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Principles of Laser Materials Processing [Kietas viršelis]

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(Kettering University and University of Michigan in Ann Arbor)
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Coverage of the most recent advancements and applications in laser materials processing This book provides state-of-the-art coverage of the field of laser materials processing, from fundamentals to applications to the latest research topics. The content is divided into three succinct parts:





Principles of laser engineering-an introduction to the basic concepts and characteristics of lasers, design of their components, and beam delivery



Engineering background&-a review of engineering concepts needed to analyze different processes: thermal analysis and fluid flow; solidification of molten metal; and residual stresses that evolve during processes



Laser materials processing-a rigorous and detailed treatment of laser materials processing and its principle applications, including laser cutting and drilling, welding, surface modification, laser forming, and rapid prototyping





Each chapter includes an outline, summary, and example sets to help readers reinforce their understanding of the material. This book is designed to prepare graduate students who will be entering industry; researchers interested in initiating a research program; and practicing engineers who need to stay abreast of the latest developments in this rapidly evolving field.
PREFACE xxv
PART I PRINCIPLES OF INDUSTRIAL LASERS 1
1 Laser Generation
3
1.1 Basic Atomic Structure
3
1.2 Atomic Transitions
7
1.2.1 Selection Rules
7
1.2.2 Population Distribution
8
1.2.3 Absorption
8
1.2.4 Spontaneous Emission
9
1.2.5 Stimulated Emission
10
1.2.6 Einstein Coefficients: Ae,B12,B21
11
1.3 Lifetime
13
1.4 Optical Absorption
14
1.5 Population Inversion
17
1.6 Threshold Gain
18
1.7 Two-Photon Absorption
21
1.8 Summary
23
References
24
Appendix 1A
24
Problems
25
2 Optical Resonators
26
2.1 Standing Waves in a Rectangular Cavity
26
2.2 Planar Resonators
33
2.2.1 Beam Modes
34
2.2.1.1 Longitudinal Modes
35
2.2.1.2 Transverse Modes
36
2.2.2 Line Selection
38
2.2.3 Mode Selection
39
2.2.3.1 Transverse Mode Selection
39
2.2.3.2 Longitudinal Mode Selection
40
2.3 Confocal Resonators
43
2.4 Generalized Spherical Resonators
48
2.5 Concentric Resonators
49
2.6 Stability of Optical Resonators
51
2.7 Summary
56
Appendix 2A
56
Problems
57
3 Laser Pumping
63
3.1 Optical Pumping
63
3.1.1 Arc or Flash Lamp Pumping
63
3.1.2 Diode Laser Pumping
65
3.1.2.1 Longitudinal Pumping
65
3.1.2.2 Transverse Pumping
65
3.1.3 Pumping Efficiency
66
3.1.4 Energy Distribution in the Active Medium
66
3.2 Electrical Pumping
68
3.3 Summary
70
4 Rate Equations
71
4.1 Two-Level System
71
4.2 Three-Level System
73
4.3 Four-Level System
76
4.4 Summary
79
Appendix 4A
80
Problems
80
5 Broadening Mechanisms
83
5.1 Line-Shape Function
83
