Quality Engineering: Off-Line Methods and Applications

391 Pages·2013·59.789 MB·\391

by  Chao-Ton Su (Author)

IndustrIal EngInEErIng & ManufacturIng
S
Quality
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Read the Reviews
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“This book provides a high-quality reference for all engineers who wish to apply
experimental design to actual product and process designs. It is well orga-
nized and provides numerous practical examples and case studies that help the
reader understand factorial experimental techniques, Taguchi Methods, and other
m odern techniques more easily.” Q
Off-Line Methods and Applications
—grEgory H. Watson, Past-President of ASQ, Past-Chairman of IAQ, and Chairman of Business
Excellence Solutions, Ltd.
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“During my 30 years in the semiconductor industry I have witnessed quality
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engineering methods become widely applied to shorten R&D cycle time, optimize
product/process parameters, and save cost. This book provides the complete l
structure of quality engineering with plenty of practical cases. It will help readers i
t
to learn these methods quickly and contribute to business success.”

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—long-cHIn tu, Vice President, Taiwan Semiconductor Manufacturing Company

“Quality engineering methods are commonly used in industry to upgrade the
E
quality level. This book is well written and is of great interest both to students
and professionals wishing to develop or expand their knowledge of quality
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engineering. It contains clear presentation and practical implementation that
a re often missing from other texts.” g
—fugEE tsung, Hong Kong University of Science and Technology
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“Unimicron has learned how to use quality engineering approaches (both the n
DOE and Taguchi methods) that can reduce variation and enhance a product’s
e
quality. This book aims to demonstrate the power of these approaches and shows
how these methods can be implemented in either a manufacturing or nonmanu-
e
facturing organization. The payback in customer satisfaction and growth will be
dramatic when these approaches are carefully conducted.” r

—tzyy-Jang tsEng, Chairman, Unimicron Technology Corporation i
n
“Professor Su has extensive experience contending with problems regarding
g
quality in the manufacturing and service industries and has made eminent
contributions to the field of quality engineering. I believe that he is one of the
best-qualified persons to author a book on quality engineering.”

—norIakI kano, Tokyo University of Science
Chao-Ton Su
K16440
ISBN: 978-1-4665-6947-8
90000
9 781466 569478
K16440_Cover_mech.indd 1 1/4/13 11:46 AM

