Machining Dynamics – Fundamentals, Applications and Practices
Kai Cheng
Editor
Contents
List of Contributors xvii
1 Introduction .1
1.1 Scope of the Subject .1
1.2 Scientific and Technological Challenges and Needs 2
1.3 Emerging Trends 4
References 6
2 Basic Concepts and Theory 7
2.1 Introduction 7
2.2 Loop Stiffness within the Machine-tool-workpiece System .7
2.2.1 Machine-tool-workpiece Loop Concept .7
2.2.2 Static Loop Stiffness 8
2.2.3 Dynamic Loop Stiffness and Deformation .9
2.3 Vibrations in the Machine-tool System 10
2.3.1 Free Vibrations in the Machine-tool System 10
2.3.2 Forced Vibrations .13
2.4 Chatter Occurring in the Machine Tool System .15
2.4.1 Definition .15
2.4.2 Types of Chatters 16
2.4.3 The Suppression of Chatters 16
2.5 Machining Instability and Control 17
2.5.1 The Conception of Machining Instability 17x Contents
2.5.2 The Classification of Machining Instability .19
Acknowledgements 19
References 19
3 Dynamic Analysis and Control 21
3.1 Machine Tool Structural Deformations 21
3.1.1 Machining Process Forces .22
3.1.2 The Deformations of Machine Tool Structures and Workpieces .30
3.1.3 The Control and Minimization of Form Errors 39
3.2. Machine Tool Dynamics .43
3.2.1 Experimental Methods .43
3.2.2 The Analytical Modelling of Machine Tool Dynamics .47
3.3. The Dynamic Cutting Process .54
3.3.1. Mechanic of Dynamic Cutting 55
3.3.2. The Dynamic Chip Thickness and Cutting Forces 59
3.4. Stability of Cutting Process .63
3.4.1 Stability of Turning 64
3.4.2. The Stability of the Milling Process 68
3.4.3. Maximizing Chatter Free Material Removal Rate in Milling .74
3.4.4. Chatter Suppression-Variable Pitch End Mills .79
3.5. Conclusions .82
References 83
4 Dynamics Diagnostics: Methods, Equipment and Analysis Tools .85
4.1 Introduction 85
4.2 Theory 86
4.2.1 An Example .88
4.2.2 The Substructure Analysis .90
4.3 Experimental Equipment 92
4.3.1 The Signal Processing 92
4.3.2 Excitation Techniques 93
4.3.3 The Measurement Equipment 93
4.3.4 Novel Approaches 94
4.3.5 In-process Sensors .96Contents xi
4.3.6 Dynamometers .96
4.3.7 The Current Monitoring .97
4.3.8 The Audio Measurement 97
4.3.9 Capacitance Probes 97
4.3.10 Telemetry and Slip Rings .98
4.3.11 Fibre-optic Bragg Grating Sensors .98
4.4 Chatter Detection Techniques 98
4.4.1 The Topography .100
4.4.2 The Frequency Domain 100
4.4.3 Time Domain .105
4.4.4 Wavelet Transforms .109
4.4.5 Soft Computing 110
4.4.6 The Information Theory .111
4.5 Summary and Conclusions .111
Acknowledgements 112
References 112
5 Tool Design, Tool Wear and Tool Life 117
5.1 Tool Design 118
5.1.1 The Tool-workpiece Replication Model 118
5.1.2 Tool Design Principles .120
5.1.3 The Tool Design for New Machining Technologies 123
5.2 Tool Materials 124
5.2.1 High Speed Steel 124
5.2.2 Cemented Carbide 124
5.2.3 Cermet 125
5.2.4 Ceramics 125
5.2.5 Diamond .126
5.2.6 Cubic Boron Nitride .127
5.3 High-performance Coated Tools 127
5.3.1 Tool Coating Methods .128
5.3.2 The Cutting Performance of PVD Coated Tools .129
5.3.3 The Cutting Performance of CVD Coated Tools .132xii Contents
5.3.4 Recoating of Worn Tools .133
5.4 Tool Wear .133
5.4.1 Tool Wear Classification .134
5.4.2 Tool Wear Evolution 136
5.4.3 The Material-dependence of Wear .138
5.4.4 The Wear of Diamond Tools .139
5.5 Tool Life .142
5.5.1 The Definition of Tool Life .142
5.5.2 Taylor’s Tool Life Model 142
5.5.3 The Extended Taylor’s Model .144
5.5.4 Tool Life and Machining Dynamics 145
References 148
6 Machining Dynamics in Turning Processes 151
6.1 Introduction 151
6.2 Principles 151
6.2.1 The Turning Process 153
