CNC Programming using Fanuc Custom Macro B / Edition 1

by S.K Sinha

Overview

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Master CNC macro programming

CNC Programming Using Fanuc Custom Macro B shows you how to implement powerful, advanced CNC macro programming techniques that result in unparalleled accuracy, flexible automation, and enhanced productivity. Step-by-step instructions begin with basic principles and gradually proceed in complexity. Specific descriptions and programming examples follow Fanuc's Custom Macro B language with reference to Fanuc 0i series controls. By the end of the book, you will be able to develop highly efficient programs that exploit the full potential of CNC machines.

COVERAGE INCLUDES:

• Variables and expressions
• Types of variables—local, global, macro, and system variables
• Macro functions, including trigonometric, rounding, logical, and conversion functions
• Branches and loops
• Subprograms
• Macro call
• Complex motion generation
• Parametric programming
• Custom canned cycles
• Probing
• Communication with external devices
• Programmable data entry

Product Details

ISBN-13:	9780071713320
Publisher:	McGraw Hill LLC
Publication date:	06/01/2010
Pages:	288
Product dimensions:	5.90(w) x 8.90(h) x 0.80(d)

About the Author

S. K. Sinha earned his Ph.D. in mechanical engineering from the Indian Institute of Technology in 1993. He has 18 years of teaching experience in CNC programming and has been working in the CNC area for the past 10 years.

