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Educating Engineers about Product Design Methodology

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A successful product designer must combine natural creativity with the systematic use of structured design methodology and modern computer-aided design tools. Practice without proper instruction and formal guidance fails to recognize the vast knowledge of the design process developed by successful professionals. However, designing a product solely by theory without the experience derived from practice is ineffecti ve because many subtleties and exceptions are learned by working on actual design project. In this paper, the authors discuss how formal lectures on product design and development methodology can be effectively combined with a hands-on design project leading to viable solutions by novice engineering students to open-ended problems.
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Educating Engineers about Product Design Methodology
Paul M. Kurowski
Department of Mechanical & Materials
Engineering
Faculty of Engineering
The University of Western Ontario
pkurowski@eng.uwo.ca
George K. Knopf
Department of Mechanical & Materials
Engineering
Faculty of Engineering
The University of Western Ontario
gknopf@eng.uwo.ca
Abstract
A successful product designer must combine natural creativity with the systematic use of structured design
methodology and modern computer-aided design tools. Practice without proper instruction and formal guidance
fails to recognize the vast knowledge of the design process developed by successful professionals. However,
designing a product solely by theory without the experience derived from practice is ineffective because many
subtleties and exceptions are learned by working on actual design project. In this paper, the authors discuss how
formal lectures on product design and development methodology can be effectively combined with a hands-on
design project leading to viable solutions by novice engineering students to open-ended problems.
1. Introduction
In recent years a heated debate has raged amongst
instructors as to whether the goal of engineering
design education is to engage students in loosely
supervised projects or teach theory with established
methodologies [5][8][9][11][12]. Taken to the
extreme, both approaches to product design education
will lead to unsatisfactory results. Practice without
instructional guidance and formal structure fails to
recognize the vast knowledge developed by design
professionals over time and often leads to poor quality
solutions. Similarly, designing products by theory
without the experience derived from practice is
ineffective because many subtleties and exceptions are
learned by doing [4]. A successful designer must
combine natural creativity with the systematic use of
product design methods and tools [8].
Undergraduate students are abundantly creative
and continuously amaze us with their inventiveness.
Our challenge as University educators is not to make
our students more creative but to show them how to
use this creativity in a structured way to assure that
their solutions satisfy real customer requirements and
measurable engineering targets [8][11]. Engineering
design is always customer-driven design with a clear
need for the product or process. The goal of formal
procedures and implementing proven methods is to
provide the students with the means to document,
justify, and communicate their design decisions. The
course must both enhance the novice designer’s
creativity and ensure that the proposed design solution
will lead to a high-quality, competitive product. These
issues are introduced in the Mechanical and Materials
Engineering at the University of Western Ontario in a
compulsory second year course entitled Product
Design and Development.
To emphasize the relationship between theory and
practice this half-course combines extensive formal
lectures on product design methodology with an
intense hands-on product development project. The
student’s success in this course depends upon how
well he or she can justify critical design decisions and
demonstrate whether the proposed solution truly meets
the customers’ needs and requirements.
2. Course in Product Design and
Development
The primary goal of the undergraduate course in
Product Design and Development is to apply, analyze,
and evaluate a variety of techniques that enable
designers to develop high-quality products [8][12]. A
quality product must meet the customer’s
requirements, perform to specifications, be cost
effective, safe to operate, and have minimal negative
impact on the environment during production, use or
disposal. The formal design methods and the
application of supporting tools [1][2][3][6][7][10]
introduced in the lectures enable students to create the
documentation and communicate key design
decisions to the customer or client.
Designing a “quality product” for function, cost and
manufacturability involves a variety of tools and
structured techniques ensuring that all elements of the
product life-cycle from conception through to final
disposal are systematically addressed by the engineer
during the product design process. The role of the
engineering design process in the product life-cycle is
summarized in figure 1. Although the act of doing
design is restricted to the first three phases, critical
design issues arise from all six phases of the product’s
life-cycle [11].
Figure 1. The six phases of a product’s life-
cycle and the role of the design process
(dashed line box).
2.1 Course topics
The lectures in the second-year design course cover
design philosophy, methodology, and general problem
solving techniques. Students practice concurrent
engineering design methodologies by implementing
design techniques in a group project. Tutorial hours
associated with the courses are used primarily for
project planning, weekly assessment of design
notebooks, periodic review meetings focusing on the
product development file, and design team
presentations. Considerable effort is spent on the
design project outside the regular scheduled time. In
addition, a formal timeline for deliverables is enforced
in order to reinforce a professional work ethic.
