1. Understanding Customer
Requirements
Principles of Design
Zahed Siddique
Assistant Professor
School of Aerospace and Mechanical Engineering
University Of Oklahoma
zsiddique@ou.edu
University of Oklahoma AME 4163

2. Need to focus
Moving in the wrong direction at a fast pace
is still moving in the wrong direction.
Right
W r ong
University of Oklahoma AME 4163

3. Information on QFD….
 Developed in Japan in the mid 1970s
 Introduced in USA in the late 1980s
 Toyota was able to reduce 60% of cost to
bring a new car model to market
 Toyota decreased 1/3 of its development
time
 Used in cross functional teams
 Companies feel it increased customer
satisfaction
University of Oklahoma AME 4163

4. Why….?
 Product should be designed to reflect
customers’ desires and tastes.
 House of Quality is a kind of a conceptual map
that provides the means for interfunctional
planning and communications
 To understand what customers mean by quality
and how to achieve it from an engineering
perspective.
 HQ is a tool to focus the product development
process
University of Oklahoma AME 4163

5. QFD Target
University of Oklahoma AME 4163

6. Important points
 Should be employed at the beginning of every project
(original or redesign)
 Customer requirements should be translated into
measurable design targets
 It can be applied to the entire problem or any
subproblem
 First worry about what needs to be designed then
how
 It takes time to complete
University of Oklahoma AME 4163

7. Components of
House of Quality
Customer
Evaluation
Units
Whats
Who vs.
Whats
This Product
How Muches
Targets
This Product
Who
Hows vs
Hows
Hows
Whats vs
Hows
Now
Now vs
What
Hows vs
How
Muches
University of Oklahoma AME 4163

8. Extensions to House
of Quality
Customer
Evaluation
Weighted Importance
Importance %
Units
This Product
Targets
Technical Difficulty
This Product
Useful Data
Target
Ratio of Improvement
University of Oklahoma AME 4163

9. Step 1: Who are the
customers?
 To “Listen to the voice of the customer”
first need to identify the customer
 In most cases there are more than one
customer
 consumer
 regulatory agencies
 manufacturing
 marketing/Sales
Customer
Evaluation
Units
Targets
Customers drive the
development of the product,
not the designer
University of Oklahoma AME 4163
This Product
This Product
Who
Whats
Who vs.
Whats
Hows vs
Hows
Hows
Whats vs
Hows
Now
Now vs
What
How Muches
Hows vs
How
Muches
Customers drive the
development of the product,
not the designer

10. Step 2: Determine the
customers’ requirements
 Need to determine what is to be
designed
 Consumer
 product works as it should
 lasts a long time
 is easy to maintain
 looks attractive
 incorporated latest technology
 has many features
Customer
Evaluation
Units
Whats
This Product
How Muches
Targets
Now
This Product
Who
Who vs.
Whats
Hows vs
Hows
Hows
Whats vs
Hows
Now vs
What
Hows vs
How
Muches
List all the
demanded qualities
at the same level of
abstraction
University of Oklahoma AME 4163

11. Step 2: cont...
 Manufacturing
 easy to produce
 uses available resources
 uses standard components and methods
 minimum waste
 Marketing/Sales
 Meets customer requirements
 Easy to package, store, and transport
 is suitable for display
University of Oklahoma AME 4163

12. Kano Model
Customer Satisfaction
Basic Quality: These requirements are
not usually mentioned by customers.
These are mentioned only when they are
Excitement
absent from the product.
Absent
Performance Quality: provides an
Satisfiers
increase in satisfaction as performance
improves
Excitement Quality or “wow requirements”: are often
unspoken, possibly because we are seldom asked to
express our dreams. Creation of some excitement features
in a design differentiates the product from competition.
Delighted
Performance
implemented
Basic
Fully
+
-
Disgusted
University of Oklahoma AME 4163

