QUALITY FUNCTION
DEPLOYMENT
A tool for customer-focused design of products
and services
Paul Roberts
Principal Fellow Quality & Reliability
Warwick Manufacturing Group
University of Warwick
paul.roberts@warwick.ac.uk
RELATIONSHIPS
CORRELATION
9 STRONG
3 MEDIUM
1 WEAK
The QFD chart
STRONG +
STRONG
NEGATIVE
STRONG TARGET
BETTER
WORSE
Foam thickness
Foam stiffness
Pan height
Back thickness
IMPORTANCE
Profile of back
45
WHATs
CUSTOMER
RATING
Height of back
90
HOWs
Armrest recess width
Armrest recess depth
MIN
Width of armrest
MAX
1
2 3
4
5
Arm rest folds right away 5
Arm rest wide enough
5
Enough leg room
8
Doesn't cause bum ache 8
Tall person shoulder
7
comfort
Short person lumbar
7
comfort
IMPORTANCE
45 68
222 87 96 114 114
Our Company
TECHNICAL &
REGULATORY
REQUIREMENTS
T.B.I.
1080mm
80mm
COMPETITIVE
ASSESSMENT
55mm
50mm
OBJECTIVE
TARGET
VALUES
BETTER 5
4
3
2
WORSE 1
FST 1000
Max. deflection
RELATIO NSHIPS
9 STRONG
3 MEDIUM
1 WEAK
CORRELATION
ST RONG +
MAX
MIN
TARGET
POSITIVE
NEGATIVE
2
3
4
5
6
7
8
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
8
5
Doesn't give you bum ache
8
12
Doesn't hurt the shoulders of a taller person
7
3
Lumbar support doesn't hurt shorter person
7
3
Doesn't hit person behind when you recline
7
5
Back can be adjusted to any position and doesn't slip 8
2
2
4
4
5 3
450 mm
25 mm
T.B.I.
T.B.I.
580 mm
55 mm
80 mm
50 mm
WORSE
BET TER
3
5
4
4
4
3
2
4
4
4
4
4
4
2 2
1
3
1
= A
= B
= C
4
4
Over rails
2
25 mm
1
Interchange
DEGREE O F TECHNICAL DIFFICULTY
TECHNICAL
COMPETITIVE
COMPARISONS
1
2
3
4
5
FST 1000
16 G LOAD CASE
MAX ALLOWABLE DEFLECTION
INTERFACE TO FLOOR RAILS
Eng Char.
Importance Ratings
ABSOLUTE
RELATIVE
2
8
2
5
20 MN/m
4
Fit more passengers in
5 min +
9
Easy to move around
7000 N Test
6
Light weight
70 mm at 7000 N
Durable
1 gm/hr
6
1x10 cycles
6
Test 013
Fabric stain resistant
5N
6
3 mm Test
6
1x10 strokes
100 washers
5
Easy to clean
100 N
Doesn't soak up spilt drink
WORST
1
5
Enough leg room
TECHNICAL
TARGETS
Technical and
Regulatory Requirements
9
5
Arm rest wide enough
T.B.I.
Comfortable Upright
1
Arm rest fold right away
x= 150, y= 50
Cost
Low Operatin g Low Service Comfortable
Reclined
Costs
Costs
Passengers Feel Comfortable
IMPO RTANC E
ST RONG -
CUSTOMER
RATING
BEST
mb
er
Mountings
SERVICE COMPLAIN TS
MARKET
QUALITY
REQUIREMENTS
Nu
Structure All Foam
Number of fasteners
Location of fasteners
It em
Fabric
Width of armrest
Armrest recess depth
Armrest recess width
Height of back
Profile of back
Profile of pan
Back thickness
Pan height
Back hinge location
Loci of hinge
Clutch locking force
Clut ch resist ance (open)
Fabric tear resistance
Fabric wear resistance
Washable fabric
Stain resistant fabric
Liquid resistant fabric
ENGINEERING
CHARACTERISTICS
Back
Fatigue performance
Structural strength
Structural stiffness
Material FST performance
Foam stiffness
Foam t hickness
Mountings interchangeable
Armrest
114 54 54 182 290 24 204 105 87 63 81 72 54 54 54 108 117 81 135 81 27 120 123 36 63 36
5
2
2
8 12
1
9
4
4
3
3
3
2
2
2
5
5
3
6
3
1
5
5
2
3
2
3
4
5
QFD – the issues
„
Remoteness from the final customer.
„
Lack of visibility of the customer chain.