The general topics covered by the course include
understanding the customer, establishing measurable
design specifications, preparing a realistic project
plan, generating and evaluating concepts, developing
the details for a viable solution, and demonstrating the
effectiveness of the proposed solution. Techniques
introduced in the lectures and utilized in the team-
based project include Quality Function Deployment
(QFD) [8][11][12], Gantt Charts, Critical Path Method
(CPM), Functional Decomposition, Morphological
Analysis, Decision Matrices, Design for Reliability
(DfR), Preliminary Hazard Analysis (PHA), Failure
Modes and Effects Analysis (FMEA), Design for
Assembly (DFA), Design for Disassembly, and
Design for Environment (DfE) guidelines. Computer-
aided engineering tools such as CAD, FEA, and
Motion Analysis are used to assist students in their
product design. Issues related to surveying customers,
product safety, risk assessment, and design for
reliability are also investigated.
Upon successful completion of the course our
students gain complete design experience: from
identification of the need to prototype testing, all
executed in a structured process where creativity is
enhanced by the state-of-the-art product design
techniques and methodologies. Each student is able to
view product design as an open-ended problem
solving activity and produces appropriate design
documentation including maintaining a detailed
individual notebook, Product Development File (PDF)
and final product design report to be submitted to the
client. Furthermore, the student understands issues of
product safety, reliability and the principles of life-
cycle engineering including re-manufacturing and
design for zero waste.
2.2 Invited lecturers
In addition to the lecture and design practice,
several practicing engineers who are recognized
leaders in their engineering disciplines are invited to
speak to the students. The invited industry leaders talk
openly about design challenges, ethical issues and
social aspects of the practicing professional engineer.
The presentations are very well received by the
students and provide an important link to real world
design challenges.
3. Team-Based Design Project
Students learn about the process of concurrent
engineering design by developing a creative product
for a specific customer’s need. Each group is required
to maintain a PDF which is a series of documents and
appendices that cover the entire history of the design.
When completed, the information stored in this file is
used to draft a formal report that is presented to the
client or sponsor of the project. The PDF represents
an internal “company” record of the project whereas
the formal design report is the end result that is
delivered to the client.
In the context of the course the PDF and formal
report are graded on completeness and quality of both
the proposed design solution and the thorough
documentation provided to support the design
decisions. The approach taken by the team to solving
the problem is emphasized more than the final
proposed solution.
3.1 Project theme
The primary goal of design project is to critically
apply the product design techniques introduced in
lectures. This is achieved if the participants are given a
properly defined project. The students must be able to
relate to the project theme and identify potential
customers for the product. Since the objective is
customer-driven design, it is also essential that the
students have access to potential end-users in order to
develop realistic customer requirements and provide
knowledgeable individuals to critically evaluate the
proposed solution. In this manner it is the customer,
and not the engineering student, who identifies what
is truly needed and whether the solution is useful.
Over the past decade, the design projects associated
with this course involved products assisted individuals
with limited physical abilities.
The initial part of the design process requires the
team to select a specific client group and identify a
need. A past example is an assistive device that would
enable a person with severe arthritis in the hands to
undertake recreational painting. Another design team
would explore another recreational activity, such as
sport fishing, enjoyed by the same client group. In all
cases the team must consult potential end-users of the
product to identify the activity or task requiring
assistance, and demonstrate that specifications were
developed from their needs.
Additional constraints placed on the design solution
ensured that the proposed product must be safe,
affordable, simple to use and easy to maintain. The
estimated cost of manufacturing the final product must
be less than $20. This is based on the rule-of-thumb
that the estimated retail price for a consumer product
is often 3x the manufacturing cost.
3.2 Forming the design teams
Two approaches have been used in creating the four
member design teams. The first approach is to assign
students into groups with the goal of increasing the
diversity and backgrounds of the teams. The second
approach is to permit students to select there own
design team members. Both approaches have
advantages and disadvantages.
By assigning students to teams it is possible to
enhance concurrent engineering practice. Concurrent
engineering is only effective if the participants in the
group have different backgrounds, perspectives, and
areas of expertise. Unfortunately, this group dynamic
may result in serious internal conflicts amongst
novice, overly confident designers. On occasion this
behavior can result in complete breakdown of the
functioning of the group. In contrast, a self forming
team reduces this risk of internal conflict but
significantly increases the chances that the team will
develop a preconceived “favorite” solution without
thoroughly understanding the problem. The final
decision of which approach to use is also dependent
upon the course instructor’s preference.
