Lasers Based Manufacturing (eBook)

Dr. Shrikrishna N. Joshi has completed his doctoral studies in the area of "Intelligent modeling and optimization of electric discharge machining process" from IIT Bombay in the year 2009. Since then he is working as an Assistant Professor in the Department of Mechanical Engineering, IIT Guwahati. His research interests are Micro-machining and Micro-bending using Lasers; Computer aided design and manufacturing (CAD/CAM); Manufacturing process modeling and optimization; and Mechatronics. He is guiding five PhD students those who are working on various research areas such as laser bending, laser induced plasma micro-machining, thin-wall milling and single point diamond turning. Dr. Joshi has about 25 papers published in international journals and conferences of national/international reputes. Dr. U.S. Dixit obtained a bachelor's degree in Mechanical Engineering from the University of Roorkee (now Indian Institute of Technology Roorkee) in 1987, an M.Tech. in Mechanical Engineering from Indian Institute of Technology (IIT) Kanpur in 1993, and a Ph.D. in Mechanical Engineering from IIT Kanpur in 1998. A Professor in the Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Dr. Dixit has published numerous papers and five books. He has also edited a book on Metal Forming, guest-edited a number of special journal issues, and is an associate editor for the Journal of Institution of Engineers Series C.

Preface 6
About the Conference 8
Editorial Acknowledgments 9
Contents 10
About the Editors 13
1 A Simple Analytical Model of Laser Bending Process 14
Abstract 14
1 Introduction 14
2 Modeling by ABAQUS 17
3 Model for the Prediction of Bending Angle 19
4 Validation of Model 23
5 Estimation of Yield Stress by Inverse Analysis and Model Updating 26
6 Conclusion 27
References 27
2 Laser Forming of Mild Steel Sheets Using Different Surface Coatings 29
Abstract 29
1 Introduction 30
1.1 What Is ``Laser''? 30
1.2 Forming Process 31
1.3 Manufacturing Through Lasers 31
2 Laser Forming 32
2.1 Parameters Affecting Laser Forming 33
2.2 Advantages and Disadvantages of Laser Forming 33
3 Literature Review of Some Recent Work 34
4 The Objective of the Present Work 35
5 Experimental Details 36
6 Effect of Surface Coatings on Energy Absorption 38
7 Effect of Different Coatings on Line Bending of Mild Steel Sheets 42
8 Effect of Surface Coatings on Generation of Complex Shaped Surfaces 45
8.1 Dome Shaped Surfaces 45
8.2 Bowl Shaped Surfaces 48
9 Conclusion 49
References 50
3 Finite Element Simulations of Laser Bending of Small Sized Sheets 52
Abstract 52
1 Introduction 52
2 Finite Element Modeling Using ABAQUS 53
3 Effect of Parameters on Bending Angle 56
3.1 Effect of Laser Power 57
4 Conclusions 63
References 64
4 Numerical and Experimental Studies on Pulsed Laser Forming of Sheet Metal 65
Abstract 65
1 Introduction 65
2 Literature Review 66
3 Theory of Pulsed Laser Forming 67
4 Finite Element Formulation 68
5 Experimental Validations 71
6 Results and Discussion 73
7 Summary 76
8 Scope for Future Study 76
References 76
5 Experimental Studies on TGM and BM Dominated Curvilinear Laser Bending of Aluminum Alloy Sheets 78
Abstract 78
1 Laser Bending Process 79
2 Laser Bending Mechanisms 81
2.1 Temperature Gradient Mechanism (TGM) 81
2.2 Buckling Mechanism (BM) 82
2.3 Upsetting Mechanism (UM) 84
3 Edge Effect in Laser Bending Process 85
