EDGE™

Using QFD to Establish Design Specifications

prepared by Prof. Marcos Esterman (ISE)

Prof. Edward Hensel (ME)

& Prof. Paul Stiebitz (ISE)

Copyright © 2005 Rochester Institute of TechnologyAll rights reserved.

EDGE™

Outline

• QFD Overview • Drill Example

Copyright © 2005 Rochester Institute of TechnologyAll rights reserved.

EDGE™

Specification Table

EDGE™

Questions to be Addressed in Developing Specifications

• What is the function of the product?

• What is the state of the product?– e.g. size

• What costs are involved?

• What sort of buying experience will customers encounter?

• What will be experienced in the field?

Clausing, D., Total Quality Development,: A Step-By-Step Guide to World Class Concurrent Engineering, ASME Press, NY 1994, pp. 126 - 127

EDGE™

Setting the Final Values

• Develop Technical Models– Analytical– Physical

• Develop Cost Models

• Trade-offs where Necessary – E.G. Cost vs. Performance– Conjoint Analysis

• Specification Flow-down

EDGE™

Quality Function Deployment (QFD)

¤ Ž ¤ mŽ mŽ ¤ m¤ mŽ ¤ Ž ¤ mŽ mŽ ¤ m¤ mŽ ¤ Ž ¤ mŽ mŽ ¤ m¤ mŽ ¤ Ž ¤ mŽ mŽ ¤ m¤ mŽ ¤ Ž ¤ mŽ mŽ ¤ m¤ mŽ ¤ Ž ¤ mŽ mŽ ¤ m¤ mŽ ¤ Ž ¤ mŽ mŽ ¤ m¤ mŽ ¤ Ž ¤ mŽ mŽ ¤ m¤ mŽ ¤ Ž ¤ mŽ mŽ ¤ m¤ mŽ ¤ Ž ¤ mŽ mŽ ¤ m¤ mŽ ¤ Ž ¤ mŽ mŽ ¤ m¤ mŽ ¤ Ž ¤ mŽ mŽ ¤ m¤ mŽ ¤ Ž ¤ mŽ mŽ ¤ m¤ mŽ ¤ Ž ¤ mŽ mŽ ¤ m¤ mŽ ¤ Ž ¤ mŽ mŽ ¤ m¤ mŽ ¤ Ž

PartsCharacteristics

EngineeringCharacteristics

Key ProcessOperations

ProductionRequirements

Houseof Quality

PartsDevelopment

ProcessPlanning

ProductionPlanning

I II III IV

Cu

sto

me

rA

ttri

bu

tes

En

gin

ee

rin

gC

ha

ract

eri

stic

s

Pa

rts

Ch

ara

cte

rist

ics

Ke

y P

roce

ssO

pe

ratio

ns

Hauser, J., Clausing, D.., “The House of Quality”, Harvard Business Review, May/June 1988, Vol. 66, Iss. 3, pg. 63 – 74.

These are tasks completed by a cross-functional team.

EDGE™

The House of Quality

2. customer/sponsor

requirements3

. cu

sto

mer

’s a

sse

ssm

ent

of

imp

ort

an

ce

4. design specifications/engineering metrics

6. a

sse

ssm

en

t o

f c

om

pet

ito

rso

r ex

isti

ng

de

sig

n

7. correlation

matrix

8. absolute importanceof each specification

10. target specifications

9. relative importanceof each specification

11. risk evaluation ofeach specification

5. relationshipmatrix

(how customerrequirementsare driven byspecifications/

metrics)

1. design objective

12. assessment of competitorsor existing design

EDGE™

1. Design Objective• What aspect of the design is this QFD analysis focused on?

2. Customer Needs• Subjectively describe the voice of customer (VOC)

• What does the customer/sponsor say they want the design to do, or how it should perform

3. Customer Needs Importance• Linear Scale of 1-10

• 10 = absolutely essential, 1 = unimportant• Non-Linear Scale

• 9 = Very Important• 3 = Somewhat Important• 1 = Not Very Important

• Pair-wise Comparison

House of Quality - Notes

EDGE™

House of Quality – Notes (cont.)

