1

Plant LayoutPlant Layout

A Systematic Layout Planning A Systematic Layout Planning (SLP) Approach(SLP) Approach

Mohamed Iqbal PallipurathMohamed Iqbal Pallipurath

2

THE NEED FOR THE NEED FOR GOOD FACILITIES PLANNINGGOOD FACILITIES PLANNING

1.1. Plant facilities influence operating costs and profits.Plant facilities influence operating costs and profits.2.2. Planning allows facilities and its operations (OSHA, Planning allows facilities and its operations (OSHA,

ISO 14001, etc.) to comply with laws and/or ISO 14001, etc.) to comply with laws and/or regulations.regulations.

3.3. Facilities are fixed investments involving high capital-Facilities are fixed investments involving high capital-cost expenditures.cost expenditures.

4.4. Facilities are inflexible and long term commitments.Facilities are inflexible and long term commitments.5.5. The planning, design and construction of facilities The planning, design and construction of facilities

require long lead times.require long lead times.6.6. Good planning helps to avoid disruptions in Good planning helps to avoid disruptions in

production and shipping or delivery.production and shipping or delivery.

3

THE NEED FOR THE NEED FOR GOOD FACILITIES PLANNINGGOOD FACILITIES PLANNING

7.7. The quality of facilities influences the attitudes of The quality of facilities influences the attitudes of and the ability to attract suitable employees.and the ability to attract suitable employees.

8.8. Industrial facilities must be planned to meet Industrial facilities must be planned to meet anticipated future requirements yet compete anticipated future requirements yet compete profitably today.profitably today.

9.9. Facilities need to be planned for an appropriate Facilities need to be planned for an appropriate degree of flexibility, expandability, versatility…degree of flexibility, expandability, versatility…

10.10. Good plans help management to take advantage Good plans help management to take advantage of business opportunities that arise.of business opportunities that arise.

11.11. Good planning is an aid to obtain approval and Good planning is an aid to obtain approval and financing monies.financing monies.

12.12. Good planning reduces the high materials handling Good planning reduces the high materials handling $ resulting from “ad hoc” expansion of plant $ resulting from “ad hoc” expansion of plant facilities.facilities.

ECONOMIC IMPACT OF FACILITIES PLANNINGECONOMIC IMPACT OF FACILITIES PLANNING

Time

Eco

nom

ic I

nves

tmen

t/C

onse

quen

ce (

$)

Plan20:1

Design2:1

Build & Install1:10

Resources invested to provide the facilities

Consequence on operations of facilities

5

DEFINING PERFORMANCE DEFINING PERFORMANCE OBJECTIVESOBJECTIVES

1.1.

2.2.

3.3.

6

DEFINING PERFORMANCE DEFINING PERFORMANCE OBJECTIVESOBJECTIVES

4.4.

5.5.

6.6.

7

TYPES OF MANUFACTURING TYPES OF MANUFACTURING LAYOUT CONFIGURATIONSLAYOUT CONFIGURATIONS

I.I. Product Line LayoutProduct Line Layout

Product

A

B

C

8

CHARACTERISTICSCHARACTERISTICS

High volume productionHigh volume production Special purpose machines and Special purpose machines and

material handling equipmentmaterial handling equipment Throughput rates--highThroughput rates--high Work-in-process--lowWork-in-process--low Setup/Run time ratio--lowSetup/Run time ratio--low

System is very inflexibleSystem is very inflexible Control is relatively simpleControl is relatively simple

TYPES OF MANUFACTURING LAYOUT CONFIGURATIONSTYPES OF MANUFACTURING LAYOUT CONFIGURATIONS

GOAL: GAIN the advantages and efficiency of high volume production in a LOW/MEDIUM VOLUME (FLEXIBLE) ENVIRONMENT.

