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1
CHAPTER 7
Design for Quality and Product Excellence
Teaching Notes
The precise manner in which a person or team approaches product design, solving problems to
achieve product excellence, or developing product reliability is not as critical as doing it in a
systematic fashion. Students have been exposed to process management and improvement in
Chapter 7, but they may still have some difficulty in understanding how measurement
(metrology) and Six Sigma projects can be used at the design stage to make frequent, but gradual
changes as an approach to process improvement.
Key objectives for this chapter should include:
• To explore the typical structured product development process consisting of idea
generation, preliminary concept development, product/process development, full-scale
production, product introduction, and market evaluation.
• To learn that concurrent, or simultaneous, engineering is an effective approach for
Design for Quality and Product Excellence 2
• To appreciate the concepts of innovation and creativity. Innovation involves the
adoption of an idea, process, technology, product, or business model that is either new or
new to its proposed application. Creativity is seeing things in new or novel ways. Many
creativity tools are designed to help change the context in which one views a problem or
opportunity, thereby leading to fresh perspectives.
• To explore Quality Function Deployment (QFD) -- a planning process to guide the
design, manufacturing, and marketing of goods by integrating the voice of the customer
throughout the organization. A set of matrices, often called the House of Quality, is used
to relate the voice of the customer to a product’s technical requirements, component
requirements, process control plans, and manufacturing operations.
• To investigate manufacturing specifications, consisting of nominal dimensions and
tolerances. Nominal refers to the ideal dimension or the target value that manufacturing
seeks to meet; tolerance is the permissible variation, recognizing the difficulty of
meeting a target consistently.
• Tolerance design involves determining the permissible variation in a dimension. A
scientific approach to tolerance design uses the Taguchi loss function. Taguchi assumes
• To understand why reliability is often modeled using an exponential probability
distribution and use the reliability function, specifying the probability of survival, which
is: R(T) = 1 – e-T.
• To explore systems composed of individual components with known reliabilities,
configured in series, in parallel, or in some mixed combination, and how it ties into
Design for Quality and Product Excellence 3
formal reliability evaluation, using techniques such as accelerated life testing and burn-
in.
• To examine the characteristics of Design Failure Mode And Effects Analysis
(DFMEA) -- a methodology to identify all the ways in which a failure can occur, to
estimate the effect and seriousness of the failure, and to recommend corrective design
actions.
• Fault Tree Analysis (FTA), sometimes called cause and effect tree analysis, is a
method to describe combinations of conditions or events that can lead to a failure. In
effect, it is a way to drill down and identify causes associated with failures and is a good
complement to DFMEA.
• To investigate good product design, which anticipates issues related to cost,
manufacturability, and quality. Improvements in cost and quality often result from
simplifying designs, and employing techniques such as design for manufacturability
(DFM) – the process of designing a product for efficient production at the highest level
of quality.
• To study social responsibilities in the design process including product safety and
environmental concerns, which have made Design for Environment (DfE) and design
for disassembly important features of products, because they permit easy removal of
components for recycling or repair, eliminate other environmental hazards, and makes
repair more affordable.
• To explore Design for Excellence (DFX), an emerging concept that includes many
design-related initiatives such as concurrent engineering, design for manufacturability
design for assembly, design for environment and other “design for” approaches. DFX
• To introduce concept engineering (CE) -- a focused process for discovering customer
requirements and using them to select superior product or service concepts that meet
those requirements.
• To appreciate that the purpose of a design review is to stimulate discussion, raise
questions, and generate new ideas and solutions to help designers anticipate problems
before they occur.
Design for Quality and Product Excellence 4
• To appreciate that Six Sigma performance depends on reliable measurement systems.
ANSWERS TO QUALITY IN PRACTICE KEY ISSUES
Testing Audio Components at Shure, Inc.
1. The general definition of reliability as: the probability that a product, piece of equipment,
or system performs its intended function for a stated period of time under specified
operating conditions, is thoroughly tested by Shure. Tests are tailored to various market
segments, according to the type of use (or abuse) the equipment is likely to incur. For the
consumer market, Shure uses the cartridge drop and scrape test, which is particularly
2. For the microphone drop test, the measures are probably variable measures of sound and
response levels, within an acceptable range. Thus, standard variables control charts may
be used. For the perspiration test, it may be that a p-chart or u-chart is used for attribute
measures. The cable and cable assembly flex test might use a p-chart to measure the
Applying QFD in a Managed Care Organization
1. Although this example of QFD involved the design of a tangible items, it is more difficult
to implement in a service context, as opposed to a pure manufacturing context, because
Design for Quality and Product Excellence 5
both customer requirements and technical requirements are harder to quantify and assess
that with tangible products.
