Slides prepared
by John Loucks
ã 2002 South-Western/Thomson Learning TM
11
Chapter 5, Part B
Facility Layout:
Manufacturing and Services
2
Overview
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Facility Layout
Manufacturing Facility Layouts
Analyzing Manufacturing Facility Layouts
Service Facility Layouts
Wrap-Up: What World-Class Companies Do
3
Facility Layout
Facility layout means planning:
for the location of all machines, utilities, employee
workstations, customer service areas, material
storage areas, aisles, restrooms, lunchrooms,
internal walls, offices, and computer rooms
for the flow patterns of materials and people
around, into, and within buildings
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4
Locate All Areas In and Around Buildings
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Equipment
Work stations
Material storage
Rest/break areas
Utilities
Eating areas
Aisles
Offices
5
Characteristics of the Facility Layout Decision
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Location of these various areas impacts the flow
through the system.
The layout can affect productivity and costs generated
by the system.
Layout alternatives are limited by
the amount and type of space required for the
various areas
the amount and type of space available
the operations strategy
. . . more
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6
Characteristics of the Facility Layout Decision
Layout decisions tend to be:
Infrequent
Expensive to implement
Studied and evaluated extensively
Long-term commitments
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7
Manufacturing Facility Layouts
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Materials Handling
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The central focus of most manufacturing layouts is to
minimize the cost of processing, transporting, and
storing materials throughout the production system.
Materials used in manufacturing include:
Raw material
Purchased components
Work-in-progress
Finished goods
Packaging material
Maintenance, repair, and operating supplies
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9
Materials Handling
A materials-handling system is the entire network of
transportation that:
Receives material
Stores material in inventories
Moves material between processing points
Deposits the finished products into vehicles for
delivery to customers
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10
Materials Handling
Material-Handling Principles
Move directly (no zigzagging/backtracking)
Minimize human effort required
Move heavy/bulky items the shortest distances
Minimize number of times same item is moved
MH systems should be flexible
Mobile equipment should carry full loads
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Materials Handling
Material-Handling Equipment
Automatic transfer devices
Containers/pallets/hand carts
Conveyors
Cranes
Elevators
Pipelines
Turntables
AGVS
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12
Basic Layout Forms
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Process
Product
Cellular
Fixed-Position
Hybrid
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Process (Job Shop) Layouts
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Equipment that perform similar processes are
grouped together
Used when the operations system must handle a wide
variety of products in relatively small volumes (i.e.,
flexibility is necessary)
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Characteristics of Process Layouts
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General-purpose equipment is used
Changeover is rapid
Material flow is intermittent
Material handling equipment is flexible
Operators are highly skilled
. . . more
15
Characteristics of Process Layouts
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Technical supervision is required
Planning, scheduling and controlling functions are
challenging
Production time is relatively long
In-process inventory is relatively high
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Product (Assembly Line) Layouts
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Operations are arranged in the sequence required to
make the product
Used when the operations system must handle a
narrow variety of products in relatively high volumes
Operations and personnel are dedicated to producing
one or a small number of products
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Characteristics of Product Layouts
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Special-purpose equipment are used
Changeover is expensive and lengthy
Material flow approaches continuous
Material handling equipment is fixed
Operators need not be as skilled
. . . more
18
Characteristics of Product Layouts
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Little direct supervision is required
Planning, scheduling and controlling functions are
relatively straight-forward
Production time for a unit is relatively short
In-process inventory is relatively low
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Cellular Manufacturing Layouts
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Operations required to produce a particular family
(group) of parts are arranged in the sequence required
to make that family
Used when the operations system must handle a
moderate variety of products in moderate volumes
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Characteristics of Cellular Manufacturing
Relative to Process Layouts
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Equipment can be less general-purpose
Material handling costs are reduced
Training periods for operators are shortened
In-process inventory is lower
Parts can be made faster and shipped more quickly
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Characteristics of Cellular Manufacturing
Relative to Product Layouts
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Equipment can be less special-purpose
Changeovers are simplified
Production is easier to automate
22
Fixed-Position Layouts
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Product remains in a fixed position, and the
personnel, material and equipment come to it
Used when the product is very bulky, large, heavy or
fragile
23
Hybrid Layouts
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Actually, most manufacturing facilities use a
combination of layout types.