II. Flow Line Workcell

T T T

M M T M

D D M D

SG CG CG D

SG

T = turningD = drillingM = millingCG = center grindingSG = surface grinding

10

GT-FLOW LINE WORKCELL GT-FLOW LINE WORKCELL CHARACTERISTICSCHARACTERISTICS

Buffer1

Buffer2

Bufferm

Workstation1

Workstation1

Workstationm

11

GT-FLOW LINE WORKCELL GT-FLOW LINE WORKCELL CHARACTERISTICSCHARACTERISTICS

1.1. Processes GT-based families of parts with frequent Processes GT-based families of parts with frequent job change-over and small to medium batch sizesjob change-over and small to medium batch sizes

2.2. Piece by piece (continuous flow) Piece by piece (continuous flow) processing/movementprocessing/movement

3.3. No backtracking in sequence flow, but machine No backtracking in sequence flow, but machine skipping does occurskipping does occur

4.4. Accommodates flexible-type automation: CNC Accommodates flexible-type automation: CNC machines, robots for part handlingmachines, robots for part handling

5.5. Finite buffers (resulting in machine blocking and Finite buffers (resulting in machine blocking and starvationstarvation

TYPES OF MANUFACTURING LAYOUT CONFIGURATIONSTYPES OF MANUFACTURING LAYOUT CONFIGURATIONS

III. Cellular Manufacturing(GT Workcell)

13

CHARACTERISTICSCHARACTERISTICS

1.1. Dissimilar processes/machinesDissimilar processes/machines

2.2. Similar parts (families) run in small to Similar parts (families) run in small to medium batch sizesmedium batch sizes

3.3. Mini - job shopsMini - job shops

Process(Functional) LayoutProcess(Functional) Layout

S S S

S S S

T T T

T T T

T T T

G G G

G G G

M

M

M

B B

B B

GC GC

GC GC

HT

HTHT

Sawing Turning

Heat Treating

Grinding

Milling

BoringGear Cut

“Shaft”

15

CharacteristicsCharacteristicsof Process Layoutsof Process Layouts

Low Volume, High Variety Production with Random Low Volume, High Variety Production with Random Routing (Spaghetti-Like Flow)Routing (Spaghetti-Like Flow)

General Purpose Machines--General Purpose Machines-- Machine setups are frequent and longMachine setups are frequent and long Work-In-Process -- HighWork-In-Process -- High Throughput Rates tend to be LowThroughput Rates tend to be Low Material Handling -- HighMaterial Handling -- High Operator Utilization -- Low?Operator Utilization -- Low? Throughput Times (Lead Time) -- HighThroughput Times (Lead Time) -- High

System is Very Flexible, produces many different System is Very Flexible, produces many different types of parts: gears, shafts, pinions, housings, types of parts: gears, shafts, pinions, housings, clamps, etc.clamps, etc.

THE P-Q CURVETHE P-Q CURVE

P

Q

Product A

Product B

Product C

Etc.

(High)

(Low)

(Low) (High)(P) Variety

(Q)

Vol

ume

or Q

uant

ity

Part Volume/Variety Relationships with Part Volume/Variety Relationships with Manufacturing Systems ConfigurationsManufacturing Systems Configurations

ProductLine

G.T.FlowlineWorkcell

G.T.Manufacturing

Workcell

Functional(Job-Shop)

Part Variety

PartVolume

(High)

(Low)

(Low) (High)

18

MATERIAL FLOWMATERIAL FLOW

Importance of Material Flow

Properly Planned Material Flow

Effective Arrangement of Facilities

Efficient Operations

Profitability/Viability

19

Efficient Operations InvolveEfficient Operations Involve::

1.1. Good utilization of floor spaceGood utilization of floor space

2.2. Reduced materials handlingReduced materials handling

3.3. Appropriate equipment utilizationAppropriate equipment utilization

4.4. SafetySafety

5.5. Less congestionLess congestion

6.6. Less wasted time/effortsLess wasted time/efforts

7.7. FlexibilityFlexibility

20

MATERIAL FLOWMATERIAL FLOW

KEY QUESTIONSKEY QUESTIONS

1.1. What is the most effective What is the most effective sequencesequence of moving of moving materials?materials?

Eliminate?Eliminate?Combine?Combine?Improve?Improve?Change Order?Change Order?