2. The detailed calculations in the Importance of the hows row and Percentage of
importance of the hows row used to arrive at these figures can be shown and verified on
the spreadsheet labelled QIP-QFD Healthcare.xlsx. Note that some discrepancies
involving incorrect multiplication, were found in part of the QFD “House of Quality.”
Design for Quality and Product Excellence 6
Direction of
Rate of
Co.
Rate of
Absol.
%
Font
Use of
Gloss.
Q&A
Tbl. of
Lang.
Improvement
Import.
Now
Plan
Improv.
Wgt.
Improve
size
Update
Photos
colors
Terms
Sect.
Contnt.
Frindly.
Ease-use
4.5
3.2
4.5
1.4
6.3
25.2%
3
1
3
3
9
3
9
3
Design for Quality and Product Excellence 7
3. The lessons that can be learned and applied to other service organizations that seek to
design or redesign their products and services include the facts that QFD provides for a
ANSWERS TO REVIEW QUESTIONS
1. Product design and development consists of six steps:
• Idea Generation. New or redesigned product ideas should incorporate customer
needs and expectations.
• Preliminary Concept Development. In this phase, new ideas are studied for
feasibility.
• Product/Process Development. If an idea survives the concept stage, the actual
design process begins by evaluating design alternatives and determining
2. Competitive pressures are forcing companies to reduce time to market, which means that
the time for product development is also squeezed. The problems incurred in speeding up
the process are well known. If done too hastily, the result will be the need to revise or
scrap the design, cost increases or project over-runs, difficulty in manufacturing the
3. Concurrent engineering is a process in which all major functions involved with bringing a
product to market are continuously involved with product development from conception
Design for Quality and Product Excellence 8
functions of such teams are to perform and coordinate the activities in the product
development process simultaneously, rather than sequentially. Companies exploit
4. Design for Six Sigma (DFSS) uses a set of tools and methodologies in the product
development process to ensure that goods and services will meet customer needs and
achieve performance objectives, and that the processes used to make and deliver them
achieve Six Sigma capability. DFSS consists of four principal activities:
5. Concept development is the process of applying scientific, engineering, and business
knowledge to produce a basic functional design that meets both customer needs and
manufacturing or service delivery requirements. Developing new concepts requires
innovation and creativity.
Innovation involves the adoption of an idea, process, technology, product, or business
model that is either new or new to its proposed application. The outcome of innovation is
a discontinuous or breakthrough change and results in new and unique goods and services
that delight customers and create competitive advantage.
Innovations can be classified as:
1. An entirely new category of product; for example the iPod
2. First of its type on the market in a product category already in existence; for
Design for Quality and Product Excellence 9
6. Conceptual designs must be translated into measurable technical requirements and,
subsequently, into detailed design specifications. Detailed design focuses on establishing
7. QFD benefits companies through improved communication and teamwork between all
constituencies in the production process, such as between marketing and design, between
design and manufacturing, and between purchasing and suppliers. Product objectives are
8. In the QFD development process, a set of matrices is used to relate the voice of the
customer to a product’s technical requirements, component requirements, process control
plans, and manufacturing operations. The first matrix, called the House of Quality,
provides the basis for the QFD concept.
Building the House of Quality consists of six basic steps:
* Identify customer requirements.
Design for Quality and Product Excellence 10
9. Manufacturing specifications consist of nominal dimensions and tolerances. Nominal
refers to the ideal dimension or the target value that manufacturing seeks to meet;
tolerance is the permissible variation, recognizing the difficulty of meeting a target
10. The Taguchi loss function is a useful concept for process design. Taguchi suggests that
there is not strict cut-off point that divides good quality from poor quality. Rather, he
assumed that losses can be approximated by a quadratic function so that larger deviations
11. Reliability is the probability that a product, piece of equipment, or system performs its
intended function for a stated period of time under specified operating conditions. There are
four key components of this definition, including probability, time, performance, and
12. A functional failure is one incurred at the start of the product's life due to defective
materials, components, or work on the product. A reliability failure is one that is incurred
after some period of use. For example, if a new TV set suffers a blown picture tube during
Design for Quality and Product Excellence 11
13. Reliability engineers distinguish between inherent reliability, which is the predicted
reliability determined by the design of the product or process, and the achieved
14. Failure rate is defined as the number of failures per unit of time during a specified time
15. The product life characteristics curve, is the so-called "bath-tub curve" because of its shape.
the distinctive failure rate patterns of various designs and products, over time.
