALOGUE FOR FINDING BEST

LOCATION OF A MANUFACTURING PLANT

(ALSO KNOWN AS VARIGNON’S FRAME AFTER INVENTOR)



R2

R1

Rm

M1

M2

Mn

1

2

m

m+1

m+2

m+n

P



In the absence of friction, the common knot P of (m+n) strings comes to equilibrium at least Cost location

[Here we draw an analogy between

Min. Potential Energy

&

Min. Travel Cost ]

Assumptions:

R1,R2, ……Rm Locations of Raw Material Sources

M1,M2 …Mn location of markets

Euclidean (Straight tine travel)

Each weight (there are m+n in all

Wi = No. of annual trips between P and that pt X (Cost per unit distance)



MULTI-OBJECTIVE CONSIDERATIONS IN

LOCATION DECISIONS FACTORS AFFECTING LOCATION ARE :

SUBJECTIVE / OBJECTIVE (labour attitudes) (eg. Costs)

INTANGIBLE / TANGIBLE

INCOMMENSURATE UNITS



A Decision Matrix approach with proper evaluation of weights of factors, Normalization of scores can help in ranking alternative locations.

(THIS IS DEMONSTRATED THROUGH A CASE STUDY)



MULTI PLANT OPERATION -

AN EXAMPLE OF PLANT ADDITION

A P

1P

2 BC

Y

X

Z

E

D

P1 Existing plant

P2 Existing plant

A,B,C,D,E Warehouses

X,Y,Z Possible Locations

for new plant



Owing to increase of weekly demand to 72,000 there is a capacity deficit of 25,000/wk and it is felt that a plant of capacity 25000 could be set up X,Y or Z.



Problem Data P1 P2 X Y Z

Wee

kly

fore

cast

of

mar

ket

Dem

and

A 0.42 0.32 0.64 0.44 0.48 10,000

B

C

D

E

Capacity

Unit Prod Cost



OPTIMUM PRODUCTION -

DISTRIBUTION SOLUTIONS P1 P2 X

A 10 10

B 8 7 15

C 16 16

D 19 19

E 10 2 12

27 20 25 72

Product Cost = 192,500

Distn. Cost = 026,450

Total = 218,950



OPTIMUM PRODUCTION -DISTRIBUTION SOLUTIONS (Cont.) P1 P2 Y

A 10 10

B 15 15

C 8 16

D 19 19

E 10 2 12

27 20 25 72



Total = 220,710



OPTIMUM PRODUCTION -DISTRIBUTION SOLUTIONS (Cont.)

P1 P2 Y

A 10 10

B 15 15

C 10 6 16

D 12 19

E 12 12

27 20 25 72



Total = 218,400*

(* MINIMUM)

(Demand and Capacity in thousands)hence choose plant at size Z



LOCATIONAL DYNAMICS Suppose third plant is set up at site Z.

After some time demand drops from, 72,000 to 56,000 per week

Which plant to shut down ?

Which to run at partial capacity ?

(These are again location decisions)



Alternatives for investigation :

1.Run all plants at partial capacity

2.SHUT DOWN P1, Use Overtime in others

3. SHUT DOWN P2, Use Overtime in others

4. SHUT DOWN Z, Use Overtime in others



Warehouse demands (A-9000), (B-13000), (C-11,000),

(D-15,000), (E-8,000)DATA

PLANTS P1 P2 Z

Overtime Prodn. Cost O.T Capacity

3.37 7000

3.33 5000

3.27 6000

Fixed Costs (per week) (Don’t Depend on Prodn. Vol)

- WHILE OPERATING 12,000 9,000 13,000

- WHILE SHUTDOWN 5,000 4,000 6,000



EVALUATING SHUT DOWN OPTIONS

1 2 Z

A 9 9

B 13 13

C 11 11

D 14 1 15

E 8 8

F 11 5 16

27 20 25 72

1



EVALUATING SHUT DOWN OPTIONS(contd..)