5.2 Line-Broadening Mechanisms
84
5.2.1 Homogeneous Broadening
84
5.2.1.1 Natural Broadening
84
5.2.1.2 Collision Broadening
86
5.2.2 Inhomogeneous Broadening
89
5.3 Comparison of Individual Mechanisms
90
5.4 Summary
92
Appendix 5A
93
Problems
93
6 Beam Modification
96
6.1 Quality Factor
96
6.2 Q-Switching
99
6.2.1 Mechanical Shutters
100
6.2.2 Electro-Optic Shutters
101
6.2.3 Acousto-Optic Shutters
103
6.2.4 Passive Shutters
103
6.3 Q-Switching Theory
104
6.4 Mode-Locking
107
6.4.1 Active Mode Locking
111
6.4.2 Passive Mode-Locking
112
6.5 Laser Spiking
113
6.6 Lamb Dip
114
6.7 Summary
115
Appendix 6A
116
Problems
116
7 Beam Characteristics
118
7.1 Beam Divergence
118
7.2 Monochromaticity
121
7.3 Beam Coherence
122
7.3.1 Spatial Coherence
122
7.3.2 Temporal Coherence
125
7.4 Intensity and Brightness
128
7.5 Frequency Stabilization
128
7.6 Beam Size
129
7.7 Focusing
130
7.8 Radiation Pressure
131
7.9 Summary
131
References
132
Appendix 7A
132
Problems
133
8 Types of Lasers
135
8.1 Solid-State Lasers
136
8.1.1 The Ruby Laser
136
8.1.2 Neodymium Lasers
138
8.1.2.1 The Nd:YAG Laser
139
8.1.2.2 The Nd:Glass Laser
139
8.2 Gas Lasers
139
8.2.1 Neutral Atom Lasers
140
8.2.2 Ion Lasers
142
8.2.3 Metal Vapor Lasers
144
8.2.4 Molecular Gas Lasers
146
8.2.4.1 Vibrational–Rotational Lasers
147
8.2.4.2 Vibronic Lasers
155
8.2.4.3 Excimer Lasers
156
8.3 Dye Lasers
158
8.4 Semiconductor (Diode) Lasers
160
8.4.1 Semiconductor Background
161
8.4.2 Semiconductor Lasers
164
8.4.3 Semiconductor Laser Types
170
8.4.3.1 Homojunction Lasers
170
8.4.3.2 Heterojunction Lasers
170
8.4.3.3 Quantum Well Lasers
172
8.4.4 Low-Power Diode Lasers
172
8.4.5 High-Power Diode Lasers
172
8.4.6 Applications of High-Power Diode Lasers
174
8.5 Free Electron Laser
174
8.6 New Developments in Industrial Laser Technology
176
8.6.1 Slab Lasers
176
8.6.2 Disk Lasers
177
8.6.3 Ultrafast (Femtosecond) Lasers
178
8.6.4 Fiber Lasers
180
8.7 Summary
182
References
183
Appendix 8A
184
Appendix 8B
184
Appendix 8C
185
Problems
186
9 Beam Delivery
188
9.1 The Electromagnetic Spectrum
188
9.2 Reflection and Refraction
189
9.2.1 Reflection
189
9.2.2 Refraction
190
9.3 Birefringence
191
9.4 Brewster Angle
192
9.5 Polarization
194
9.6 Mirrors and Lenses
200
9.7 Beam Expanders
202
9.8 Beam Splitters
204
9.9 Beam Delivery Systems
205
9.9.1 Conventional Systems
205
9.9.2 Fiber Optic Systems
207
9.9.2.1 Optical Fiber Characteristics
208
9.9.2.2 Waveguide Structure
208
9.9.2.3 Background
209
9.9.2.4 Fiber Types
210
9.9.2.5 Beam Degradation
212
9.9.2.6 Application of Optical Fibers in High-Power Laser Systems
220
9.10 Summary
221
References
222
Appendix 9A
223
Problems
224
PART II ENGINEERING BACKGROUND 229
10 Heat And Fluid Flow
231
10.1 Energy Balance During Processing
231
10.2 Heat Flow in The Workpiece
232
10.2.1 Temperature Distribution
232
10.2.1.1 Thick Plate with Point Heat Source (Three Dimensional)
236
10.2.1.2 Thin Plate with Line Heat Source (Two Dimensional)
238
10.2.2 Peak Temperatures
