Facility Layout

1Facility Layout

2

Facility Layout and Basic Formats

Process Layout

Layout Planning

Assembly Line balancing

Service Layout

OBJECTIVES

3Facility LayoutDefined

Facility layout can be defined as the process by which theplacement of departments, workgroups withindepartments, workstations, machines, and stock-holding points within a facility are determined

This process requires the following inputs:

Specification of objectives of the system in terms of outputand flexibility

Estimation of product or service demand on the system

Processing requirements in terms of number of operationsand amount of flow between departments and work centers

Space requirements for the elements in the layout

Space availability within the facility itself

4

Machine Objectives ofFacility Layout

Minimize material-handlingcosts

Utilize space efficiently Utilize labor efficiently Eliminate bottlenecks Facilitate communication and

interaction Reduce manufacturing cycle

time Reduce customer service time Eliminate wasted or redundant

movement Increase capacity

Facilitate entry, exit, andplacement of material, products,and people

Incorporate safety and securitymeasures

Promote product and servicequality

Encourage proper maintenanceactivities

Provide a visual control ofactivities

Provide flexibility to adapt tochanging conditions

Arrangement of areas within a facility to:

5Basic Production Layout Formats

Process Layout (also called job-shop orfunctional layout)

Product Layout (also called flow-shoplayout)

Group Technology (Cellular) Layout

Fixed-Position Layout

6

Process Layout Similar equipment or functions are grouped together, ex:

all lathes in one area, all drilling machines in one area.

A part being worked on then travels, according toestablished sequence of operations, from area to area.

Used in hospitals, such as maternity ward, ICU, ICCU etc.

7Manufacturing Process Layout

8

PaintBooth

OilReplacement

FinalInspection

EngineRepairs

UnderbodyRepairs Car washing

& cleaning

Interiors,Door Repairs,

etc.

ElectricalRepairs

WheelAlignment

DentsRepairSpare

PartsStore

Office

Process Layout of an Automobile Service Station

9ProcessLayout

A low output rateand, thus, high cost

of item per unit

Routing &scheduling is tediousand time consuming

for differentproducts

Work-In-Process(WIP) Inventory is

usually high inbatch processing

High cost of supervisionbecause of special

treatment to every productto be processed

Material handling istime consuming as no

fixed route is there

Breakdown of a machinedoes not lead to halt inproduction as substitutemachines are kept ready

for such situations

The system promotescreativity on part of

workers due to variety oftasks performed by them

Disadvantages

Advantages

The system is flexible todesign changes in

products or processes incomparison to product

layout

Maintenance cost islow because of lowcost general purpose

machines

Advantages & Disadvantages of Process Layout

10

Process Layout: Interdepartmental Flow

Given The flow (number of moves) to and from all

departments The cost of moving from one department to

another The existing or planned physical layout of the

plant Determine

The best locations for each department,where best means maximizing flow, withminimizing costs

11

Process Layout: CRAFT ApproachComputerized Relative Allocation of

Facilities Technique

It is a heuristic program; it uses a simplerule of thumb in making evaluations: "Compare two departments at a time and

exchange them if it reduces the total cost ofthe layout."

It does not guarantee an optimal solution

CRAFT assumes the existence of variablepath material handling equipment such asforklift trucks

12

Process Layout: Systematic LayoutPlanning

Numerical flow of items between departments Can be impractical to obtain Does not account for the qualitative factors that may

be crucial to the placement decision Systematic Layout Planning

Accounts for the importance of having eachdepartment located next to every other department

Is also guided by trial and error Switching departments then checking the results of the

closeness score

13

Designing ProcessLayouts

Goal: minimize material handling costs Block Diagramming

minimize nonadjacent loads use when quantitative data is available

Relationship Diagramming based on location preference between areas use when quantitative data is not available

14

Block Diagramming

Unit load quantity in which

material is normallymoved

Nonadjacent load distance farther

than the next block

STEPS create load summary chart calculate composite (two

way) movements develop trial layouts

minimizing number ofnonadjacent loads

15

Example of Systematic LayoutPlanning: Reasons for Closeness

Code

1

2

3

4

5

6

Reason

Type of customer

Ease of supervision

Common personnel

Contact necessary

Share same price

Psychology

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Example of Systematic LayoutPlanning:

