CNC Programming H ndbook

Second Edition

c C Programming Handbook Second Edition A Camp hensiv uid Practical CNC rogramming

t r mi

989 ue York, NY lOO 18 .com

Li of Congress Cataloging-in-Publication Data

Smid, Peter. CNC programming handbook: comprehensive guide to practical CNC programming!

Smid.

11-3158-6 1. Machine-louls--Numerical control--Programming --Handbooks, manuals,etc . .I.

Title.

TJ1189 .S 2000 1.9'023--dc21

00-023974

Second on

CNC Programming Handbook

Industrial Press Inc. 989 ue of Americas, w York, NY 10018

Copyright 2003. in the United States America.

This book or parts thereof may not reproduced, stored in a retrieval

system. or transmitted in any form without tbe permission of publishers.

5678910

Dedication To my

who my mother dmila,

never to give

Acknowledgments In this second edition of the CNC Programming Handbook, I would like to express my thanks and appreciation to Peter Eigler for being the bottomless source of new ideas, knowledge and inspiration - all that in more ways than one. My thanks also go to Eugene Chishow, for his always quick thinking and his ability to point out the elusive detail or two that I might have missed otherwise. To Ed Janzen, I thank for the many suggestions he of-fered and for always being able to see the bigger picture. To Greg Prentice, the President of GLP Technologies, Inc., - and my early mentor - you will always be my very good friend.

Even after three years of improving the CNC Programming Handbook and developing the enclosed compact disc, my wife Joan will always deserve my thanks and my gratitude. To my son Michael and my daughter Michelle - you guys have contributed to this handbook in more ways than you can ever imagine.

I have also made a reference to several manufacturers and software developers in the book. It is only fair to acknowledge their names:

FANUC and CUSTOM MACRO or USER MACRO or MACRO B are registered trademarks of Fujitsu-Fanuc, Japan

GE FANUC is a registered trademark of GE Fanuc Automation, Inc., Charlottesville, VA, USA

MASTERCAM is the registered trademark of eNC Software Inc., Tolland, CT, USA

AUTOCAD is a registered trademark of Autodesk, Inc., San Rafael, CA, USA

HP and HPGL are registered trademarks of Hewlett-Packard, Inc., Palo Alto, CA, USA

.. IBM is a registered trademark of International Business Machines, Inc., Armonk, NY, USA

.. WINDOWS is a registered trademarks of Microsoft, Inc., Redmond, WA, USA

About the Author Smid is a professional consultant, educator and with many of practi-

experience, in the industrial and ed his career, he has an extensive experience with CNC and CAD/CAM on all levels. He to manufacturing industry and educational ns on practical use of Com-

ro.-.'7iOl"'I Numerical Control technology, part programm CAD/CAM, advanced ma-chining, tooling, setup, and many other related comprehensive industrial back-ground in CNC programming, machining and company training has assisted

hundred companies to benefit from his wide-rang knowledge.

Mr. long time association with advanced chinery vendors, as well as his affiliation with anum

industrial technology programs and broaden his professional and consulting computer applications and programming, hardware

companies and CNC ma-of Community and Technical Col-

skills training, have enabled him to areas of CNC and CAD/CAM trainingl

evaluation, system benchmarking. and operations management.

hundreds of customized Over the yearsl Mr. Smid has tional programs to thousands of across United States, Canada and companies and private sector

.rliOTtTc.' at colleges and universities as well as to a large number of manufacturing

individuals.

He has actively participated in many shows, conferences, workshops various seminars, including delivering presentations a of speaking engagements to organizations. He is also the author and many in-house publications on of CNC and CAD/CAM. During his years as a professional in the CNC educational field, he has developed tens of thousands of pages of high quality training materials.

The author suggestions and other input and industria! users. You can e-mail him through the publisher of this handbook of the CD.

You can also e-mail him from the CNC Programming Handbook at www-industriaipress.com

TABLE OF CONTENTS 1 ~ NUMERICAL CONTROL 1 Axes and Planes 16

Point of Origirl 16 DEFINITION OF NUMERICAL CONTROL Ouadrarlts. 16 Right Hand Coordinate System 17

NC and CNC Technology. MACHINE GEOMETRY. 17

CONVENTIONAL AND CNC MACHINING 2 Axis Orientation - Milling . 17 NUMERICAL CONTROL ADVANTAGES 2 Axis Onenlation - Turning. 18

Setup Time Reduction 3 Additlona! Axes. 18 Lead Time Reduction. 3 Accuracy and RepealabiliJy 3 Contouring of Complex Shapes. 3 5 - CONTROL SYSTEM 19 Simplified Tooling and Work Holding. 3 Cutting Time and Productivity Increase. 4 GENERAL DESCRIPTION 20

TYPES OF CNC MACHINE TOOLS 4 Operation Panel 20 Mills and Machining Centers. 4 Screen Display and Keyboard 21 Lathes and Turning Centers 5 Handle. 22

PERSONNEL FOR CNC 5 SYSTEM FEATURES 22 CNC Programmer 5 Parameter Settings 22 CNC Machine Operator 6 System Defaults 23