2.2. What is the What is the intensityintensity and direction? and direction?

Need to visualize the flowNeed to visualize the flow

21

FLOW OF MATERIAL vs P-Q MIXFLOW OF MATERIAL vs P-Q MIX

I

II

III

IV

LAYOUT TYPE

I Product LineII Flow Line WorkcellIII G.T. WorkcellIV Functional

TYPE ITYPE I

Operation Process Chart showing intensity of material flow and the out-flow of chips and scrap. (Muther, SLP)

0-4

0-5

0-1

0-2

0-3

0-6

Casting Sheet Steel

Turn

Drill

Storage

4 Tons 10 Tons

Turnings0.7 Tons

Turnings0.3 Tons

Bolts Scrap2 Tons

Offal1 Ton

3.3 Tons

3 Tons

9 Tons

7 Tons

10.5 Tons

9 Tons

Blank

Form

Trim

Assemble/Inspect

TYPE IITYPE II

1

Operation Part or Product A B C D

Saw

Center

Turn

Heat Treat

Grind

Mill

2

3

4

5

1

2

3

4

5

1

2

4

3

5

1

2

3

4

*

Multi-Product Process Chart

*Shows problem flow to be resolved by design engineering and manufacturing engineering

TYPE IIITYPE III5 8 7 13 1 10 2 11 14 3 15 4 9 612

4

1

6

8

3

9

2

14

12

5

7

13

11

10

Part-Machine Matrix ofProduction Flow Analysis

PartsMachines

Exceptions

TYPE IVTYPE IV

1 2 3 5 6 7 8 9 10 TOTALS4

1

2

3

4

5

6

7

8

9

10

TOTALS

FROM-TO CHART

TO

FROM

Turn

Hob

Slot

Broach

Heat Treat

Drill

Inspect

Wash

Mill

Store

Tur

n

Hob

Slo

t

Bro

ach

Hea

t Tre

at

Dri

ll

Insp

ect

Was

h

Mil

l

Sto

re

3 3 6 1 5 1

7 5 1

1

3

31

1 5

57

1

1

9

xy

910

1212

8 576

22 12

10576262

20

414

752

2

684631223216026- - -

- -

- -

- -

-

-

-

-

- -

-

-

-

-

-

-

-

-

-

=

=

=

=

=

=

=

=

------

- - - -

-

-

-

-

-

-

-

-

------

-

-

-

-

-

- - - -

-

----

-

-

- -

-

-

--

-

-

Number of Parts

Number of Pieces

RANK THE FLOWSRANK THE FLOWS

KEYA:E:I:O:U:

Absolutely NecessaryEspecially ImportantImportantOrdinaryUnimportant

FL

OW

- O

F -

MA

TE

RIA

L I

NT

EN

SIT

Y

500

10

00

150

0

2000

2

500

30

00

350

0

4000

4

500

A

E

I

OU

Act

ivit

yP

air

(Rou

te)

Seq

.N

o.

8-13

1-3

3-4

8-15

3-12

11-1

5

10-1

3

3-7

7-15

1-14

4-12

4-9

4-15

1-7

2-3

11-1

5

3-5

1-4

1-12

2-8

11-9

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

27

NON-FLOW (CLOSENESS) NON-FLOW (CLOSENESS) RELATIONSHIPSRELATIONSHIPS

Flow based on routings is not the sole Flow based on routings is not the sole basis for layout arrangements.basis for layout arrangements.

Adapted from Muther

28

NON-FLOW (CLOSENESS) NON-FLOW (CLOSENESS) RELATIONSHIPSRELATIONSHIPS

Other FactorsOther Factors Supporting ServicesSupporting Services

Tool Room (not routed)Tool Room (not routed) Rest AreasRest Areas Central Coolant TanksCentral Coolant Tanks Shop Superintendent’s OfficeShop Superintendent’s Office

Adapted from Muther

29

NON-FLOW (CLOSENESS) NON-FLOW (CLOSENESS) RELATIONSHIPSRELATIONSHIPS

Other FactorsOther Factors Separation of AreasSeparation of Areas

Welding away from assemblyWelding away from assembly

Outside Doors / Separate / N/COutside Doors / Separate / N/C

DirtyDangerous Separate

DelicateHigh Pop

Adapted from Muther

30

NON-FLOW (CLOSENESS) NON-FLOW (CLOSENESS) RELATIONSHIPSRELATIONSHIPS

In some cases, flow is simply not In some cases, flow is simply not importantimportant