„
Informal (or inappropriate) customer
requirement definition.
„
Complex technologies.
„
Technology-led products.
„
Unclear relationship between customer
requirements and technology.
QFD provides:
„
A structured approach.
„
A strong customer focus.
„
A tool which is applied early in the product life
cycle.
„
Coverage of the whole process.
„
A framework for cross-functional teamwork.
„
A record of design/production decisions.
Definition of QFD
“A system for translating customer
requirements into company
requirements at each stage, from
research and development through
engineering and manufacturing to
marketing, sales and distribution.”
Source: American Suppliers Institute
Definition of QFD
„
Practically this means that it provides a
mechanism for targeting and prioritising
design effort to give maximum customer
satisfaction.
„
In manufacturing this will focus on the design
of the product.
„
In service organisations it will be the design
of the service.
The Customer Chain
„
„
„
„
There is rarely only one level of customer for
a product.
For example, the customer chain for a
breakfast cereal would be: distributor,
wholesaler, retailer, purchaser and consumer.
All of these customers must be taken into
account for a successful design.
They may be given a different weighting in
case of conflict.
Information flow from the
customer
The Kano Model Of Quality
Customer
Satisfaction
Excitement
Quality
(unspoken)
Degree of
Achievement
en
ok
p
S
rm
r fo
e
P
ce
an
Basic Quality
(unspoken)
Who is the customer in QFD?
Sources of Information for
QFD
„
Postal questionnaires.
„
Interview questionnaires.
„
Clinics.
„
Focus groups.
„
Listening.
Unsuitable sources of
information
„
Government statistics.
„
Surveys.
„
Reports.
„
Trade and business papers.
Customer requirements
Technical & Regulatory
Requirements
Technical & Regulatory
requirements
„
National regulations
„
EC regulations
„
Local regulations
„
British Standards, International Standards etc
„
Automated manufacture
„
Size restrictions
Why organize customer
requirements?
„
Simplify later use of charts
„
Team reaches a common understanding
„
Identify areas missed by the sampling of
customer needs
How to Create an Affinity
Diagram
„
Team brainstorms ideas
„
„
„
Each idea is written on
a single card
Cards are laid out on a
wall or table
„
„
Normal rules apply
Ensure sufficient
access for all team
members
The cards are moved
into like piles
Low
motivation
1
2
High
absenteeism
Acceptance
of defects
5
9
Lack of
innovation
6
10
Poor
management
of change
Low pride 7
in work
11
Poor
internal
communication
Short-term
attitude
3
4
Lack of
teamwork
High internal
barriers
Lack of
vision
8
12
Management
by fear
How to Create an Affinity
Diagram
„
Team brainstorms ideas
„
„
„
Each idea is written on
a single card
Cards are laid out on a
wall or table
„
„
„
Normal rules apply
Ensure sufficient
access for all team
members
The cards are moved
into like piles
Cards that do not fit into
any pile may be
grouped in a
miscellaneous pile
Low
motivation
1
2
High
absenteeism
Acceptance
of defects
Low pride
in work
3
7
Lack of
teamwork
4
9
Lack of
innovation
6
10
Poor
management
of change
High internal
barriers
11
Poor
internal
communication
8
Lack of
vision
12
Management
by fear
Short-term
attitude
5
How to Create an Affinity
Diagram
„
Cards may be
duplicated if necessary
When team members no
longer wish to move
cards
„
„
„
Each pile is given a title
The grouping process is
repeated for the titles
The groups of titles are
given a title
LOW
MORALE
POOR INTERINTERPOOR
DEPARTMENTAL
RELATIONSHIPS LEADERSHIP
Low
motivation
Lack of
teamwork
Lack of
innovation
High
absenteeism
High internal
barriers
Poor
management
of change
Acceptance
of defects
Poor
internal
communication
Lack of
vision
Management
by fear
Low pride
in work
Short-term
attitude
The Completed Diagram
Poor Employee Satisfaction
Low Morale
w
w
w
w
Low
motivation
Low pride in
work
High
absenteeism
Poor Interdepartmental
Relationships
w
w
w
Lack of
teamwork
High internal
barriers
Poor internal
communication
Poor Leadership
w
w
w
w
Acceptance of
defects
w
Short-term
attitude
Lack of vision
Lack of
innovation
Poor
management of
change
Management
by fear
Practical Hints
„
Group cards in silence
„
Do not attempt to name the piles before
grouping has been completed
„
The name of the group should be a short
phrase rather than a single word
„
„
Single word titles tend to lose their meaning
The name of the group may come from a
card in the pile
Finally, Discuss the Diagram
„