SAFETY RELATED TO CNC WORK. 6 Memory Capacity. 24 MANUAL PROGRAM INTERRUPTION. 25

2 ~ CNC MILLING Single Block Operation. 25 7 Feedhold 25 Emergency Stop 25

CNC MACHINES - MILLING. 7 MANUAL DATA INPUT - MDI 26 Types of Milling Machines . 7 PROGRAM DATA OVERRIDE 26 Machine Axes 8 Rapid Motion Override. 26 Vertical Machining Centers. 8 Spindle Speed Override 27 Horizontal Machi ning Centers 9 Feedrale Override. 27 HOrIZontal Boring Mill 10 Dry Run Operation 27 Typical Specifications 10 Z Axis Neglect . 28

Manual Absolute Setting 28

3 - CNC TURNING 11 Sequence Return 28 Auxiliary Functions Lock 28 Machine Lock 28

CNC MACHINES - TURNING 11 Practical Applications 29 Types of CNC Lathes. 11 SYSTEM OPTIONS. 29 Number of Axes 11 G raphlD Display. 29

AXES DESIGNATION 11 In-Process Gauging . 30 Two-aXIs Lathe . 12 Stored Stroke Limits. 30 Three-axis Lathe 12 Drawing Dimensions Input 30

Four-axis Lathe. 13 Machining Cycles. 30 Six-axis Lathe 13 Cutting Tool Animation. 30 Connection \0 External DeVices 30

FEATURES AND SPECIFICATIONS 13 Typical Machine Specifications. 13 Control Features 14 6 - PROGRAM PLANNING 31

4 - COORDINATE GEOMETRY 15 STEPS IN PROGRAM PLANNING 31 INITIAL INFORMATION 31

REAL NUMBER SYSTEM 15 MACHINE TOOLS FEATURES. 31 RECTANGULAR COORDINATE SYSTEM. 15 Machine Type and Size. 31

ix

X Table of Contents ---------~-.-. - --------_.-... --- - --

Control System. 31

PART COMPLEXITY 32 8 - PREPARATORY COMMANDS 47 MANUAL PROGRAMMING 32 DESCRIPTION AND PURPOSE. 47

Disadvantages . 32 Advantages 32 APPLICATIONS FOR MILLING. 47

CAD/CAM AND CNC 32 APPLICATIONS FOR TURNING 49 I nteg ration 33 G CODES IN A PROGRAM BLOCK 50 Future of Manual Programming 33 Modality of G-commands. 50

TYPICAL PROGRAMMING PROCEDURE 33 Conflicting Commands in a Block 50 34 Word Order in a Block 51 PART DRAWING

Title Block. 34 GROUPING OF COMMANDS 51 Dimension ing 34 Group Numbers 51 Tolerances. 35 G CODE TYPES. 52 Surface Fintsh 35 G Codes and Decimal POln! _ 52 Drawing ReVisions 36 Special InSHucllons 36

METHODS SHEET. 36 9 - MISCELLANEOUS FUNCTIONS 53 MATERIAL SPECIFICATIONS 36

Malerial Unlformit)' 36 DESCRIPTION AND PURPOSE. 53 Machinability Rating. 37 Machine Related Functions . 53

MACHINING SEOUENCE 37 Program Related Functions 53 TOOLING SELECTION 38 TYPICAL APPLICATIONS 54 PART SETUP 38 Applications for Milling 54

Applications for Turning 54 Setup Sheet 38 Special MOl Functions. 54

TECHNOLOGICAL DECISIONS 38 Application Groups 54 Cutter Path 38 M FUNCTIONS IN A BLOCK 55 Machine Power Rating. 39 StarlU p of M Functions. 56 Coolants and Lubricants 39 Duration of M Functions .sf)

WORK SKETCH AND CALCULATIONS 40 PROGRAM FUNCTIONS 56 Identification Methods. 40 Program Stop 56

QUALITY IN CNC PROGRAMMING 40 Oplional Program Stop. 57 Program End. 58 Subprogram End !'iR

7 ~ PART PROGRAM STRUCTURE 41 MACHINE FUNCTIONS 58 Cooiant Functions 58

BASIC PROGRAMMING TERMS 41 Spindle Functions. 59 O-lsr3cter 41 Gear Range Selection 60 l/-Jcr0 41 Mil r. hi n e Ac:r.ess ori flS flO

41 42

10 - SEQUENCE BLOCK 61 PROGRAMMING FORMATS 42 WORD ADDRESS FORMAT 42 BLOCK STRUCTURE 61 FORMAT NOTATION 43 8u ildlng the Block Structure 61

43 Block Structure for Milling 61 System Formal 43 PROGRAM IDENTIFICATION 62 System Format 44

Word Addresses' 45 Program Number 62 ProgrClm Nome. 62

SYMBOLS IN PROGRAMMING 45 SEQUENCE NUMBERS 63

and ivli nus Sign. 45 Sequence Number Command. 63

PROGRAM HEADER 45 Sequence Block Format 63 TYPICAL PROGRAM STRUCTURE. 46 Numbering Increment 64

Long Program:> Dnd Block Numbers. 64 END OF BLOCK CHARACTER. 64 STARTUP BLOCK OR SAfE BLOCK 65

PROGRAM COMMENTS CON NG WORDS IN A BLOCK

MING VALUES ITY.

11 - INPUT OF DIMENSIONS

AND METRIC UNITS Unit Values

AND INCREMENTAL MODES Commands G90 and G9l .