Table of Contents

Preface xi

Acknowledgments xiii

1 Introduction 1

1.1 Part Programming Techniques 2

Conventional Part Programming 2

Conversational Part Programming 3

Part Programming Using CAM Software 3

Macro Programming 4

Comparison of the Four Methods 4

1.2 Certain Applications of Macro Programming 4

Complex Motions 5

Families of Parts 5

Custom Canned Cycles 6

"Intelligent" Programs 7

Probing 7

Machine Status Information/Manipulation 8

Communication with External Devices 8

1.3 Does My Machine Have Macro Capability? 9

1.4 Aim of the Present Text 11

1.5 How to Use This Text 11

2 Variables and Expressions 13

2.1 Macro Variables 13

2.2 Macro Expressions 13

2.3 Assigning a Value to a Variable 16

2.4 Display of Variables 18

2.5 Real versus Integer Values 19

2.6 Undefined Variables 22

Null Variables in Word Addresses 22

Null Variables in Arithmetic Operations 23

Null Variables in Conditional Expressions 23

2.7 A Simple Use of Macro Programming Features 24

2.8 Retaining Programs in MDI Mode 24

3 Types of Variables 27

3.1 Local and Global Variables 27

3.2 Effect of System Reset on Macro Variables 28

3.3 Levels of Local Variables 29

3.4 Range of Values Stored in Variables 33

3.5 System Variables 35

System Variables versus System Parameters 35

System Variables on Fanuc 0i Series Controls 36

Displaying System Variables 36

Interface Signals 37

System Variables for Input Interface Signals 40

System Variables for Output Interface Signals 40

Geometry and Wear Offset Values 40

Workpiece Coordinate System Shift Amount 43

Macro Alarms 44

Time Information 45

Automatic Operation Control 45

Execution Pause 48

Mirror Image Information 48

Number of Machined Parts 48

Modal Information 49

Current Tool Position 52

Work Offset Values 55

4 Macro Functions 57

4.1 Types of Macro Functions 57

Priority of Operations in Arithmetic Expressions 57

Priority of Operations in Boolean Expressions 58

Effect of Order of Calculations 58

Nesting of Brackets 59

4.2 Arithmetic Operations 59

Division versus Block-Skip Function 60

4.3 Trigonometric Functions 60

4.4 Rounding Functions 63

ROUND, FIX, and FUP 64

4.5 Miscellaneous Functions 67

SQRT 67

ABS 67

LN 68

EXP 68

Arbitrary Exponent of a Number 69

4.6 Logical Functions 69

Bitwise Functions 69

Boolean Functions 71

Bitwise versus Boolean Operations 72

Enabling Boolean Operations 73

An Application Example of Bitwise Operation 73

4.7 Conversion Functions 75

5 Branches and Loops 79

5.1 Unconditional Branching 79

5.2 Conditional Branching 80

5.3 Conditional Execution of a Single Macro Statement 93

5.4 Execution in a Loop 94

5.5 Arithmetic Operations on Macro Variable Numbers 103

Methods of Zero Shift 106

Machine Coordinate System 107

External Workpiece Coordinate System 107

G54-G59, G54.1 P1-P48 Workpiece Coordinate Systems 108

Zero Shift by Manipulating Offset Distances 109

Zero Shift through System Variables 109

Work Offset Display on a Milling Machine 110

System Variables for Various Work Offset Values 111

Zero Shift through a Program 111

5.6 Nested WHILE Statement 115

6 Review of Subprograms 121

6.1 Introduction 121

What Is a Subprogram? 121

Why Is It Used? 121

Subprograms versus Subroutines of a Conventional Computer Language 122

6.2 Subprogram Call 122

6.3 Multiple Call of a Subprogram 125

6.4 Subprogram Nesting 132

7 Macro Call 137

7.1 Introduction 137

7.2 Macro versus Subprogram 137

7.3 Macro Call 138

Simple Call (G65) 138

Modal Call (G66) 141

Call with User-Defined G-Code 145

Call with User-Defined M-Code 147

7.4 Subprogram Call without Using M98/M198 148

Subprogram Call Using an M-Code 148

Subprogram Call Using a T-Code 150

7.5 Argument Specification 151

Argument Specification I 152

Argument Specification II 153

Mixed Argument Specification 154

An Example of a G-Code Macro Call with Arguments 155

7.6 Processing of Macro Statements 163

What Is Buffering? 163

How Many Blocks Are Buffered? 163

When Are the Buffered Blocks Processed? 163

Processing When the Next Block is Not Buffered 163

Processing in Radius Compensation Cancel (G40) Mode 164

Processing in Radius Compensation Mode (Case 1) 164

Processing in Radius Compensation Mode (Case 2) 164

Effect of Buffering of Macro Statements on Program Execution 165

8 Complex Motion Generation 167

8.1 Introduction 167

8.2 Arc with Uniformly Varying Radius 167

8.3 Helical Interpolation with Variable Radius 175

8.4 Parabolic Turning 181

Roughing Operation 184

Step-Removal Operation 184

8.5 Turning a Sine Curve 188

9 Parametric Programming 193

9.1 Introduction 193

9.2 Locator Pin 194

9.3 Bolt Holes on a Flange 200

10 Custom Canned Cycles 207

10.1 Introduction 207

10.2 Deep-Hole Peck Drilling on a Lathe 207

10.3 Drilling with Reducing Peck Lengths on a Milling Machine 215

11 Probing 223

11.1 Introduction 223

11.2 Skip Function on a CNC Machine 224

11.3 Probing a Pocket 224

11.4 Finding Center of a Hole 228

11.5 Finding Angle of an Edge 231

11.6 Adjusting Wear Offset 233

12 Communication with External Devices 237

12.1 Introduction 237

12.2 Switching Principle 237

12.3 Input Types and Wiring 239

12.4 Connector Pin Assignment 240

12.5 Discrete Sensors for Sourcing/Sinking PLC Inputs 244

12.6 Output Types and Wiring 246

13 Programmable Data Input 251

13.1 Introduction 251

13.2 Data Input for WCS Offset Distances 252

13.3 Data Input for Additional WCS Offset Distances 253

13.4 Data Input for Compensation Values on a Milling Machine 254

13.5 Data Input for Compensation Values on a Lathe 255

13.6 Data Input for Parameter Values 258

A Limitation of G10 L50 Method 262

Appendix A List of Complex Macros 263

Appendix B List of Parameters 265

Index 267