4 Curvilinear Laser Bending 86
5 Experimental Studies on TGM and BM Curvilinear Laser Bending of Aluminum Alloy 88
5.1 Experimental Details 88
5.2 Results and Discussion 92
5.2.1 Laser Bending Using TGM 92
5.2.2 Laser Bending of Thin Sheets Using BM 95
6 Conclusions 98
References 99
6 Mathematical Formulation for Development of Compound Curve Surface by Laser Line Heating 101
Abstract 101
1 Introduction 101
2 Basics of Differential Geometry of Surfaces 102
2.1 Surfaces 102
2.2 Regular Surfaces 102
2.2.1 The First Fundamental Form 104
Curve Length on a Surface 104
Surface Area 105
2.2.2 Second Fundamental Forms 105
Normal Curvature and Principal Curvature 106
2.2.3 Gaussian and Mean Curvatures 107
3 Surface Development 108
3.1 Determination of Strain Field 108
3.1.1 Formulation 108
3.2 Determination of the Planar Developed Shape 109
3.3 Heating Line Generation 110
3.3.1 Bending Paths 110
3.3.2 Shrinkage Path 112
4 Conclusions 112
References 113
7 Surface Alloying of Aluminum with Copper Using CO2 Laser 114
Abstract 114
1 Introduction 114
2 Significances of Surface Alloying 115
3 Significance of (CO2) Laser for Surface Alloying 115
4 Details of Experiments 116
5 Results and Discussions 117
5.1 Crystal Size and Lattice Strain 117
5.2 Surface Roughness 118
5.3 Micro Hardness Analysis 118
5.4 Microstructure and Morphology Analysis 120
5.5 Porosity Challenges in Alloying 122
5.6 Conclusions 123
References 123
8 Effect of Pulsed Nd:YAG Laser Parameters in Preplaced TiC Coating on Aluminium Substrate 124
Abstract 124
1 Introduction 125
2 Various Types of Laser Surface Modification Techniques 125
2.1 Laser Surface Modification Without Use of External Material 126
2.1.1 Laser Surface Heat Treatment 126
2.1.2 Laser Surface Melting and Re-solidification 126
2.1.3 Laser Shock Peening 127
2.2 Laser Surface Modification by Using External Material 127
2.2.1 Based on Degree of Mixing of Coating Material with Substrate Surface 128
Laser Alloying 128
Laser Dispersing 128
Laser Cladding 128
2.2.2 Based on the Mode of Supply of Coating Material 129
Preplaced Powder Method 129
Powder Injection Method 130
Wire Feeding Method 130
3 Advantages, Limitations and Applications of Laser Coating Process 131
3.1 Advantages 131
3.2 Limitations 131
3.3 Applications 132
4 TiC Coating on Al Substrate Using Pulse Nd:YAG Laser 132
4.1 Laser Coating on Al Substrate 132
4.2 Laser Coating with TiC 134
4.3 Laser Coating Using Pulsed Laser 135
5 Experimental Planning Procedures 136
6 Results and Discussion 137
6.1 Micro-hardness 137
6.2 Microstructure Analysis 140
7 Conclusion 141
References 142
9 Finite Element Simulation of Laser Cladding for Tool Steel Repair 145
Abstract 145
1 Introduction 146
2 Process Modelling 149
2.1 Physical Description of Process 149
2.2 Model Assumptions 151
2.3 Governing Equations 151
2.4 Numerical Formulation 153
2.5 Loading and Boundary Conditions 154
2.6 Material Properties 155
3 Results and Discussion 156
3.1 Temperature Field 156
3.2 Results in Dilution and Heat Affected Zone 157
3.3 Residual Stress Analysis 158
4 Conclusions 159
References 160
10 Excimer Laser Micromachining and its Applications 163
Abstract 163
1 Introduction 164
2 Types of Excimer Laser 165
3 Laser Interaction with Polymers 169
4 Excimer Laser Machining Process 172
5 Different Polymers Used for Industrial Micromachining 176
6 Applications of Excimer Laser 177
