Product design for modularity

PRODUCT DESIGN FOR

MODULARITY

PRODUCT DESIGN FOR MODULARITY

Ali K. Kamrani, Ph.D.

University of Michigan-Dearborn

Sa' ed M. Salhieh

Wayne State University

SPRINGER SCIENCE+BUSINESS MEDIA. LLC

Library of Congress Cataloging-in-Publication Data

A C.LP. Catalogue record for this book is available

from the Library of Congress.

Copyright © 2000 by Springer Science+Business Media New York

Originally published by Kluwer Academic Publishers in 2000

Softcover reprint ofthe hardcover Ist edition 2000

AII rights reserved. No part of this publication may be reproduced, stored in a

retrieval system or transmitted in any form ar by any means, mechanical, photo￾copying, recarding, or otherwise, without the prior written permission of the

publisher, Springer Science+Business Media, LLC.

Printed 01/ acid-fi·ee paper.

ISBN 978-4613-5697-4 ISBN 978-1-4615-1725-2 (eBook)

DOI 10.1007/978-1-4615-1725-2

Dedicated to our parents, our brothers and sisters, and Sonia.

Contents

Contents

List of Figures

List of Tables

Preface

Acknowledgements

Chapter 1: Product Development Process: An Introduction

I. The Evolution of Product Development

2. Sequential Product Development

3. Simultaneous/Integrated Product Development

4. Generic Product Development Process

5. Product Development Categories

Chapter 2: Modular Design

I. Modularity Types

2. Modular Systems Characteristics

3. Modular Systems Development

4. Modularity Advantages

Chapter 3: Design for Modularity

I. Needs Analysis

2. Product Requirements Analysis

vii

IX

Xlll

xv

xix

I

3

4

5

16

19

19

21

25

47

49

51

63

Contents

3. Product/Concept Analysis 65

4. Product/Concept Integration 69

5. Case Study: Decomposition Analysis of a Four-Gear Speed Reducer

Design Based on the Methodology 73

Chapter 4: Design for Assembly

I. DFMA Methodology

2. Case Study: DFMA Analysis of a Fog Lamp Design

3. Summary and Conclusion

97

97

III

121

Chapter 5: Design for Manufacture and Template-Based Process Planning 123

I. Geometric and Parametric Design 123

2. Group Technology (GT) 126

3. Design for Manufacture 129

4. Structure for a Template-Based Process Planning System 134

5. APPENDIX A: Crankshaft Parametric File Structure and Listings 140

6. APPENDIX B: GD&T Data File 147

7. APPENDIX C: Formulation Used for Material Removal 148

8. APPENDIX D: Sample Process Plan 162

Chapter 6: Flexible and Modular Cell Design

I. Traditional Manufacturing Systems-An Overview

2. Cellular Manufactuirng Systems

3. Cellular Manufacturing Systems Design

References

Index

169

170

172

174

195

201

List of Figures

Figure 1. Design for Modularity Life Cycle xv

Figure 1.1. Sequential Product Development 3

Figure 1.2. Simultaneous/Integrated Product Development 4

Figure 1.3. Product Development Process 5

Figure 1.4. Needs Recognition 6

Figure 1.5. Parametric Analysis Plot 7

Figure 1.6. Matrix Analysis 8

Figure 1.7. Establishing Design Specifications 10

Figure I.B. Needs-Metrics Matrix 10

Figure 1.9. Concept Generation 12

Figure 1.10. Concept Selection 13

Figure 1.11. Detail Design 14

Figure 2.1. Function and Module Types 21

Figure 2.2. Component-Swapping Modularity 23

Figure 2.3. Component-Sharing Modularity 23

Figure 2.4. Fabricate-to-Fit Modularity 24

Figure 2.5. Bus Modularity 24

Figure 2.6. PC Assembly Diagram 26

Figure 2.7. Structural Decomposition of a Vehicle System 26

Figure 2.B. Structural Decomposition of a Carriage Unit 27

Figure 2.9. Requirements Decomposition 28

Figure 2.10. Ball Bearing Design Constraint-Parameter

Incidence Matrix 29

Figure 2.11. Decomposed Constraint-Parameter Incidence Matrix 30

Figure 2.12. Hierarchical Decomposition of a Complex System 30

Figure 2. /3. Monocode Structure 33

List of Figures

Figure 2.14. Polycode Structure 33

Figure 2.15. Hybrid Structure 34

Figure 2.16. Part-Machine Incidence Matrix 35