The team should discuss the diagram
To gain a better understanding of the topic
and the relationships between different
aspects of the topic
„ To identify areas missed during brainstorming
„
Affinity Diagram
RY
DA
Comfortable Upright
Passengers Feel Comfortable
Cost
N
CO
SE
Low Operating Low Service Comfortable
Costs
Reclined
Costs
PR
IM
AR
Y
MARKET
QUALITY
REQUIREMENTS
Technical and
Regulatory Requirements
Customer and technical/
regulatory requirements
TERTIARY
Arm rest folds right away
Arm rest wide enough
Enough leg room
Doesn't give you bum ache
Doesn't hurt shoulders of
taller person
Lumbar support doesn't
hurt shorter person
Doesn't hit person behind
when you recline
Back can be adjusted to any
position and doesn't slip
Doesn't soak up spilt drink
Easy to clean
Fabric stain resistant
Durable
Light weight
Easy to move around
Fit more passengers in
FST 1000
16 G LOAD CASE
MAX ALLOWABLE DEFLECTION
INTERFACE TO FLOOR RAILS
Establishing Customer Importance
Ratings & Customer Competitive
Comparisons
Importance Ratings and
Competitive Comparisons
Obtaining Customer Ratings
& Comparisons
„
Postal questionnaires
„
Telephone interviews
„
Face to face interviews
„
Clinics
„
Focus groups
„
Listening
Customer questionnaire
BIG PIZZAS LTD
For the Pizza you have just eaten please tell us how
important the following items were to you and please
tell us how you rate your satisfaction with each item.
Poor
Fair
Good
2
3
4 5
1
2
3
4 5
VARIED CHOICE OF CHEESE
1
2
3
4 5
1
2
3
4 5
NO ANCHOVIES
1
2
3
4 5
1
2
3
4 5
Excellent
Extremely important
1
Very good
Important
LOTS OF CHEESE
Very important
PLEASE RATE
Not very important
How do you rate
our Pizza on this
item
Not important
How important is
this item
Customer importance
ratings & competitive
comparisons
Customer complaint
history
Customer complaint
history
Establishing engineering
characteristics
What I
want is
1, 2, 3
To achieve
this we will
need x, y, z.
Engineering
characteristics
Engineering characteristics
Technical competitive
comparisons
„
„
„
Provide hard facts
Focus on the market
Give the impetus to improve
Technical competitive
comparisons
Technical competitive
comparisons – aircraft seat study
Engineering characteristics –
grouping data
Human
Process
requirements requirements
Train assembly
staff to attach
covers on the back
and side of seat
only.
Engineering
Units of
characteristics measurement
Seat gap width
Seat gap depth
Arm rest width
Seat back thickness
Seat back profile
Grind off any lumps
Seat pan profile
of set adhesive
Seat pan height
after assembly.
Foam thickness
Foam hardness
Wipe excess
adhesive off seat
structure during
assembly.
mm
mm
mm
mm
mm (x,y,z)
mm (x,y,z)
mm
Mm
Vickers
Engineering characteristics
Engineering
characteristics
Seat back thickness
Seat back profile
Company
(A = us)
Measured Average Value
Value on
data
value
selected 1-5 scale
as
normal
A
B
C
28 mm
36 mm
25 mm
A
Smooth,
doubly curved
Flat
Smooth, singly
curved
B
C
Relationships
30
29.6
3.2
2.5
3.6
4
-
9
1
3
Establishing Links
„
Highlights the relationship between:
„
Customer requirements and engineering
characteristics
„
Technical and regulatory requirements and
engineering characteristics
„
The symbols used are:
~ Strong relationship
c Medium relationship
U Weak relationship
Establishing Engineering
Characteristics Importance
Ratings
„
Values assigned to relationship symbols:
ƒ
ƒ
ƒ
Strong relationship
Medium relationship
Weak relationship
~=9
c=3
U=1
It e
m
N
um
Armrest recess depth
Armrest recess width
Height of back
Profile of back
Profile of pan
Back thickness
Pan height
Back hinge location
Loci of hinge
Clutch locking force
Clutch resistance (open)
Fabric tear resistance
Fabric wear resistance
Washable fabric
Stain resistant fabric
Liquid resistant fabric
Fatigue performance
Structural strength
Structural stiffness
Material FST Performance
Foam stiffness
Foam thickness
Mountings interchangeable
Number of fasteners
Location of fasteners
be
r
Width of armrest
Armrest
Back
Fabric
Structure
All
Establishing links –
relationships matrix
Establishing links –
correlation matrix
STRONG PO SITIVE RELATIONSHIP
PO SITIVE RELATIONSHIP
NEGATIVE RELATIONSHIP
STRONG NEGATIVE RELATIONSHIP
Foam
Mountings
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
Armrest
ENGIN EERIN G
CHARACTERISTICS
Fabric
Arm rest wide enough
Enough leg room
Doesn't give you bum ache
Doesn't hurt shoulders of
taller person
7
7
Easy to clean
Fabric stain resistant
Durable
Light weight
Easy to move around
Fit more passengers in
ABSOLUTE
ENG. CHAR.
