ME2110

Topic 3 :

Problem Understanding

© GIT 2

Key Concepts

• Design is a Problem Solving Process

• Multiple Phases of Design

• Customer Requirements

• Intrinsic requirements

• Problem understanding Form

• Product Functions

• “drill down to the how's”

• Quality Function Deployment

• House of Quality

ICQ - 1

1. List three (3) phases of design.

2. List (ordered) the section headings of a

technical design report

3. Describe the motions of the Crest brush head

(bristles) in two (2) words.

© GIT 3

2. Customer Requirements

© GIT 4

Review Class Notes

Key Concepts:

Customer side : Needs, Wants, Desires

Product side : Features, Benefits, Quality

Design process is most successful iff. customers’

“quality function” is embedded in the product

QFD - Quality Function Deployment:

Design process originated in Japan to rigorously

ensure customer-centric product development

Seeding questions: How will this design be used? What is the

purpose of the design? What is target Market? Why will people

buy it? Why is it important?

DT1 - Problem Understanding Form

© GIT 5

Ensures evaluation of relative importance of Customer Requirements

Establishes relationships between Customer Requirements and Design

Requirements using Relationship Matrix

• Customer WHATS into Design HOWS

Analysis:

• Blank Row – customer requirement not met; Engineer doesn’t care

• Blank Column – design requirement that customer doesn’t want

• Consider/Think/Infer all intrinsic requirements

Relationship

Matrix

Design Requirements

Cu

sto

mer

Re

qu

irem

ents

1 n Relationship Weight

Strong 9

Medium 3

Weak 1

3. Product Functions

© GIT 6

• Actions the product must be capable of DOING

• Abstract formulation of task

What is a Product Function?

Approach:

• Drill down to the “Hows”

What it is NOT:

• A specific solution path - eg. “Turn Light On”

• A Constraint – eg. “Be smaller than…”

7

DT3 Example: Active-Safety Car Seat

Consider the design of active-safety seats to

increase occupant safety

Use a Function Tree to establish/identify the

product functions

Conventional Car Seat Movie Moving Car Seat Movie

© GIT

© GIT 8

DT3 Example: Active-Safety Car Seat

Close, but not quite there…

© GIT 9

Active Safety Car-Seat

Be

Comfortable

Provide

Active Safety

Maintain

cushioning

Conform to

User Shape

Constrain

occupant

Adjust Occ.

motion

Sense

Collision

Increase

head space

Increase

lower-leg

clearance

DT3 Example: Active-Safety Car Seat

Technically accurate, but not only solution

© GIT 10

4. Design Specifications

• Numerical target (TPM) or constraint

• Derived from Design Standard, Design

Constraint, or Design Analysis

What is a Design Specification

Specification Categories

• Geometric

• Kinematics

• Dynamics

• Energy

• Costs

• Material

• Signals

• Safety

• Ergonomics

• Schedules

• Assembly

• Transportation

• Operation

• Quality Control

• Recycling

© GIT 11

DT4 – Design Specification Sheet/List

• List of Design Specifications, Source, Design responsibility

• Tracks versioning by including date of modification or spec change

• Specifications arranged by category

5. Quality Function Deployment

© GIT 12

Casual-wear in Japan [Photo from Dr. Singhose]

5. DT2 – House of Quality

© GIT 13

Primary design tool in QFD

Ensures comprehensive

understanding of design task

and product requirements

Builds on P.U.F by adding

“rooms” for:

Design Trade-off & Analysis

Identification

Technical Importance

identifies key design

requirements for product

non-subjectively

Customer Competitive

Assessment

Technical Competitive

Assessment

Design Target Specification

Import

ance

Relationship

Matrix

Design Requirements

Custo

mer

Requir

em

ents

1 n

Correlation

Matrix

1 n R Absolute

Relative 1/ R

n/ R

TPMs

Custo

mer

Com

p.

Assessm

ent

Technical Competitive

Assessment

Import

ance

5. H.o.Q Matrices

© GIT 14

Relationship Matrix:

• Relates Customer Requirements

to Design requirements

• WHATS to HOWS

• Symbolic Entries with larger

weighting scale

Relationship Symbol Weight

Strong 9

Medium 3

Weak 1

Correlation Matrix:

• Relates Design Requirements to

Design requirements

• Hows to HOWS

• Clearly identifies design trade-offs

• Demonstrates areas for

optimization efforts

Co-Relationship Symbol

Strong Positive

Positive

Negative

Strong Negative

5. H.o.Q – Design Understanding Analysis

© GIT 15

H.o.Q Analysis:

• Identify Blank rows and columns

• Compare customer vs technical competitive

surveys

• Identify and Resolve conflicts

• Identify advantages (marketing points)

• Confirm target performance metrics

• Identify areas for detailed design optimization

• Strong negative correlations

• Target direction indicators

House of Quality is a comprehensive summary of the

understanding of a design task.

HoQ exposes areas for detailed analysis and additional evaluation

5. HoQ – Detailed Example

© GIT 16

Product: Car door

Customer requirements?

5. HoQ – Detailed Example

© GIT 17

Product: Car door

6. Summary

© GIT 18

A. Customer/Product Requirements Problem understanding, Initial Analysis

B. Design Specification Target Performance Metrics, Design Constraints

C. Conceptual Design

I. Concept Generation

II. Concept Evaluation

D. Detail Design

E. Prototyping

F. Design Finalization

I. Specification for Production

DT1 – P.U.F DT2 – H.o.Q

DT4 – Design Spec. Sheet

DT3 – Function tree