Importance of Closeness

Value

A

E

I

O

U

X

Closeness LinecodeNumerical

weights

Absolutely necessary

Especially important

Important

Ordinary closeness OK

Unimportant

Undesirable

16

8

4

2

0

80

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Example of Systematic Layout Planning:Relating Reasons and Importance

From

1. Credit department

2. Toy department

3. Wine department

4. Camera department

5. Candy department

6I

--

U4A

--

U

--

U1I

6A

--

U1X

1X

To2 3 4 5

Area(sq. ft.)

100

400

300

100

100

Closeness rating

Reason for rating

Note herethat the (1)Credit Dept.and (2) ToyDept. aregiven a highrating of 6.

Note herethat the (1)Credit Dept.and (2) ToyDept. aregiven a highrating of 6.Letter

Number

Note here thatthe (2) Toy Dept.and the (5)Candy Dept. aregiven a highrating of 6.

Note here thatthe (2) Toy Dept.and the (5)Candy Dept. aregiven a highrating of 6.

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Example of Systematic Layout Planning:Initial Relationship Diagram

1

2

4

3

5

U U

E

A

I

The number of lineshere represent pathsrequired to be taken intransactions betweenthe departments. Themore lines, the morethe interaction betweendepartments.

The number of lineshere represent pathsrequired to be taken intransactions betweenthe departments. Themore lines, the morethe interaction betweendepartments.

Note here again, Depts. (1) and(2) are linked together, andDepts. (2) and (5) are linkedtogether by multiple lines orrequired transactions.

Note here again, Depts. (1) and(2) are linked together, andDepts. (2) and (5) are linkedtogether by multiple lines orrequired transactions.

19

Product Layout Difference between process and product

layout is the pattern of work flow. Equipment or departments are dedicated to

a particular product line Duplicate equipment is employed to avoid

backtracking, and a straight-line flow ofmaterial movement is achievable.

Used when the batch size of a givenproduct or part is large relative to the no. ofdifferent products or parts produced.

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A Product Layout

In

Out

21

Description

Type of process

Product

Demand Volume Equipment

Description

Type of process

Product

Demand Volume Equipment

Sequentialarrangement ofactivities

Continuous, massproduction, mainlyassembly

Standardized, madeto stock

Stable High Special purpose

Process

Comparison of Productand Process Layouts

Functionalgrouping ofactivities

Intermittent, jobshop, batchproduction, mainlyfabrication

Varied, made toorder

Fluctuating Low General purpose

Product

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Workers Inventory

Storage space Material handling Aisles Scheduling Layout decision Goal

Advantage

Workers Inventory

Storage space Material handling Aisles Scheduling Layout decision Goal

Advantage

Limited skills Low in-process, high

finished goods Small Fixed path (conveyor) Narrow Part of balancing Line balancing Equalize work at each

station Efficiency

Process

Comparison of Productand Process Layouts

Varied skills High in-process, low

finished goods Large Variable path (forklift) Wide Dynamic Machine location Minimize material

handling cost Flexibility

Product

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Advantages & Disadvantages of Product Layout

Monotonous repetitivetasks lead to frustration

on part of workers

ProductLayout

A highoutput rateand, thus,

low cost ofitem per unit

Highefficiency of

labor &equipment

Lesser supervision& labor trainingcosts (as labor istrained only for aspecialized task)

No need of routing orscheduling once the

line is operational (as itis already done duringthe design of the line)

Easier materialhandling and

lesser inventorycosts

Breakdown of amachine or highabsenteeism of

workers leads to halt inproduction

Advantages

Disadvantages

Inflexible to designchanges in products

or processes (thechanges in line areusually expensive)

Maintenance costis fairly high toensure smoothrunning of the

line

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Assembly line Special case of product layout.

Refers to progressive assembly linked bysome material handling device.