No Significant FlowNo Significant Flow Service, Repair, Tool RoomService, Repair, Tool Room Jewelry (one load per week)Jewelry (one load per week)

Adapted from Muther

RELATIONSHIP CHARTRELATIONSHIP CHARTI

1 U

U

U

U

U

A

2 E

2 I

2 O

3 I

4

D

2 U

U

U

U

I

2 O

2 U

U

O

4

I

2 I

2 U

U

O

2 O

2 O

2 O

3 O

4

U

E

2 U

I

2 O

2 A

2 O

3 O

4

U

U

I

2 O

2 U

I

3 U

U

I

2 U

U

E

5 X

6

E

2 I

2 E

2 O

3 I

4

U

U

U

U

U

U

UO

3 U

O

4

Adapted from Muther

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

Punch Press

AuxiliaryPunch Press

Drilling

Grinding

GeneralFabrication

Wet Tumble

SpecialProduction

Raw MaterialStorage

In-ProcessStorage

Assembly

Shop Toilet

Shop Office andTool Room

1

2

3

2

3

4

5

6

7

8

9

10

11

12

13

14

15

1

This block shows relation between “1” and “3”

Importance of Relationship (top)

Reasons in Code (bottom)

32

RELATIONSHIP CHART CodesRELATIONSHIP CHART Codes

Code

A

E

I

O

U

X

CLOSENESS

Absolutely Necessary

Especially Important

Important

Ordinary Closeness OK

Unimportant

Undesirable

4

3

2

1

0

-1

“Closeness”Rating

Value

RELATIONSHIP CHARTRELATIONSHIP CHART

Adapted from Muther

Value

1

2

3

4

5

6

7

8

9

Equip. used by same persons

Movement of material

Movement of personnel

Supervision and/or support

Require same utilities

Noise and dirt

REASON

Reasons behind the “Closeness”

Value

RELATIONSHIP DIAGRAMSRELATIONSHIP DIAGRAMS

Vowel Letter

A

No. Value

4

No. of Lines Closeness Rating

Absolutely Necessary

Color Code

Red**

E

I

O

U

X

XX

3

2

1

0

-1

-2, -3, -4, ?

Especially Important

Important

Ordinary

Unimportant

Not Desirable

Extremely Undesirable

Orange Yellow**

Green**

Blue**

Uncolored**

Brown**

Black

Conventions for diagramming activity relationships

35

PROCEDURE/EXERCISEPROCEDURE/EXERCISE

E

U

U

I

E

U

O

U

I

I

U

X

I

X

X

U

A

IO

U

A

Parts Storage

Ship/Receiving

Welding

Testing

Machining

Assembly

Paint

Figure 1: Relationship Chart

5,000

10,000

2,500

2,500

7,500

5,000

2,500

1

2

3

4

5

6

7

Dept. Desc.Sq. FeetDept. No.

36

PROCEDURE/EXERCISEPROCEDURE/EXERCISE

Figure 2: From-To Chart (in Loads per Weeks)

1

1

TOFROM

2

3

4

5

6

7

2 3 4 5 6 7

50

50

120

120

20

120

20

20

5080

40170

170

37

Determine Total Flow

1

1

TOFROM

2

3

4

5

6

7

2 3 4 5 6 7

50

120

20

120

20

140

5080

90170

170

1

38

Rank the Flows2

0

20

40

60

80

100

120

140

160

180

200

0 1 2 3 4 5 6 7 8 9 10 11

Tot

al F

low

1-6

2-3

4-6

2-7

4-7

2-5

3-5

1-2

3-6

3-7

5-7

39

Combine Flow & Non-Flow Relationships3

Activity Pairs

1-21-31-41-51-61-72-32-42-52-62-73-43-53-63-74-54-64-75-65-76-7

30023010220-20-2-2042104

100040401030210033000

Combined Total Points

40027050423-22-1-2075104

Non Flow: Flow1 to 1 Ratio

40

Rank the Combined Points4

0

1

2

3

4

5

6

7

8

9

10

0 1 2 3 4 5 6 7 8 9 10 11

Tot

al P

oint

s

1-6

4-6

2-3

4-7

1-2

2-5

6-7

2-7

1-5

2-6

3-5

Activity Pairs5-

6

12 3-6

3-4

3-7

41

Develop Combined Relationship Chart(Flow and Non-Flow)