3.3 Monitoring progress
During the twelve week duration of the design
project, students are required to keep the log of all
activities in individual design notebooks. As a team,
they are required to report progress in several design
reviews and in the final presentation. Each team must
submit the final report along with all the relevant
project documentation that they have collected in a
Project Design File.
A design review meeting is be held at the end of
each of three design phases, or more often if deemed
necessary. At each meeting the design team provides
a short presentation that clearly states the design
problem, progress made, and problems encountered. In
addition, a detailed plan for the next phase of work
must be presented at this meeting.
Enforcing this structured design process where
students are required to go through clearly defined
design phases is perhaps the biggest challenge for the
course instructor. It is authors’ experience that many
students initially see this as an unnecessary constraint
to their creativity. Many teams try to bypass the initial
design stages like identification of need, development
of product specifications, generation of multiple
concepts and concept selection. Instead, they try to
start the project with a pre-conceived idea using an
intuitive approach to design process which does not
assure that customer need will be satisfied and a
competitive product will be created.
3.4 Evaluating individual performance
Each student keeps a hard-cover design notebook
describing their individual contributions to the design
project. This includes all sketches, notes, experimental
data, design ideas, and record of communication with
team members, clients and potential vendors. No
pages can be removed and each page must be dated
and initialized when used. At the beginning of each
laboratory period, the prior week's entries in the
design notebook are be evaluated by the course
instructor or a teaching assistant. The design
notebooks are collected at the end of the term and
assigned a grade based on both the weekly
assessments and the final number of “quality entries”.
A quality entry is a significant sketch or drawing of
some aspect of the design; a listing of functions, ideas,
or other features; a table such as morphology chart or
decision matrix; or a page of text.
Furthermore, each team receives a grade for the
PDF, design report and prototype. The mark assigned
to an individual is adjusted based on feedback from all
team participants. In this regard, students are required
to submit a questionnaire that describes their own
contribution to the team effort and that by the other
members of the group. The individual contribution is
then calculated using all evaluations forms and the
observations of the instructor and teaching assistants.
This process provides the students with a mechanism
to have a voice in the grading process. Historically,
the majority in a group provide the same observations
identifying those individuals who made greater or
lesser contributions.
4. Design Solution A Case Study
Each year the students are divided into
approximately 25 design teams of four to work on
design solutions for some kind of assistive devices that
satisfy the specialized needs of disabled or elderly
individuals. The teams that satisfactorily follow the
product design and development process often
generate relevant, innovative product solutions.
The goal of a sample project we present here is to
design a device that helps seniors make an easy
transition from sitting to standing”. We will follow the
team through their design projects. Of course, only a
limited number of details of this representative project
can be shown in here.
The team begins with interviews with potential end
users of the product and identifies the need for a
device that would assist in standing up and sitting
down. The most important customer requirements are
listed and assigned a rating of importance through
further interviews (figure 2). Competitive products
already available on the market are also identified and
rated based on the established customer requirements.
Figure 2. A sample response to a survey used
to identify key customer preferences.
Next, the Quality Function Deployment (QFD)
technique (figure 3) is used to develop design
specifications and to compare them with design
specifications of the existing competitive products.
Figure 3. Portion of the QFD chart showing
development of design specifications.
The identification of customer requirements by
means of customer surveys and translating them into
engineering requirements using the QFD techniques
ensures that design process is customer driven. Once
the design specification and engineering targets have
been established the team moves forward to the
concept generation and concept evaluation phase.
Techniques such as Functional Decomposition and
Morphological Analysis (figure 4) are used to develop
innovative solutions. In our case, the design team
makes use of these two techniques to produce over
ten design concepts. Sketches for only two of these
concepts are shown here (figures 5 and 6).
Figure 4. Example of concepts being
developed through functional decomposition
and morphological analysis.
Figure 5. Design concept 1: chair with spring
loaded seat.
Figure 6. Design concept 2: chair with foot
step and handles.
Having developed design concepts, concept
evaluation techniques including Feasibility Judgment,
Technology Readiness Assessment, Go/no-go
Screening and Decision Matrix Method are used to
select the best concept for detail development.
Go/no-go Screening technique (figure 7), combined
with Decision Matrix Method indicates that Spring
Compressive Chair is the most promising design
concept..
Figure 7. Go/no-go technique used to select
the best design concept for detail
development.
