Quality Function DeploymentSpecifications

R i c h a r d C o w a n , P h . D. , P. E .C h r i s t o p h e r S a l d a n a , P h . D.W o o d r u f f S c h o o l o f M e c h a n i c a l E n g i n e e r i n gG e o r g i a I n s t i t u t e o f T e c h n o l o g yA t l a n t a , G e o r g i a , U S A

2

Phases of Design

CustomerUnderstand the Design Process

Specification DevelopmentSpecification of Information

Conceptual DesignSpecification of a PrincipleFunctional DecompositionGenerate ConceptsConcept EvaluationConcept SelectionPreliminary Design/Embodiment

Detail Design

Specification of ProductionProcess Planning

Manufacture

3

Customer desires (qualitative)

House of Quality (HOQ)

Product performance (quantitative)

Specification is a:Metric with Target Value & unitsmass < 0.1 kg volume < 250 cm3

Customer Needs Engineering Requirements and Specifications

HOQ

HOQ Translates Needs to Specifications

4

Question Customer Statement Interpreted Need ImportanceTypical uses • Independent use by student • Operable by person with

disabilities• (must) 4

Likes • Portable, Mobile• Auditory sound provided when page is

turned• Adjustable stand for different book sizes

• Portable• Signals when performing desired

actions• Adjusts to different book sizes

• (good) 3

Dislikes • Used so much that we wore it out• Heavy• Need consistent page turning

• Lightweight• Repairable by staff• Easily replaceable parts• Predictable page turning• Low failure rate• Long mean time between failures

• (good) 3• (good) 3• (must) 4• (must) 4• (should) 2

Suggested Improvements

• Built in delay for multiple button pushes• Be able to turn newspaper pages• Be able to turn scrapbook pages• Multiple students can share

• Turns variety of page types• Accounts for accidental, repeat

button pushes• Operable by multiple persons

• (should) 2• (good) 3• (must) 4

Customer Needs (e.g., Page Turner)

5

Relationship Matrix in HOQ

Engi

neer

ing

Requ

irem

ents

Customer Requirements (Explicit and

Implicit) adju

stab

le r

ange

of d

imen

sion

s

forc

e on

the

page

rate

of w

ear

of c

ompo

nent

s

# sp

ecia

lty c

ompo

nent

s

# to

ols

need

ed to

rep

air

gran

ular

ity o

f pag

e tu

rnin

g co

ntro

l

erro

r ra

te in

pag

e tu

rnin

g

▼ ▲

operable by person with disabilities

Portable/Mobile

Signals when performing desired actions

lightweight

repairable by staff

easily replaceable parts

num

ber

of a

ssem

bly

and

disa

ssem

bly

orie

erro

r in

alig

ning

par

ts

tole

ranc

e of

use

r-in

itate

d m

otio

ns

grip

forc

e re

quir

ed o

f ope

rato

r

tota

l mas

s

carr

ying

dim

ensi

ons

audi

tory

vol

ume

of s

igna

ls

mat

ch s

igna

ls w

ith u

ser

gene

rate

d ac

tion

inte

nsity

of v

isua

l sig

nals

predictable page turning

low failure rate

safely handles variety of reading materials

●

▽ ●

○○ ○

●● ● ●

●● ○

○ ●●

●○

●

▼▼ ▼Direction of Improvement ▲ ▼ ▼ ▲▼ ▼ ▼ ◇ ◇ ◇ ▼

what

how

Strong ●Medium ○Weak

6

Correlation Matrix in HOQ

force on the page

tolerance of user-initated motions

grip force required of operator

total mass

carrying dimensions

auditory volume of signals

match signals with user generated actions

intensity of visual signals

mber of assembly and disassembly orientati

error in aligning parts

# specialty components

# tools needed to repair

granularity of page turning control

error rate in page turning

rate of wear of components

adjustable range of dimensions

+

−

erro

r ra

te in

pag

e tu

rnin

g

−

# to

ols

need

ed to

rep

air

gran

ular

ity o

f pag

e tu

rnin

g c

Column #

tole

ranc

e of

use

r-in

itate

d m

o

grip

forc

e re

quir

ed o

f ope

rato

tota

l mas

s

rate

of w

ear

of c

ompo

nent

s

adju

stab

le r

ange

of d

imen

sio

forc

e on

the

page

carr

ying

dim

ensi

ons

audi

tory

vol

ume

of s

igna

ls

mat

ch s

igna

ls w

ith u

ser

gene

inte

nsity

of v

isua

l sig

nals

num

ber

of a

ssem

bly

and

disa

erro

r in

alig

ning

par

ts

# sp

ecia

lty c

ompo

nent

s

Engineering requirements

7

Customer needs/perceptions:• These are the ‘whats’• Assigned numerical importance (e.g., 1 to 10)

Engineering metrics/requirements:• These are the ‘hows’• Determine most important ones using Relationships• Determine synergies/conflicts with Correlations

Relationship matrix (RM):• Maps relationship between ‘hows’ and ‘whats’• Quantitative relationship levels (e.g., 1, 3 and 9)

Correlation matrix (CM):• Maps correlation between engineering requirements• Strong positive, positive, negative, strong negative

House of Quality (HOQ) components

7

8

Specifications: Performance/engineering requirements that product must meet or exceed.