245
10.2.3 Cooling Rates
247
10.2.4 Thermal Cycles
252
10.2.5 Gaussian Heat Source
253
10.2.6 The Two-Temperature Model
255
10.3 Fluid Flow in Molten Pool
259
10.3.1 Continuity Equation
260
10.3.2 Navier–Stokes Equations
261
10.3.3 Surface Tension Effect
262
10.3.4 Free Surface Modeling
265
10.4 Summary
266
References
267
Appendix 10A
269
Appendix 10B Derivation of Equation (10.2A)
270
Appendix 10C Moving Heat Source
271
Appendix 10D
272
Appendix 10E
273
Appendix 1OF
274
Appendix 10G
275
Problems
277
11 THE MICROSTRUCTURE
281
11.1 Process Microstructure
281
11.1.1 Fusion Zone
282
11.1.1.1 Initial Solidification
282
11.1.1.2 Microstructure
291
11.1.1.3 Nucleation and Grain Refinement in Molten Pool
299
11.1.1.4 Coring
300
11.1.2 Zone of Partial Melting
302
11.1.3 Heat-Affected Zone
302
11.1.3.1 Pure Metals
303
11.1.3.2 Precipitation-Hardening and Nonferrous Alloys
305
11.1.3.3 Steels
306
11.2 Discontinuities
311
11.2.1 Porosity
312
11.2.2 Cracking
314
11.2.2.1 Hot Cracking
316
11.2.2.2 Liquation Cracking
319
11.2.2.3 Cold Cracking
319
11.2.2.4 Reheat Cracking
324
11.2.2.5 Lamellar Tearing
325
11.2.3 Lack of Fusion
325
11.2.4 Incomplete Penetration
326
11.2.5 Undercut
326
11.3 Summary
327
References
328
Appendix 11A
329
Problems
330
12 Solidification
334
12.1 Solidification Without Flow
334
12.1.1 Solidification of a Pure Metal
334
12.1.2 Solidification of a Binary Alloy
336
12.1.2.1 Temperature and Concentration Variation in a Solidifying Alloy
336
12.1.2.2 Interface Stability Theories
337
12.1.2.3 Mushy Zone
341
12.2 Solidification with Flow
344
12.2.1 Mushy Fluid
346
12.2.2 Columnar Dendritic Structure
348
12.3 Rapid Solidification
349
12.4 Summary
351
References
352
Appendix 12A
353
Appendix 12B Criterion for Solidification of an Alloy
354
Problems
360
13 Residual Stresses and Distortion
361
13.1 Causes of Residual Stresses
361
13.1.1 Thermal Stresses
361
13.1.2 Nonuniform Plastic Deformation
366
13.2 Basic Stress Analysis
368
13.2.1 Equilibrium Conditions
370
13.2.2 Strain—Displacement Relations
371
13.2.3 Stress–Strain Relations
372
13.2.3.1 Linear Elastic Behavior
372
13.2.3.2 Plastic Flow of Metals
373
13.2.3.3 Elastic–Plastic Conditions
374
13.2.4 Plane Stress and Plane Strain
375
13.2.4.1 Plane Stress
375
13.2.4.2 Plane Strain
375
13.2.4.3 Plane Stress/Plane Strain Equations
377
13.2.4.4 Compatibility Equation
377
13.2.4.5 Stress–Strain Relations for Plane Stress/Plane Strain
378
13.2.5 Solution Methods
378
13.3 Effects of Residual Stresses
379
13.3.1 Apparent Change in Strength
380
13.3.2 Distortion
381
13.4 Measurement of Residual Stresses
383
13.4.1 Stress Relaxation Techniques
383
13.4.1.1 Sectioning Technique
384
13.4.1.2 Drilling Technique
384
13.4.1.3 Strain Analysis
384
13.4.2 X-Ray Diffraction Technique
389
13.4.2.1 Principle of the X-Ray Diffraction Technique
389
13.4.2.2 The Film Technique
391
13.4.2.3 The Diffractometer Technique
392
13.4.3 Neutron Diffraction Technique
392
13.4.4 Residual Stress Equilibrium