2

Z

2 OT

Z OT

A 9 9

B 8 5 13

C 11 11

D 9 6 15

E 8 8

20 25 5 6 56

2



EVALUATING SHUT DOWN OPTIONS (contd...)

1

Z

1 OT

Z OT

A 6 3 9

B 13 13 C 11 11 D 14 1 15 E 8 8 F 7 2 9 27 25 5 6 65

3



EVALUATING SHUT DOWN OPTIONS (contd..)

1

Z

1 OT

Z OT

A 9 9

B 9 4 13 C 3 8 11 D 15 15 E 3 5 8 F 3 3 27 25 5 6 65

4



EVALUATING SHUT DOWN OPTIONS (contd..)

Fixed Variable

34,000 169,650

27,000 177,730

29,000 173,150

27,000 178,400

Total Cost

203,650 204,730 202,150 205,400

1 2 3 4

* Min Cost for Alternative 3

Hence Shut Down Plant 2

*



SUMMARY

The strategic importance of location decisionsHierarchy of Location decisionsAnalogue model for Facility locationImportant factors in plant locationA case study on new plant location and shut down under dynamic conditions.Multi-objective plant location case to be studied in the next lecture along with facility location models



3. Layout Planning



OBJECTIVES IN PLANT LAYOUT

1. Minimize investment in equipment.2. Minimize overall production time.3. Utilize existing space most effectively.4. Provide for employee convenience,

safety and comfort.5. Maintain flexibility of arrangement6. Minimize Material handling cost.7. Minimize variation in types of material

handling equipment.8. Facilitate the manufacturing process.9. Facilitate the organizational structure



LAYOUT TYPES

PRODUCT

• PROCESS CELLULAR(Group Technology)

• MIXED A D EB C F

• LAYOUT BY FIXED POSITION

- Ship building

- Special Structures



LINKS AMONG PRODUCT, PROCESS, SCHEDULE AND LAYOUT DESIGN

PRODUCTDESIGN

LAYOUTDESIGN

SCHEDULEDESIGN

PROCESSDESIGN



PRODUCT LAYOUT1.Smooth and logical flow lines

2.Small in process inventories.

3.Total production time/unit short.

4.Reduced material handling

5.Little operator skill, training simple

6.Simple production planning & control

7.Less space for work in transit and temporary

1 2 3 n

INPUT FINAL OUTPUT



PROCESS LAYOUT

ADVANTAGES :A

B C D

F

E

1. Better utilization of machines, hence fewer m/cs needed.

2. High degree of FLEXIBILITY with regard to equipment or manpower allocation for specific tasks

3. Comparatively low investment in machines required.

4. Grater job satisfaction for operator.

5. Specialized supervision is possible.



PROCESS LAYOUT

LIMITATIONS :

A

B C D E

FG

H

1. Since longer flow lines usually result, material handling is more expensive.

2. Production planning and control systems are more involved.

3. Total production time usually longer.

4. Large in process inventories.

5. Space and capital tied up by work in processes.

6. Because of the diversity of jobs in specialized departments, higher grades of skill are required.



P - Q CHARTProduct Layout

Combination Layout

Process Layout

Q

Quantity to be Made

P (No. of Products or “VARIETY”



INPUT DATA & ACTIVITES

1. Flow of Materials 2. Activity Relationship

3. Relationship Diagram

4. Space Reqd. 5. Space Available

6. Space Relationship Diagram

7. Modifying Considerations

9. Development Layout Alternatives

10. EvaluationSYSTEMATIC

LAYOUT PLANNING (MUTHER 1961)

8. Practical Limitation

Ana

lysi

sS

earc

hS

ele

ctio

n


1

Raw mtl.

