Design Process in Refrigerator

8/12/2019 Design Process in Refrigerator

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May-08 1

Course# DSGN1110 DESIGN PROBLEM ACQUISITION Engineering Design Methodologies

Three Kinds of Design Problems (reminder!)

1. No Solution Ex is ts

Examples: the first PDA, the first car, the first PC, theinvention of the Web, the introduction of air conditioningin buildings.

Relatively unconstrained, but high risk for developers.Vague information, little "background" available.

2. New Si tuat ion

Examples: new subway for a city, new building,introduction of a particular CAD package, "technologyadoption" in general, Car with 3-wheels.

3. Replacement Examples: new subway trains for existing system, new

PCs or software, the "Semantic Web", innovationswithin a product class (the blackberry), renovating abuilding, new car models

May-08 2


DESIGN PROCESS

Customer

Needs

Functional

Requirements

Design

Parameters

Process

Variables

Conceptual

Design

Product

Design

Process

Design

Product Development

May-08 3


DESIGN PROCESS- Definit ions

Functional Requirements (FR):A set of

independent requirements that characterizes the

functional needs of a product or process. Each FR is

independent of other FR.

Design Parameters (DP): are the KEY physical

variables (other equivalent in software design) in thephysical domain that characterize the design that

satisfies the specified FRs.

Process Variables (PV): are the KEY process

variables (other equivalent in software design) in the

process domain that characterize the process that

satisfies the specified DPs.

May-08 4


DESIGN PROCESS- Defini tions- Example

Refrigerator Door

FUNCTIONAL REQUIREMENTS

FR1= Provide access to the items stored in

FR2= Minimize energy costs

DESIGN PARAMETERS

DP1= vertically hung door

DP2= Thermal insulation in the door

PROCESS VARIABLES

PV1= Dimensional characteristics

PV2= Insulation material properties


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DESIGN PROCESS- Example

Functional Requirements (FR) & Design Parameters (DP)

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DESIGN OF A DRILL

4

Cutting

geometry/Coat

Surface finish


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May-08 10


EXPERIMENT TO GET OPTIMUM VALUES

BY HIT & TRIAL (MAY NOT BE OPTIMAL SOL.)

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DESIGN PROCESS- Example

Tap-1 (Coupled design) 2-FR, 4-DP;

Tap-2 (Uncoupled design-GOOD) 2-FR, 2-DP

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May-08 13


WHAT IS WRONG HERE??

May-08 14


DESIGN MATRIX FOR REFRIGERATOR DOOR-1ST

FR1= Provide access to items in refrigerator

FR2= Minimize energy loss

DP1=Vertically hung door

DP2= Thermal insulation material in the door

Design matrix will be:XFR1 0 DP1

=XFR2 X DP2

May-08 15


DESIGN MATRIX FOR REFRIGERATOR DOOR-2ND

FR1= Provide access to items in refrigerator

FR2= Minimize energy loss

DP1=Horizontally hung doorDP2= Thermal insulation material in the door

New Design matrix will be:

XFR1 0 DP1=

0FR2 X DP2

May-08 16


ADAPTED- http://www.petovdesign.com/fridge/fridge.htm

Whirlpool Design Contest 2003, Prague, Czech Republic / 1st prize


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May-08 17


DESIGN PROCESS- COUPLED DESIGN

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QUESTIONS ???

SUMMARY

Concentrate on FUNCTIONAL requirements before goingto the design solutions

DESIGN parameters (DP) should be equal to theFUNCTIONAL requirements (FR)

Try to achieve an UNCOUPLED design by making abalance between FRs & DPs. It may not be possible always!!

Goal should be to achieve ROBUST design with minimuminformation content.

May-08 20


Technical Questioning

To remain focused on the heart of a designproblem, one should always question the currentunderstanding of the project

The TECHNICAL questions should not only beasked at the beginning of a project, but at every

Gate Point, and especially any time when acritical decision needs to be made.

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Technical Questioning (Ask again &

again)

What is the problem really about?

What implicit expectations and desires are

involved?

Are the stated customer needs, requirements,and constraints truly appropriate?

What avenues are open for creativity and

inventive problem solving?

What attributes must the product have?


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May-08 22


Technical Questioning (Ask again &

again) What aspects of the design task can and should

be quantified now?

Do any biases exist with the chosen task

statement or terminology?

Has the design problem been posed at the

appropriate level of abstraction?

What are the technical and technologicalconflicts inherent in the design task?

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Why? Why?? Why??? (to dig deep)

This method simply involves asking the question

Why? of a given undesired situation, in order touncover hidden or implied assumptions, issues,contradictions, or most especially root causes of theundesired situation.

Example 1: The Soup

Father: Son, you must finish your soup.

Son: Why?

Father: Because you must have a well-balanced

meal.Son: Why?

Father: So that you may be able to do whatever youwant.

Son: Well, what I want to do is throw out this soup.

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Example 2: Traffic Congestion

Why do people object to traffic congestion?

Because it causes them irritation.

Why does it cause irritation?

Because it delays one unexpectedly.

Why are unexpected delays irritating?

Because they force one to alter one's plans.

Why do road travelers have plans?

Because the car journey is not an end in

itself...or is it?

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Example 3: Flying

Why do airplanes fly?

Because the sum of lift and thrust forces exceeds thatof the drag and mass forces.

Why is that?

Correct reasoning:

Because of Newton's Laws. Why? There is no why here - this is

essentially a root cause.

Incorrect reasoning:

Because we designed it that way. Why? Because we want the plane to fly. Ahah! A causal loop.

It is interesting to note that when tracing causesthrough purely physical systems, one generally finds

a root cause within 5 Why?questions


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May-08 26


5 Whys

It is interesting to note that whentracing causes through purely physical

systems, one generally finds a root cause

within 5 Why?questions

May-08 29


More on Technical Questioning

What are the key issues in the design problem?

SafetyProductivityCompetitionTechnologySchedulingSome of these issues can be addressed during the

kickoff meeting (e.g. scheduling), while others will

require you to do some research and report back tothe team

Your team should agree how to divide up this

background work so that there is no duplication of

effort.

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FIVE FACTORS FOR SUCCESS

1. AGREEMENTAMONG TEAMS

2. A PLAN WITH DIRECTIONS,RESPONSIBILITIES,ACCOUNTABILITY

and PROGRESS MEASUREMENTTOOL

3. COMMUNICATION BETWEEN TEAM

4. A CONTROLLED SCOPE

5. MANAGEMENT / SPONSOR SUPPORT

May-08 31


Assignment# 2

PROBLEM: City parking meters in all over Ontario

are being damaged and broken (for ??). The

cities are not only losing revenues from parking

meters but also spending money in repairing

existing ones and on buying new ones. Suggest

at least 2 options to eliminate this problem.

Justify your options with arguments in support of

your answers. Start from: What is the

problem? and Why is that happening?

You can work in a group (2-3 persons) or at your

own

You have to present your solution in front of

class


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Questions

Documents

Design Process in Refrigerator