394
13.5 Relief of Residual Stresses and Distortion
395
13.5.1 Thermal Treatments
396
13.5.1.1 Preheating
396
13.5.1.2 Postheating
396
13.5.2 Mechanical Treatments
396
13.5.2.1 Peening
397
13.5.2.2 Proof Stressing
397
13.5.2.3 Vibratory Stress Relief
397
13.6 Summary
397
References
398
Appendix 13A
399
Appendix 13B
400
Problems
400
PART III LASER MATERIALS PROCESSING 407
14 Background on Laser Processing
409
14.1 System-Related Parameters
409
14.1.1 Power and Power Density
410
14.1.2 Wavelength and Focusing
410
14.1.2.1 Determining the Focal Position
412
14.1.2.2 Depth of Focus
412
14.1.3 Beam Mode
413
14.1.4 Beam Form
414
14.1.5 Beam Quality
416
14.1.6 Beam Absorption
417
14.1.6.1 Measurement of Absorptivity
420
14.1.6.2 Beam–Plasma Interaction
421
14.1.7 Beam Alignment
422
14.1.8 Motion Unit
424
14.2 Process Efficiency
424
14.3 Disturbances that Affect Process Quality
426
14.4 General Advantages and Disadvantages of Laser Processing
427
14.4.1 Advantages
427
14.4.2 Disadvantages
427
14.5 Summary
428
References
429
Appendix 14A
429
Problems
430
15 Laser Cutting and Drilling
431
15.1 Laser Cutting
432
15.1.1 Forms of Laser Cutting
432
15.1.1.1 Fusion Cutting
432
15.1.1.2 Sublimation Cutting
432
15.1.1.3 Photochemical Ablation
433
15.1.2 Components of a Laser Cutting System
433
15.1.3 Processing Conditions
434
15.1.3.1 Beam Power
435
15.1.3.2 Beam Characteristics
435
15.1.3.3 Traverse Speed
437
15.1.3.4 Assist Gas Functions
438
15.1.3.5 Effect of Focal Position
443
15.1.4 Laser Cutting Principles
443
15.1.4.1 Beam Absorption During Laser Cutting
444
15.1.4.2 Process Modeling
447
15.1.5 Quality of Cut Part
453
15.1.5.1 Striations of the Cut Surface
453
15.1.5.2 Dross Formation
455
15.1.6 Material Considerations
456
15.1.6.1 Metals
457
15.1.6.2 Nonmetals
460
15.1.7 Advantages and Disadvantages of Laser Cutting
464
15.1.7.1 Advantages
464
15.1.7.2 Disadvantages
464
15.1.8 Specific Comparison with Conventional Processes
465
15.1.8.1 Laser, Plasma Arc, and Oxyacetylene (Oxy-Fuel) Cutting
465
15.1.8.2 Laser Cutting and Electrical Discharge Machining
466
15.1.8.3 Laser Cutting and Abrasive Waterjet Machining
466
15.1.8.4 Laser Cutting and Punching/Nibbling
466
15.1.9 Special Techniques
467
15.2 Laser Drilling
468
15.2.1 Forms of Laser Drilling
468
15.2.1.1 Single-Pulse Drilling
468
15.2.1.2 Multipulse Percussion Drilling
469
15.2.1.3 Trepanning
470
15.2.2 Process Parameters
470
15.2.2.1 Beam Characteristics
470
15.2.2.2 Drilling Characteristics
471
15.2.2.3 Process Defects
471
15.2.3 Analysis of Material Removal During Drilling
472
15.2.3.1 Basic Analysis
473
15.2.3.2 Approximate Analysis
478
15.2.4 Advantages and Disadvantages of Laser Drilling
483
15.2.4.1 Advantages
483
15.2.4.2 Disadvantages
483
15.2.5 Applications
484
15.3 New Developments
484
15.3.1 Micromachining
484
15.3.1.1 Transparent Dielectric Materials
485
15.3.1.2 Metals and Semiconductors
486
15.3.2 Laser-Assisted Machining
489
15.4 Summary
492
References
493