Absolute Oats G90 - G91

Combinations in a Block PROGRAMMING

MINIMUM MOTION INCREMENT. DIMENSIONAL INPUT

FuJI Address Forma! , Zero Decimal Point Programming, Input

CALCULATOR TYPE INPUT

12 SPINDLE CONTROL

SPINDLE FUNCTION Spindle Speed Input,

DIRECTION OF SPINDLE ROTATION Direction for Milling Direction for Turning. Direction Specilication , Spindle Startup

SPINDLE STOP.

Material

ORIENTATION SPEED - R/MIN

Spindle Speed - Units Spindle Speed - Metric Units

CONSTANT SURFACE Maximum Spindle SpAAri Part Diameter Calculation in

13 - FEEDRATE CONTROL

FEEDRA TE CONTROL < FEEDRATE FUNCTION.

Feedrate per Minute, Feedrate per Revolution

FEEDRATE SELECTION ACCELERATION

66 67 68

69

69 70 70 71 72 72 72

73

73 74 74 75 76 76

77 77 77 78 78 79 79 80 80 81 81 81 82 82 82 84 85

87

87 87 87 88 88 88

Exact Command Exact Mode Command Automatic Corner Override

Mode Mode

Circular Morion Feedrates MAXIMUM

E

Maximum Feedrate Considerations, AND OVERRIDE

Feedhold SWitch Feedrate Override Switch Feedrate Override Functions

IN THREADING

14 - TOOL FUNCTION

T FUNCTION FOR MACHINING Tool Storage Magazine Fixed Tool Selection, Random Memory Tool Selection Regist8T1flg Tool Numbers Programming Format Empw Tool or Dummy Tool

TOOL CHANGE FUNCTION - M06 . Conditions for Tool

AUTOMATIC TOOL ATC System

MaXimum Tool Diameter Maximum Tool Length MaXimum Tool Weight. ATC Cycle, MDIOperatlon

PROGRAMMING THE Single Tool Work Programming Several Tools. Keeping Track of Tools, Any Tool in Spindle - Not the First. First Tool in the No Tool in the First Tool In the Spindle with Manual No Tool In the Spindle With Manual First Tool In the Spindle and an Oversize Tool No Tool in the Ie and an Oversize Tool

T FUNCTION FOR Lathe Too! Station Tool

TOOL Offset.

WAil( Off

xii

Relatlonshi p.

POINT Zero, .

POINT

Centers.

TOOL POINT

16 - RE MMANDS

POSITION REG COMMAND Position Definition Proqrammlnq Format Tool Position

MACHINING Tool Set at Machine Zero Tool Set Away from Machine Zero. Position in Z )\xis .

LATHE APPLICATION. Tool Setup . Three-Tool Setup Groups Center line Tools Setup. External Tools Setup Internal Tool Setup. Corner Tip Detail . Programmtr'\g Example

17 - POSITION COMPENSATION

DESCRIPTION. Programming Commands Programming Formar Incremental Mode Motion Length Calculation. Position Compensation Along the Z axis

G47 and G4B. Face Milling.

18 d WORK OFFSETS

WORK AREAS AVAILABLE Additional Work Offsets

WORK OFFSET DEFAULT AND Work Offset Change Z Axis Application

HORIZONTAL MACHINE APPLICATION.

of Offsets. Offset

Offset

OFFSETS.

and Offset Numbers

108

109

109 109 110 112

112

113

113 3

13 114

114 114 114 115 115

115 116 116 116 117 117 117 117

119

1

119 119 119 120 120 122 122 122

123 124

24 125 126 127 128

Center Line Tools Tools

Tools Command Point and Tool Work Offset

19 ~ TOOL LENGTH OFFSET

PRINCIPLES

Face.

OFFSET COMMANDS Distance-Ta-Go in Z AXIs.

SETUP On-Machine Tool Length Selting OffMachlne Tool Setting Tool Offset Value Register.

Z AXIS Pres~t Tool Tool length Touch Off

a Master Tool Drfference

PROGRAMMING Tool Offset not Available. Tool Length Offse1 and G92 Tool Offset and G54G59 Tool Length Offset and Tools

CHANGING TOOL OFFSET. HORIZONTAL TOOL LENGTH

APPLICATION.

20 - RAPID POSITIONING

RAPID TRAVERSE MOTION GOO Command

RAPID MOTION TOOL Single Axis MOllon . Multiaxis Motion.

Angular Motion. Reverse Rapid Motion

TYPE OF MOTION & OF RAPID MOTION

MOTION FORMULAS, TOTHE PART

21 - MACHINE ZERO RETURN

1 MACHINE REFERENCE POSITION 128 128 129 129

Machining Centers. lathes.

the Machine Axes Program Commands Command Group

129 129 130 130 130

131

131 131 131 132 132 132

133 134 134

1 "135 135 136 136 137 137 138 138 139 140 141 141

143

143 143

144 144 144 146 146 146 147 147 148

149

149 150 150 151 151

RETURN PRIMARY MACHINE Intermediate Point . Absolute and Incremental Mode Return from the Z Depth Position

Return Required for the ATe, Zero Return for CNC Lathes

151 151 152 153 155 155

POSITION CHECK COMMAND. 156 FROM MACHINE RO POINT.