3

5

1

Saw

Lathe-1 Drill Inspect -1Mill

21

78

11 12 13 14

Fin. goods Packing Inspect-26

4

2

15

10

6

4

3

2 5 4 3

9

Lathe-2

16’ 16’ 16’ 16’ 16’ 16’

24’

16’

24’

16’

Fig. 1(a) Product Layout



Operation

Inspection

Storage



5

Raw mtl.

3

1

11

Saw

Lathe Drill Mill

7

119

Fin. goods Packing Inspection6

4

2

6

10

15

2

3

4

5 4

12 13 14

2

8

1

3

Fig 1(b) Process Layout



Table 1:

EXAMPLE PROCESSING SEQUENCES FOR 3

PRODUCTSProduct Processing Sequence

A

B

C

Saw, mill, inspect, turn, mill, drill, inspect, package Drill, turn, mill, inspect, package Saw, turn, drill, mill, inspect, package



Table 2:

FLOW RATES FOR PRODUCTS CONSIDERED IN

TABLE1

Product Flow Rate (pallet loads/day)

A

B

C

8

3

5



As such, the construction of a from-to chart is

a convenient means of reducing a large

volume of data into a workable from. By

inspecting the data displayed in the from-to

chart, the layout analyst can identify the

departments having large volumes.



To From

R.M. Saw Lathe Drill Mill Ins. Pkg. F.G.

R.M 13 3

Saw 5 8

Lathe 5 11

Drill 3 5 8

Mill 8 16

Ins. 8 16

Pkg. 16

F.G.

Fig 2 From-to chart showing number of materials handling trips per day between departments.



Normally, the from-to chart is used to

analyze the flow in process layouts. The

item movement that occurs over some

specified period of time is totaled for all

products and entered in the from-to

chart. Figure 3



To From

R.M. Saw Lathe Drill Mill Ins. Pkg. F.G.

R.M 16 40 72 88 60 36 20

Saw 16 24 56 72 44 20 36

Lathe 40 24 32 48 20 44 60

Drill 72 56 32 16 36 60 76

Mill 88 72 48 16 52 76 92

Ins. 60 44 20 36 52 24 40

Pkg. 36 20 44 60 76 24 16

F.G. 20 36 60 76 92 40 16

Fig 3 From-to chart showing distance between Centers of departments. As given in Figure 1(b)



To From

R.M. Saw Lathe Drill Mill Ins. Pkg. F.G. Total

R.M 208 216 424

Saw 120 576 696

Lathe 160 528 688

Drill 96 80 288 464

Mill 128 832 960

Ins. 160 384 544

Pkg. 256 256

F.G. 0

Total 0 208 376 504 1184 1120 384 256 4032

Fig

4 F

rom

-to

ch

art

sh

ow

ing

dis

tan

ce

tra

ve

led

pe

r

da

y u

sin

g t

he

pro

ces

s la

you

t as

giv

en

in F

ig 1

(b) module 7: Facility Location and Layout


1 Office2 Foreman3 Conference room4 Parcel post5 Parts shipment6 Repair and service parts7 Service area8 Receiving9 Testing10 General storage

O4

U U U 12

U U 12

U 12

U

I5

OU

E3

U U U

U 14

A1

U U

E3

A1

E5

O4

UU

UU

U

O4

U

U

E3

3

12

U

U

U

U

11

12

U

O2



Code

1

2

3

4

5

6

7

8

9

10

Reason

Flow of materials

Ease of supervision

Common personnel

Contact necessary

Convenience

Rating Definition

A

E

I

O

U

X

Absolutely

Especially Important

Important

Ordinary closeness OK

Unimportant

Undesirable

Fig.:5 Activity relationship

chart



5 8 7

10 9 6

4 2 3

1

Legend

A Rating

E Rating

I Rating

O Rating

U Rating

X RatingFig 6 Activity relationship

diagram



Table 3: PRODUCTION SPACE REQUIREMENTS

Process

Equipment

No.