16. The reliability function represents the probability that an item will not fail within a certain
period of time, T. It is directly related to the cumulative distribution function: F(T) =
17. The reliability of series, parallel, and series parallel is relatively easy to compute, given the
reliability of components in each system. For the series system, RS = R1R2R3. Thus
reliabilities are multiplicative.
For a parallel system, the relationships are a little more complex, since the units are designed
18. Robust design refers to designing goods and services that are insensitive to variation in
manufacturing processes and when consumers use them. Robust design is facilitated by
Design for Quality and Product Excellence 12
19. The purpose of Design Failure Mode and Effects Analysis (DFMEA) is to identify all the
ways in which a failure can occur, to estimate the effect and seriousness of the failure,
and to recommend corrective design actions. A DFMEA usually consists of specifying
20. Fault Tree Analysis (FTA), sometimes called cause and effect tree analysis, is a method
to describe combinations of conditions or events that can lead to a failure. In effect, it is
21. Product design can have a major impact on manufacturability. If careful thought and
planning is not done by the designer (or design team), the end product can end up being
22. Key design practices for high quality in manufacturing and assembly include: 1) analyze all
design requirements to assess proper dimensions and tolerances, 2) determine process , 3)
23. Social responsibilities in the design process include safety and environmental concerns,
which have made Design for Environment (DFE) and Design for Disassembly important
Design for Quality and Product Excellence 13
24. Design for Excellence (DFX) is an emerging concept that includes many design-related
initiatives such as concurrent engineering, design for manufacturability design for
assembly, design for environment and other “design for” approaches. DFX objectives
include higher functional performance, physical performance, user friendliness, reliability
25. The purpose of a design review is to stimulate discussion, raise questions, and generate
new ideas and solutions to help designers anticipate problems before they occur. To
facilitate product development, a design review is generally conducted in three major
stages of the product development process: preliminary, intermediate, and final. The
Design for Quality and Product Excellence 14
26. Methods of product testing for reliability include: life testing, accelerated life testing,
SOLUTIONS TO PROBLEMS
Note: Data sets for several problems in this chapter are available in the Excel workbook
C07Data on the Student Companion Site for this chapter accompanying this text. Click on the
appropriate worksheet tab as noted in the problem (e.g., Prob. 7-5) to access the data.
1. A hospital developed a design process consisting of the following steps: Plan, Design,
Measure, Assess, and Improve. Below is a list of specific activities that comprise these five
steps in random order. Place the activities in the most appropriate order within the correct
step of the design process.
Pilot or test design
Submit proposal
Define measures to assess design performance
Implement design
Identify potential solutions to reduce out of control conditions
Develop business plan
Disseminate improvements throughout the organization
Monitor process performance
Select the best solution to improve control
Identify out of control conditions
Propose new concept
Create design to meet requirements
Identify new improvement opportunities
Monitor the new process design
Implement the best solution to improve control
Verify proposal alignment with strategic objectives
Establish design team
Identify causes of out of control conditions
Analyze causes
Identify and validate customer requirements
Identify and evaluate best practices
Answer
1. Although the terms might vary slightly, the following model captures the stages of the
design process for the hospital:
Design for Quality and Product Excellence 15
2. Newfonia, Inc., is working on a design for a new smartphone. Marketing staff conducted
extensive surveys and focus groups with potential customers to determine the
characteristics that the customers want and expect in a smartphone. Newfonia’s studies
have identified the most important customer expectations as
• Initial cost
• Reliability
• Ease of use
• Features
• Operating cost
• Compactness
Develop a set of technical requirements to incorporate into the design of a House of
Quality relationship matrix to assess how well your requirements address these
expectations. Refine your design as necessary, based upon the initial assessment.