SECONDARY MACHI

- LINEAR INTERPOLATION

LIN COMMAND Starr and End of the Linear Motion Single Axis Linear Interpolation . Two Axes Linear Interpolation Three Axis Linear Interpolation

PROGRAMMING FORMAT LINEAR FEEDRATE

Feedrate Range Individual Axis Feedrate ,

PROGRAMMING EXAMPLE

~ BLOCK SKIP FUNCTION

TYPICAL APPLICATIONS, BLOCK SKIP SYMBOL CONTROL UNIT SETTING

SKIP AND MODAL COMMANDS

Variable Stock Removal Machining Pattern Trial Cut for Program Proving, Barfeeder Application, Numbe(ed Block Skip,

24 - DWELL COMMAND

PROGRAMMING APPLICATIONS for for Accessories

DWELL COMMAND Dwell Command Structure,

DWELL SETTING

Time AND DWELL

Number of Revolutions Setting MINIMUM

REVOLUTIONS

157 158

159

159 159 159 160 160 160 161 161 161

162

163

163

1 163 164 1 165 166 68 69

170 170

171

171 171 171

171 172

172 173 173 173 173 174 174 174

LONG Machine X AXIS is the Axis,

and Dwell,

FIXED AND DWELL.

CYCLES

POINT-TO-POINT MACHINING Tool Motions VS, Fixed Cycles,

FIXED SELECTION FORMAT

AND INITIAL LEVEL SELECTION R LECTION . Z CALCULATIONS

PTION OF FIXED CYCLES G81 Drilling Cycle, G82 Spot-Drilling Cycle, G83 - Hole Drilling Cycle Standard G73 Hole Drilling G84 Cycle - Standard G74 - Tapping Cycle - Reverse G85 - Cycle, G86 Cycle, G87 Backboring Cycle , G8S - Boring Cycle , G89 Boring Cycle, G76 P(cision Bonng

F CYCLE CANCELLATION FIXED CYCLE REPETITION

The L or K Address. LO or KO in a Cycle ,

26 - MACHI HOLES

SINGLE HOLE EVALUATION. Tooll ng Selection and Applications, Program Data ,

DRILLING 0 Types of Drilling Types of Drills Progiamming ConsIderatIons, Nominal Drill Diameter Effective Drill D,ameter Drill Pomt Center Through Hole Blind Hole Flat BoHom

PECK DRILLING Typical Peck Calculating the Number of Pecks

xiii

175 175 176 176 176

177

177 178

178 179 180 180 181 181 182 183 183 183 184 184 186 186 187 187 187 188 188 189

189 189 190 190

191

191 19i 194

194 194 194 195 195 195 195 196 196 197 197 198

199 199 199

xiv Table of Contents

Selecting the Number of Pecks _ 200 Controlling Breakth rough Depth. 200 28 - FACE MILLING 227

REAMING 201 Reamer Design 201 CUTTER SELECTION . 227 Sprndle Speeds for Reaming 201 Basic Selection Criteria 227 Feeorates for Reamir\~ 201 Face Mill Diameter _ 227 Stock Allowance 202 Insert Geometry . 228 Other Reaming ConSiderations 202 CUTTING CONSIDERATIONS 228

SINGLE POINT BORING 202 Angle of Entry 229 Single Point Boring Tool 202 Milling Mode 229 Spindle Orientation_ 203 N uJrloer of Cuttiny IIlSl:;rls 230 Block Tools 203 PROGRAMMING TECHNIQUES 230

BORING WITH A TOOL SHIFT 203 Single Face Mill Cut 231 Precision Bormg Cycle G76 203 Multiple Face Mill CU1S 232 Backboring Cycle G87, USING POSITION COMPENSATION. 233 Programming Example 204 Precau1ions in Prog ramming and Sew p_ 205

ENLARGING HOLES 205 29 ~ CIRCULAR INTERPOLATION 235 Counters inking 205 Counterborlng , 206 ELEMENTS OF A CIRCLE, 235 Spotfacing 207

Radius and Diameter , 235 MULTILEVEL DRILLING 207 Circle Area and Circumference 236 WEB DRILLING 208 QUADRANTS. 236 TAPPING 209 Quadrant Points 236

Tap Geometry 210 PROGRAMMING FORMAT 237 Tapping Speed and Feedra1e . 210 Arc Cutting Direction 237 Pipe Taps. 2 1 Ci reular I nterpolation Block. 237 Tapping Check List. 2'12 Arc Start and End POlntS_ 238

HOLE OPERATIONS ON A LATHE 212 Arc Center and Hadius 238 Tool Approach Motion 213 Arc Center Vectors, 238 Tool Return Motion, 213 Arc Planes 239

alld Reaming on Lathes, 214 RADIUS PROGRAMMING 240 Cycle - G74, 214 Blend Radius 240 Tapp!ng on Lathes 215 Partial Radius 240 Other Operations 216

FULL CIRCLE PROGRAMMING 240 80ss Milling 242

27 - PATTERN OF HOLES 217 Internal Ci rcle Cutting - Linear Start 243 Internal Circle Cutting - Circular Start , 243