5

I

O

A

E

I

O

I

XX

O

X

XXA

E

I

Parts Storage

Ship/Receiving

Welding

Testing

Machining

Assembly

Paint

5,000

10,000

2,500

2,500

7,500

5,000

2,500

1

2

3

4

5

6

7

42

Develop Relationship Diagram6

Place “A” Relationship Values on Grid

Add the “E” Relationship Values and Adjust Diagram to Minimize Distance X Flow Value

Place “A” Relationship Values on Grid

i

ii

iii

6. Relationship Diagram6. Relationship Diagram+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

4 6 1

7 2 3

5AEI

OUX

XX

7. 7. Measures of EffectivenessMeasures of EffectivenessMin Z = Min Z = LL DDijijijijjjii

LL ijij = Load between departments i & j, often measured = Load between departments i & j, often measured by the value of the Vowel Letter.by the value of the Vowel Letter.A = 4, E = 3, I = 2, O = 1, U = 0, X = -1A = 4, E = 3, I = 2, O = 1, U = 0, X = -1

DDijij = Distance between departments i & j (move only = Distance between departments i & j (move only at Right angles)at Right angles)

*Many Variations of this Concept*Many Variations of this Concept

8. 8. Space Relationship DiagramsSpace Relationship Diagrams

9.9. LayoutsLayouts

45

Department Pair

1-21-31-41-51-61-72-32-42-52-62-73-43-53-63-74-54-64-75-65-76-7

Lij

20014030212-11-1-1043000

Dij

202313121113222311222

Zij

40034030212-32-2-2043000

7. 7. Diagram Score:Diagram Score:

21

46

Types of LayoutsTypes of Layouts

Product

CM

Job-Shop (process)

Number of Part Numbers

(P)

(Q)

Number of pieces/part#

47

PRODUCT LAYOUTPRODUCT LAYOUT

Product Layout: Continuous Flow Production SystemProduct Layout: Continuous Flow Production System

Definition: Layout is dictated by the product. (P)

Suited to manufacturing processes with single output

Equipment arrangement operation sequence

High production (volume) items and stable demand, similar products:

48

PRODUCT LAYOUTPRODUCT LAYOUT

Materials move by Materials move by unitsunits in a product line, not by lots. in a product line, not by lots.

UNIT1. 2. 3.

*?

demand

Operations performed at various workstations

*The Output is determined by the slowest operation

TASK is to BALANCE the workstations in terms of the work done (time) and satisfy the required

output.

*

49

PRODUCT LAYOUTPRODUCT LAYOUT

Two Types of ProblemsTwo Types of Problems:: Required Information:

Fabrication Lines

Assembly Lines

Sequence of operations or job elements

Time required for each operation or independent element

Output required

(R)

(T)

(Q)

50

EXAMPLEEXAMPLE

Design a fabrication line to manufacturing a product Design a fabrication line to manufacturing a product with the following 7 operations. Initially assume:with the following 7 operations. Initially assume:

No scrap losses

100% eff. & 480 min/day

1000 units required per day

51

EXAMPLEEXAMPLE

Specifically determineSpecifically determineA)A) The number of machines required at each The number of machines required at each workstation, andworkstation, andB)B) The % of idle time for the following operations:The % of idle time for the following operations:

Opn #

1234567

Operation

SawCenter

Turn (RGH)Heat TreatFin Turn

GrindMill

52

OUTPUT REQ’D: 1000 UNITS/DAYOUTPUT REQ’D: 1000 UNITS/DAY

A

B

C

D=A*B*C

Std Time (Output)