6.1 Fabrication of Microfluidic System 177
6.2 Fabrication of Micro Lens Array 179
7 Excimer Laser Micromachining Under Gaseous Environment 179
8 Conclusions 182
Acknowledgments 182
References 182
11 Laser Induced Micromachining and Preliminary Experiments on Manufacturing of Micro-channel on Mild Steel 184
Abstract 184
1 Introduction 184
1.1 Laser Induced Micromachining 185
1.1.1 Process Mechanism of Laser Induced Micromachining 187
1.2 Laser Induced Plasma Micromachining 189
1.3 Laser Induced Plasma Assisted Ablation (LIPAA) 190
1.4 Advantages of LIMM 191
1.5 Limitations of LIMM 191
2 Literature Review on Laser Induced Micromachining 192
2.1 Numerical Studies of LIMM 192
2.2 Experimental Studies on LIMM 193
3 Preliminary Experimentation on Laser Induced Micromachining 200
4 Summary 202
References 203
12 Fabrication of Micro Lens Array by Excimer Laser Micromachining 206
Abstract 206
1 Introduction 206
2 Parameters of Laser Radiation 207
3 Key Terminologies in Laser Material Interactions 207
4 Mechanism of Laser Ablation of Polymers 208
5 Analysis and Observations 210
5.1 Nature of Ablation 210
5.2 Plume Interaction During the Laser Pulse 211
5.3 Ablation Rate and Threshold 211
5.4 Mask Projection Technique 213
6 Fabrication of Micro Lens Array 216
6.1 Experimental Setup 217
6.2 Experimental Procedure 218
7 Result and Discussion 218
7.1 Analysis of Masks 218
7.2 Analysis of Micro Lens Profiles 219
7.2.1 Measurement of Ablation Rate of PMMA 220
7.2.2 Calculation of Theoretical Profile 221
7.2.3 Micro Lens Profile---Experimental Results 222
8 Conclusions 223
Acknowledgments 223
References 223
13 Studies on CO2 Laser Micromachining on PMMA to Fabricate Micro Channel for Microfluidic Applications 226
Abstract 226
1 Introduction 227
1.1 Theoretical Background 228
1.2 Mechanism of Material Removal During CO2 Laser Micromachining of PMMA 233
2 Experimental Set-Up 233
2.1 Micromachining of PMMA Substrate 233
2.2 Characterization of Micro-machined PMMA Substrate 234
3 Optimization of CO2 Laser Process Parameters for Smooth Surface 235
3.1 Hybrid Micro Machining to Obtain Smooth Surface 239
3.2 Field Emission Scanning Electron Microscope (FESEM) Imaging of PMMA Substrate 239
4 Wettability Measurements for Microchannels 240
4.1 Bacterial Cell Viability Studies on Surface Obtained by Hybrid Micromachining 242
5 Conclusion 242
References 242
14 Energy Based Analysis of Laser Microchanneling Process on Polymethyl Methacrylate (PMMA) 244
Abstract 244
1 Introduction 244
2 Determination of Material Properties 246
3 Energy Based Modeling of CO2 Laser Microchanneling of PMMA 250
4 Material Removal Mechanism 255
5 Results and Discussion 256
6 Conclusions 257
Acknowledgments 257
References 257
15 Fiber Laser Micro-machining of Ti-6Al-4V 259
Abstract 259
1 Introduction 260
1.1 Advantages of Fiber Lasers Over Other Solid State and Gas Lasers 262
1.2 Need of Laser Beam Micro-grooving Process 262
1.3 Importance of Ti-6Al-4V Micro-grooves in Research and Industrial Perspective 263
1.4 Basic Mechanism of Laser Micro-grooving Process of Ti-6Al-4V 264
1.5 Literature Review on Laser Beam Micro-machining of Ti-6Al-4V 265
2 Working Principle of Fiber Laser Generation 268
3 Experimental Studies on Fiber Laser Micro-machining of Ti-6Al-4V 269
3.1 Fiber Laser Micro-machining Setup 269
3.2 Experimental Planing 270
3.3 Experimental Results and Discussions 272