6.3 Methodology and Tools for the Dynamic Analysis and Control 154
6.4 Implementation Perspectives 155
6.5 Applications 156
6.5.1 The Rigidity of the Machine Tool, the Tool Fixture
and the Work Material 156
6.5.2 The Influence of the Input Parameters .162
6.6 Conclusions 164
References 164
7 Machining Dynamics in Milling Processes 167
7.1 Introduction 167
7.1.1 Forced Vibration 167
7.1.2 Self-excited Vibration 168
7.1.4 Nomenclature in This Chapter .170
7.2 The Dynamic Cutting Force Model for Peripheral Milling 171
7.2.1 Oblique Cutting 172
7.1.3 The Scope of This Chapter 169Contents xiii
7.2.2 The Geometric Model of a Helical End Mill .173
7.2.3 Differential Tangential and Normal Cutting Forces .174
7.2.4 Undeformed Chip Thickness .175
7.2.5 Differential Cutting Forces in X and Y Directions 178
7.2.6 Total Cutting Forces in X and Y Directions 180
7.2.7 The Calibration of the Cutting Force Coefficients .181
7.2.8 A Case Study: Verification 186
7.3 A Dynamic Cutting Force Model for Ball-end Milling 186
7.3.1 A Geometric Model of a Ball-end Mill 186
7.3.2 Dynamic Cutting Force Modelling 188
7.3.3 The Experimental Calibration of the Cutting Force Coefficients 194
7.3.4 A Case Study: Verification 198
7.4 A Machining Dynamics Model 200
7.4.1 A Modularisation of the Cutting Force 200
7.4.2 Machining Dynamics Modelling 203
7.4.3 The Surface Generation Model 205
7.4.4 Simulation Model .207
7.5 The Modal Analysis of the Machining System 207
7.5.1 The Mathematical Principle of Experimental Modal Analysis 208
7.5.2 A Case Study .209
7.6 The Application of the Machining Dynamics Model .213
7.6.1 The Machining Setup .213
7.6.2 Case 1: Cut 13 214
7.6.3 Case 2: Cut 14 219
7.7 The System Identification of Machining Processes 224
7.7.1 The System Identification 225
7.7.2 The Machining System and the Machining Process 226
7.7.3 A Case Study .227
7.7.4 Summary 231
References 231
8 Machining Dynamics in Grinding Processes .233
8.1 Introduction 233xiv Contents
8.2 The Kinematics and the Mechanics of Grinding 236
8.2.1 The Geometry of Undeformed Grinding Chips .236
8.3 The Generation of the Workpiece Surface in Grinding 242
8.4 The Kinematics of a Grinding Cycle 248
8.5 Applications of Grinding Kinematics and Mechanics 253
8.6 Summary 259
References 261
9 Materials–induced Vibration in Single Point Diamond Turning 263
9.1 Introduction 263
9.2 A Model-based Simulation of the Nano-surface Generation 264
9.2.1 A Prediction of the Periodic Fluctuation of Micro-cutting Forces .265
9.2.2 Characterization of the Dynamic Cutting System 269
9.2.3 A Surface Topography Model for the Prediction
of Nano-surface Generation 271
9.2.4 Prediction of the Effect of Tool Interference .275
9.2.5 Prediction of the Effect of Material Anisotropy .277
9.3 Conclusions 278
Acknowledgements 279
References 279
10 Design of Precision Machines .283
10.1 Introduction 283
10.2 Principles 284
10.2.1 Machine Tool Constitutions .284
10.2.2 Machine Tool Loops and the Dynamics of Machine Tools .288
10.2.3 Stiffness, Mass and Damping .290
10.3 Methodology 293
10.3.1 Design Processes of the Precision Machine .293
10.3.2 Modelling and Simulation 295
10.4 Implementation .298
10.4.1 Static Analysis .298
10.4.2 Dynamic Analysis 298
10.4.3 A General Modelling and Analysis Process Using FEA 300Contents xv
10.5 Applications 303
10.5.1 Design Case Study 1: A Piezo-actuator
Based Fast Tool Servo System .303
10.5.2 Design Case Study 2: A 5-axis Micro-milling/
grinding Machine Tool .313
10.5.3 Design Case Study 3: A Precision Grinding Machine Tool .317