Machine Center

Dimensions Per Machine

(ft) Depth Width

Machine Center

Area per Machine

(ft2)

Total Process

Area (ft2)

Saw Armstrong hack saw

3 10 x 9 190 570

Mill K & T plain mill Vertical mill Hand mill

5 7

4

13.5 x 10.5 11 x 10.25 7.25 x 9.75

142 113 71

710 791 284

Cont…..



Process

Equipment

No.

Machine Center


(ft) Depth Width

Machine Center

Area per Machine

(ft2)

Total Process

Area (ft2)

Drill 2 Spindle Avey 1 Spindle Delta 6 Spindle Delta

2 2 1

8.25 x 6.5 7.5 x 4.5 7.45 x 10.5

54 34 82

108 68 82

Turn Gisholt Monarch Hardinge W & S turret B & S automatic

1 2 1 1

1

9.25 x 17.75 14 x 6.25 9.5 x 5 8.5 x 20.25 7.5 x 15.5

164 88 48 173 116

164 176 48 173 116

Cont…..



Process

Equipment

No.

Machine Center


(ft) Depth Width

Machine Center

Area per Machine

(ft2)

Total Process

Area (ft2)

Form Gas furnance Arbor press X

1 8 x 7

56 56

Paint Dip tank Spray booth

2 1

7 x 12 9 x 11

84 99

168 99

Clean Tumble 1 7 x 6 42 42

Assemble Bench Bench Avey drill

1 1 2

8 x 7 8 x 7 8.25 x 6.5

56 56 54

56 56 108

Packaging Bench 1 8 x 7 56 56

Total square feet required 40 % aisle space

Production space required

3,931 1,572 5,503



Table 4:Non-production activity space requirements

Activity Area (ft2)

Storage Warehouse Other Office Main Office Hallway Rest rooms Locker rooms Men Women Foreman Desk Maintenance Desk Parts Tool crib Receiving and shipping Total space required

180 180

500 120 100

84 60

24

20 80 50 50

1,448



To the 5,503 square feet of floor for

production, we must add the 1,448

square feet shown in Table 4 to give an

estimate of 6,951 square feet of floor

space required in total.



5(500)

8(200)

10(1,750)

7(575)

9(500)

6(75)

4(350)

2(125)

3(125)

1(1,0)

Designing the Layout

Fig 5 Space relationship diagram


10

6

2

3

9

785

1

4

80’

65’

The Plant Layout Problem

Fig. 6

Block plan



SUMMARY

Objectives in different kinds of LayoutProcess, Product, Mixed

Systematic Layout Planning for Process LayoutsFrom to charts to measure material handling effortStep by Step procedure for a sample layoutA precursor to Computerized Layout Planning



4. Computerised Layout Planning



CONSTRUCTION PROGRAMSCORELAPALDEPPLANET, LSP, LAYOPT, RMA Comp I

IMPROVEMENT PROGRAMSCRAFTRUGR (based on graph theory)

LAYOUT PLANNINGPACKAGES



ALDEP

Automated

Layout

DEsign

Program

Development within IBM

Seehof, J.M and W.O. Evans “Automated Layout Design Program:, The Journal of Industrial Engineering, Vol 18, No. 12, 1967, pp 690 - 695.



ALDEP based on closeness Ratings

A 43 = 64

E 43 = 16

I 41 = 4

O 40 = 1

U 0 = 0

X -45 = -1,024

Can handle 63 departments on 3 floors



SCORING PATTERN OF ALDEP

50

8

2 4

1

7 6

3

For a Cell (0) the scores of all eight neighbours areadded together (as per REL chart)

Then the cell (0) is deletedso that it is not counted again. We then proceed to the next cell till all cells are exhausted. The final cumulativescore is the Layout Score



INPUT REQUIREMENTS FOR ALDEP

Length, Width and area requirements for each floor.Scale of layout printout (max 30x50)No. of depts. in the layoutNo. of layouts to be generatedMinimum allowable score for an acceptable layout.Minimum dept. preference (A or E)REL chart for the depts.Location and size of restricted area for each floor.