13. Types of customer
requirements
 Functional requirements describe the product’s
desired behavior
 Human factors
 Physical requirements
 Reliability
 Life-cycle concerns
 Resource concerns
 Manufacturing requirements
University of Oklahoma AME 4163

14. How to determine the
Whats?
 Customer survey (have to formulate the
questions very carefully)
 If redesign, observe customers using existing
products
 Combine both or one of the approaches with
designer knowledge/experience to determine
“the customers’ voice”
University of Oklahoma AME 4163

15. Affinity Diagram
 Provides structure for verbal data by
creating natural clusters or groups
 Ensures that the list of demanded
qualities are complete and expressed at
the same level of detail
University of Oklahoma AME 4163

16. Constructing Affinity Diagram
 Set a brainstorming session to list all possible requirements
 Record each element of the list on small cards
 Place all cards on a table randomly
Silent mode
 Spend time reading all demanded qualities
 Start at the same time, once everyone is ready - everyone quickly
and without thought find two demanded qualities that have
something in common
 If you find a demanded quality is not where you think it belongs,
move it. If it is moved again, make a duplicate and talk about it
later.
 The process continues until all demanded qualities are in a group.
University of Oklahoma AME 4163

17. Constructing Affinity Diagram
Discussion Mode
 Begin discussion after group composition for the demanded
qualities becomes stable
 First review the demanded qualities that seemed to have more
than one home
 Select a descriptive name for the groups. Group names must also
be demanded qualities, but at a higher level of abstraction
 Look at each group and judge if all elements are at the same level
of abstraction
 Check each group by asking “If this is the name of the group, what
elements should be included but are missing?”
 Next test for missing groups.
 Check with the types of customer requirements list
University of Oklahoma AME 4163

18. Step 3: Determine Relative Importance
of the Requirements: Who vs. What
 Need to evaluate the importance of
each of the customer’s requirements.
 Generate weighing factor for each
requirement by rank ordering or other
methods
Customer
Evaluation
Units
Who vs.
Whats
How This Muches
Product
Targets
This Product
Who
Whats
Hows vs
Hows
Hows
Whats vs
Hows
Now
Now vs
What
Hows vs
How
Muches
University of Oklahoma AME 4163

19. Rank Ordering
 Order the identified customer requirements
 Assign “1” to the requirement with the lowest priority
and then increase as the requirements have higher
priority.
 Sum all the numbers
 The normalized weight
Rank/Sum
 The percent weight is: Rank*100/Sum
University of Oklahoma AME 4163

20. Step 4: Identify and Evaluate the Competition:
How satisfied is the customer now?
 The goal is to determine how the customer perceives the
competition’s ability to meet each of the requirements
 it creates an awareness of what already exists
 it reveals opportunities to improve on what already exists
The design:
1. does not meet the requirement at all
2. meets the requirement slightly
3. meets the requirement somewhat
4. meets the requirement mostly
5. fulfills the requirement completely
Customer
Evaluation
Units
Who vs.
Whats
How This Muches
Product
Targets
This Product
Who
Whats
Hows vs
Hows
Hows
Whats vs
Hows
Now
Now vs
What
Hows vs
How
Muches
University of Oklahoma AME 4163

21. Step 5: Generate Engineering
Specifications: How will the customers’
requirements be met?
 The goal is to develop a set of engineering
specifications from the customers’ requirements.
Restatement of the design problem and customer requirements in
terms of parameters that can be measured.
Each customer requirement
should have at least one
engineering parameter.
Customer
Evaluation
Units
Who vs.
Whats
How This Muches
Product
Targets
This Product
Who
Whats
Hows vs
Hows
Hows
Whats vs
Hows
Now
Now vs
What
Hows vs
How
Muches
University of Oklahoma AME 4163