Quality
Engineering
Off-Line Methods and Applications

Quality
Engineering
Off-Line Methods and Applications
Chao-Ton Su
National Tsing Hua University
Taiwan
Boca Raton London New York
CRC Press is an imprint of the
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Contents
Preface ..............................................................................................................................................xi
Acknowledgments ........................................................................................................................xv
Author ..........................................................................................................................................xvii
Chapter 1 Introduction ..............................................................................................................1
1.1 Quality....................................................................................................................................1
1.1.1 The meaning of quality .........................................................................................1
1.1.2 Quality activities .....................................................................................................3
1.2 Robust design ........................................................................................................................4
1.3 Quality engineering .............................................................................................................6
1.3.1 Overview .................................................................................................................6
1.3.2 Taguchi’s quality engineering ..............................................................................6
1.4 Structure of this book ..........................................................................................................7
References ........................................................................................................................................8
Chapter 2 Fundamentals of experimental design ..............................................................11
2.1 Basic principle .....................................................................................................................11
2.2 Factorial experiments .........................................................................................................13
2.2.1 Single-factor experiment......................................................................................13
2.2.1.1 An example ...........................................................................................13
2.2.1.2 Statistical analysis ................................................................................14
2.2.2 Two-factor experiment .........................................................................................18
2.3 Two-level full factorial design ..........................................................................................21
2.3.1 Introduction of 2k design .....................................................................................21
2.3.2 Data analysis for two-level full factorial experiment ......................................22
2.3.2.1 The 22 design.........................................................................................22
2.3.2.2 The 23 design .........................................................................................28
2.4 Two-level fractional factorial design ................................................................................32
2.4.1 One-half fraction of 2k factorial design ..............................................................32
2.4.2 The 2k−p fractional factorial design .....................................................................36
2.5 Three-level factorial design ...............................................................................................37
2.6 Steps of DOE project...........................................................................................................39
References ......................................................................................................................................43
Chapter 3 Principles of quality engineering.......................................................................45
3.1 Taguchi’s perspectives .......................................................................................................45
3.1.1 General philosophy ..............................................................................................45
3.1.2 Unique points ........................................................................................................46
v
vi Contents
3.2 Noise factors ........................................................................................................................47
3.3 Relationship between quality characteristics and parameters ....................................48
3.4 Classification of parameters ..............................................................................................49
3.4.1 Signal factors .........................................................................................................49
3.4.2 Control factors .......................................................................................................49
3.4.3 Noise factors ..........................................................................................................50
3.5 Three phases of quality engineering ...............................................................................51
3.5.1 System design ........................................................................................................51
3.5.2 Parameter design ..................................................................................................52
3.5.3 Tolerance design ...................................................................................................52
3.6 Two-step optimization procedure ....................................................................................54
References ......................................................................................................................................55
Chapter 4 Utilization of orthogonal arrays .........................................................................57
4.1 Introduction to orthogonal arrays ....................................................................................57
4.1.1 Orthogonal arrays ................................................................................................57
4.1.2 Orthogonality ........................................................................................................59
4.2 Use of orthogonal arrays ...................................................................................................60
4.3 Interaction ............................................................................................................................64
4.4 Linear graphs ......................................................................................................................65
4.5 Orthogonal arrays and fractional factorial designs ......................................................67
4.6 Special techniques for modifying orthogonal arrays ...................................................68
4.6.1 Column-merging method....................................................................................68
4.6.2 Branching design ..................................................................................................68
4.6.3 Dummy-level technique ......................................................................................71
4.6.4 Compound factor method ...................................................................................72
4.7 Summary .............................................................................................................................73
References ......................................................................................................................................76
Chapter 5 Quality loss function and static signal-to-noise ratios ..................................77
5.1 The concept of quality loss ................................................................................................77
5.2 Taguchi’s quality loss .........................................................................................................80
5.2.1 Taguchi’s definition of quality ............................................................................80
5.2.2 Loss function .........................................................................................................80
5.3 Types of quality loss functions .........................................................................................82
5.3.1 The nominal-the-best case ...................................................................................83
5.3.2 The smaller-the-better case .................................................................................86
5.3.3 The larger-the-better case ....................................................................................86
5.3.4 The asymmetric nominal-the-best loss function .............................................87
5.4 SN ratio .................................................................................................................................88
5.4.1 Introduction ...........................................................................................................88
5.4.2 Basic definition of SN ratio ..................................................................................88
5.5 SN ratios for static problems .............................................................................................91
5.5.1 The smaller-the-better type SN ratio .................................................................92
5.5.2 The larger-the-better type SN ratio ....................................................................93
5.5.3 The nominal-the-best type SN ratio ..................................................................94
5.5.4 Signed target type SN ratio .................................................................................98
References ....................................................................................................................................100
Contents vii
