Chapter 6
Facility Layout
Slides prepared by
Laurel Donaldson
Douglas College
Copyright © 2010 by The McGraw-Hill Companies, Inc. All rights reserved.
Learning Objectives
LO 1
LO 2
LO 3
Describe the basic plant/facility layout types.
Solve simple assembly line balancing problems.
Develop simple process (functional) layouts.
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2
Chapter Outline
Types of Layout
Assembly Line Balancing
Designing Process Layouts
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3
Layout
Layout: the arrangement of departments,
work centers, equipment, etc.
want to have smooth movement (of work,
people, materials, info) through the system
LO 4
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4
Basic Layout Types
Product layout
 arranges
production resources linearly
according to the progressive steps
by which a product is made
Process layout
arranges production resources together
according to similarity of function
LO 4
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5
Product (Line) Layout
Raw
materials
or customer
Material
and/or
labour
Station
1
Material
and/or
labour
Station
2
Material
and/or
labour
Station
3
Station
4
Finished
item
Material
and/or
labour
 Used for Repetitive or Continuous Processing
 More common for goods than services
LO 4
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6
Product Layout
(Assembly Line)
Standardized
processing operations
to achieve
smooth, rapid, high-volume flow
 Standardized product/service
 allows continuous processing and
 specialization of labour & equipment
 Product demand is stable
 enough to justify high investment in specialized equipment
 Divide work into series of tasks
 by technological processing requirements
 Can use fixed path material handling
 conveyors
LO 4
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7
Product (Line) Layouts
Advantages: Efficient and Easy to Use
1. High degree of labour & equipment utilization
= lower cost per unit
2. Minimal work-in-process inventories
3. Simplified accounting, purchasing and inventory control
4. Easier training and supervision
Disadvantages: Inflexible
1.
2.
3.
4.
LO 4
Higher equipment cost
Dull, repetitive jobs = stress, low morale
Lack of flexibility in product or production rates
Work stoppage at any point ties up the whole operation
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8
Assembly Lines
Lucy at the Chocolate Factory
LO 4
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9
Process (Functional) Layout
Used for Intermittent processing
Job Shop or Batch Processes
Common in Services
LO 4
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10
Process (Functional) Layout
LO 4
Like machines
& equipment
are grouped
together
Flexible and
capable of
handling a
wide variety of
products or
services
Used for
intermittent
processes
(job-shop,
batch, most
services)
General
purpose
equipment and
variable-path
equipment
(forklift, pallet
jack, tote)
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11
Process (Functional) Layout
Advantages: Flexibility
Less vulnerable to shutdown
(from mechanical failure or absenteeism)
Lower maintenance costs
(and reduced investment in spare parts)
Disadvantages: Inefficiency
Scheduling can be difficult
(= low equipment utilization rates)
Setup, material handling, and
labour and costs can be high
Increased work-in-process
inventory
LO 4
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12
Cellular Layout
 Cellular layout
 Layout in which machines are grouped into a cell that can
process items that have similar processing requirements
 Group technology
 The grouping into part families of items with similar design
(size, shape and function) or manufacturing (type and
sequence of operations required) characteristics
LO 4
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13
Comparison of functional and cellular layouts
333 Lathes
Drill
Grind
Heat
treat
111
Gear
cutting
Functional Layout
LO 4
333
Assembly
111
222
222
Mill
333
111
444
222
111
444
111
222
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111
444
14
111
Lathe
222
333
Mill
Mill
Drill
Drill
Lathe Mill
444
Mill
Heat
treat
Gear
cut
111
Heat
treat
Grind
222
Heat
treat
Grind
333
Drill
Gear
cut
444
Cellular Layout
LO 4
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Assembly
Comparison of functional and cellular layouts
15
Cellular Layouts
Benefits:
faster processing time and reduced setup times
 increased capacity
less material handling and work-in-process
inventory
Conversion is a major undertaking
Three primary methods:
visual inspection,
examination of design and production data,
and production flow sequence and routing analysis.
LO 4
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16
Other Layout Types
Warehouse layouts
Important consideration: frequency of order
Retail layouts
Important consideration: traffic flow
Office layouts
Objective: optimize the physical transfer of
information or paperwork
New trend: create an image of openness
(low rise partitions)
LO 4
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17
Fixed Position Layouts
Layout in which the product or project
remains stationary, and workers, materials,
and equipment are moved as needed.
Nature of the product dictates this type of
layout
Weight
Size
Bulk
Large construction projects
LO 4
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18
Design Product Layouts: Line Balancing
process of assigning tasks to workstations
so that the workstations have
approximately equal time requirements.
LO 4
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19
Line Balancing Procedure
Draw and label a
PRECEDENCE
DIAGRAM
Acceptable
efficiency?
Repeat if NO
LO 4
Calculate DESIRED
CYCLE TIME
required for line
Calculate
EFFICIENCY of Line
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Calculate theoretical
MINIMUM NUMBER
OF
WORKSTATIONS
GROUP Elements
into Workstations
• Cycle Time and
Precedence
CONSTRAINTS
20
Cycle Time
Cycle time is the maximum time
allowed at each workstation to
complete its set of tasks on a unit.