Vertical Scanning Pattern for placing depts. in ALDEP



Mechanism of ALDEP :(a) 1st dept placed randomly.

(b) Scan the REL chart for a dept with A,E rating (min dept preference) continue this step till no such dept exists

(c) Pick up the next dept. in a random fashion and again proceed by scanning the REL chart [step (b)].



AN EXAMPLE OF ALDEP



The Available Space



B

Placement of 1st Department



Placement of 2nd Department

B

D

D



Placement of 3rd Department

D

B

D

A



Placement of 4th Department

C

B

D

D

AC

C



Final Layout

B

D

D

A

C

CC



FEATURES OF CORELAP

Retain the rectangular shape of each departmentThe layout is built around a central departmentPlacement and choice based on the total and current placement ratioThe final layout may end up with irregular boundaries



CRAFTComputerized

Relative

Allocation of

Facilities

Technique



Armour, G.C. and E.S.Buffa, “A Heuristic Algorithm and Simulation Approach to Relative Location of Facilities”

Management Science, Vol 9, No. 1, 1963, pp 294-309

Buffa, E.S, G.C. Armour and T.E. Vollman “Allocating Facilities with CRAFT” Harvard Business Review, Vol 42, No.2, 1964, pp 136 - 159.



AN EXAMPLE OF CRAFT



Product, Process & Schedule Data

Product Processing sequence

Daily production

No of items in Trolley

Trolley loads/ day

1 ABCBCD 100 5 20

2 ACBD 50 5 10

3 ACBCBD 200 40 5



INITIAL LAYOUT

A D

B C

From /To

A B C D

A --- 1 2 1

B 1 --- 1 2

C 2 1 --- 1

D 1 2 1 ---

Distance Matrix for initial layout(Assuming Rectilinear Distances)



LOAD MATRIXFrom/To A B C D

A --- 20 15

B --- 45 15

C 45 --- 20

D ---



UNIT COST MATRIXFrom/To A B C D

A --- 1 2 1

B 1 --- 1 1

C 2 1 --- 1

D 1 1 1 ---



LOAD x UNIT COST MATRIX

(Flow Matrix)From /To

A B C D

A --- 20 30 50

B --- 45 15 60

C 45 --- 20 65

D --- 00

00 65 75 35



INITIAL LAYOUT (Distance Matrix)

A D

B C

From /To

A B C D

A --- 1 2 1

B 1 --- 1 2

C 2 1 --- 1

D 1 2 1 ---



MATERIAL HANDLING EFFORT FOR INITIAL LAYOUT

From /To

A B C D

A --- 20 30

B --- 45 15

C 45 --- 20

D ---

From /To

A B C D

A --- 1 2 1

B 1 --- 1 2

C 2 1 --- 1

D 1 2 1 ---

From /To

A B C D

A --- 20 60 80

B --- 45 30 75

C 90 --- 20 110

D --- 00

00 110 105 50 265



P air w ise E x chang es

A BB DA C

A CC DB A

A DD AB C

B CA DC B

B DA BD C

C DA CB D

In it ia l L ayou tA DB C

265 Material Handling Effort



ALTERNATIVE 1(Distance Matrix)

A B C D

A ---- 1 1 2

B 1 ---- 2 1

C 1 2 ---- 1

D 2 1 1 ----

B DA C

Material Handling Effort = Flow x Distance Matrix = 220



ALERNATIVE 2 (Distance Matrix)

A B C D

A ---- 1 2 1

B 1 ---- 1 2

C 2 1 ---- 1

D 1 2 1 ----

C D B A




ALTERNATIVE 3 (Distance Matrix)