An example of a hybrid layout is where departments
are arranged according to the types of processes but
the products flow through on a product layout.
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New Trends in Manufacturing Layouts
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Designed for quality
Designed for flexibility - to quickly shift to different
product models or to different production rates
Cellular layout within larger process layouts
Automated material handling
U-shaped production lines
. . . more
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New Trends in Manufacturing Layouts
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More open work areas with fewer walls, partitions, or
other obstacles
Smaller and more compact factory layouts
Less space provided for storage of inventories
throughout the layout
26
Planning Manufacturing Facility Layouts
Two Categories of Software Tools
 Computer aided design (CAD)
Allows 3-D, full-color views of facility design
Allows virtual walk-throughs
Ex. – ArchiCAD, AutoSketch, AutoCAD
 Computer simulation
Can simulate proposed system layout in operation
and measure its performance
Ex. – ProModel, VisFactory, SIMPROCESS
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Planning Manufacturing Facility Layouts
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Process and Warehouse Layouts
Product Layouts
Cellular Manufacturing Layouts
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Planning Manufacturing Facility Layouts
Process Layouts
Primary focus is on the efficient flow of materials
The wide variety of potential product routings
through the facility can be evaluated using
computer simulation
 Warehouse Layouts
Primary focus is the fast storage and retrieval of
inventory items
Decisions about aisle size/placement and location
of each inventory item can be evaluated using
computer simulation
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Planning Manufacturing Facility Layouts
Product Layouts
 Primary focus is on the analysis of production lines
 The goal of the production line analysis is to:
Determine how many workstations to have
Determine which tasks to assign to which
workstation
Minimize the number of workers & machines used
Provide the required amount of capacity
 Line balancing is a key part of the analysis
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Planning Product Layouts
Line Balancing Procedure
1. Determine the tasks involved in completing 1 unit
2. Determine the order in which tasks must be done
3. Draw a precedence diagram
4. Estimate task times
5. Calculate the cycle time
6. Calculate the minimum number of workstations
7. Use a heuristic to assign tasks to workstations
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Planning Product Layouts
Line Balancing Heuristics
 Heuristic methods, based on simple rules, have been
developed to provide good (not optimal) solutions to
line balancing problems
 Heuristic methods include:
Incremental utilization (IU) method
Longest-task-time (LTT) method
… and many others
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Planning Product Layouts
Incremental Utilization Method
 Add tasks to a workstation in order of task
precedence one at a time until utilization is 100% or
is observed to fall
 Then the above procedure is repeated at the next
workstation for the remaining tasks
 Pro – Appropriate when one or more task times is
equal to or greater than the cycle time
 Con – Might create the need for extra equipment
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Planning Product Layouts
Longest-Task-Time Method
 Adds tasks to a workstation one at a time in the order
of task precedence.
 If two or more tasks tie for order of precedence, the
one with the longest task time is added
 Conditions for its use:
No task time can be greater than the cycle time
There can be no duplicate workstations
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Example: Armstrong Pumps
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Line Balancing
Armstrong produces bicycle tire pumps on a
production line. The time to perform the 6 tasks in
producing a pump and their immediate predecessor
tasks are shown on the next slide.
Ten pumps per hour must be produced and 45
minutes per hour are productive.
Use the incremental utilization heuristic to
combine the tasks into workstations in order to
minimize idle time.
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Example: Armstrong Pumps
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Line Balancing
Task
A
B
C
D
E
F
Tasks that
Immediately
Precede
-A
-B,C
D
E
Time to
Perform
Task (min.)