Appendix 15A
498
Problems
499
16 Laser Welding
502
16.1 Laser Welding Parameters
502
16.1.1 Beam Power and Traverse Speed
503
16.1.2 Effect of Beam Characteristics
505
16.1.2.1 Beam Mode
505
16.1.2.2 Beam Stability
505
16.1.2.3 Beam Polarization
505
16.1.2.4 Pulsed Beams
505
16.1.3 Plasma Formation, Gas Shielding, and Effect of Ambient Pressure
506
16.1.3.1 Plasma Formation
506
16.1.3.2 Gas Shielding
508
16.1.3.3 Effect of Ambient Pressure
511
16.1.4 Beam Size and Focal Point Location
511
16.1.5 Joint Configuration
512
16.2 Welding Efficiency
514
16.3 Mechanism of Laser Welding
515
16.3.1 Conduction Mode Welding
515
16.3.2 Keyhole Welding
516
16.3.2.1 Power Absorption in the Keyhole
519
16.3.2.2 Keyhole Characteristics
521
16.4 Material Considerations
528
16.4.1 Steels
529
16.4.2 Nonferrous Alloys
529
16.4.3 Ceramic Materials
531
16.4.4 Dissimilar Metals
532
16.5 Weldment Discontinuities
532
16.5.1 Porosity
532
16.5.2 Humping
533
16.5.3 Spiking
533
16.6 Advantages and Disadvantages of Laser Welding
534
16.6.1 Advantages
534
16.6.2 Disadvantages
535
16.7 Special Techniques
535
16.7.1 Multiple-Beam Welding
535
16.7.1.1 Multiple-Beam Preheating and Postweld Heat Treatment
535
16.7.1.2 Multiple-Beam Flow Control
540
16.7.2 Arc-Augmented Laser Welding
545
16.8 Specific Applications
547
16.8.1 Microwelding
547
16.8.2 Laser-Welded Tailored Blanks
547
16.8.2.1 Advantages of Tailored Blank Welding
548
16.8.2.2 Disadvantages of Tailored Blank Welding
549
16.8.2.3 Applications of Laser-Welded Tailored Blanks
550
16.8.2.4 Formability of Tailor-Welded Blanks
551
16.8.2.5 Limiting Thickness or Strength Ratio
556
16.9 Summary
559
References
560
Appendix 16A
563
Problems
565
17 Laser Surface Modification
568
17.1 Laser Surface Heat Treatment
568
17.1.1 Important Criteria
570
17.1.2 Key Process Parameters
570
17.1.2.1 Beam Power, Size, Speed, and Shielding Gas
570
17.1.2.2 Beam Mode
571
17.1.2.3 Beam Absorption
577
17.1.2.4 Initial Workpiece Microstructure
579
17.1.3 Temperature Field
580
17.1.4 Microstructural Changes in Steels
581
17.1.4.1 Pearlite Dissolution
581
17.1.4.2 Austenite Homogenization
585
17.1.4.3 Transformation to Martensite
586
17.1.5 Nonferrous Alloys
588
17.1.5.1 Solution Treatment
589
17.1.5.2 Aging
589
17.1.6 Hardness Variation
589
17.1.7 Residual Stresses
592
17.1.8 Advantages and Disadvantages of Laser Surface Treatment
592
17.1.8.1 Advantages
592
17.1.8.2 Disadvantages
593
17.2 Laser Surface Melting
594
17.3 Laser Direct Metal Deposition
595
17.3.1 Processing Parameters
596
17.3.2 Methods for Applying the Coating Material
596
17.3.3 Dilution
600
17.3.4 Advantages and Disadvantages of Laser Cladding
601
17.3.4.1 Advantages
601
17.3.4.2 Disadvantages
601
17.4 Laser Physical Vapor Deposition (LPVD)
601
17.5 Laser Shock Peening
603
17.5.1 Background Analysis
605
17.5.2 Advantages and Disadvantages of Laser Shock Peening
608
17.5.2.1 Advantages
608
17.5.2.2 Disadvantages
608
17.6 Summary
608
References
609
Appendix 17A
612
Appendix 17B
