Design of Experiments for Engineers and Scientists (eBook)

Cover 1
TOC$Contents 8
Preface 12
Acknowledgements 13
CH$Introduction to industrial experimentation 14
Introduction 14
Some fundamental and practical issues in industrial experimentation 16
Summary 18
Exercises 18
References 18
CH$Fundamentals of Design of Experiments 19
Introduction 19
Basic principles of Design of Experiments 20
Randomization 21
Replication 22
Blocking 23
Degrees of freedom 23
Confounding 24
Design resolution 25
Metrology considerations for industrial designed experiments 25
Measurement system capability 26
Some tips for the development of a measurement system 27
Selection of quality characteristics for industrial experiments 28
Exercises 28
References 29
CH$Understanding key interactions in processes 30
Introduction 30
Alternative method for calculating the two order interaction effect 33
Synergistic interaction vs antagonistic interaction 35
Scenario 1 36
Scenario 2 38
Summary 40
Exercises 40
References 41
CH$A systematic methodology for Design of Experiments 42
Introduction 42
Barriers in the successful application of DOE 42
A practical methodology for DOE 44
Planning phase 44
Designing phase 46
Conducting phase 46
Analysing phase 47
Analytical tools of DOE 47
Main effects plot 47
Interactions plots 48
Cube plots 49
Pareto plot of factor effects 49
Normal Probability Plot of factor effects 49
Normal Probability Plot of residuals 50
Response surface plots and regression models 51
Model building for predicting response function 53
Confidence interval for the mean response 54
Summary 55
Exercises 55
References 56
CH$Screening designs 57
Introduction 57
Geometric and non-geometric P–B designs 57
Summary 65
Exercises 66
References 66
CH$Full factorial designs 67
Introduction 67
Example of a 22 full factorial design 67
Objective 1: Determination of main/interaction effects which influence mean plating thickness 68
Objective 2: Determination of main/interaction effects which influence variability in plating thickness 70
Objective 4: How to achieve a target plating thickness of 120 units? 71
Example of a 23 full factorial design 73
Objective 1: To identify the significant main/ interaction effects which affect the process yield 74
Objective 2: To identify the significant main/ interaction effects which affect the variability in process yield 76
Objective 3: What is the optimal process condition? 77
Example of a 24 full factorial design 78
Objective 1: Which of the main/interaction effects affect mean crack length? 79
Objective 2: Which of the main/interaction effects affect variability in crack length? 79
Objective 3: What is the optimal process condition to minimize mean crack length? 82
Summary 83
Exercises 84
References 85
CH$Fractional factorial designs 86
Introduction 86
Construction of half-fractional factorial designs 86
Example of a 2(7 4) factorial design 76 89
An application of 2-level fractional factorial design 93
Example of a 2(5 – 1) factorial design 98
Objective 1: To identify the factors which influence the mean free height 99
Objective 2: To identify the factors which affect variability in the free height of leaf springs 100
How do we select the optimal factor settings to minimize variability in free height? 102
Summary 103
Exercises 103
References 105
CH$Some useful and practical tips for making your industrial experiments successful 106
Introduction 106
Get a clear understanding of the problem 107
Project selection 107
Conduct exhaustive and detailed brainstorming session 108
Teamwork and selection of a team for experimentation 109
Select the continuous measurable quality characteristics or responses for the experiment 109
Choice of an appropriate Experimental Design 111
Iterative experimentation 111
Randomize the experimental trial order 112
Replicate to dampen the effect of noise or uncontrolled variation 112
Improve the efficiency of experimentation using blocking strategy 114
Understanding the confounding pattern of factor effects 114
Perform confirmatory runs/experiments 115
Summary 115
Exercises 116
References 116
CH$Case studies 118
Introduction 118
Case studies 118
Optimization of a radiographic quality welding of cast iron 118
Reducing process variability using Experimental Design technique objective of the experiment 123
Slashing scrap rate using fractional factorial experiments 127
Optimizing the time of flight of a paper helicopter 130
Optimizing a wire bonding process using Design of Experiments 136
Training for Design of Experiments using a catapult 140
Optimization of core tube life using designed experiments 145
Optimization of a spot welding process using Design of Experiments 154
Summary 160
References 161
IDX$Index 162