4. Design Specifications (Engineering Metrics)• What must be achieved in order deliver the customer

requirements • Quantifiable• Measurable

5. Relationship Matrix• Relationship between CUSTOMER NEDS and DESIGN

SPECIFICATIONS• Fundamental question answered: “If the specification is

successfully achieved, will the customer need be satisfied and to what degree”?• 9 = strong correlation• 3 = medium correlation• 1 = weak correlation

EDGE™

6. Customer Perception Benchmarking• Customer’s perception of your products ability to meet identified need relative to

competitive solutions

7. Correlation Matrix• Indication of how the design specifications reinforces or oppose each

other.• The level of correlation can be attained through analysis, experiment,

or engineering judgment.• Important to consider direction of improvement for Design Specification

++ = strongly positively correlated+ = positively correlated- = negatively correlated-- = strongly negatively correlated

8. Absolute Importance of Specification• Inner Product (sum product) of customer need importance and

relationship matrix column corresponding to individual specification

House of Quality – Notes (cont.)

EDGE™

House of Quality – Notes (cont.)

9. Relative Importance of Specification• the absolute scores normalized to 1.0

10. Target Specifications• Quantitatively describe information about

product/specifications• The ideal value of the specification to satisfy customer

• If possible, capture tolerance

11. Risk Evaluation• Indication of the likelihood of successfully achieving each

specification12. Technical Specification Benchmarking

• Assessment product performance relative to competitive solutions on particular specification

EDGE™

Relationship Matrix Evaluation: Tips for Success

• Maintain a high hurdle for significance– Less than 50% of the cells should be populated

• Usually involves much discussion to build team consensus– Do not allow the matrix to exceed 30 x 30– Rank order customer needs

• Set a time limit then stop– Take a poll at the beginning of each cell

• If there is consensus, move on• Sanity Check

– Does the relationship make sense?– Is it supported by field data?

Clausing, D., Total Quality Development,: A Step-By-Step Guide to World Class Concurrent Engineering, ASME Press, NY 1994, pp. 133 - 134

EDGE™

Process Check

• Are there any empty columns or rows?– Empty row

• Customer need not being addressed

– Empty column

• Superfluous EM

• Missing customer need

• Column with too many relationships– EM probably defined too broadly

• Iterate between Customer Needs, Design Specifications & Relationships until consensus built

Clausing, D., Total Quality Development,: A Step-By-Step Guide to World Class Concurrent Engineering, ASME Press, NY 1994, pp. 135

EDGE™

Conclusions So Far & What To Do Next

• Most important design specifications identified– Do they make sense

• If not, investigate• If so, these become the critical parameters to

track through development and assign resources to

• Analyze the degree of interdependence among the engineering metrics– Correlation Roof

• Develop the next decomposition of the system parameters to subsystem parameters

EDGE™

Total System to Subsystem Matrix

Total System Expectations Mis

feed

Rat

e

Mul

tifee

d R

ate

Jam

Rat

e

Cop

y R

ate

Jam

Cle

aran

ce T

ime

Pap

er D

amag

e R

ate

UM

C

Pap

er S

peed

Del

iver

y T

ime

Misfeed Rate < 70/106 9

Multifeed Rate < 30/106 9

Jam Rate < 100/106 9 9 9Copy Rate 70 +/- 2 CPM 9 9Jam Clearance Time < 20 Sec 9

Paper Damage Rate < 100/106 9 9UMC < $6000 9

< 7

0/10

6

< 3

0/10

6

< 3

0/10

6

70 +

/- 2

CP

M

< 2

0 S

ec

< 4

0/10

6

< $

250

11.7

+/-

0.3

ips

141

+/-

10

mse

c

Subsystem Expectation(Friction Retard Feeder)

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The Dynamic Nature of Setting Specifications

Clausing, D., Total Quality Development,: A Step-By-Step Guide to World Class Concurrent Engineering, ASME Press, NY 1994, pp. 100

EM

Concepts

Design

EM

Concepts

Design

Rigid Freeze

Progressive Freeze

Complete, but not Frozen

Do it once, do it right