Transcript but before we go too far with PDS

ES1050 – Introductory Engineering
Design and Innovation Studio
Introduction to Design
Process
Customers’ Needs
Product Design Specifications
Sept. 23, 2009
Prof. Paul Kurowski
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WHAT versus HOW

First, designers need to know WHAT the customer wants

Then, designers need to determine HOW to meet the
customer requirements
2
WHAT THE CUSTOMER WANTS?
Customer requirements:
1.
2.
3.
4.
5.
Must be discriminatory
Must be measurable
Must be orthogonal (no overlapping of requirements)
Must be universal (applicable to all alternatives under
consideration)
Must be external to problem (not impose design
choices)
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1. Customer requirements must be discriminatory
Requirements must reveal the differences between alternatives
to help distinguish one from the other during an evaluation.
If you say that a bicycle should be suitable for riders whose
body mass is between 20kg and 200kg, this requirements is
useless. It does not allow for discrimination between people.
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2. Customer requirements must be measurable
There must exist an objective method to measure if the
requirement has been satisfied. For example a questionnaire
can be used to find to what extend the requirement has been
satisfied
1. The product does not meet the requirement at all.
2. The product meets the requirement slightly.
3. The product meets the requirement somewhat.
4. The product meets the requirement mostly.
5. The product fulfills the requirement completely.
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3. Customer requirement must be orthogonal
The requirements must not overlap. Each requirement should identify a
unique feature of the alternative. There should be no overlapping of
requirements. This is often difficult because overlapping is so hard to
identify.
For example, in the initial list of criteria for choosing a new product, a
company proposed two criteria:
• Product must give smooth ride over rough roads
• Product should reduce shocks from bumps
What is wrong?
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4. Must be universal
A universal requirement characterizes an important attribute of all the
proposed alternatives. If only some of the alternatives have the feature
measured by the requirement, then it is not universal and either the
issue is not well defined or some of the alternatives have features not
consistent with the issue being addressed.
For example in the initial list of criteria for choosing a transportation
system, it was stated:
• The new system must use the existing network of re-fuelling
stations
What is wrong?
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5. Must be external to problem; must not impose
design choices
For example in the initial list of criteria for a new bicycle it
was stated:
•
The new bicycle must have an aluminum frame
What is wrong?
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A customer requirement for an All Terrain Vehicle has
been defined as: “Must have a chain drive”
What is wrong with this definition?
A
Is not discriminatory
B
Is not measurable
C
Is not orthogonal (specifies overlapping requirements)
D
Is not universal (not applicable to all alternatives under
consideration)
E
Is not external to problem (imposes design choices)
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DIFFERENT PERSPECTIVES OF THE SAME PROBLEM
As marketing
requested it
As production
manufactured it
As sales
ordered it
As plant
installed it
As engineering
designed it
What the customer
really wanted !
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Customer Requirements:
WHAT?
BBQ lighter
Examples of customer requirements
 Lights up a BBQ
 Easy to use
 Lightweight
 Stylish
 Reliable
 Affordable
Customer Requirements are qualitative
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Product Design Specifications:
HOW?
Product Design Specifications describe features and
characteristics present in the product.
Product Design Specifications are quantitative, must be
measurable in numbers with clearly specified units.
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Product Design Specifications:
HOW
BBQ lighter
Selected product design specifications
 Length 20 cm
 Weight 0.1N
 Flame length 30mm
 Works 200 times on one load
 0.2N force required to release the trigger
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Other names for engineering design
specifications include:
Engineering design specifications
Engineering requirements
Design requirements
Functional requirements
Objectives and constraints
Technical requirements
Technical specifications
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Boat trailer – in class exercise
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Kano Diagram of Customer Satisfaction




Basic features
 Must be present,
expected
Performance features
 The more there is
the happier the
customer
Excitement features
 Exciting, new,
unexpected
features
Over time, excitement
features become basic
features
Play
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Product Design Specifications:
How can we classify product design specifications and
what is their importance in satisfying customers’
requirements?
Not all customers’ requirements can be met 100%,
some are mutually exclusive so a compromise must
be found.
How to satisfy customers?
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Understanding the Customer
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Quality Function Deployment * (QFD) is a
technique developed in Japan during the
mid-1970's for better understanding the
design problem, in particular of customer
needs.
* Deployment: the distribution of forces in preparation for battle or work
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Quality Function Deployment
(QFD)
General Comments:



No matter how well the design team thinks it
understands a problem, it should employ the QFD
technique for all design projects, because in the process
the team will learn what it doesn't know about the
problem.
The customer's requirements must be translated into
measurable design targets before a large amount of time
and resources are invested in the design effort.
It is important to first consider what needs to be
designed and, only after that is fully understood, to
worry about how the design will look and work.
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