Answer
2. Analysis of customer responses for Newfonia’s proposed smartphone indicates the
likelihood of several strong relationships between customer requirements and associated
technical requirements of the design, such as value vs. price; features vs. compactness; and
Design for Quality and Product Excellence 16
3. Newfonia, Inc. (Problem 2), faces three major competitors in this market: Oldphonia,
Simphonia, and Colliefonia. It found that potential consumers placed the highest
importance on reliability (measured by such things as freedom from operating system
crashes and battery life), followed by compactness (weight/bulkiness), followed by
flexibility (features, ease of use, and types of program modules available). The operating
cost was only occasionally noted as an important attribute in the surveys. Studies of their
products yielded the information shown in the table in C07Data file for Prob.7-3on the
Student Companion Site for this chapter. Results of the consumer panel ratings for these
competitors are also shown in that spreadsheet. Using this information, modify and
extend your House of Quality from Problem 1 and develop a deployment plan for the
new smartphone. On what attributes should the company focus its marketing efforts?
Answer
3. With the new data given for Newfonia’s potential customers, a partial House of Quality
for the design of the smartphone can be built, as shown below. Note the strong
PARTIAL HOUSE OF QUALITY MATRIX
FOR NEWPHONIA’S SMARTPHONE CASE
Cost
Size
(in.)
Wt.
(oz.)
Featr.
(num.)
Opr.P
rog.
Bat.
Life
Opr.
Cost
Importan
ce
12 3 45
Compet
Eval.
12 3 45
Selling
Pts.
1 2 3 4
5
Reliable
Keeps
operating
•
x
G S H
*
Compact
Fits
pocket
•
x
GSH
Design for Quality and Product Excellence 17
4. Georgio’s Giant Gyros conducted consumer surveys and focus groups concerning a new
giant gyro sandwich design, and the facility to sell it, and identified the most important
customer expectations (not in any order of priority) as
• Tasty, attractive, moderately healthy food
• Speedy service
• An easy-to-read menu board
• Accurate order filling
• Perceived value
Develop only a set of technical requirements to incorporate into the design of the product
and its delivery. Use a House of Quality relationship matrix to assess how well your
requirements address these expectations. Include some technical dimensions that may be
used to measure tasty, attractive, and “healthy” food; speedy service, acceptable menu
boards, order accuracy, or perceived value. Refine your design as necessary based upon
the initial assessment.
Answer
4. Analysis of customer responses for Georgio’s Giant Gyros indicates that there are likely to
be several strong relationships between customer requirements and associated technical
Design for Quality and Product Excellence 18
PARTIAL HOUSE OF QUALITY MATRIX
FOR GEORGIO’S GIANT GYROS
Price
Size
Calories
Sodium
% t-Fat
Facility
layout
Work
procedures
Imprtnce
12 3 45
Compet.
Eval.
12 3 4 5
Selling
Pts.
1 2 3 4 5
Taste
Moistness
•
• = Very strong relationship
= Strong relationship
= Weak relationship
Design for Quality and Product Excellence 19
5. Georgio’s Giant Gyros (Problem 4) acquired some additional information about product
characteristics. It found that consumers placed the highest importance on taste appeal
(especially flavor) and order accuracy, followed by healthy food (measured by sodium
content and calories), value, and service. The menu board was only casually noted as one
of the least important attributes in the surveys. Georgio faces three major competitors in
this market: Mario’s, Gyroking, and Antonio’s. Studies of their products yielded the
information shown in the worksheet tab Prob.7-4 in the Excel file C07Data on the
Student Companion Site for this chapter. Results of the consumer panel ratings for each
of these competitors can also be found there (a 1–5 scale, with 5 being the best). Using
this information, modify and extend your House of Quality from Problem 2 and develop
a deployment plan for a new gyro. Assume that a separate study will be made on the
physical facilities. On what attributes should the company focus its marketing efforts?
Answer
5. With the new data given in C07Data.xlsx for Prob. 7-05 for Georgio's customers, a partial
Design for Quality and Product Excellence 20
PARTIAL HOUSE OF QUALITY MATRIX
FOR GEORGIO’S GIANT GYROS
Price
Size
Calories
Sodium
% t-Fat
Facility
layout
Work
procedures
Imprtnce
12 3 45
Compet.
Eval.
12 3 4 5
Selling
Pts.
1 2 3 4 5
Taste
Moistness
•
A GK
G A K
Kitchen
capacity
•
•
AKG
A G K
*
Menu
Size & font
•
A K G
A KG