Acknowledgements 320
References 320
Index 323
Index
ABAQUS, 300
accelerometer, 208
AC motor, 286
acoustic emission (AE), 146–148
adaptive control, 257
air bearing, 289
ALGOR, 302
aluminium oxide (Al2O3), 125
analysis, 294, 298–300
dynamic, 283, 294, 299–300
harmonic, 299
modal, 299
preliminary, 314
spectrum, 300
static, 294, 298
transient, 300
angular velocity, 188
ANSYS, 300
ARMA, 228, 269
ARMAX, 225, 228, 229, 230
ARX, 225
attritious wear, 245
audio measurement, 97
ball end mill, 122, 186–187
brainstorming, 293
built–up edges (BUEs), 120, 172
CAD model, 157
calibration, 181, 194
capacitance probes, 97
carriage, 314
cast iron, 132, 157, 158, 285
cemented carbide, 124–125
ceramics, 125–126
cermet, 125
chatters, 15, 145, 167
Arnold–type, 16
detection, 98–99
marks, 269
reduction, 16
regenerative, 16
suppression, 79
turning, 67
velocity dependent, 16
chemical vapour deposition (CVD),
128, 132
chip, 134, 236
formation, 236
geometry, 234
hammering, 134
shape ratio, 238
size, 244
thickness, 237, 265
chromium nitride (CrN), 128, 129
comb cracks, 134
conceptual design, 294
contact length, 237
control system, 284, 287
COSMOS, 300
crater depth, 135–136
crystallographic orientations, 265,
266, 276–277
cubic boron nitride (CBN), 124, 127
current monitoring, 97
cutter, 178
run–out, 178
cutting, 244324 Index
cutting conditions, 197, 205, 213,
312
cutting direction, 267
cutting efficiency ratio, 243
cutting edge density, 258
cutting forces, 22
axial, 188
coefficients, 181, 183, 194, 198
differential, 178, 191
dynamic, 54, 186, 188, 215
model, 186, 188
normal, 174
proncipal, 172
tangential, 173, 174
total, 180, 193
cutting parameters, 163, 197,199,
213
depth of cut, 163
feed rate, 163
specific energy, 172, 175
speed, 163
cutting plane, 267
cutting process models, 25
cycle time, 257
cylindrical grinding, 248
damping, 9, 290, 291
coefficient, 12
joint, 292
material, 292
ratio, 12
damper, 292
data dependent systems (DDS), 271
DC brushless motor, 286
deflection, 248, 249, 250
deformations, 30
machine tool structures, 30
tools, 32, 33, 34, 36
workpiece, 32, 33, 37–39
delay, 205
Deform 2D/3D, 302
depth of cut, 163, 188, 250
axial, 188
radial, 190
detailed design, 294
diamond, 129
diamond–like carbon (DLC), 128,
129, 132
diamond turning machine, 311
dies, 313
down–hill slope, 198
down milling, 32, 74, 176, 178, 181,
189, 190, 191, 193, 200
dressing, 234
conditions, 235, 247
depth, 245
kinematics, 234, 246
lead, 245
tools, 234
drive system, 284, 286
drying machining, 132
ductile regime machining (DRM),
126
dwell stage, 248, 251
dynamic chip thickness, 59
milling, 62
turning, 60
dynamic cutting force coefficients
(DCFC), 58–59
dynamic cutting system, 269
dynamics, 1, 3, 64, 68, 145, 151, 288
analysis, 44, 154, 293
disgnostics, 85
machine tool, 43, 47–49,
machining, 2, 3, 145, 151, 312
milling process, 61
model, 200, 213
turning process, 59
dynamometers, 96
edge chipping, 134
elastic deflection, 244
elastic deformation, 244
envelope curve, 206, 207
environmentally friendly machining
(EFM), 123–124
excitation, 152
excitation techniques, 93
experimental analysis, 294
fast Fourier transform (FFT), 101,
215, 216, 271Index 325
fast tool servo (FTS), 303, 308, 311
fibre–optic bragg grating sensors, 98
finite element analysis (FEA), 5,
157, 159–160, 161, 283, 298–299,
300–302, 306
fixture system, 284, 286–287
flank wear land width, 134–135
flexure hinge, 305
flute edge, 174
flute geometry, 188
flute number, 188
form errors, 39–40
fracture wear, 245
frequency domain, 99, 100–105
frequency response function (FRF),
44, 51–54, 294
