MEC 400 – INTRODUCTION TO ENGINEERING

AND PROBLEM SOLVING

CHAPTER 2Introduction to Mechanical

Engineering Design

What is Engineering Design? A creative and comprehensive process Integrates mathematics, basic sciences, engineering sciences, engineering

economics and other subjects for the creation of components, systems, products and processes to satisfy specific needs and constraints.

i.e. constraints include economic, safety, health, environmental and social factors, the requirements of standards and legislation, and other considerations such as maintainability, serviceability, and manufacturability.

- Phases of design process:1. Phase I = Conceptual Design2. Phase II = Embodiment Design3. Phase III = Detail Design4. Phase IV = Planning for Manufacture5. Phase V = Planning for Distribution6. Phase VI = Planning for Use7. Phase VII = Planning for Retirement of product

1. Phase I - Conceptual Design

2. Phase II - Embodiment Design

3. Phase iii – Detail Design

Step 1Identify

Problems

Prob. StatementBenchmarking

QFDPDS

Step 4Concept

Evaluation

Pugh conceptDecision MatrixTaguchi Method

Step 3Generating

concept

Brainstorming Functional Pchart

Step 2Gather

Information

ReferencesElectronic Media

Internet

Step 1Product

architecture

Arrangement of physical elementsModularity

Step 3Parametric

design

Robust design Set

tolerances,DFM,DFA,DFE

Tolerances

Step 2Configuration

designPreliminary selection of

materials and manufacturing

processesModeling

Sizing of partsStep 1

Product architecture

Engineering drawings

Finalize PDS

Problem Definition Most important steps in the engineering design process.

1. Identifying customer needs:a. Interview customersb. Focus groupc. Customer surveyd. Customer complaints

Benchmarking – method for measuring company operation against the best company inside and outside of the industries

◦ Select the product, process, or functional area that is to be benchmark.

◦ Identify the performance metrics that will be measured and used for comparison.

◦ Compare the best in class product or process with the in house equivalent using the performance metrics

◦ Specified program and actions to meet an exceed the competition.

QFD – Quality Function Deployment A planning and problem solving tool that is finding growing acceptance

for translating customer requirements into engineering characteristics of a product.

A largely graphical method that systematically looks at all the elements that go into the product definition.

Helps organizations seek out both spoken and unspoken needs. QFD links the needs of the customer (end user) with design,

development, engineering, manufacturing, and service functions. Also known as ‘House of Quality’

House of quality

PDS – Product Design Specification

A statement of what a product to be designed is intended to do. Its aim is to ensure the development of a product meets the need of the

users. The PDS is a specification of what is required but not the specification of

the product itself.

Gather Information

Information from Internet Engineering URLs

Patent Literature Intellectual Property Patents

Handbook

Concept Generation

Brainstorming Functional decomposition Morphological chart

Kerusi Kereta

Keselamatan Pengguna

Ubahsuai Penyandar

Kepala

Ubahsuai Penyandar

Ubahsuai Tempat duduk

●Pergerakan ke depan & belakang●Bentuk

●Titik ubahsuai

●Pergerakan bersudut ●Bentuk

●Titik ubahsuai

●Pergerakan ke atas dan bawah

●Bentuk ●Titik ubahsuai

●Jenis ●Titik ubahsuai

●Bentuk ●Pergerakan

Memuatkan System

Pengesan Sel Beban

Rajah 3.3: Penguraian Fungsi Pokok

Morphological chart Chart arranges a functions and sub-functions in a logical order Each sub-function list the possible how Purpose to uncover combinations of ideas that comprise design concepts

that might not ordinarily be generated

Evaluation of concepts

1. Comparison Based on Absolute Criteria 2. Pugh’s Concept Selection Method 3. Weighted Decision Matrix

Kriteria Konsep 1 Konsep 2 Konsep 3 Kerusi Standar

d

Tempat duduk:Mekanisme yang mempunyai banyak pilihan titik rehat dan pergerakan yang lancar

+ - - D

Penyandar : Keselesaan, mudah untuk diubah-suai

+ S - A

Penyandar kepala:Pergerakan yang mudah dan tidak memenuhi ruang

S - + T

Keselamatan pengguna: Ringkas dan selamat S - - U

Lokasi pengesan: Pergerakan yang mudah dan kestabilan pengesan terjamin

+ + - M

∑+3 1 1

∑-0 3 4

∑S2 1 0

Pugh’s Concept Selection Method