Computer Numerical Control of Machine Tools (eBook)

Front Cover 1
Computer Numerical Control of Machine Tools 4
Copyright Page 5
Table of Contents 6
Preface 12
Preface to the first edition 14
Acknowledgement 16
Chapter 1. Principles of machine tools 18
1.1 Material cutting techniques 18
1.2 Material removal techniques onmachine tools 19
1.3 Function of machine tools 20
1.4 Size and form 20
1.5 Kinematic principles of operation of machine tools 20
1.6 Surface texture 22
Chapter 2. Control of machine tools 24
2.1 Levels of control 24
2.2 Zero level of control 24
2.3 First level of control 24
2.4 Second level of control 25
2.5 Third level of control 26
2.6 Fourth level of control 26
2.7 Fifth level of control: numericalcontrol 26
2.8 Computer numerical control 39
2.9 Direct numerical control (DNC) 40
2.10 Adaptive control 45
2.11 Applications of numerically controlled machines 46
2.12 Cost of manufacture 48
2.13 Break-even charts 50
Chapter 3. Construction of machine tools 54
3.1 Constructional features 54
3.2 Power units 54
3.3 Providing the cutting speed 54
3.4 Power units for moving the carriages holding tool or work 55
3.5 Power units for ancillary services 57
3.6 Speed control units 57
3.7 Control of feed rates 58
3.8 Control of translational (linear) movements 59
3.9 Control of rotational movements 63
3.10 Actuating mechanisms 64
3.11 Tool holders 67
3.12 Tool changing arrangements 69
3.13 Work holders 83
3.14 Linking structure 96
3.15 Overall considerations 102
Chapter 4. Modes of operation 108
4.1 Designation of axes on NC machinetools 108
4.2 Linear and rotary motions 115
4.3 Machine operating systems 117
4.4 Positioning control (symbol P) 117
4.5 Line motion control (symbol L) 119
4.6 Contouring control (symbol C) 120
4.7 Selection of control mode 122
4.8 Adaptive control 123
Chapter 5. Output transducers 124
5.1 Transducers 124
5.2 Positional transducers 124
5.3 Optical gratings 133
5.4 Encoders 135
5.5 Inductosyns 138
5.6 Magnescales 140
Chapter 6. Principles of operation of NC machine tools 142
6.1 Basic principles 142
6.2 Closed loop systems 144
6.3 Open loop systems 145
6.4 Input signals 146
Chapter 7. Information storage 148
7.1 Input signals 148
7.2 Indirect methods of input 150
7.3 Punched cards 150
7.4 Magnetic tape 151
7.5 Magnetic discs 152
7.6 Punched tape 154
7.7 Block formats 160
Chapter 8. Structure of part programs 162
8.1 Part programs 162
8.2 Types of control information 162
8.3 Word addressed format 163
8.4 Optional block skip character (/) 164
8.5 Sequence or block number (N) 164
8.6 Preparatory function (G) 165
8.7 Dimensional information words (X,Y,Zetc.) 165
8.8 Decimal point 166
8.9 Feed rate (F) 166
8.10 Spindle speed (S) 167
8.11 Tool number (T) 167
8.12 Miscellaneous function (M) 167
8.13 End of block (EOB) 168
8.14 Heidenhain plain-language programming 168
8.15 Word addressed programming of plotters 169
Chapter 9. Writin art ro rams 171
9.1 Creating part programs 171
9.2 What the programmer has to know 172
9.3 Drawings for numerically controlled machines 172
9.4 The component 176
9.5 Work holding positions 180
9.6 The machine tool 180
9.7 The control system 186
9.8 Circular interpolation 188
9.9 Parabolic interpolation 191
9.10 Polar coordinates 192
9.11 Cutter diameter compensation 193
9.12 Screw thread cutting 195
9.13 Dwell 196
9.14 Programming aids 196
9.15 Subroutines 204
9.16 Other prcgramming aids 206
9.17 Writing the part program 208
9.18 Checking (proving) the program 208
Chapter 10. Setting up NC machine tools 211
10.1 Setting-up procedure 211
10.2 Setting milling and drilling machines 213
10.3 Use of sensor probes on milling and drilling machines 216
10.4 Setting milling and drilling tools 220
10.5 Use of table mounted sensor probes for tool setting on machining centres 226
10.6 Tool length compensation 227
10.7 Cutter diameter compensation 227
10.8 Setting turning centres or CNClathes 228
10.9 Setting of lathe tools 228
10.10 Tool offsets 229
10.11 Tool nose radius compensation 232
Chapter 11. Part programming for milling and drilling work 234
11.1 Example program 1 234
11.2 Position of the zero datums 235
11.3 Work holding method and machine setting point 235
11.4 Sequence of operations 235
11.5 Speeds and feeds for the tools to beused 237
11.6 Construction of part program 1 239
11.7 Example program 2 10
11.8 Construction of part program 2 250
Chapter 12. Part programming for lathe work 257
12.1 Example program 3 257
12.2 Position of the zero datums 258
12.3 Size of work blanks 258
12.4 Sequence of operations 258
12.5 Construction of part program 3 259
12.6 Tool tip radius compensation 263
Chapter 13. Computer-aided part programming 267
13.1 Computer-aided programming 267
13.2 Using the computer as a text editor 268
13.3 Using the computer as a graphical simulator 269
13.4 Part programming languages 269
13.5 Conversational programming 272
13.6 Computer-aided machining (CAM) 283
Appendix A: Preparatory functions:G codes 314
Appendix: B: Miscellaneous functions:Mcodes 320
Appendix: C: Com ñ u ter fundam en tals 324
Index 328