5.4
3.2
1.5
2.8
17.1
12.8
Total = 42.8
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Example: Armstrong Pumps
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Line Balancing – Network (Precedence) Diagram
A
B
D
E
F
C
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Example: Armstrong Pumps
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Line Balancing – Cycle Time
Productive Time per Hour
Cycle Time =
Demand per Hour
= 45/10 = 4.5 minutes per pump
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Example: Armstrong Pumps
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Line Balancing – Minimum Number of Workstations
Minimum
(Total Task Time)(Demand per Hour)
Number of =
Productive Time per Hour
Workstations
= [(42.8)(10)]/45 = 9.51 workstations
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Example: Armstrong Pumps
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Line Balancing – Incremental Utilization Heuristic
WS Tasks Mins./pump
#WS’s
Incr.Util.
1
A
5.4
5.4/4.5=1.2= 2
60.0%
1
A,B
5.4 + 3.2
8.6/4.5=1.9= 2
95.0%
1
A,B,C 8.6 + 1.5
10.1/4.5=2.2= 3
49.8%
2
C
1.5
1.5/4.5=.33= 1 33.3%
2
C,D
1.5 + 2.8
4.3/4.5=.96= 1
95.6%
2
C,D,E 4.3 + 17.1 21.4/4.5=4.8= 5
95.1%
3
E
17.1
17.1/4.5=3.8= 4
95.0%
3
E,F
17.1 + 12.8 29.9/4.5=6.6= 7
94.9%
4
F
12.8
12.8/4.5=2.8= 3
94.8%
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Example: Armstrong Pumps
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Line Balancing – Utilization of Production Line
Minimum Number of Workstations
Utilization =
Actual Number of Workstations
= 9.51/10 = .951 = 95.1%
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Planning Product Layouts
Rebalancing a Production Line
 Changes that can lead to production lines being out of
balance or having insufficient/excess capacity are:
Changes in demand
Machine modifications
Variations in employee learning and training
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Planning Cellular Manufacturing Layouts
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Cell Formation Decision
Which machines are assigned to manufacturing
cells
Which parts will be produced in each cell
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Planning Cellular Manufacturing Layouts
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Fundamental Requirements for Parts to be Made in
Cells
Demand for the parts must be high enough and
stable enough that moderate batch sizes of the
parts can be produced periodically.
Parts must be capable of being grouped into parts
families.
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Planning Cellular Manufacturing Layouts
More-Complex Issues to be Resolved
 If all the parts cannot be cleanly divided between
cells, how will we decide which are to be the
exceptional parts?
 If inadequate capacity is available to produce all the
parts in cells, which parts should be made outside the
cells?
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Planning Cellular Manufacturing Layouts
Cell Formation Procedure
1. Form the Parts-Machines Matrix.
2. Rearrange the Rows.
Place the machines that produce the same parts in
adjacent rows.
3. Rearrange the Columns.
Place the parts requiring the same machines in
adjacent columns.
4. Use the rearranged parts-machines matrix to identify
cells, the machines for that cell and the parts that will
be produced in that cell.
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Example: Maxx Superchargers
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Cell Formulation
Maxx produces superchargers for high
performance cars and trucks. Maxx has implemented
a group technology program in its shop and now must
formulate the manufacturing cells. Maxx has
identified six parts that meet the requirements for
CM.
The parts-machines matrix on the next slide
identifies the 6 parts and 5 machines on which the
parts are presently produced.
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Example: Maxx Superchargers
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Cell Formulation – Original Matrix
Parts
Machines
A
B
C
D
E
1
2
X
X
X
X
X
3
X
4
X
5
X
X
6
X
X
X
X
X
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Example: Maxx Superchargers
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Cell Formulation – Rows Rearranged
Parts
Machines
A
E
D
C
B
1
2
X
X
X
X
X
3
X
X
4
5
X
X
6
X
X
X
X
X
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Example: Maxx Superchargers
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Cell Formulation – Columns Rearranged
Parts
Machines
A
E
D
C
B
3
X
X
5
X
X
6*
X
X
X
1
2
4
X
X
X
X
X
X
X
* exceptional part
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Example: Maxx Superchargers
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Cell Formulation – Summary
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2 manufacturing cells (MC1, MC2) will be used.