Chapter 6 Parameter design for static characteristics .....................................................101
6.1 The experiment setup of parameter design ..................................................................102
6.2 Procedures of static parameter design ..........................................................................104
6.2.1 Steps of static parameter design .......................................................................104
6.2.2 Taguchi’s two-step optimization procedure ...................................................105
6.3 Data analysis of parameter optimization experiment ................................................108
6.3.1 Estimation of control factor effects ..................................................................108
6.3.2 Analysis of variance ...........................................................................................110
6.3.3 Prediction and confirmation .............................................................................114
6.4 The issue of interactions ..................................................................................................117
6.5 Examples of parameter design with static characteristics ..........................................118
6.6 Case studies of parameter design with static characteristics .....................................127
6.6.1 Case study: Optimization of Cu wire bonding process for IC assembly .........127
6.6.1.1 The problem ........................................................................................127
6.6.1.2 Implementation of Taguchi methods for Cu wire bonding .........128
6.6.1.3 Comparison of cost savings..............................................................131
6.6.2 Case study: Optimization of optical performance of broadband tap
coupler ..................................................................................................................131
6.6.2.1 The problem ........................................................................................131
6.6.2.2 Implementation of Taguchi methods for improving tap
coupler optical performance ............................................................132
6.6.2.3 A comparison .....................................................................................136
6.7 Operating window ...........................................................................................................136
6.8 Computer-aided parameter design ................................................................................140
6.9 Analysis of discrete data .................................................................................................150
6.9.1 SN ratio for fraction defective type problem ..................................................150
6.9.2 Analysis of ordered categorical data ...............................................................154
References ....................................................................................................................................163
Chapter 7 Parameter design for dynamic characteristics ...............................................165
7.1 Introduction .......................................................................................................................165
7.2 Basic SN ratios for dynamic problems ...........................................................................168
7.2.1 Zero-point proportional equation ....................................................................168
7.2.1.1 Dynamic-type SN ratio .....................................................................169
7.2.1.2 Dynamic-type SN ratio calculation .................................................169
7.2.1.3 Taguchi’s dynamic-type SN ratio ....................................................175
7.2.2 Reference-point proportional equation ...........................................................177
7.2.3 Linear equation ...................................................................................................179
7.3 Procedures of dynamic parameter design ....................................................................181
7.3.1 Steps of dynamic parameter design .................................................................182
7.3.2 Two-step optimization procedure for dynamic problems ...........................182
7.4 Examples of parameter design with dynamic characteristics ...................................184
7.5 Case studies of parameter design with dynamic characteristics ..............................187
7.5.1 Case study: Improvement of measurement accuracy of blood glucose
strip .......................................................................................................................188
7.5.1.1 The problem ........................................................................................188
7.5.1.2 Implementation ..................................................................................188
7.5.1.3 Comparison ........................................................................................190
viii Contents
7.5.2 Case study: Optimization of optical whiteness ratio for flexible
display ............................................................................................................191
7.5.2.1 The problem ........................................................................................191
7.5.2.2 Implementation ..................................................................................192
7.5.2.3 Comparison ........................................................................................201
7.6 Other types of dynamic problems .................................................................................201
7.6.1 When true values of signal factor levels are unknown ................................201
7.6.2 When ideal functions are not linear ................................................................203
7.6.3 When input is not confined to one signal factor ............................................205
7.6.4 When no noise exists ..........................................................................................207
References ....................................................................................................................................210
Chapter 8 Implementing parameter design ......................................................................211
8.1 Analysis in planning stage ..............................................................................................211
8.1.1 Project scope ........................................................................................................211
8.1.2 Energy transformation .......................................................................................212
8.1.3 Ideal function ......................................................................................................212
8.1.4 Measure of response ..........................................................................................213
8.1.5 P-diagram ............................................................................................................213
8.2 Selection of quality characteristic ..................................................................................214
8.2.1 Four different levels of quality proposed by Taguchi ...................................214
8.2.2 Guidelines for selecting quality characteristics .............................................214
8.2.2.1 Continuous and easy to measure ....................................................215
8.2.2.2 Absolute zero ......................................................................................215
8.2.2.3 Additive or monotonic ......................................................................215
8.2.2.4 Complete .............................................................................................216
8.2.2.5 Fundamental .......................................................................................216
8.3 Selection of noise and control factors ............................................................................217
8.3.1 Selection of noise factors ....................................................................................217
8.3.2 Selection of control factors ................................................................................217
8.3.3 Control and noise factors in product development cycle .............................218
8.4 Differences between Taguchi methods and classical experimental design ............218
8.4.1 Purpose of the experiment ................................................................................219
8.4.2 Response ..............................................................................................................219
8.4.3 Modeling ..............................................................................................................220
8.4.4 Interactions between control factors ................................................................220
8.4.5 Experimental bias ...............................................................................................220
8.4.6 Experimental layout ...........................................................................................221
8.4.7 Significance tests .................................................................................................221
References ....................................................................................................................................222
Chapter 9 Tolerance design ...................................................................................................223
9.1 Concepts of tolerance design ..........................................................................................223
9.2 Procedures of tolerance design .......................................................................................225
References ....................................................................................................................................232
Chapter 10 Mahalanobis–Taguchi system ...........................................................................233
10.1 Mahalanobis distance ......................................................................................................233
10.2 Feature selection ...............................................................................................................237