Unit 1 Introduction of CNC Machine Tool 1
1.1 Machining Center Configurations 1
1.2 Vertical Machining Centers 2
1.3 Horizontal Machining Centers 5
1.4 Other Programmable Features of Machining Centers 8
1.4.1 Spindle Speed 8
1.4.2 Spindle Activation and Direction 8
1.4.3 Spindle Range 8
1.4.4 Feedrate 8
1.4.5 Coolant 9
1.4.6 Tool Changes 9
1.4.7 What Else Might Be Programmable 9
Exercises 10
Unit 2 Tooling for CNC Machine 12
2.1 Introduction 12
2.2 Material for Cutting Tools 13
2.3 The Practical Application of Cemented Carbides 15
2.3.1 Solid Tools 15
2.3.2 Brazed Tips 15
2.3.3 Indexable Inserts 16
2.4 Tooling Systems 19
2.5 Automatic Tool Changer System 22
2.5.1 Turret Head 22
2.5.2 Carousel Storage with Spindle Direct Tool Changer 23
2.5.3 Horizontal Storage Matrix Magazine with Pivot Insertion Tool Changer 24
Exercises 26
Unit 3 Program Zero and Coordinate System 27
3.1 What is Coordinate System 27
3.2 Plus and Minus 30
3.3 Program Zero 31
3.4 Absolute vs.Incremental 33
Exercises 35
Unit 4 Mathematics for NC Programming 36
4.1 Introduction 36
4.2 Geometry 37
4.2.1 Properties of Intersecting Lines 37
4.2.2 Tangency 38
4.3 Trigonometry 40
4.3.1 The Pythagorean Theorem 40
4.3.2 Right Triangle Trigonometry 41
4.3.3 Oblique Triangle Trigonometry 44
Exercises 48
Unit 5 Word Address Programming 50
5.1 Introduction 50
5.2 Programming Language Format 50
5.3 Programming Language Terminology 52
5.4 Program and Sequence Numbers(O,N Codes) 53
5.5 Preparatory Functions(G Codes) 55
5.6 Dimension Words(X,Y,Z,…Codes) 56
5.7 Feedrate(F Codes) 57
5.8 Spindle Speed(S Codes) 57
5.9 Miscellaneous Machine Functions(M Codes) 58
5.10 Why Learn Manual Programming 59
Exercises 62
Unit 6 Speeds and Feeds 63
6.1 Cutting Speeds and Feeds 63
6.2 Spindle Speeds 65
6.3 Feed Rates 67
6.3.1 Feed Rates for Turning 68
6.3.2 Feed Rates for Milling 69
6.3.3 Feed Rates for Drilling 70
6.4 Feed Rate and Spindle Speed Override 71
Exercises 72
Unit 7 Preparation for Programming 73
7.1 The Importance of Preparation 73
7.2 Typical Mistakes 74
7.2.1 Syntax Mistakes 75
7.2.2 Motion Mistakes 75
7.2.3 Mistakes of Omission 76
7.2.4 Process Mistakes 76
7.3 Steps for Preparing to Write a CNC Program 77
7.3.1 Study and Mark Up the Print 77
7.3.2 Prepare the Machining Process 77
7.3.3 Develop the Needed Cutting Conditions 81
7.3.4 Do the Required Math 81
7.3.5 Check the Required Tooling 83
7.4 Plan the Work Holding Setup 84
7.5 Other Documentation 85
7.5.1 Setup Sheet 85
7.5.2 Program Listing 86
7.6 Is It All Worth It 86
Exercises 87
Unit 8 Programming Techniques 88
8.1 Introduction 88
8.2 Programming Hole Operation 88
8.3 Programming Linear Profiles 90
8.4 Programming Circular Profiles 91
8.4.1 Circular Interpolation Commands 91
8.4.2 Circular Interpolation Via Direct Radius Specification 92
8.4.3 Profiling Arcs at Constant Feed Rate 94
8.5 Programming with Subprogram 96
8.5.1 Subprogram Concept 96
8.5.2 Commands for Calling a Subprogram and Returning to the Main Program 97
8.5.3 General Rules for Subprogramming 98
Exercises 99
Unit 9 Three Kinds of Compensation 100
9.1 Introduction 100
9.2 What is Compensation 101
9.3 Understanding Offsets 103
9.3.1 How Many Offsets do You Have 104
9.3.2 Offsets and Trial Machining 104
9.3.3 Organization of Offsets 105
9.3.4 Wear Offsets Versus Geometry Offsets 106
9.3.5 How Offsets are Instated 106
9.4 Tool Length Compensation 108
9.4.1 The Reason for Tool Length Compensation 108
9.4.2 How Tool Length Compensation is Used 110
9.5 Cutter Radius Compensation 111
9.5.1 Reasons for Using Cutter Radius Compensation 112
9.5.2 How does Cutter Radius Compensation Work 116
9.6 Fixture Offsets 117
Exercises 118
Unit 10 Machine Design 120
10.1 Repeatability 120
10.2 Basic Structure 122
10.3 Machine Spindles 123
10.4 Spindle Drives 126
10.5 Machine Slides 128
10.6 Slide Drives 130
Exercises 133
Unit 11 Setup and Maintain 135
11.1 Tasks Related to Setup and Operation 135
11.1.1 Setup Tasks Versus Production Maintaining Tasks 136
11.1.2 Tasks Related to Setup 137
11.2 Tasks Related to Maintaining Production 143
11.2.1 Workpiece Unload and Load 144
11.2.2 Maintaining Critical Dimensions(with Close Tolerances)during Each Tool's Life 145
11.2.3 Replacing Worn Tools 147
11.3 Other Possible Tasks to be Done During the Production Run 149
Exercises 150
Unit 12 Three Modes of Operation 151
12.1 The Manual Mode 152
12.2 The Manual Data Input Mode 153
12.2.1 The Manual Data Input Position of the Mode Switch 154
12.2.2 The Edit Position of the Mode Switch 155
12.3 The Program Operation Mode 157
12.3.1 The Memory(or Auto)Mode Switch Position 159
12.3.2 The Tape Mode Switch Position 160
Exercises 162
Unit 13 Program Verification Techniques 163
13.1 Introduction 163
13.2 Safety Priorities 165
13.2.1 Operator Safety 165
13.2.2 Machine Tool Safety 166
13.2.3 Workpiece Safety 167
13.3 Typical Mistakes 168
13.3.1 Syntax Mistakes in the Program 169
13.3.2 Motion Mistakes in the Program 170
13.3.3 Setup Mistakes 170
13.3.4 Mistakes of Omission 171
13.4 Procedures to Program Verification 172
13.4.1 The Machine Lock Dry Run 172
13.4.2 Free Flowing Dry Run 173
13.4.3 Normal Air Cutting Cycle Execution 175
13.4.4 Running the First Workpiece 176
13.4.5 Making Good Parts 177
13.5 Conclusion to Program Verification 178
Exercises 179
Unit 14 CAD/CAM 180
14.1 Introduction 180
14.2 Computer-Aided Anything(CAA) 181
14.3 What is CAD/CAM Software 182
14.4 Description of CAD/CAM Components and Functions 184
14.4.1 CAD Module 184
14.4.2 CAM Module 187
14.4.3 Geometry vs.Toolpath 189
14.4.4 Tool and Material Libraries 191
14.4.5 Verification and Post-Processor 192
14.4.6 Portability 193
14.5 Software Issues and Trends 195
Exercises 198
Appendix A G＆M Code Reference 199
Appendix B The Sample of CNC Machine Specification 203
Appendix C Vocabulary 208
References 232