A B C D

A ---- 2 1 1

B 2 ---- 1 1

C 1 1 ---- 2

D 1 1 2 ----

D AB C





A B C D

A ---- 2 1 1

B 2 ---- 1 1

C 1 1 ---- 2

D 1 1 2 ----

A DC B





A B C D

A ---- 1 2 1

B 1 ---- 1 2

C 2 1 ---- 1

D 1 2 1 ----

A BD C





A B C D

A ---- 1 1 2

B 1 ---- 2 1

C 1 2 ---- 1

D 2 1 1 ----

A CB D




P air w ise E x chang es

A BB DA C

A CC DB A

A DD AB C

B CA DC B

B DA BD C

C DA CB D

In it ia l L ayou tA DB C

265

220 265 215* 215* 265 220

MaterialHandlingEffort



LIMITATIONS OF CRAFT

CRAFT yields a good heuristic solution that does not guarantee optimality

This is because not all (n!) combinations are evaluated, but only (nC2) pair-wise exchange options are considered.

In case departments are on unequal size, their centroids are exchanged which can result in irregular shapes of departments



n nC2 = [n(n-1)]/2

n!

1 0 1 2 1 2 3 3 4 4 6 24 5 10 120 6 15 720 7 21 5040 8 28 40320 9 36 362880 10 45 3628800 11 55 39916800 12 66 479001600

8

Factorial Growthmodule 7: Facility Location and Layout


20! = 2.4329 X 1018 20C2 = 190

30! = 2.65252 X 1032 30C2 = 435

40! = 8.15915 X 1047 40C2 = 780



SUMMARY OF THE CRAFT PROCEDURE

This example demonstrates one iteration of the basic CRAFT procedure

The best layout so produced is compared with the starting layout. If it is inferior to the starting layout, the starting layout is declared optimal and the search stops

Otherwise a new iteration with the discovered layout as the starting node is initiated



CONCLUSIONS

Computer packages for layout planning Construction programs (ALDEP, CORELAP) Improvement programs (CRAFT)

Based on SLP procedure Activity relationships Material Handling Effort

Good for generation of alternative layoutsLimitations of irregular shapes, ignoring realistic constraints



An Example of ALDEP



The Available Space



B

Placement of 1st Department



Placement of 2nd Department

B

D

D



Placement of 3rd Department

B

D

D

A



Placement of 4th Department

B

D

D

A

C

CC



Final Layout

B

D

D

A

C

CC



5. Product Layouts



KINDS OF PRODUCTION SYSTEMS

Flow Shop

The same set of operations performed in sequence repetitively.

Job Shop

Facilities capable of producing many different jobs in small batches

Project

A major one time job requiring sequencing and coordination among interrelated tasks.



INPUTS AND OUTPUTS OF

A PRODUCTION SYSTEM

PRODUCTIONSYSTEM

DESIRABLEGOODS/

SERVICES

UNDESIRABLE OUTPUTS•Pollution•Noise•Scrap

MenM/csMaterialsMoneyEnergyInformation…...

FEED BACK



NATURAL DOMAINS OF THE FLOW SHOP, JOB SHOP & PROJECTS

Projects &

Job Shops

JobShop

FlowShop

HIGH

VARIETY

LOW

SMALL QUANTITYLARGE



UNDERLYING IDEAS IN MASS MANUFACTURE

Logical breakdown of work

Division of work into work stations.

Adam Smith

Henry Ford

Interchangeable and replaceable parts

E.Whitney



WS1 WSn

WS2

FinalAssembly

InputMaterial



ADVANTAGES OF FLOW-LINE PRODUCTION

1. Smooth flow of material from one work station to next



2. Since work fed from one station to next, small inprocess inventories.

3. Total production time/unit short.

4. Reduced material handling.

5. Little skill required by operators. Hence training simple, short and inexpensive.

6. Simple production planning and control systems.

7. Less space occupied by work in tranit for temporary storage.



DISADVANTAGES OF FLOW-LINE PRODUCTION

1. A breakdown of one m/c may lead to a complete stoppage of following m/cs. Hence maintenance is a challenging job.

2. Inflexible with regard to changes in product design.

3. Pace determined by “bottleneck” machine. Line balancing is thus a major problem in design.



4. Supervision is general rather than specialized, as the supervision of a line is looking after diverse machines on a line.