22. Step 6: Relate Customers’ requirements
to Engineering Specifications: Hows
measure Whats?
 This is the center portion of the house. Each cell
represents how an engineering parameter relates to
a customers’ requirements.
Customer
Evaluation
Units
Who vs.
Whats
How This Muches
Product
Targets
This Product
Who
Whats
Hows vs
Hows
Hows
Whats vs
Hows
Now
Now vs
What
Hows vs
How
Muches
9 = Strong Relationship
3 = Medium Relationship
1 = Weak Relationship
Blank = No Relationship at all
University of Oklahoma AME 4163

23. Step 7: Identify Relationships Between
Engineering Requirements: How are the
Hows Dependent on each other?
 Engineering specifications maybe
dependent on each other.
Customer
Evaluation
Units
Who vs.
Whats
How This Muches
Product
Targets
This Product
Who
Whats
Hows vs
Hows
Hows
Whats vs
Hows
Now
Now vs
What
Hows vs
How
Muches
9 = Strong Relationship
3 = Medium Relationship
1 = Weak Relationship
-1 = Weak Negative Relationship
-3 = Medium Negative Relationship
-9 = Strong Negative Relationship
Blank = No Relationship at all
University of Oklahoma AME 4163

24. Step 8: Set Engineering Targets:
How much is good enough?
 Determine target value for each
engineering requirement.
 Evaluate competition products to
engineering requirements
 Look at set customer targets
 Use the above two information to
set targets
Customer
Evaluation
Units
Who vs.
Whats
How This Muches
Product
Targets
This Product
Targets
Who
Whats
Hows vs
Hows
Hows
Whats vs
Hows
Now
Now vs
What
Hows vs
How
Muches
University of Oklahoma AME 4163

25. Relationships Among
Engineering Characteristics
Identifying performance measure conflicts
Engineering Characteristics
Record Performance measures for each customer
Relative Importance
demanded quality
Record customer performance ratings for your
Customer Similar product Attributes
and competitors’ products
Customer
Evaluation
Customer
Evaluation
Importance for each demanded quality needs
Relationship between demanded customer qualities and
The first step is to list all the demanded qualities at the same
to be determined
Technical benchmarking
Engineering Performance
level of abstraction
Units
Technical Difficulty associated with achieving
Targets/improvements and importance of
Setting Technical Targets
technical characteristics
Determining
Targets
Important
Characteristics Technical Difficulty
Engineering
Influence
Customer
Qualities
Objective
Measures
Targets
Importance
University of Oklahoma AME 4163

26. Components of
House of Quality Customer
Evaluation
Weighted Importance
Importance %
Units
Whats
Who vs.
Whats
This Product
How Muches
Targets
This Product
Who
Hows vs
Hows
Hows
Whats vs
Hows
Now
Now vs
What
Hows vs
How
Muches
Rank
Technical Difficulty
Selected
Addition to the
House of Quality
presented in text
book
University of Oklahoma AME 4163

27. Creating the
Requirement List
 Contents of Requirement List
 Specify if the individual items are demands or wishes in the
clearest possible terms
 Tabulate Quantitative and Qualitative aspects
 Collect further information
 If possible rank wishes as being of major, medium or minor
importance
 Living document
 Arrange the requirements in clear order
 Define the main objective and the main characteristics
 Split into identifiable groups
 Enter the Requirement list on standard forms and circulate
 Examine Objections
University of Oklahoma AME 4163

28. Requirement List
for
Requirements list
Project, product
User
Changes DW
Identification
Classification
Page
Requirements Responsible
Date of Change
Specify wether item is D or W
Design Group Resposible
Objective or property with qualitative and quantitative data
Replaces Issues of:
University of Oklahoma AME 4163

29. Name 1
Name 2
Name 3 Requirement
List Example
Use information from House
of Quality as an starting point
for creating the requirement
list.
Need to identify requirements
for the product that are basic
and necessary but are not
specified by the customers.
University of Oklahoma AME 4163

30. Example House of Quality
Design a device to toast breads
and other similar types of food
University of Oklahoma AME 4163