experimental testing, 95, 96
measurement, 92
friction angle, 22
friction coefficient, 241
geometric model, 186, 187
grain fracture, 258
grain shape, 245
granite, 285
grinding, 233
conditions, 235–236, 246, 247
control strategies, 253, 255
cycle, 248, 255
dwell time, 257
force, 234, 238, 242
kinematics, 234, 236, 248
mechanics, 236
power, 234, 251, 254, 255, 259
simulation, 245–246, 255–256
specific energy, 240
temperature, 234
wheel, 234, 247
vibrations, 234
grinding burn, 253
grit, 235, 236, 238, 241, 243
density, 245
shape, 245
gross fracture, 134
hammer test, 44–45, 95, 208
harmonic excitation, 289
helical end mill, 173
helix angle, 174
Helix lag angle, 170
Hertz distribution, 242
high speed machining, 123
high speed steel (HSS), 124
homogeneity, 285
I–DEAS, 302
inertia, 291
infeed rate, 249
infeed stage, 248
information theory, 111
in–process sensors, 96
inspection system, 284, 287
ISO 3685:1993, 135, 136
KDP single crystal, 264
kinematics, 242, 248, 253, 260
Laplace domain, 203, 209
laser Doppler velocometer (LDV),
94
leadscrew, 317
linear motor, 286
low pollution machining, 123–124
lumped–parameter techniques
(LPT), 298
machine base, 284
machine column, 284
machine configuration, 294
machine design, 283, 293
machine dynamics, 283, 288
machine layout, 294
machine performance, 284, 287–288
machine specifications, 294
machine structure, 284, 285
machine tool constitutions, 284
machine tool loops, 288, 289
machine tool vibrations, 288
machine–tool–workpiece loop, 7
machining instability, 17, 18, 19
machining processes, 1 , 151, 153,
167, 226
grinding, 233, 246
milling, 167326 Index
turning, 151, 153
machining systems, 21, 226
machining setup, 213, 214
mass, 290, 291
material anisotropy, 276
material induced vibration, 263, 270
material removal rates (MRR), 41,
76
mean arithmetic roughness (Ra), 277
mechanical components, 313
mechanics, 242, 253, 260
medical components, 313
MEMS, 313
metal cutting, 118
grinding, 233
milling, 167
turning, 151, 153, 263
metal matrix composite (MMC),
132, 137
metrology, 287
micro cutting, 263
micro milling machine, 313
microplasticity model, 265
milling, 167
ball–end, 169
dynamics, 213
face, 169
model, 176, 200, 213
peripheral, 169, 171, 213
plane, 189, 199
slot, 185, 197
minimum quantity lubricant (MQL),
123–124, 132–133
modal, 87, 294
analysis, 88–90, 154, 207,208, 209
constant, 88
mass, 88
parameters, 210, 212
mode, 87, 88
mode coupling, 289
modelling, 295
modularisation, 200
cutting force, 200
monitoring system, 284
moulds, 313
multi–degree of freedom, 204, 208
multi frequency solution, 68
multiscale modelling, 5–6
mutual information, 111
National Aeronautics and Space
Administration (NASA), 128
nanometric cutting, 263
nano–surface, 264
NASTRAN, 302
natural frequency, 9, 155, 159–160,
161
non–interference, 276
oblique cutting, 172
optimisation, 154, 155
optical components, 313
overshoot, 254
PATRAN, 302
physical vapour deposition (PVD),
128, 129
piezo–actuator, 303
effective stroke, 304
nominal stroke, 304
piezoelectric accelerometer, 93–94,
208
plastic deformation, 244
ploughing, 236, 243, 244
plunge grinding, 248
poly–crystal diamond (PCD), 126,
137
polycrystalline, 263
polymer concrete, 285, 314
position loop, 289
postprocessor, 302
precision machines, 263, 283
preliminary analysis, 314
preliminary design, 314
preprocessor, 300
process damping, 57
pulsating excitation, 289
radial immersion angle, 170, 190
rake angle, 120, 122, 172
effective, 170, 175
normal, 170, 175
radial, 170, 175
reanalysis, 315Index 327
redesign, 315
regenerative displacement, 203, 205
tool, 203, 289