TYPICAL HOLE PATTERNS 217 Circle Cutting Cycle 244

RANDOM HOLE PATTERN 217 ARC PROGRAMMING. 245

STRAIGHT ROW HOLE PATTERN 218 FEEDRATE FOR CIRCULAR MOTION 245 Feedrate for Outside Arcs 246

ANGULAR ROW HOLE PATTERN 218 Feedrate for InSide Arcs. 246 Pattern Defined by Coordinates, 218 Patlern Defined by Angle L1~

CORNER PATTERN 220 30 - CUTTER RADIUS OFFSET 247 GRID PATTERN 220

Ang ular Grid Pattern 221 MANUAL CALCULATIONS 247

ARC HOLE PATTERN. 222 Tool Path Center Points 248 Cutter RadiUs 249 BOLT HOLE CIRCLE PATTERN 223 Center Points CAlculation 249

Bolt Circle Formula _ 224 COMPENSATED CUTTER PATH. 250 Pattern Orientation , 224 Types of Cutter Radius Offset. 250

POLAR COORDINATE SYSTEM 225 Definition and Applications. 250 Plane Seleclion 226 PROGRAMMING TECHNIQUES 250 Order of Machining, 226 Direction of Cutting Motion 251

Table of Co ntents

or Right - not CW or CCW =,f(set Commands

of the Cutler of Offset Types

Format r\ddr8ss H or D 7,

and Wear Oifsets APPLYING CUTIER

Methods, Cffset Cancellation, ::::utter Direction

~:lok-Ahead Offset

OFFSET

WORKS

for Look-Ahead Cutter Radius Offset

:JVERVIEW OF PRACTICAL EXAM

Part Tolerances \,leasu red Part Size,

Offsets

RULES . MILLING

Amount General Selting,

Data Nominal or Middle) TOOL NOSE US OFFSET

Nose Offset Command!::

Offset

31 - PLANE SELECTION

WHAT A MACHINING IN PLANES

Mathematical Planes Machine Planes, Program Commands for Planes Definition, Default Control Status

STRAIG MOTION IN CIRCULAR INTERPOLATION IN

G 17-G 18-G 19 as Modal Commands Absence of Axis Data in a Block, Cutter Radiu:J Otr~et in Planes

PRACTICAL EXAMPLE FI D IN PLANES

32 - PHERAL MILLIN

251 251 252 252 253 253 L5Ll 254 254 256 256 256 257 257 258 259 LOO 261 262 262 ?fi2 263 263 264 264 265 2GO 265 266 266 266 266 266 267 267 268 268

269

269 269 269 270 270 271 271

272 272 273 273

275

Steel End Mills Solid Carbide End Mills Indexable Insen End Mills Relief Ailgles End Mill Size Number of Flutes

SPEEDS Coolants and Lubricants, Tool Chatter

STOCK Infeed .

In and OUI Ramping Direction of Cut Width and of CUI

33 - SLOTS AND PO KETS

OPEN AND

Closed Boundary, RAMMING SLOTS

Slot Example. Closed Slot Example

MILLING. General Principles Pocket

RECTANGULAR Stock Amount, ",,,,,'nm!,,,r Amount

of Cut _ Semifinishing Motions

Tool Path ular Pocket Program Example

CIRCULAR POCKETS, Minimum Cutter Diameter _ Method of Linear Linear and Circular Approach,

ng a Circular Pocket,

CIRCULAR POCKET

- TURNING AN BORING

FUNCTION - TURNING T Address

LATHE OFFSETS Offset Entry Independent Tool Offset. Tool Offset With Motion. Offset

MULTIPLE

Shoulder Tolerances Diameter and Shoulder Tolerances,

OFFSET SETTING,

xv

276 276 276 276 276 277

277 278 278 279 279 279 279 280

281

281 28

281 283

284 285 285 286 286 287 287 287 288

289 289 289 290 291

292

293

293 293 294 294 294 295 295 295 296 296 297 297 298

XVI

FUNCTIONS AUTOMATIC

Fillish

RANGES

Stock and Stock Allowance

A IN CSS MODE

FORMAT.

REMOVAL ON LATHES

- STRAIGHT CUTTING CYCLE Format

Turning Example Cutting ht and Taper Cutting Example

. FACE CUTTING CYCLE. Format

MULTIPLE REPETITIVE CYCLES.

and Part Contour. Ch,pbreaking Cycles

CONTOUR CUTTING CYCLES Boundary Definition Stan Point and tile Points P and 0 .

TYPE I AND TYPE II CYCLES. Programming Type I and Type II

G71 . STOCK REMOVAL IN TURNI G7 Format- OT/llTI15T G71 Format - OT/16T/18T/20T/21T G71 for External Roughing. G71 for Internal Direction of G7 .

G72 - STOCK REMOVAL IN FACING. G72 Cycle Format - 10TI1 G72 Cycle Format - OT/16TI18T/20T/21

G73 - PATTERN REPEATING G73 Cycle Form

Table

TH ON CNC LATHES Form of a Thread.

Operations.

TERMINOLOGY OF THREADING PROCESS

in Thread Starl Position Thread Diameter and Thread Cutting Motion Retract from Thread i1eturn to Stzlrt Position

THREADING FEED AND SPINDLE Feedra1e Selection.