3.4 Influence of Process Parameters on Micro-groove Geometry and Surface Roughness 272
3.4.1 Influence of Scan Speed on Width, Depth and Surface Roughness on Ti-6Al-4V Micro-grooves 274
3.4.2 Influence of Pulse Frequency on Width, Depth and Surface Roughness on Ti-6Al-4V Micro-grooves 275
3.4.3 Influence of Number of Pass on Width, Depth and Surface Roughness on Ti-6Al-4V Micro-grooves 277
3.4.4 Influence of Average Power on Width, Depth and Surface Roughness 278
3.5 Photographic Exhibits of Ti-6Al-4V Micro-grooves and Its Surface Characteristics 280
4 Conclusions 282
Acknowledgments 283
References 283
16 Nd:YAG Laser Marking on Zirconia Ceramic 286
Abstract 286
1 Introduction 287
2 Basic Mechanism of Laser Marking 289
2.1 Marking by Material Removal from the Surface 289
2.1.1 Etching 289
2.1.2 Surface Melting 290
2.1.3 Ablation 290
2.1.4 Engraving 291
2.2 Marking by Surface Modification 292
2.2.1 Foaming 292
2.2.2 Carbonisation 292
2.2.3 Annealing 293
2.2.4 Colouring 293
3 Nd:YAG Laser Marking Process Parameters 294
3.1 Pulse Frequency 294
3.2 Scanning Speed 295
3.3 Focused Spot Size 295
3.4 Laser Power 295
3.5 Lamp Current 297
3.6 Pulse Width 297
3.7 Air Pressure 297
4 Evaluation of Nd:YAG Laser Marking Quality Characteristics 298
4.1 Mark Width 298
4.2 Mark Depth 298
4.3 Mark Intensity 298
5 Laser Marking Technique and Procedure Used for Experimentation 299
6 Optimization of Nd:YAG Laser Marking Based on RSM and ANN Model 301
6.1 Experimental Planning and Development of Empirical Model Based on RSM 301
6.1.1 Analysis of Process Parameters on Marking Quality Characteristics on Zirconia 302
Parametric Influences on Mark Width 302
Parametric Influences on Mark Depth 304
Parametric Influences on Mark Intensity 306
6.1.2 Multi-objective Optimization of Nd:YAG Laser Marking Quality Characteristics 308
6.2 Development of Artificial Neural Network 309
6.2.1 ANN Results and Analysis 312
6.3 Optimization and Prediction Through ANN 316
7 Conclusions 318
Acknowledgments 318
References 318
17 Nd:YAG Laser Microdrilling of SiC-30BN Nanocomposite: Experimental Study and Process Optimization 320
Abstract 320
1 Introduction 321
1.1 Laser Beam Machining 321
1.1.1 Laser Beam Drilling 323
Laser Beam Microdrilling 324
2 Mechanism of Material Removal During Laser Beam Drilling 326
3 Overview of Proposed Optimization Methodology 328
4 Experimental Setup Used in the Present Research 329
4.1 Nd:YAG Laser Beam Machining Set up 329
4.2 Selection of Process Parameters and Workpiece Material 333
5 Experimental Observation 334
6 Determination of Optimal Parameter Settings 336
6.1 Grey Relational Generating 336
6.2 Determination of Grey Relational Coefficients 337
6.3 Grey Relational Grades Determination 337
7 ANOVA Analysis 339
8 Confirmation Test 341
9 Conclusion 342
References 342
18 Pulsed Nd:YAG Laser Micro-turning Process of Alumina Ceramics 345
Abstract 345
1 Introduction 346
2 Laser Micro-turning Process 347
3 Development of Laser Micro-turning System 351
4 Experimental Methodology of Laser Micro-turning 353
5 Various Measurement Schemes 354
6 Results and Discussion 355
6.1 Study the Influences of Overlap Factors on Surface Roughness Criterion 356
6.1.1 Influence of Spot Overlap on Surface Roughness (Ra) 358
6.1.2 Influence of Circumferential Overlap on Surface Roughness (Ra) 359
6.1.3 Microscopic Analysis of Laser Micro-turned Surface 361
