Metrology is practised almost every day, often unknowingly, in our day-to-day tasks. It provides the science, techniques, and precision measuring devices that are used to determine if parts or features of parts fit within the tolerances and dimensions specified for the part. Measurement is closely associated with all the activities pertaining to scientific, industrial, commercial, and human aspects. Its role is ever increasing and encompasses different fields such as communications, energy, medical sciences, food sciences, environment, trade, transportation, and military applications. In addition, metrology is also concerned with the reproduction, conservation, and transfer of units of measurements and their standards. In this competitive world, economic success of most of the manufacturing industries critically depends on the quality and reliability of the products manufactured—requirements in which measurement plays a key role.
This book aims to shed light on some of the unexplored aspects of metrology. It talks about the different studies performed and techniques used in this field in detail. It consists of a theoretical and practical study incorporating standards of measurement, linear measurement, comparators, limits, fits, and tolerances. It also deals with optical measurement and interferometry, metrology of surface finish and nanometrology. Most of the topics introduced in this book cover new techniques and the applications of this field. It explores all the important aspects of the subject in the present-day scenario. This book is designed to meet the needs of students of mechanical engineering and allied disciplines. It will serve as a reference to a broad spectrum of readers. It will have immensely beneficial to professionals and students involved in the area at various levels.
Preface ix
1. Metrology: An Introduction 1
1. Introduction 1
2. Metrology 2
3. Need for Inspection 8
4. Accuracy and Precision 11
5. Objectives of Metrology and Measurements 14
6. General Measurement Concepts 16
7. Errors in Measurements 22
8. Systematic or Controllable Errors 23
9. Random Errors 25
10. Methods of Measurement 26
Epilogue 27
References 28
2. Standards of Measurement 32
1. Introduction 32
2. Standard of Measurement and their Roles 33
3. Standards and Their Roles 35
4. Standards Organization 37
5. National Physical Laboratory 41
6. Line and End Measurements 48
7. Brookes Level Comparator 49
8. Displacement Method 50
Epilogue 51
References 52
3. Limits, Fits, and Tolerances 55
1. Introduction 55
2. Limits 56
3. Interchangeability 56
4. Terminology for Fits and Tolerances 60
5. Hole Basis and Shaft Basis Systems 63
6. Classification of Gauges 65
7. Taylor’s Principle 68
8. Tolerances 69
Epilogue 72
References 72
4. Linear Measurement 75
1. Introduction 75
2. Precision Linear Measurements 76
3. Methods of Linear Measurements 78
4. Linear Measurement Instruments 81
5. Surface Plate 87
6. V-blocks 89
7. Errors in Measurements 89
8. Depth Gauge 93
9. Combination Set 95
10 Callipers 98
11. Micrometer Instruments 101
Epilogue 104
References 105
5. Angular Measurement 108
1. Introduction 108
2. Measuring Angles 108
3. Sine Bar 113
4. Angle Gauges 117
5. Spirit Level 121
6. Optical Instruments for Angular Measurement : Auto collimator 124
Epilogue 127
References 128
6. Comparators 130
1. Introduction 130
2. Types of Comparators 130
3. Mechanical Comparators 133
4. Reed Type Comparator 136
5. Electrical Comparators 136
6. Pneumatic Comparators 138
7. Disadvantages of Pneumatic Comparators 140
8. Op-Amps: Ubiquitous ICs with Multiple Applications 140
Epilogue 147
References 147
7. Optical Measurement and Interferometry 151
1. Introduction 151
2. History 152
3. Optical Measurement Techniques 152
vi
Metrology: Machinist Handbook
4. Interferometry 160
5. Interferometers 166
Epilogue 172
References 172
8. Metrology of Gears and Screw Threads 176
1. Introduction 176
2. Gear Terminology 177
3. Gear Module 178
4. Measurement of Gear Elements 180
5. Gear Measurement 186
6. Measurement of Screw Thread Elements 189
7. Measurement process 192
Epilogue 194
References 195
9. Metrology of Surface Finish 198
1. Introduction 198
2. Surface Metrology Concepts 199
3. Surface Roughness 199
4. Methods of Measuring Surface Finish 203
Epilogue 205
References 205
10. Nanometrology 209
1. Introduction 209
2. Nanometrology Process 211
3. Measurement Techniques 217
Epilogue 219
References 220
Index 223
Yanira Ziegler pursued her Ph.D. in Mechanical Engineering from Public University, Sheffield. She has served as a Visiting Professor at various universities across Europe & America. Her elementary areas of scholarly interests lie in the fields of subtractive manufacturing, automatic control and industrial metrology. Ziegler has been an eminent speaker in seminars across Europe, United States of America, Canada and Middle Asia. She has also won 10 awards and recognitions for her researches and services.