Ie Speed Selection. Maximum Threading Feedrate Lead Error

REFERENCE POINT BLOCK-BY-BLOCK THREADING

THREADING MULTIPLE REPETITIVE

G76 Format- lOT/11T/15T G76 Format OT/16T/18T . Programming Example First Thread Calculation

THREAD INFEED Radial Infeed . Compound Infeed

Thread Insert Angle Parameter A Thread Cutting Type - Parameter P

ONE-BLOCK METHOD CALCULATIONS. Initial Considerations Z Axis Start Position Calculation.

THREAD RETRACT Thread Pullout Functions Single AXlS Pullout Two-Axis Pullout

HAND OF THREAD THREADING TO A S

Insert iv'lod Ification . Program Testing.

OTHER THREAD RMS. Thread Depth .

TAPERED Depth and Clearances Taper Calculation Block Block Tapered Thread a Tapered Thread and a MultI

MULTISTART Threading Feedrate Calculation, Shift Amount

THREAD

Cycle.

339 339 340

340 341 341 342 342 343 344 344 344 345 345 346 347 348 348 349 350 350 351 351 352 353 353 353 354 354

355 355 355 357 357 357 357

358 358 360

360

361 361 361 362 363 363

364 364 365 366

39 - SUBPROGRAMS

MAIN PROGRAM SUBPROGRAMS Subprogram Benefits . ItJtJll\iflci;ltiull (.)f n::;

SUBPROGRAM FUNCTIONS. ram Call Function .

Subprogram End FunClion. . Block Number to Return to. . Number of ram Repetitions LO Call.

SU DEVELOPMENT. Pattern Recognition

Tool Motion and Subprograms . Modal Values and Subprograms.

MULTI NESTING One Level Nesting Two Level Three Level Four Level Nesting .

CHANGE SUBPROGRAM 100000 000 HOLE GRID.

40 ~ DATUM SHIFT

DATUM SHIFT WITH G92 OR Zero Shift.

COORDINATE SYSTEM G52 Command

COORDINATE

Dat

xviii

41 - MIRROR IMAGE

RULES OF MIRROR IMAGE

MIRROR IMAGE BY Control Setting

. Manual Mirror Setting E

Mirror Functions

MI

Mirror Image Example Mirror Image Example

IMAGE ON CNC

42 ~ COORDINATE ROTATION

COMMANDS. Center of Rotation , Radius of Rotation Coordinate Rotation Cancel Common Applications

APPLICATION

43 - SCALING FUNCTION

PTION. Function Usage .

PROGRAMMING FORMAT

393

393 393 394 394 394 395 395 395 395 395 396 396 396 397 398 398

399

399 399 399 401 401

401

405

405 405 405 406 406 407 407

44 - CN LATHE ACCESSORIES 409

CHUCK CONTROL Chuck Functions Chucking Pressure Chuck Jaws,

TAILSTOCK AND TSllslock Quill. Center, Quill Functions Programmable Tailstock Safety Concerns,

81-DIRECTIONAL Programming

INDEXING

409 410 L110 410 410

11 41 I 411 411 411

412 412

ATIACHMENT. Bar

ADDITIONAL OPTIONS

PROGRAMMING EXAMPLE

45 - HELICAL MILLING

HELICAL MILLING OPERATION

Format, Arc Modifiers for

and THREAD MILLING,

Thread Conditions tor Thread Thread

Clearance Radius Productivity of Thread

THE HELIX, THREAD MILLING

Straight Thread In itial Calculations Starting Position Motion Rotation and Direction Lead'in Motions , Thread Rise Calculation Milling the Thread Lead-Out IV" 1,lIn."

THREAD MILLING SIMULATION METHOD HELICAL RAMPING

of ntenls

413 413 414 4 '14 414 4'15 415

415

417

417 417 417 4'18

18

418 418 418 4'19 419 419 419

419 421 421 421 422 422 423 424 424 425 425 425 425 426 426 427

46 - HORIZONTAL MACHINING 429

INDEXING AND ROTARY INDEXING TABLE (8 AXIS)

Units 01 Increment _

and Unclamp Functions .nl'l,

Tab I e of Contents XIX

438 RUNNING THE FIRST PART 459 438 PROGRAM CHANGES 460 439 Program Upgrading Program StruclU re 439 460 Program Updating . 461

BORING MILL. 439 Documentation Change, 461 ALTERNATE MACHINE SELECTION. 461

47 . WRITING A CNC PROGRAM 441 MACHINE WARM UP PROGRAM 462 eNC MACHINING AND SAFETY. 462

WRITING. 441 SHUTTING DOWN A CNC MACHINE 463 442 Emergency Stop Switch, 463 442 Parking Machine Slides 464 442 Setting the Control System, 464

'JGRAM OUTPUT FORMATTING 443 Turning the Power Off, 464

PROGRAMS 445 EQUIPMENT MAINTENANCE 464 Length Reduction. 445 Mode and Tape Mode 4

XX

477 Hardware Specifications. 487 478 Hardware Requirements, 488 478 and Features, 488

S;ne ~ Cosine - Tangent 479 Inverse Trigonometric Functions 480 Degrees and Decimal 480 Post Processor L188 Pythagorean Theorem 480 IMPORTANT FEATURES. 489 Solvfng Rjght 481 489