Specifications sheet:• Indicates changes to engineering requirements• Indicates importance of the engineering requirement (demand or wish)• Provides a quantifiable requirement (unit and value, or standard)• Assigns responsibility• Provides source justification (standard, calculation, report, survey, etc.)

Connection to HOQ / QFD

Specification List

9

Specification List

Issued: Specification

for:

Page 1 Changes D/W Requirements Resp. Source

Replaces issue of

D = DemandW = Wish

10

What• Hot• Taste/flavor• Smell• Stimulating• Aesthetics• Color• Cost• Grind• Not toxic

HOQ Example (e.g., Coffee)

How• Serving temperature (Hot)• Taste jury (Taste)• Smell jury (Smell)• Measure caffeine level

(Stimulating)• Jury (Aesthetics)• Color standard (Color)• Price (Cost)• Filter & weight (Grind)• Lethal Dose 50% (Median, LD 50)

11

House Of House Of House Of House Of Quality #1 Quality #2 Quality #3 Quality #4

What (#1) How → What (#2) How → What (#3) How → What (#4) How

Cust. Req. Characteristic Feature Process Production Hot Serving Temp. Water Temp. Water Speed Thermometer Smells Good Smell Jury Bean’s Origin Heater Output Flow Control Tastes Good Taste Jury Water Quality Brew Time Timer Cheap Price Weight/Serving Brew Temp. Cleaning Plan Good Color

Color Std. Fineness Of Ground.

Grind Setting Disposal Plan (Raw, Brewed)

Non-Poisonous Analysis Age Of Coffee Water Source No Grounds Filter/Weigh (Raw, Brewed) Filter Quality Time To Serving Reinitialize (Renew Filter,

Grounds)

Entries in Houses of Quality From QFD Deployment are Sources Of Specifications

Coffee Example11

12

Issued:Specification

For: CUP OF COFFEE Page 1

Changes D/W Requirements Resp. SourceCup Of Coffee

EnergyHot

MaterialGood ColorNon-PoisonousNo Grounds

SafetyNon-Poisonous

SignalsGood ColorSmells GoodTastes Good

CostsCheap

Quality ControlGood ColorSmells GoodTastes Good

1st HoQ WHATs fromclass

“““

“

“““

“

“““

Replaces Issue Of

Coffee Specifications #1

D = DemandW = Wish

13

Next Level Of Detail In Specs...

House Of House Of House Of House Of House Of Quality #1 Quality #1 Quality #2 Quality #3 Quality #4

What How →What (#2) How→What (#3) How→What (#4) How

Cust. Req. Characteristic Feature Process Production Hot Serving Temp. Water Temp. Water Speed Thermometer Smells Good Smell Jury Bean’s Origin Heater Output Flow Control Tastes Good Taste Jury Water Quality Brew Time Timer Cheap Price Weight/Serving Brew Temp. Cleaning Plan Good Color Color Std.

Fineness Of Ground.

Grind Setting Disposal Plan (Raw, Brewed)

Non-Poisonous Analysis Age Of Coffee Water Source No Grounds Filter/Weigh (Raw, Brewed) Filter Quality Time To Serving Reinitialize (Renew Filter,

Grounds)

14

Issued:Specification

for: Cup Of Coffee Page 1

Changes D/W Requirements Resp. Source

10/3/9510/3/95

10/3/95

10/3/95

10/3/95

Cup Of Coffee

Energy:Serving Temperature

Material:Color StdNon-PoisonousBrewed Coffee Should Yield Minimum Coffee

Grounds When FilteredSafety:

Non-PoisonousSignals:

Color StdSmells JuryTaste Jury

Costs:Minimize Price

Quality Control:Color StdSmells JuryTaste Jury

1st HoQ from class

NIST STDFDA1st HoQ from class

FDA

NIST STD1st HoQ from class

“

1st HoQ from class

NIST STD1st HoQ from class

“

Replaces issue of

Coffee Specifications #2

D = DemandW = Wish

15

House Of House Of House Of House Of House Of Quality #1 Quality #1 Quality #2 Quality #3 Quality #4

What How →What (#2) How → What (#3) How → What (#4) How

Cust. Req. Characteristic Feature Process Production Hot Serving Temp. Water Temp. Water Speed Thermometer Smells Good Smell Jury Bean’s Origin Heater Output Flow Control Tastes Good Taste Jury Water Quality Brew Time Timer Cheap Price Weight/Serving Brew Temp. Cleaning Plan Good Color Color Std. Fineness Of

Ground. Grind Setting Disposal Plan

(Raw, Brewed) Non-Poisonous Analysis Age Of Coffee Water Source No Grounds Filter/Weigh (Raw, Brewed) Filter Quality TIME TO

SERVING

REINITIALIZE (RENEW

FILTER, GROUNDS)

Continue with Next Level of Detail in Specs

16

Coffee Specifications #3

D = DemandW = Wish

17

Summary – Specification SheetElements• List engineering requirements from HOQ• Add other specifications that are useful• Make sure specifications can be measured• Do not specify specifications dependent on

design decisions, design choices come later!

Describing this figure in text• Describe the contents, not the tool itself!• What are critical specifications?• Use numerical information from figure.

See Ch. 4 in book for detail, templates online