Design Specifications and
QFD
Establishing the Need
• Sources:
– The market: what do customers want?
– New technology:
• Creates a market
• Risky and expensive
• Can be financially rewarding
– Higher level system
• Support for industries such as planes,
automobiles
Collecting Information
• Customer: Inside or outside of company
– External
•
•
•
•
Obsolescence of product
Discover of new technology
New market requirements
Competitor superiority
– Internal
•
•
•
•
Excess capacity
Drop in profitability
New technology
New production methods
Collecting Information
• Company: what are its objectives?
–
–
–
–
–
Wants to grow and increase market share
Wants flexibility in unstable market
Wants high profits
Life cycle of product
Enterprise potential and limitations
Collecting Information
• Laws and Regulations:
–
–
–
–
Environmental control
Safety regulations
Factory regulations
Standards, company and government
• Market
– Demands
– Potential for product
– Competition
Questions
• What is the need or problem really
about?
• What implicit wishes and expectations
are involved?
• What paths are open for development?
Quality Function Deployment
• Developed in the mid-70’s
– Method for developing specifications from
voice of customer
– Gives interdisciplinary teams a map for
working together
• Toyota needed to improve rust record
– Body durability broken into 53 items
– Ran experiments on details of production,
temperature control, coating composition
Pre-Production and Start-up Costs at
Toyota Body Shop
Before and After QFD
Jan. 1977
Pre-QFD
Apr. 1984
Post-QFD
(39% of Pre-QFD Costs)
Source: “The House of Quality,” J. Hauser and D. Clausing,
Harvard Business Review, May-June 1988, pp. 63-73.
QFD vs. no QFD
No QFD
Design
Changes
90% of changes
complete
With QFD
20-24
months
14-17
months
1-3
months
Job #1
+3
months
Why Use QFD?
A recent survey of 150 US companies:
• 69% use QFD
• 71% began using it since 1990
• 83% felt that it improve customer
satisfaction
• 76% felt it facilitated rational decision
making
QFD
• Why use QFD?
– Helps uncover new information
– Can be applied to entire design problem or
portions of it
– Focuses team on what need to be
designed, not how to design it
– Helps overcome favoritism
Steps of QFD
• Identify the customer
• Determine customer requirements
• State whether desires are demands or
wishes, rank the wishes
• Competition benchmarking
• Translate customer desires into
measureable engineering requirements
• Set targets for design: dates
QFD: Step by Step
1. Who are the customers?
2. Determine customer requirements
– Collection of information
•
•
•
•
•
•
•
Specify information needed
Determine type of data collection
Determine content of questions
Design questions
Order questions
Take data
Reduce data
QFD: Step by Step
2. Determine customer requirements
Delighted
Excitement
Customer
Satisfaction
Absent
Fully
Implemented
Basic
Disgusted
Product Function
QFD: Step by Step
3. Determine relative importance of
requirements
4. Identify and evaluate competition:
How satisfied is the customer now?
5. Generate product specifications: how
will customers’ requirements be met?
QFD: Step by Step
6. Translate into measureable
engineering req’ts
– If there is not measureable requirement,
then it is not well understood
– Two solutions
• Break into finer parts
• Repeat step three
QFD: Step by Step
7. Identify relationships between
customer and engineering requirements.
8. Set targets for design: how much is
good enough?
House of Quality
Hows
vs.
Hows
Hows
Now
Whats
Whats vs. Hows
Now
vs.
What
How
Muches
Hows vs.
How Muches
Who
Who
vs.
Whats