ADVANCED CALCULATIONS 482 489 CONCLUSION. 482 User Interlace, 489 CAD Interface, 489

MANAGEMENT, 53 - CNC AND CAD/CAM 483 490

490

PROGRAMMING MANUALLY? 483 490 483 THE END AND INNING. 483

TOOL PATH GEOMETRY PMENT 484 A - RE NeE TABLES 491 TOOL PATH GENERATION 484 COMPLETE ENVIRONMENT 484 491

Multi Machine Support , 485 494 Associative Operations 485 494 Job Setup 485 Tooling List and Job CommenlS, 485 495 Connection Between Computers 485 Metric rse Threads 495 Text Editor 486

486 Metric Fine 495 486 486 Index 497 for Solids 486

Software Specifications , 487

NUMERICAL CONTROL

Numerical Co~trol technology as it is known today, emerged nud 20th It can be traced to the year of1952, u.s. Air Force, names Parsons and the Massachusetts of Technology in

MA, It was not production manu-facturing until 1960's. real boom came

of CNC, the of 1972, a decade v.:ith introduction of micro computers. The hIstOry and development of this fascinating technology has been well documented publications.

In the manufacturing field, and particularly in the area of working, Control has .... "' ..... "''"' ....

SOlnethuJll"Z of a revolution. in the computw ers became standard in every company and in

the machine equipped with Numerical SVS1leIn fOWld their special place in the

shops. recent evolution of electronics the never ceasing computer development, including its impact on Numerical Control, brought changes to the manufacturing sector in general metalworking in-dustry in particular.

DEFINITION OF NUMERICAL CONTROL

In publications and articles, descriptions have been used during the to defme what Numerical Control It would be to try to yet another defInition, just the purpose this handbook. Many of

defmitions the same same basic COl1lcer:)t. use different

The of all the known definitions can be summed simple statement:

UI.-UUHl) are of the of alpha-selected symbols, for a decimal

sign or the parenthesis symbols. All in-"'''''HV''':> are urn .......... in a logical a predetermined

collection of all instructions necessary to ma-a part is called an NC Program, Program, or a

""w,t:rY,I'1'" Such a can be for a future repeatedly to identical machining re-

Ne and eNC Technology In ~trict to the terminology. there is a

ence m the meaning abbreviations NC and CNC. NC for the original Numerical Control technology, whereby abbreviation stands for the newer Co~nputeriz~d Numerical Control technology, a

mode~ spm-off of lts older However, practice, eNC IS the abbreviation. To clarify the proper us-

af each tenn, look at the major between CNC ,.."~ .. ~~,,

Both perform the same tasks, bon of the purpose machining a cases, the internal design of the system the logical instructions that process the data. At this point

ends.

The system (as to the CNC system) uses a fLXed logical functions, that are built-in and nently wired the control These LI..llI',",U'JJJ" not be changed by the programmer or machine tor. Because of t?e ftxed wiring logic, control IS synonymous with the term 'hardwired', The can interpret a part program, but it does not al-

VH .... "AF>.~.., to the using the away from the

typically in an environment. the NC quires the compulsory use of punched tapes for

information.

The CNC but not the NC system, uses an internal micro (i.e., a computer). This

storing a variety of routines that are capable logical That means programmer or the machine '"'''"''' . ...,.~,'' .. can change the on the control itself (at ma-chine), with instantaneous results. flexibility is greatest advantage of CNC systems probably key element that to such a use of the tech-nology in modern manufacturing. The CNC programs and the logical are stored on special computer chips, as software rather by c.onnections, such as that control the logical hOns. contrast to the system, the system is syn-onymous with the term 'softwired'.

When describing a particular that to the control technology, it is customary to use

or in mind NC can also mean CNC 1n everyday talk, but can never to the

1

2

technology, described in this handbook under the abbrevia-tion ofNe. The 'C'stands for Computerized, and it is not applicable to hardwired All manufactured today are of the design, Abbreviations such as C&C or C 'n are not correct and reflect poorly on anybody uses them

CONVENTIONAL AND CNC MACHINING

What makes CNC machining superior to the conven-tional methods? Is it superior at all? Where are benefits? If the CNC and the conventional machining pro-cesses are a common general approach to ma-chining a part will -.... -.M-1. Obtain and study drawing 2. Select the most suitable machining method 3. Decide on the setup method (work holding) 4. Select the cutting tools 5. Establish and 6. Machine part

This same both types of mac run-mg. IS m way how data are input. A feedrate 10 inches per minute (10 mlmin) is the same in manual or CNC applications, but the method of applying it is not. The same can be about a coolant it can be activated a knob, pushing a switch or programming a special All will result in a coolant rushing out of a HV" ...........

a certain amount of knowledge on part user is required. alL working, particularly meta! cut-ting, is mainly a skill, but it is also, to a great an art and a profession of large number of people. So appli~

of Computerized Numerical Control. Like any skill or art or profession, it to the detail is neces-sary to be successful. It takes more than technical know 1-

to be a CNC machinist or a CNC Work I>v?,"' ..... " ...... ,' ... and what is called a 'gut-feel', is a much needed supplement to any skill.