This selected concept must now be developed into a
viable functional product through engineering
analysis, mechanical prototyping, experimentation,
and evaluation for manufacturability, safety, reliability
and impact on the environment. Example of the CAD
model for the assembly and Bill of Materials (BOM)
are shown in Figures 8 and 9, respectively.
Figure 8. CAD model of a spring loaded seat.
Figure 9. Exploded view and the BOM of a
spring loaded chair seat.
Detailed design is aided by design analysis using
the Finite Element Analysis (FEA) to ensure the
adequate structural performance of the product (figure
10).
Figure 10. Stresses in the seat calculated
determined using FEA.
Other design teams used different simulation tools
like Motion Analysis or Flow Analysis depending on
the needs and the nature of their design project.
Having completed detailed design and analysis the
design team proceeds to evaluate their design using
techniques such as Design for Manufacturing (DFM),
Design for Assembly (DFA) (figure 11) and Design
Failure Modes and Effect Analysis (DFMA) (figure
12).
Figure 11. Design for Assembly worksheet
used to evaluate the product for the ease of
assembly.
Figure 12. Design FMEA used to prioritize the
risk of different failure modes.
The use of DFA and DFM in product design allows
students to consider manufacturing and assembly
issues which could not have been illustrated by
prototype serving only to demonstrate essential
principles of the design. The entire project is
accompanied by cost analysis and is managed using
Gantt charts and Critical Path Method (CPM). It also
includes design considerations for recycle ability and
disassembly upon the end of the useful life.
Finally the team constructs a physical prototype for
testing key features for function and performance
(figure 13). This completes the design process.
Figure 13. Photograph of the spring loaded
chair seat prototype.
5. Use of CAE tools in the design process
The use of simulation tools like FEA and Motion
Analysis in the design project enables the instructors
to incorporate the traditional design approach of
creating prototypes (figure 14). In contrast Simulation
Aided Design Process occurs when design iterations
are performed on numerical models and prototype is
used only for design validation rather than as a design
tool (figure 15).
Figure 14. Traditional approach to design
where multiple prototypes are created.
Figure 15. Simulation driven design process
where the prototype is NOT used as a design
tool but only for design validation.
6. Conclusions
The most important outcome of the course is not
that students have learned and applied in design
practice so many different methods and tools used in
the design process. Neither it is the fact that they have
designed something potentially useful.
The most important outcome of completing the
Product Design and Development course is the
realization that structured methods, established
guidelines, and formal techniques exist that will help
practicing engineers develop high-quality products.
Not every technique discussed in the class is
applicable to each design problem encountered in
industry.
Many of the techniques become redundant with
extensive practical experience. However, design
engineers are always faced with new challenges
demanding viable, cost effective solutions. These tools
provide the sophisticated practitioner with guidance
through the process and the means to communicate to
the client or customer that the proposed solution works
as it should if properly constructed and implemented.
The techniques also force the design to address key
issues related to form, functionality, safety,
manufacturability, serviceability, reliability, cost, and
environmental impact throughout the product life-
cycle.
7. References
[1] Bralla, J.G., Design for Excellence. New York:
McGraw-Hill, 1996.
[2] Bralla, J.G., Handbook of Product Design for
Manufacturing. New York: McGraw-Hill, 1986.
[3] Boothroyd, G., Dewhurst, P., and Knight, W., Product
Design for Manufacture and Assembly. New York: Marcel
Dekker, 1994.
[4] Buhl, H.A., Creative Engineering Design. Ames Iowa:
The University of Iowa Press, 1968.
[5] Cross, N., Engineering Design Methods: Strategies for
Product Design. New York NY: John Wiley & Sons, 2001.
[6] Dieter, G.E., Engineering Design: A Materials and
Processing Approach. New York: McGraw-Hill, 1991
[7] Lindbeck, J.R., Product Design and Manufacture.
Englewood Cliffs, N.J.: Prentice Hall, 1995.
[8] Otto, K.N. and Wood, K.L. Product Design: Techniques
in Reverse Engineering and New Product Development.
Upper Saddle River, N.J.: Prentice Hall, 2001.
[9] Pahl, G. and Beitz, W., Engineering Design: A
Systematic Approach. London: Springer-Verlag, 1996.
[10] Redford, A. and Chal, J., Design for Assembly.
London: McGraw-Hill, 1994.
[11] Ullman, D.G., The Mechanical Design Process. New
York: McGraw-Hill, 1992.
[12] Ulrich, K.T. and Eppinger, S.D., Product Design and
Development (Third Edition). New York: McGraw-Hill,
2004.
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