Parts 3 and 5 will be produced in MC1 on
machines A and E.
Parts 1, 2 and 4 will be produced in MC2 on
machines B, C and D.
Part 6 is an exceptional part that cannot be
produced within a single cell.
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Service Facility Layouts
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Characteristics of Services
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There may be a diversity of services provided
There are three dimensions to the type of service:
Standard or custom design
Amount of customer contact
Mix of physical goods and intangible services
There are three types of service operations:
Quasi manufacturing
Customer-as-participant
Customer-as-product
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Characteristics of Service Facility Layouts
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The encounter between the customer and the service
must be provided for.
The degree to which customer-related features must
be provided varies with the amount of customer
involvement and customer contact.
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Planning Service Facility Layouts
Quasi-Manufacturing Services
Several topics previously discussed under
Manufacturing Layouts are relevant here:
Principles of material handling
CAD and simulation software
Line balancing
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Planning Service Facility Layouts
Customer-as-Participant & Customer-as-Product
An important element is providing for customer
waiting lines
Amount of space needed for service counters
and waiting customers
Placement of waiting lines in overall layout
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Planning Service Facility Layouts
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For many service operations, layouts are like process
layouts in manufacturing
The departments of hospitals are grouped and located
according to their processes
In some cases, closeness ratings are used to reflect the
desirability of having one department near another
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Using Closeness Ratings
to Develop Service Facility Layouts
Start
Let m = 1 and n = 6.
Step 1
Identify dept. pairs with CR of m.
Step 2
Develop layout with dept. pairs idenStep 3
tified in Step 2 adjacent to one another.
Let m = m + 1
and n = n - 1.
No
Does
m = 3 and n = 4
?
Yes
Stop
Identify dept. pairs with CR of n.
Step 4
Fit the dept. pairs identified in Step 4
into the trial layout from Step 3.
Step 5
Examine the trial layout from Step 5.
If any CRs of dept. pairs are violated,
rearrange depts. to comply with CRs.
Step 6
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Using Closeness Ratings
to Develop Service Facility Layouts
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Typical Closeness Ratings
Closeness
Rating
1
2
3
4
5
6
Meaning
of Rating
Necessary
Very Important
Important
Slightly Important
Unimportant
Undesirable
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Example: AG Advertising
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Using Closeness Ratings
AG Advertising is moving into a new office suite
having seven large, roughly equal size rooms, one for
each department of the firm. Lisa, the manager, must
now assign each department to a room. She has
developed a grid of closeness ratings (on the next
slide) for the 21 unique pairs of departments.
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Example: AG Advertising
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Closeness Ratings Grid
Dept. A
Dept. B
Dept. C
Dept. D
Dept. E
Dept. F
Dept. G
5
6
4
4
2
2
1
4
5
3
6
3
5
2
1
1
4
3
6
2
3
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Example: AG Advertising
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Unassigned Rooms of Office Suite
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Example: AG Advertising
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Layout Satisfying All Pairings of
Departments with 1 Closeness Ratings
CR = 1
B–D
B–F
C–G
B
D
F
C
G
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Example: AG Advertising
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Trying to satisfying all pairings of departments with
6 closeness ratings, we see that Dept. C needs to be
moved.
CR = 1
B–D
B–F
C–G
B
F
D
G
C
CR = 6
A–D
B–C
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Example: AG Advertising
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Layout Satisfying All Pairings of Departments with 6
Closeness Ratings (note that we swapped Dept. D and
Dept. F)
CR = 1
B–D
B–F
C–G
B
F
A
D
E
G
C
CR = 6
A–D
B–C
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Wrap-Up: World-Class Practice
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Strive for flexibility in layouts
Multi-job training of workers
Sophisticated preventive-maintenance programs
Flexible machines
Empowered workers trained in problem solving
Layouts small and compact
Services follow the above practices plus incorporate
customer needs in design
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End of Chapter 5, Part B
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