IMPORTANCE RATINGSRELATIVE
Height of back
Profile of back
Profile of pan
Back thickness
Pan height
Back hinge location
Loci of hinge
Clutch locking force
Clutch resistance (open)
Fabric tear resistance
Fabric wear resistance
Washable fabric
Stain resistant fabric
Liquid resistant fabric
Fatigue performance
Structural strength
Structural stiffness
Material FST Performance
Foam stiffness
Foam thickness
Mountings interchangeable
Number of fasteners
Location of fasteners
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
7
Doesn't hit person behind
when you recline
Doesn't soak up spilt drink
Mountings
5
5
8
8
Lumbar support doesn't
hurt shorter person
Back can be adjusted to any
position and doesn't slip
Foam
Armrest recess width
E
TERTIARY
Arm rest folds right away
Structure
Armrest recess depth
C
RY
Comfortable Upright
Passengers Feel Comfortable
Cost
DA
Low Operating Low Service Comfortable
Costs
Reclined
Costs
PR
IM
AR
Y
RE
E Ite
O m
F Nu
IM m
MARKET
P O ber
RT
QUALITY
A
REQU IREMEN TS
N
N
CO
SE
Back
EG
Width of armrest
D
All
Establishing technical targets
and ratings
8
5
6
6
6
9
4
5
114
5
54
54 182 290
2
2
8
12
24 204 105
87
63
81
72
54
54
54 108 117
81 135 81
27 120 123 36
63 36
1
4
3
3
3
2
2
2
3
1
3
9
4
5
5
6
3
5
5
2
2
Technical Targets &
Engineering Importance
Rating
Establishing Technical
Targets and Ratings
„
Determine target values for the Engineering
Characteristics.
„
Determine the technical difficulty of achieving
the target value. (1=easily – 5=very difficult)
„
Calculate the Importance Rating.
Establishing technical targets
Establishing the degree of
difficulty
2
4
4
5
3
3
5
4
4
4
3
2
4
4
4
4
4
4
2
2
1
3
1
580 mm
T.B.I.
T.B.I.
25 mm
450 mm
x= 150, y= 50
T.B.I.
100 N
5N
3 mm Test
1x10 strokes
100 washers
Test 013
1 gm/hr
1x10 cycles
7000 N Test
70 mm at 7000 N
5 min +
20 MN/m2
25 mm
Interchange
4
Over rails
50 mm
TECHN ICAL
TARGETS
Worse
TECHN ICAL
COMPETITIVE
COMPARISON S
1
2
3
4
Best
5
Analysis of Chart
6
4
6
2
55 mm
DEGREE OF TECHN ICAL DIFFICU LTY 1
80 mm
1 = easily, 5 = very difficult
=A
=B
=C
Benefits of QFD
„
Less time in development.
„
Fewer and earlier changes.
„
Fewer start-up problems (and costs).
„
Fewer field problems.
„
Improved customer focus (and satisfaction).
„
Better targeted design and development.
„
A better knowledge base.
Practical points
„
Requires management commitment.
„
Success is determined by the accuracy of
customer requirements.
„
Always start small.
„
Involve the right people.
„
Matrix analysis can be used for any decisionmaking process.
The QFD team
(manufacturing)
„
„
„
„
„
„
„
„
„
Designers.
Marketing.
Manufacturing engineers.
Sales support.
Manufacturing.
Production control.
Quality.
Maintenance.
Suppliers.
QFD cascade
Design
Requirements
Part
Characteristics
Manufacturing
Operations
Production
Requirements
Customer
Requirements
Design
Requirements
Part
Characteristics
Manufacturing
Operations
Things to do next
„
Agree project.
„
Establish scope, limitations and constraints.
„
Establish objectives.
„
Agree approximate resources, timing and
milestones.
„
Agree team session format.
„
Agree methods of data collection.
„
Gather customer data.