Figure 3.1. Overview of the Proposed Design Environment 49

Figure 3.2. Design for Modularity 51

Figure 3.3. Customer Satisfaction Process 52

Figure 3.4. Kano's Model 53

Figure 3.5. The House of Quality 58

Figure 3.6. Function-Structure Diagram 66

Figure 3.7. Computer Physical Decomposition 66

Figure 3.8. Overall Function Flow Diagram 68

Figure 3.9. Function Flow Diagram 68

Figure 3.10. System-Level Specification Decomposition Hierarchy 70

Figure 3.1 1. System Diagram 74

Figure 3.12. Four-Gear Speed Reducer 76

Figure 3.13. Physical Decomposition of Pump System 76

Figure 3.14. Overall Function of the Speed Reducer 77

Figure 3.15. Components' Functions 77

Figure 3.16. System-Level Specification Hierarchy Structure 79

Figure 3.17. Functional Similarity Matrix 81

Figure 3.18. Physical Similarity Matrix 82

Figure 3.19. Combined Similarity Matrix 82

Figure 3.20. Functional Modules 83

Figure 3.21. Physical Modules 83

Figure 3.22. Combined Modules 83

Figure 4.1. Elements ofDFMA 100

Figure 4.2. Traditional Process vs. Concurrent Engineering Process 100

Figure 4.3. The Subtract and Operate Procedure 102

Figure 4.4. Paper Clip Example [51] 102

Figure 4.5. DFMA Functional Criteria Flowchart [8] 103

Figure 4.6. Original Arm Bracket Assembly 104

Figure 4.7. DFMA-Designed Arm Bracket Assembly 104

Figure 4.8. Design for Manual Assembly Worksheet [8, 9] 106

Figure 4.9. Manual Handling-Estimated Times (seconds) [8,9] 107

Figure 4.10. Manual Insertion-Estimated Times (seconds) [8,9] 108

Figure 4.11. Exploded View of Fog Lamp (current design) 112

Figure 4.12. Assembly Sequence of Current Fog Lamp Design 112

Figure 4.13. Functionality Tables for Fog Lamp Design 117

Figure 4. 14. Exploded View of Fog Lamp (proposed design) 119

Figure 4.15. Alternative Design I 120

Figure 4. 16. Alternative Design 2 120

Figure 4./7. Alternative Design 3 121

Figure 5.1. Geometric Modeling Classification 124

Figure 5.2. DFM Process 130

Figure 5.3. CAPP Characteristics 133

Figure 5.4. Integrated Product Design and Process Planning 134

Figure 5.5. Sample Parametric File Format 137

Figure 5.6. Surfaces that Require Machining 138

Figure 5.7. General Crank Dimensions 140

Figure 5.B. Fillet Radii 140

Figure 5.9. Oil Hole Coordinate System 141

Figure 5.10. Counterweight Dimensions 141

Figure 5.11. Lightening Hole Dimensions 142

Figure 5.12. Balance Hole Dimensions 142

Figure 6.1. The Three Kinds of Traditional Manufacturing Systems 171

Figure 6.2. Layouts of Manned and Unmanned Cells 173

Figure 6.3. The Dendrogram Constructed for Sample Parts 190

List of Tables

Table 2.1. Ball Bearing Design Parameters 28

Table 2.2. Ball Bearing Design Constraints 29

Table 2.3. Machines Combined Similarity Methods 43

Table 3.1. Functional Objectives 64

Table 3.2. Operational Functional Requirements 64

Table 3.3. Relationships between Component Functions 69

Table 3.4. GFR vs. SLS 71

Table 3.5. Relationships between Components' Functions 78

Table 3.6. System-Level Specifications 79

Table 3.7. Impact of SLS on GFR 81

Table 4.1. Analysis Results for the Existing and the

Proposed Design Using DFMA Methodology 118

Table 4.2. Analysis Results for the Existing Design and

Alternative Design I 119

Table 4.3. Analysis Results for the Existing Design and

Alternative Design 2 120

Table 4.4. Analysis Results for the Existing Design and

Alternative Design 3 121

Table 5.1. Product-to-Process Features Associativities 125

Table 5.2. GD&T Classifications 126

Table 5.3. Sample GD&T and Process Machines Associativity 126

Table 5.4. Overview ofY-CAPP and G-CAPP Characteristics 132

Table 5.5. CAPP Systems Development Techniques 133

Table 6.1. Characteristics of Cell ular vs. Traditional

Manufacturing Systems 173

Table 6.2. KAMKODE Coding Structure 176

Table 6.3.

Table 6 . ..f.

Table 6.5.

Table 6.6.

Table 6.7.

Table 6.8.

Table 6.9.

Table 6.10.

Table 6.11.

Table 6.12.

Table 6. 13.