5. Generally high investments are required owing to the specialized nature of the machines and their possible duplication in the line.



WHEN TO GO FOR MASS PRODUCTION?

10.0/PC

5.00/PC

2.50/PC

10,000

20,000



DESIGN OF AN ASSEMBLY LINE

The Objective

Minimize the total idle time or the no. of workstations for a given assembly line speed.

Division of Work Into Parts

The Precedence Diagram



Grouping of Tasks Into Work Stations

The feasible range of cycle timesLine balancing methods

Helgeson & Birnie

(RPW)

Kilbridge & Wester

(No. of predecessors)

Arcus COMSOAL

(Generation of alternatives

by simulation)Choice of the best design



PRECEDENCE DIAGRAM

2

1

3

6

4 5

7 8

12

10 11

9

5

3 4 2 6

71

4 4

5

63

Element No.Durationj



No. of work elements = N = 12

Tmax Cycle Time Ti

7 Cycle Time (5+3+4……+7)

50

N

i=1

Let desired cycle time be 10



Then the objective is to group the work elements into stations so that no stations time exceeds 10 units



2

1

3

6

4 5

7 8

12

10 11

9

5

3 4 2 6

71

4 4

5

63

WS-1 (8)

WS-2 (9)

WS-3 (9)

WS-4 (6)

WS-5

(10)

WS-6 (8)



Line efficiency =N

i=1K X CT

X 100% STi

= (50 / 6 X 10) X 100 = 83.3%

Balance delay = (1 - LE)

= 16.7%

Smoothness index

= N

i=1 (S Tmax - Sti)2

= 4+1 + 1+ 16+ 4 = 26 = 5.09 (Closer to zero the

better )



Ranked Positional Weights

The positional weight on a work element is its own processing time plus the processing times of all the following work elements

At each work station a list of eligible jobs is prepared for placement

In RPW, the work element with the highest positional weight is selected and assigned to the current work station



PRECEDENCE DIAGRAM

2

1

3

6

4 5

7 8

12

10 11

9

5

3 4 2 6

71

4 4

5

63

Element No.Durationj

7

1115

8

1315

24

28

30

31

33

50

PositionalWeight



PRECEDENCE DIAGRAM

2

1

3

6

4 5

7 8

12

10 11

9

5

3 4 2 6

71

4 4

5

63 7

1115

8

1315

24

28

30

31

33

50

1,4 2,5 3,6 10,7,9

8,11 12

8 9 9 7 10 7



EVALUATION OF DESIGN (RPW)

Balance Delay = [(10 x 6) - 50] / (10 x 6)

= 10/60 = 16.7 %

Line Efficiency = 1- BD = 83.3 %

Smoothness Index =

= sq root ( 4+1+1+9+0+9)

= 4.9



RESONS FOR HIGH BALANCY DELAY

1. Wide range of work element times.

2. A large amount of inflexible line mechanization

3. Indiscriminate choice of cycle times.



PROBLEMS AND PROSPECTS OF MASS PRODUCTION

Variable work element times

Breakdown at work stationMulti product linesModular Production & group TechnologyAutomation and Robotics

FMS & CIM

Buffers



SUMMARY

Advantages and disadvantages of Assembly Lines (product layouts)

Basic principles of assembly linesDivision of Labour Interchangeability of Parts

Precedence diagram and market requirements of design



SUMMARY (contd)

Grouping of elements in a product layout RPW, COMSOAL, Kilbridge & Wester, Other

heuristic procedures

Measures of efficiency Balance delay /Line efficiencry Smoothness index

Emerging concepts Multi product lines, buffer, automation,worker

empowerment



Documents

Project and Production Management Module 7 Facility Location and Layout Prof Arun Kanda & Prof S.G. Deshmukh, Department of Mechanical Engineering, Indian