Opn Std Time Cont. Output Machines Req’d

Theoretical Prod. Time

Actual Prod. Time

1 2 3 4 5 6 7 Totals

1.20 min 0.80 min 1.00 min 2.40 min 0.40 min 3.00 min 1.20 min 10.0 min

400 pcs 600 pcs 480 pcs 200 pcs 1200 pcs 160 pcs 400 pcs per machine

3 2 3 5 1 7 3

1440 min 960 min 1440 min 2400 min 480 min 3360 min 1440 min 11,520 min

1200 min 800 min 1000 min 2400 min 400 min 3000 min 1200 min 10,000 min

Idle =11520-10000

1152013.2%

53

OUTPUT REQ’D: 1200 UNITS/DAYOUTPUT REQ’D: 1200 UNITS/DAY

Opn Number of Stations

Theo. Time Act. Time

1 2 3 4 5 6 7

3 2 3 6 (+1) 1 8 (+1) 3

1440 960 1440 2880 480 3840 1440 12,480

= = > = = > =

1440 960 1200 2880 480 3600 1440 12,000

Idle =12480-12000

124803.8%

54

OUTPUT REQ’D: 800 UNITS/DAYOUTPUT REQ’D: 800 UNITS/DAY

Opn Number of Stations

Theo. Time Act. Time

1 2 3 4 5 6 7

2 (-1) 2 2 (-1) 4 (-1) 1 5 (-2) 2 (-1)

960 960 960 1920 480 2400 960 8640

= = = = > = =

960 640 800 1920 320 2400 960 8000

Idle =6408640

7.4%

55

SUMMARYSUMMARY

Output Rate

Total Number Of Machines

% Idle

800 900

1000 1100 1200 1300 1400 1500

18 22 24

26

7.4 14.7 13.2

3.8

CONCLUSIONS:

56

INVENTORIESINVENTORIES

Now how does one handle the idle time which occurs?

*i.e., complete balance not possible.

Ans. Work in-process inventories are used to “decouple” operations.

Slack for machine breakdowns

InvenStat 1

InvenStat 2

Stat 3

57

SYSTEM UTILIZATION LEVELSSYSTEM UTILIZATION LEVELS

Production Level (pcs/hr)

Stat No. Hourly Capacity per “Machine”

40 55 60 80

1 2 3 4 5

55

40 85

105

60

73%

100% 47% 38%

67%

100%

2) 69% 65% 52%

92%

2) 55%

2) 75% 71% 57%

100%

2) 73%

2) 1005 94% 76%

2) 67%

Avg. Util. Add’l Mach.

New Util.

65% 2

54%

75% 1

64%

70% 5

61%

81% 2

72%

58

How to Handle ScrapHow to Handle Scrap

What inputs are required at each station?What inputs are required at each station? How many machines are required at each station?How many machines are required at each station?

Station 1 Station 2 Station 3?

Operation Std. Time (min/part)

Scrap% Efficiency%

1 0.3 5 0.9

2 0.5 3 1.05

3 1.1 4 1.00

150 pcs/hr

59

TERMSTERMS

Inputn =Outputn

(1.00-Scrapn)

Efficiency =Std. Time

Actual TimeX 100%

60

Station #3

150Input

Std Time = 1.1 min/pc. 54.5 pcs/std. hr.

Input =150

(1-.04)= 156.25 = 157

x 1.00 Eff.

54.5 54 pc/hr./machine

2.91

157/54 3 machines

61

Station #2

157

Std Time = .5 min/pc. 120 pcs/std. hr.

Input = =

x 1.05 Eff.

126 pcs/hr./machine

162/126 = 1.28 2

2

62

Station #1

Std Time = .3 min/pc. 200 pcs/std. hr.

Input = =

171/180 = .95 1

x .90 Eff.

180 pcs/hr./machine

63

Operation Actual production

rate (part/hr) per

Mc

Production time (min)

per Mc

Mc Theoretical time (min)

Idle time (min)

1 180 57 1 60 3

2 126 77.14 2 120 42.86

3 54 174.44 3 180 5.56

Total 308.58 360 51.42

Idle = (360 - 308.58)/360 = 0.143

Utilization = 1 - 0.143 = 0.857

64

Final LayoutFinal Layout

171162 157

12

3

150

65

Class ProblemClass ProblemA circuit line consists of four processes:

A: chip production,B: assembly,C: test, andD: package.

Three chips go into every assembly.

The production and scrap rates are as follows:

What is the output rate of this line?

Process Production Rate(Pcs/hr)

Scrap (%)

ABCD

200605570

151050