regenerative effect, 289
removal rate time constant, 250, 252,
253
resonance, 152
rigidity, 43
dynamic, 43
fixture, 156
machine tool, 156
work material, 156
rotary table, 317
rubbing, 236, 243, 244
scallop hight, 190
scanning electron microscope
(SEM), 127, 140, 266
sculptured surfaces, 188
SDRC, 302
sensor sysetm, 287
shear angle, 22, 265
oscillations, 55–57
signal processing, 92
signal–to–noise ratio (SNR), 45
silicon, 139
machining, 139–142
silicon nitride (Si3N4), 126
simulation, 207, 245–246, 264, 295
single–crystal diamond (SCD), 126
single crystal materials, 264
single–degree–of–freedom (SDOF),
46
single frequency solution, 70
single grain, 234
single mode, 46
single point diamond turning
(SPDT), 263
slideways, 284
sliding, 236
slip rings, 98
size effect, 245, 260
size error, 234, 254
soft computing, 110
solution, 302
spark–out, 248, 252
specific energy, 240
spindle frequency (SF), 171, 218,
219, 220, 221, 222, 223, 224
spring element, 314
squeeze film dampers, 292
stability, 64
limit, 71
lobes, 72
milling, 68–74
turning, 64–67
STAR, 208, 209
steel, 158, 210
step–over, 190
feedrate, 190
stiffness, 7, 248–249, 290
dynamic, 9
dynamic loop, 10, 289
static loop, 8, 289
stiffness loop, 289
stiffness–to–mass ratio, 291
structural dynamic parameters, 46
structural loop, 297
structural materials, 285
structural modification, 294
sum–squared error (residual), 226,
228, 229
surface generation, 205, 206
surface integrity, 234
surface profile, 206
surface roughness, 118, 234, 252,
253, 273, 312
peak to valley (Rmax) 119
surface topography, 224, 273, 274,
312
system identification, 224, 225–226
Taylor’s model, 142–145
telemetry, 98
temporal stability, 285
thermal loop, 289
three–dimensional (3D) surface
analysis, 272, 274
thrust bearing, 317
time domain, 99, 105–109
titanium aluminium nitride (TiAlN),
128, 129, 129–131328 Index
titanium carbon (TiC), 128, 129
titanium carbon nitride (TiCN), 128,
129, 129–131
titanium nitride (TiN), 128, 129,
129–131
tool, 117
coated, 127, 129, 132
design, 118,
edge radius, 120, 122
failure, 133, 134
geometry, 120, 122, 162
life, 142
materials, 162
rake angle, 120, 122, 172
relief angle, 120, 122
round–nosed, 119
straight–nosed, 119
wear, 133, 162
tool–work vibration, 275–276
tool–workpiece replication model,
118
tool–workpiece loop, 288
tool interference, 275
tooling system, 284, 286
tooth passing frequency (TPF), 171,
215, 216, 218, 220, 221, 222, 223,
224
tooth passing period (T), 171, 216
topography, 100
transfer function (TF), 44, 45, 46,
203, 205
turning, 151, 153, 263
two–degree–of–freedom, 175
ultra–precision machines, 263
ultraprecision machining, 126, 263
undeformed chip thickness, 122,
172, 175, 238, 244
up milling, 32, 42, 74, 177, 179, 182,
189, 190, 192, 194, 201
variable pitch cutters, 79–82
verification, 186, 198
vibrations, 10
amplitude, 169
forced, 13, 167
free, 10
frequency, 169
self–excited, 102, 167, 168–169
virtual surface, 274
wavelets, 99, 109–110
wear, 133, 162
abrasive, 141
adhesive, 141
classification, 134–135
crater, 134
diamond tools, 139–142
diffusion, 141
effects, 162–163
evolution, 136
flank, 134, 137
material–dependence, 138
progressive, 134–135
recoating, 133
tool, 133, 139
wheel, 234
conditioning, 235
diameter, 257
dressing, 234
speed, 257
topography, 234
wear, 234
width, 257
workpiece, 162
materials, 162, 173
speed, 257
surface, 242, 243
WYKO interferometric microscope,
277, 278
X–Y plane, 275
XYZ gantry configuration, 315–316
Z–Buffer scanning algorithm, 206
Zygo 3D surface profiler, 312
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