Coding of a Sample Part with KAMCODE

Example Weight Categories

Sample Parts Used for Dissimilarity Analysis

Dissimilarity Measures for Two Parts

Disagreement Measures between All Parts

Machine Investment Costs, Annual Available Machine

Time, Tool Investment Cost, and Tool Life

Annual Demand for Various Parts (d,)

Machine Reliability (R)

Cell Configuration

Number of Machine Types and Their Assignments

Number of Tool Types and Their Assignments

List afTables

177

179

180

180

190

191

191

192

192

193

193

Preface

The current marketplace is undergoing an accelerated pace of change that

challenges corporations to innovate new techniques to respond rapidly to an

ever-changing environment. At the center of this changing environment is a

new generation of empowered buyers (customers) equipped with fast￾evolving technologies that allow them to buy from markets scattered across

the globe. Empowering the customers has deprived organizations of what

was once their right-to introduce new products slowly, at their own leisure.

Organizations used to introduce new products every few years, and, for the

most part, products offered limited functionalities and features. A low-priced

quality product-irrespective of customer satisfaction-was a guaranteed

ticket for success.

New global economies and global markets changed business practices

and focused on the customer as the major player in the economy .

Organizations now fail or succeed based upon their ability to respond

quickly to changing customer demands and to utilize new technological

innovations. In such an environment, the advantage goes to the firm that can

offer greater varieties of new products with higher performance and greater

overall appeal. In order to compete in this fast-paced global market,

organizations need to produce products that can be easily configured to offer

distinctive capabilities compared to the competition. Furthermore,

organizations need to develop new methods and techniques to react rapidly

to required changes in products and market trends and to shorten the product

development cycle, which will enable them to gain more economic

competitiveness. This requires that the tasks needed to develop products be

made in parallel, starting at the early stages of product development. By

developing such techniques, organizations will be able rapidly to design

XVI Preface

changed or new products, to change parts of a product, or to change

manufacturing facilities to a new version of a product.

The concept of modularity can provide the necessary foundation for

organizations to design products that can respond rapidly to market needs

and allow the changes in product design to happen in a cost-effective

manner. Modularity can be applied to the design processes to build modular

products and modular manufacturing processes.

Modular products are products that fulfill various overall functions

through the combination of distinct building blocks or modules, in the sense

that the overall function performed by the product can be divided into sub￾functions that can be implemented by different modules or components. An

important aspect of modular products is the creation of a basic core unit to

which different components (modules) can be fitted, thus enabling a variety

of versions of the same module to be produced. The core should have

sufficient capacity to cope with all expected variations in performance and

usage. Components used in a modular product must have features that enable

them to be coupled together to form a complex product.

Designing a modular product can be done by using conventional product

development techniques, but using these techniques will not lead to a

reduction in product development lead time, and thus a new development

methodology is needed that can utilize the full strength of the modular

architecture of products. Using the concept of modularity in product design

focuses on decomposing the overall design problem into functionally

independent sub-problems, in which interaction or interdependence between

sub-problems is minimized. Thus, a change in the solution of one problem

may lead to a minor modification in other problems, or it may have no effect

on other sub-problems. That is, the modular design concept attempts to

establish a design decomposition technique that reduces the interaction

between design components (or modules) to reduce the complexity and

development time of a product.

Thus, a modular design may be defined as one that decomposes a design

problem into parts that are as independent from one another as possible. A

modular design usually is adaptable with little or no modification for many

applications. Modular design can also be viewed as the process of first

producing units that perform discrete functions, then connecting the units

together to provide a variety of functions. Modular design emphasizes the

minimization of interactions between components, enabling components to

be designed and produced independently from each other. Each component

designed for modularity is supposed to support one or more functions. When

components are structured together to form a product, they will support a

larger or general function. This shows the importance of analyzing the

Preface XVII

product function and decomposing it into sub-functions that can be satisfied

by different functional modules.

Modularity can apply to production systems, where it aims at building

production systems from standardized modular machines. The fact that a

wide diversity of production requirements exists has led to the introduction

of a variety of production machinery and a lack of agreement on what the

building blocks should be. This means that there are no standards for

modular machinery. In order to build a modular production system,

production machinery must be classified into functional groups from which

the selection of a modular production system can be made to respond to

different production requirements.

This book proposes a new methodology for modular design. The

roadmap of this methodology is shown in the following figure:

Design Concept ....

(Re)Formulation

Design for --+

Modularity (OFMo)

Design for

Assembly (OFA)

I

I

I

I

I

I

1

I

I

I

1

---------------I

Selection of Material I

and Primary Process D' I for Near Net Shape I

I

I

Feasible/Optimum I

I Design Concept F

I 1,-------------. I

1 Design for

1 Manufacture M I

I I L ______________ I

Template-Based f----+ Process Planning

Modular f------ Manufacturing Cells

Optimization Models

and Sub-System

Generation

I

Simplification of

Product Structure

Knowledge-Based

Engineering and

Decision Trees

I More Economic

Materials. Processes

and Machines

Decision Trees and

Group Technology

Optimization Models

and Manufacturing

Cells Generation

Figure I. Design for Modularity Life Cycle

-

Chapter 1 sets the necessary background for product development by

providing a discussion of sequential and parallel product development