LO 5
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21
Line Balancing Formulas
OT
Output capacity 
CT
OT  operating time per day
CT  cycle time
N min
N min
OT
CT 
D
D  desired output rate
t


CT
 Theoretica l minimum number of work stations
 t  sum of the task time s
LO 5
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22
Precedence Diagram
Tool used in line balancing to display
elemental tasks and sequence requirements
0.1 min.
1.0 min.
a
b
c
0.7 min.
LO 5
A Simple Precedence
Diagram
d
0.5 min.
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e
0.2 min.
23
Example 1: Assembly Line Balancing
Arrange tasks into three workstations.
 Use
a cycle time of 1.0 minute
 Assign tasks in order of the most number of
followers
0.1 min.
1.0 min.
a
b
c
0.7 min.
LO 5
d
0.5
min.
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e
0.2 min.
24
Example 1 Solution
Eligible
Revised
Assign Time
Task
Remaining
1.0
0.9
0.2
a, c
c
none
a
c
-
0.9
0.2
2
1.0
b
b
0.0
3
1.0
0.5
0.3
d
e
-
d
e
-
0.5
0.3
Time
Workstation Remaining
1
0.1 min.
a
c
0.7 min.
LO 5
Station
Idle Time
0.2
0.0
0.3
0.5
1.0 min.
b
d
0.5
min.
e
0.2 min.
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25
Line Balancing Rules
Some Heuristic (intuitive) Rules:
Assign the task with longest time
Assign the task with the most followers
Percentage of idle time 
 Idle time
N actual  Cycle time
100
Efficiency  100 - Percentage of idle time
LO 5
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26
Example 1 Solution
 Idle time
0.5
% of idle time 
 100 
 100  16.7%
N actual  Cycle time
3  1.0
efficiency  100%  16.7%  83.3%
WS 1
0.1 min.
a
WS 2
1.0 min.
b
WS 3
c
0.7 min.
LO 5
d
0.5 min.
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e
0.2 min.
27
Example 2
0.2
0.1
0.3
a
b
e
0.8
0.6
c
d
f
g
h
1.0
0.4
0.3
Arrange tasks into four workstations.
 Use
a cycle time of 1.0 minute
 Assign tasks in order of the most number of
followers (then longest time)
LO 5
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28
Solution to Example 2
Station 1
Station 2
b
a
Station 3
e
f
c
LO 5
Station 4
g
h
d
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29
Variable Task Times: Solutions
Reduce
variability
Use buffer
inventory
between
work
stations
Leave some
idle time in
workstations
which have
random
times
Use parallel
work
stations
design the
jobs better
use higher
quality
material,
do preventive
maintenance
LO 5
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30
Bottleneck Workstation
1 min.
30/hr.
1 min.
30/hr.
2 min.
30/hr.
1 min.
30/hr.
Bottleneck
30/hr.
1 min.
60/hr.
2 min.
30/hr.
1 min.
1 min.
60/hr.
30/hr.
2 min.
30/hr.
Parallel Workstations
LO 5
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31
Treatment of Bottlenecks
LO 5
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32
Process (Functional) Layout Design
 Arrange work centers so as to minimize
transportation cost, distance or time
 Difficult to optimize
 General rule:
 Locate departments
with high interdepartmental flow
as close as possible
LO 4
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33
Designing Process (Functional) Layouts
Information Requirements:
1. List of departments
2. Projection of work flows
3. Distance between locations
 cost per unit of distance to move loads
4. List of special considerations
 Location of entrances, elevators
 Need to be close (or far) from others
 Reinforced flooring, room dimensions, etc
LO 6
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34
Designing Process Layouts
Tools
LO 4
Block
Diagramming
QUANTITATIVE
Minimize Non-Adjacent Loads
Relationship
Diagramming
NON-QUANTITATIVE
Based on Intuitive Preferences
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35
Example: Process Layout Design
Distance between locations (metres)
From
A
B
C
Location
To
A
—
20
40
B
20
—
30
C
40
30
—
Loads between departments (per day)
From
1
2
3
LO 6
Department
To
1
—
20
90
2
10
—
70
3
80
30
—
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36
Example: Interdepartmental Work Flows
for Assigned Departments
30
170
1
A
10
0
3
B
C
From/To
Loads
Distance
Loads X Distance
1-2
10
40
400
1-3
80
20
1,600
2-1
20
40
800
2-3
30
30
900
3-1
90
20
1,800
3-2
70
30
2,100
Total
LO 6
2
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7,600
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Closeness ratings - Muther Grid
 Muther suggests the following list of reasons for closeness:
1. Use same equipment or facilities
2. Share the same personnel
3. Sequence of work flow
4. Ease of communication
5. Unsafe or unpleasant conditions
6. Similar work performed
LO 6
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38
Learning Checklist
 Process
 Discuss considerations for make or buy decisions
 Compare intermittent vs. repetitive processes
 Discuss issues in automation
 Describe the steps in production process design
 Be able to draw a process flow diagram
 Facility Layout
 List the different types and key considerations in each
 Describe advantages/disadvantages of product,
process and cellular layouts
 Create a precedence diagram, calculate cycle time,
idle time and efficiency, balance a line
 Use tools to create a process layout
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39