613
Problems
614
18 Laser Forming
616
18.1 Principle of Laser Forming
616
18.2 Process Parameters
618
18.3 Laser Forming Mechanisms
619
18.3.1 Temperature Gradient Mechanism
619
18.3.2 Buckling Mechanism
620
18.3.3 Upsetting Mechanism
622
18.3.4 Summary of the Forming Mechanisms
623
18.4 Process Analysis
624
18.5 Advantages and Disadvantages
629
18.5.1 Advantages
629
18.5.2 Disadvantages
629
18.6 Applications
629
18.7 Summary
630
References
630
Appendix 18A
631
Problems
632
19 Rapid Prototyping
633
19.1 Computer-Aided Design
633
19.1.1 Geometric Transformation
634
19.1.1.1 Translation
635
19.1.1.2 Scaling
635
19.1.1.3 Rotation
636
19.1.2 Curve and Surface Design
637
19.1.2.1 Splines
637
19.1.2.2 Bezier Curves
639
19.1.2.3 Surface Representation
640
19.1.3 Solid Modeling
642
19.1.3.1 Constructive Solid Geometry
642
19.1.3.2 Boundary Representation
644
19.1.4 Rapid Prototyping Software Formats
644
19.1.4.1 The STL (Stereolithography) Format
644
19.1.4.2 The 1GES Format
646
19.1.5 Supports for Part Building
646
19.1.6 Slicing
647
19.2 Part Building
648
19.2.1 Liquid-Based Systems
649
19.2.1.1 Beam Scanning
650
19.2.1.2 Parallel Processing
654
19.2.2 Powder-Based Systems
655
19.2.2.1 Selective Laser Sintering (SLS)
655
19.2.2.2 3D Printing
657
19.2.2.3 Ballistic Particle Manufacturing
658
19.2.3 Solid-Based Systems
658
19.2.3.1 Fused Deposition Modeling
659
19.2.3.2 Laminated Object Manufacturing
659
19.2.4 Qualitative Comparison of Some Major Systems
661
19.3 Post-Processing
662
19.4 Applications
662
19.4.1 Design
663
19.4.2 Engineering, Analysis, and Planning
663
19.4.3 Manufacturing and Tooling
663
19.5 Summary
664
References
665
Appendix 19A
665
Problems
666
20 Medical and Nanotechnology Applications of Lasers
669
20.1 Medical Applications
669
20.1.1 Medical Devices
670
20.1.2 Therapeutic Applications
672
20.1.2.1 Surgical Procedures
673
20.1.2.2 Ophthalmology
673
20.1.2.3 Dermatology
674
20.1.2.4 Dentistry
674
20.2 Nanotechnology Applications
675
20.2.1 Nanoholes and Grating
676
20.2.2 Nanobumps
677
20.2.3 Two-Photon Polymerization
680
20.2.4 Laser-Assisted Nanoimprint Lithography
686
20.3 Summary
686
References
687
21 Sensors for Process Monitoring
689
21.1 Laser Beam Monitoring
689
21.1.1 Beam Power
690
21.1.1.1 Pyroelectric or Thermopile Detector
690
21.1.1.2 Beam Dump
690
21.1.2 Beam Mode
691
21.1.2.1 Laser Beam Analyzers
691
21.1.2.2 Plastic Burn Analysis
696
21.1.3 Beam Size
697
21.1.3.1 Kapton Film
697
21.1.3.2 Other Methods
698
21.1.4 Beam Alignment
698
21.2 Process Monitoring
699
21.2.1 Acoustic Emission
699
21.2.1.1 AE Detection
701
21.2.1.2 Background
703
21.2.1.3 AE Transmission
705
21.2.1.4 Traditional AE Signal Analysis
706
21.2.2 Acoustic Mirror
707
21.2.3 Audible Sound Emission
709
21.2.4 Infrared/Ultraviolet (IR/UV) Detection Techniques
711
21.2.4.1 Infrared Detection
711
21.2.4.2 Ultraviolet Detection
718
21.2.5 Optical (Vision) Sensing
719
21.2.5.1 Optical Detectors
719
21.2.5.2 Detector Setup
719
