Contents
Unit 1 Introduction to Computer Numerical Control Manufacturing 1
1.1 Introduction 1
1.2 The History of Numerical Control 1
1.3 Numerical Control Definition, Its Concepts and Advantages 4
1.4 Definition of Computer Numerical Control and Its Components 6
1.5 NC Compared with CNC 8
1.6 Types of CNC Equipment 10
Exercises 13
Unit 2 The Axis System 15
2.1 Introduction 15
2.2 What is a Machine Axis? 15
2.2.1 Motion and Direction 15
2.2.2 Relative Tool Movement 16
2.3 The Axis System 18
2.4 EIA Axis Identification 19
Exercises 22
Unit 3 Points and Coordinates 24
3.1 Introduction 24
3.2 Coordinates and Significant Points 25
3.3 Reference Point Identification 27
3.3.1 Program Reference Zero (PRZ) 27
3.3.2 Local Reference Zero (LRZ) 29
3.3.3 Machine Home Reference (M/H) 32
3.4 Coordinate Identification Systems 33
3.5 Types of Tool Positioning Modes 34
3.5.1 Incremental Positioning 35
3.5.2 Absolute Positioning 35
Exercises 36
Unit 4 Machine movements and control 38
4.1 Introduction 38
4.2 Positioning Control 38
4.2.1 Point-to-Point 38
4.2.2 Line Motion 39
4.2.3 Contouring 41
4.2.4 Interpolation 42
4.3 Loop Systems for Controlling Tool Movement 44
4.3.1 Open Loop Systems 44
4.3.2 Closed Loop Systems 45
Exercises 47
Unit 5 Part Programming Calculations 48
5.1 Introduction 48
5.2 Useful Angle Concepts 49
5.3 Types of Angles and Triangles 51
5.4 Right Triangle 53
5.5 Similar Triangles 54
5.6 Sine-Cosine-Tangent 56
5.7 Inverse Trigonometric Functions 56
Exercises 57
Unit 6 Tooling for Computer Numerical Control 59
6.1 Introduction 59
6.2 Material for Cutting Tools 60
6.3 The Practical Application of Cemented Carbides 62
6.3.1 Solid Tools 62
6.3.2 Brazed Tips 62
6.3.3 Indexable Inserts 62
6.4 Tooling Systems 65
6.5 Automatic Tool Changer System 68
6.5.1 Turret Head 68
6.5.2 Carousel Storage with Spindle Direct Tool Changer 69
6.5.3 Horizontal Storage Matrix Magazine with Pivot Insertion Tool Changer 69
Exercises 72
Unit 7 Program Planning 73
7.1 Introduction 73
7.2 Initial Information 73
7.3 Machine Tools Features 74
7.4 Part Complexity 76
7.5 Programming 78
7.6 Typical Programming Procedure 80
7.7 Part Drawing 82
7.8 Methods Sheet and Material Specifications 83
7.9 Machining Sequence 85
7.10 Tooling Selection 87
7.11 Part Setup 88
7.12 Technological Decisions 89
7.13 Testing a CNC Program 90
Exercises 93
Unit 8 Word Address Programming 95
8.1 Introduction 95
8.2 Basic Programming Terms 96
8.2.1 Character 96
8.2.2 Word 97
8.2.3 Block 97
8.2.4 Program 97
8.3 Programming Format 99
8.4 Preparatory Commands 101
8.5 Miscellaneous Functions 103
8.5.1 Machine Related Functions 104
8.5.2 Program Related Functions 104
8.6 Program and Sequence Number(O, N CODES) 106
8.6.1 Program Number (O) 106
8.6.2 Sequence Number (N) 106
8.7 Feed Rate (F CODE) and Spindle Speed (S CODE) 107
8.8 Automatic Tool Changing 107
8.9 Tool Length Offset and Cutter Radius Compensation (H, D CODES) 108
Exercises 109
Unit 9 Basic Programming 110
9.1 Introduction 110
9.2 Programming Hole Operation 110
9.3 Linear Interpolation 111
9.3.1 Linear Command 112
9.3.2 Programming Format 115
9.4 Circular Interpolation 115
Exercises 118
Unit 10 Program Flow 120
10.1 Introduction 120
10.2 Subroutine Logic 121
10.2.1 Subroutines are “Mini-Programs” 121
10.2.2 Standard and Parametric Subroutines 124
10.2.3 Commands for Calling a Subroutine and Returning to the Main Program 125
10.3 Looping Logic in Programs 125
10.3.1 General Characteristics 125
10.3.2 Commands for Loops 126
10.4 Nesting Logic 127
10.5 Logic Planning 128
Exercises 129
Unit 11 Tool Length Offsets and Zero Presets 131
11.1 Introduction 131
11.2 The Concept of Length Offset 131
11.3 Setting up Offsets 133
11.4 Zero Preset 134
Exercises 136
Unit 12 Tool Radius Compensation 137
12.1 Introduction 137
12.2 What is Tool Radius Compensation? 137
12.3 Reference Locations 138
12.4 Tool Location on Angular Toolpaths 141
12.5 Tool Location on Radial Toolpaths 144
12.6 Automatic Tool Radius Compensation 147
12.6.1 Adjusting the Diameter Offset 151
12.6.2 Lead In and Out with Tool Radius Compensation 152
12.6.3 Error Conditions and Limitations of Automatic Compensation 153
Exercise 155
Unit 13 CAD/CAM 156
13.1 Introduction 156
13.2 Computer-aided Anything (CAA) 157
13.3 What is CAD/CAM software? 157
13.4 Description of CAD/CAM Components and Functions 160
13.4.1 CAD Module 160
13.4.2 CAM Module 162
13.4.3 Geometry Vs. Toolpath 163
13.4.4 Tool and Material Libraries 166
13.4.5 Verification and Post-Processor 167
13.4.6 Portability 168
13.5 Software Issues and Trends 170
Exercises 172
Unit 14 Beyond CNC machining 174
14.1 Introduction 174
14.2 Computer Integrated Manufacturing 175
14.3 Operational Strategies within CIM 177
14.3.1 Group Technology 177
14.3.2 Just-In-Time 177
14.4 Flexible Manufacturing System 179
14.5 FMC Vs. FMS 181
Exercises 183
附录 VOCABULARY 184
参考文献 211
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