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An Assembly Line (Product Layout)

Racks containingsteering wheelssub-assembly

Workstation 1 Workstation 3Workstation 2

Car 1 Car 3Car 2

Racks containingheadlight sub-assembly

Racks containingbacklight sub-assembly

Conveyor

26

1

6

32

8 7

4

5

The entry &exit pointsare nearby A single worker

A U-shaped Assembly Line

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Station 1Minutesper Unit 6

Station 2

7

Station 3

3

Assembly Lines Balancing Concepts

Question: Suppose you load work into the three workstations below such that each will take the correspondingnumber of minutes as shown. What is the cycle time ofthis line?

Question: Suppose you load work into the three workstations below such that each will take the correspondingnumber of minutes as shown. What is the cycle time ofthis line?

Answer: The cycle time of the line is alwaysdetermined by the work station taking the longesttime. In this problem, the cycle time of the line is 7minutes. There is also going to be idle time at theother two work stations.

Answer: The cycle time of the line is alwaysdetermined by the work station taking the longesttime. In this problem, the cycle time of the line is 7minutes. There is also going to be idle time at theother two work stations.

28

Example of Line Balancing

Youve just been assigned the job a settingup an electric fan assembly line with thefollowing tasks:

Task Time (Mins) Description PredecessorsA 2 Assemble frame NoneB 1 Mount switch AC 3.25 Assemble motor housing NoneD 1.2 Mount motor housing in frame A, CE 0.5 Attach blade DF 1 Assemble and attach safety grill EG 1 Attach cord BH 1.4 Test F, G

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Example of Line Balancing:Structuring the Precedence Diagram

Task PredecessorsA None

A

B A

B

C None

C

D A, C

D

Task PredecessorsE D

E

F E

F

G B

G

H E, G

H

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Example of Line Balancing:Precedence Diagram

A

C

B

D E F

GH

2

3.25

1

1.2 .5

11.4

1

Question: Which process step defines the maximumrate of production?

Question: Which process step defines the maximumrate of production?

Answer: Task C is the cycle time of the line andtherefore, the maximum rate of production.Answer: Task C is the cycle time of the line andtherefore, the maximum rate of production.

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Example of Line Balancing: The Bottleneck

Task Time (Mins) Description PredecessorsA 2 Assemble frame NoneB 1 Mount switch AC 3.25 Assemble motor housing NoneD 1.2 Mount motor housing in frame A, CE 0.5 Attach blade DF 1 Assemble and attach safety grill EG 1 Attach cord BH 1.4 Test E, G

Max Production =Production time per day

Bottleneck time=

420 mins3.25 mins / unit =129 unitsMax Production =

Production time per dayBottleneck time

=

420 mins3.25 mins / unit =129 units

32

Example of Line Balancing: DetermineCycle Time

Required Cycle Time, C =Production time per periodRequired output per period

Required Cycle Time, C =Production time per periodRequired output per period

C =420 mins / day100 units / day

= 4.2 mins / unitC =420 mins / day100 units / day

= 4.2 mins / unit

Question: Suppose we want to assemble100 fans per day. What would our cycletime have to be?

Question: Suppose we want to assemble100 fans per day. What would our cycletime have to be?

Answer:Answer:

33

Example of Line Balancing: DetermineTheoretical Minimum Number of

Workstations

Question: What is the theoretical minimum number ofworkstations for this problem?

Question: What is the theoretical minimum number ofworkstations for this problem?

Answer:Answer: Theoretical Min. Number of Workstations, N

N =Sum of task times (T)

Cycle time (C)

t

t

Theoretical Min. Number of Workstations, N

N =Sum of task times (T)

Cycle time (C)

t

t

N =11.35 mins / unit

4.2 mins / unit= 2.702, or 3tN =

11.35 mins / unit4.2 mins / unit

= 2.702, or 3t

34

Example of Line Balancing: Determine theEfficiency of the Assembly Line

Efficiency =Sum of task times (T)

Actual number of workstations (Na) x Cycle time (C)Efficiency =Sum of task times (T)

Actual number of workstations (Na) x Cycle time (C)

Efficiency=11.35 mins / unit(3)(4.2mins / unit) =.901Efficiency=11.35 mins / unit(3)(4.2mins / unit) =.901