21.2.5.3 Edge Detection Methodology
720
21.3 Summary
724
References
724
Appendix 21A
727
Problems
728
22 Processing of Sensor Outputs
730
22.1 Signal Transformation
730
22.1.1 The Fourier Transform
731
22.1.2 The Discrete Fourier Transform (DFT)
732
22.1.3 Properties of the Discrete Fourier Transform
733
22.1.4 Advantages of Digital Analysis
734
22.1.5 Pitfalls of Digital Analysis
734
22.1.6 The Sampling Theorem
736
22.1.7 Aliasing
736
22.1.8 Leakage
737
22.1.9 Window Functions
739
22.1.9.1 Rectangular Window
739
22.1.9.2 Triangular Window
739
22.1.9.3 Hanning Window
740
22.1.9.4 Hamming Window
741
22.1.10 Picket Fence Effect
741
22.1.11 Segmental Averaging
742
22.2 Data Reduction
742
22.2.1 Optimum Transform for Data Reduction
742
22.2.2 Variance Criterion
747
22.2.3 Class Mean Scatter Criterion
747
22.3 Pattern Classification
749
22.3.1 Pattern Recognition
749
22.3.1.1 Bayes Decision Theory
749
22.3.1.2 Bayes Decision Rule for Minimum Error
750
22.3.1.3 Discriminant Function Analysis
751
22.3.1.4 Minimum-Distance Classifier
752
22.3.1.5 General Linear Discriminant Function
755
22.3.1.6 Quadratic Discriminant Function
756
22.3.1.7 Least-Squares Minimum Distance Classification
756
22.3.1.8 System Training
759
22.3.2 Neural Network Analysis
760
22.3.3 Sensor Fusion
763
22.3.4 Time–Frequency Analysis
764
22.3.4.1 Short-Time Fourier Transform
764
22.3.4.2 Wavelet Transforms
766
22.3.4.3 Time–Frequency Distributions
767
22.3.4.4 Applications in Manufacturing
769
22.4 Summary
770
References
771
Appendix 22A
773
Problems
774
23 Laser Safety
778
23.1 Laser Hazards
778
23.1.1 Radiation-Related Hazards
778
23.1.1.1 Mechanisms of Laser Damage
779
23.1.1.2 Major Hazards
780
23.1.2 Nonbeam Hazards
782
23.1.2.1 Electrical Hazards
783
23.1.2.2 Chemical Hazards
783
23.1.2.3 Environmental Hazards
783
23.1.2.4 Fire Hazards
784
23.1.2.5 Explosion Hazards and Compressed Gases
784
23.1.2.6 Other Hazards
784
23.2 Laser Classification
784
23.3 Preventing Laser Accidents
785
23.3.1 Laser Safety Officer
785
23.3.2 Engineering Controls
785
23.3.3 Administrative and Procedural Controls
786
23.3.4 Protective Equipment
786
23.3.4.1 Protective Eyewear
786
23.3.4.2 Other Protective Equipment
790
23.3.5 Warning Signs and Labels
792
23.4 Summary
793
References
794
Appendix 23A
795
Problem
795
Overall List of Symbols 797
Index 803
Elijah Kannatey-Asibu Jr., PhD, received his BSc from the Kwame Nkrumah University of Science and Technology, Kumasi, Ghana, in 1974 and his PhD from the University of California at Berkeley in 1980. He has been with the Mechanical Engineering Department at the University of Michigan in Ann Arbor since 1983. Dr. Kannatey-Asibu's research focuses on multisensor monitoring of manufacturing processes, multiple-beam laser processing, acoustic emission investigation of manufacturing processes, and microfabrication using femtosecond lasers. He is a Fellow of the Society of Manufacturing Engineers and of the American Society of Mechanical Engineers.