6.2 Study of Defocusing Conditions at Multi-objective Optimization to Achieve Better Quality Surface 362
6.2.1 Multi-objective Optimization of Surface Roughness and Depth Deviation 363
6.2.2 Study of Laser Defocusing Conditions During Laser Micro-turning 364
6.2.3 Analysis Based on SEM Micrographs of Laser Micro-turned Surface 370
6.3 Comparative Study of Surface Roughness Criteria at Laser Focused and Defocused Conditions During Laser Micro-turning 371
7 Conclusions 381
Acknowledgments 381
References 381
19 A Literature Review on CO2 Laser Welding 383
Abstract 383
1 Introduction 383
2 Laser Welding 384
2.1 CO2 Laser Welding 384
2.2 Hybrid Laser Welding 385
3 Studies on Mechanical Properties of Welded Joints 386
4 Microstructural Studies of Welded Joints 387
5 Modelling of Laser Welding Processes 390
5.1 Analytical Modelling for Laser Welding 390
5.2 Numerical Modelling for Laser Welding 391
6 Studies on the Laser Welding Process Parameters Optimization 394
7 Study the Effect of External Process Parameters on Laser Welding 395
7.1 Study the Effect of Assistance Gases 395
7.2 Study the Effect of Electric, Magnetic Field and Electrical Potential 396
8 Image Processing and Feature Extraction 397
9 Summary 397
References 398
20 Fiber Laser Welding in a Controlled Inert Gas Atmosphere: An Experimental and Numerical Investigation 401
Abstract 401
1 Introduction 402
2 Materials and Methods 405
3 Theoretical Background 408
4 Results and Discussion 411
5 Conclusions 419
Acknowledgments 419
References 419
21 A 3-D Finite Element Analysis of Transient Temperature Profile of Laser Welded Ti-6Al-4V Alloy 422
Abstract 422
1 Introduction 422
1.1 Weldability of Titanium Alloy 424
2 Literature Survey on Welding of Ti Alloy 425
3 FEM Simulation of LBW Process 430
3.1 Preprocessing 431
3.1.1 Element Type 431
3.1.2 Material Properties 431
3.1.3 Meshing 432
3.2 Solution 432
3.3 Post Processing 433
4 Governing Equation and Boundary Conditions 433
4.1 Heat Source Model 434
5 Finite Element Modelling 435
6 Results and Discussion 436
7 Conclusions 439
References 439
22 Selective Laser Sintering: A Case Study of Tungsten Carbide and Cobalt Powder Sintering by Pulsed Nd:YAG Laser 442
Abstract 442
1 Introduction 443
1.1 Background 443
1.2 Principle of SLS Process 444
1.3 Laser Material Interaction in SLS Process 444
1.4 Sintering Mechanism of WC--Co Powder 445
1.5 Process Parameters of SLS Process 445
1.5.1 Process Parameters for Continuous Wave Lasers (Fiber/CO2) 445
1.5.2 Process Parameters for Modulated/Pulse Wave Lasers (Fiber/Nd:YAG) 446
1.6 Advantages and Disadvantages of SLS 446
1.6.1 Advantages of SLS 446
1.6.2 Disadvantages of SLS 447
1.7 Applications of Selective Laser Sintering Process 447
2 Experimental Details 447
2.1 Experimental Setup for Pulsed Laser Sintering 447
2.2 Inert Gas Chamber with Powder Spreading Arrangement 448
2.3 Design of Experiments 450
2.4 Procedure 450
3 Results and Discussion 452
3.1 Taguchi Analysis for Density, Micro-hardness and Porosity 452
3.1.1 ANOVA for Density 452
3.1.2 Optimal Parameters for Higher Density 453
3.1.3 ANOVA for Microhardness 453
3.1.4 Optimal Parameters for Higher Microhardness 453
3.1.5 ANOVA for Porosity 454
3.1.6 Optimal Parameters for Lower Porosity 455
3.2 Micro-structural Characterization 456
3.3 XRD Analysis 457
4 Conclusions 458
References 459
AuthorIndex 461
SubjectIndex 463