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Group Technology(Cellular Layout):

group dissimilar machines into work centers(called cells) that process families of parts withsimilar shapes or processing requirements

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LatheMachines

Foundry

PaintShop

DrillingMachines

Fittingshop

WeldingShop

111

111

111

111

111

222

2222

22222222 11122223333 3333

333

3333 3333

4444 444444444444

Lathe FittingDrilling Welding Paint

Foundry Lathe PaintFitting

Lathe Fitting Drilling

Foundry

Welding

Drilling Welding

111 111

2222222222 2222

4444

33333333333333

444444444444444444444Cellular Layout

Manufacturing Cell 1

Manufacturing Cell 2

Manufacturing Cell 3

Manufacturing Cell 4

Process Layout of a Factory

37

Cellular Layouts

1. Identify families of parts with similarflow paths

2. Group machines into cells based onpart families

3. Arrange cells so material movement isminimized

4. Locate large shared machines at pointof use

38

Group Technology (Cellular Layout):Benefits

1. Better human relations

2. Improved operator expertise

3. Less in-process inventory andmaterial handling

4. Faster production setup

39

Advantages andDisadvantages

of Cellular LayoutsAdvantages

Reduced materialhandling and transit time

Reduced setup time Reduced work-in- process

inventory Better use of human

resources Easier to control Easier to automate

Disadvantages Inadequate part families Poorly balanced cells Expanded training and

scheduling of workers Increased capital

investment

40

Group Technology:Transition from Process Layout

1. Grouping parts into families thatfollow a common sequence of steps

2. Identifying dominant flow patternsof parts families as a basis forlocation or relocation of processes

3. Physically grouping machines andprocesses into cells

41

Fixed Position Layout

Question: What are our primary considerationsfor a fixed position layout?

Question: What are our primary considerationsfor a fixed position layout?

Answer: Arranging materials and equipmentconcentrically around the production point intheir order of use.

Answer: Arranging materials and equipmentconcentrically around the production point intheir order of use.

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Equipments

ComputerExperts

Assemblies

Technicians Fuel

RawMaterials

Schematic Diagram to show Fixed-position Layout of a SpaceShuttle

43

Retail Service Layout

Goal--maximize net profit persquare foot of floor space

Servicescapes Ambient Conditions Spatial Layout and Functionality Signs, Symbols, and Artifacts

44

Question BowlWhich of the following is a process that involves

developing a relationship chart showing thedegree of importance of having eachdepartment located adjacent to every otherdepartment?

a. Systematic layout planningb. Assembly-line balancingc. Splitting tasksd. U-shaped line layoutse. None of the above

Answer: a. Systematic layout planning

45

Question Bowl

If the production time per day is 1200 minutes andthe required output per day is 500 units, which ofthe following will be the required workstationcycle time for this assembly line?

a. 2.4 minutesb. 0.42 minutesc. 1200 unitsd. 500 unitse. None of the above

Answer: a. 2.4minutes(1200/500=2.4minutes)

46

Question BowlYou have just finished determining the cycle time

for an assembly line to be 5 minutes. Thesum of all the tasks required on thisassembly is is 60 minutes. Which of thefollowing is the theoretical minimum numberof workstations required to satisfy theworkstation cycle time?

a. 1 workstationb. 5 workstationsc. 12 workstationsd. 60 workstationse. None of the above

Answer: c. 12workstations(60/5=12)

47

Question BowlIf the sum of the task times for an assembly line is

30 minutes, the actual number of workstationsis 5, and the workstation cycle time is 10minutes, what is the resulting efficiency ofthis assembly line?

a. 0.00b. 0.60c. 1.00d. 1.20e. Can not be computed from the data above

Answer: b. 0.60 (30/(5x10)=0.60)

48

Question Bowl

Which of the following are ways that we canaccommodate a 20 second task in a 18second cycle time?

a. Share the taskb. Use parallel workstationsc. Use a more skilled workerd. All of the abovee. None of the above

Answer: d. All of the above

49

Question Bowl

Which of the following are ambient conditions thatshould be considered in layout design?

a. Noise levelb. Lightingc. Temperatured. Scente. All of the above

Answer: e. All of the above