In a conventional machining, the operator sets up the machine and moves each cutting using one or both hands, to produce the required part. The design of a

machine tool offers many features that help the process of machining a - levers, and a15, to name just a few. same body are re-peated by the every in the batch. However, the word 'same this context really means 'similar than 'identical '. Humans are not capable to every

the same at all times - that is the of ma-'-'UU.H ... ". People cannot work at the same per[orrnam;e leve! all the without a rest. All of US have some good and some bad moments. The results these moments, when applied to a part, are to predict. There will some differences and within each batch of The parts will not always be exactly the same. dimensional tolerances and

NUMER CONTROL

of the areas the CNC user can and expect improvement:

o Setup time reduction

Cl lead reduction

o Accuracy and repeatability o Contouring of shapes o Simplified tooling and work holding o cutting time o General productivity increase

area offers only a potential improvement. Individ-ual users will different of actual improve-ment, depending on the oil-site, the CNC used, setup methods, complexity of fixturing, or cutting tools, management philosophy

engineering level of individual attitudes, etc.

Setup Time Reduction

of the the serup time should not Modular lixturing, SI

4

Cutting Time and Productivity Increase machine is commonly

is consistent. Unlike a the operator's skill, experi-

to changes) the CNe machining is under control a computer. The small amount of manual work is restricted to the setup and load-ing and unloading batch runs, the high cost of the unproductive time is spread among many parts, making it less main benefit of a consistent cutting time is jobs, where the production scheduling and work to individual machine tools can be done very "'v"''''''''''''''

The main reason COlnp:anlces chines is strictly prr,nnrn having a competitive plant manager. excellent means to a

productivity of the manufactured wisely and

companies use the CNC machine does not offer the extra

ma-invesilmellt. Also,

on of every technology offers

improvement in the overall

Like any means, it has to When more and more

just having a CNC anymore. The com-

how to use the panies that get forward are who technology efficiently and it to competitive in the global economy.

To reach the goal of a essential that users understand the h""";",,,,,,, ... nM on which CNC technology is many forms, for example, un(jen.tarldulg cuitry, complex ladder diagrams, \.-UI.IILJIL,lll;;;1 ogy, machine design, machining onnC11Dles and many others. Each one has to by the person in charge. In this Hil11UUIUU.I\.. on the that relate directly to the

understanding the most common Machining Centers and the lathes

the Turning Centers). The should be very important to every ma-

tool operator and this goal is also reflected in the handbook approach as well as in numerous

TYPES OF CNC MACHINE TOOLS ni1ffef'ent kinds of CNC machines cover an ChllClllCH

variety. Their numbers are rapidly developmentadvances. It is .

applications, they would of some groups CNC

Cl and Machining centers Cl and Turning Centers Cl Drilling machines

pter 1

Cl mills and Profilers Cl EDM machines o Punch presses and Shears Cl cutting machines Cl

o Water and Laser profilers o Cylindrical grinders Q

Cl and Spinning machines, etc.

centers and lathes dominate industry. These two groups share

market just about equally. Some industries may a higher need one of machines, depending on their needs. One must that there are many different kinds of lathes and equally many different kinds of ma-chining centers. the programming process for a vertical is to the one for a horizontal ma-chine or a simple mill. Even between different ma-chine groups, there is a amount of general hons and the is generally the same. For example, a contour with an end mill has a lot common with a contour cut a

Mills and Machining Centers Standard number axes on a milling machine is three -

the X, Y and Z axes. set on a milling system is al-ways stationary, on a machine table. The cutting tool it can move up and down (or in and out), but it does not physically follow the tool path.

CNC mills - sometimes CNC milling machines -are usually small, simple without a tool changer or other automatic features. is often quite low. In industry, they are maintenance purposes, or small usually designed for contouring,

CNC machining centers are far more drills and mills,

benefit the user gets out ability to several diverse operations

drilling, boring, counter facing and contour milling can be

CNC program. In addition, automatic tool changing,

minimize idle time, indexing to a different side a rotary movement of additional axes,

CNC machining centers can with special software that controls the speeds and

of the cutting tool, automatic in-process ",,,,,,oil''''' adjustment and other production "XU'I'Ul' .... Ul'J;:, devices.

NUMERICAL CONTROL

There are two basic machining center. They are the machining centers. The major difference two types is the nature of work that can be on them efficiently. For a

CNC machining center, most suitable type of work are flat parts, either mounted to ble, or held in a vise or a chuck. cbining on two or more in a sirable to be done on a CNC horizontal U14'.llll.lll

example is a pump and shapes. Some multi-face ULa ... 'U.llllli,!:;

done on a CNC vertical machining center ... '-I ..... I-'IJ ....... a table.

prc)gr.:imrnulg process is the same both designs, an (usually a B axis) is added to the hori-

design. Ths axis is either a lHU';;;1\.U.1J;:. axis) for the table, or a fully rotary

taneous contouring.

handbook concentrates on the CNC centers applications, with a special "" ... 'CIVIl

horizontal setup and machining. melmO(lS are also applicable to the small

tapping machines, but the "",.r'rr,..,'..,.. ....... " ... restrictions.

and Turning Centers is usually a machine tool with two axes,

the horizontal Z axis. distinguishes it from a mill is that

machine center line. In addition, cut-is normally stationary, mounted in a sliding twTet.

follows the contour of programmed tool path. the CNC lathes with a milling attachment, so called live tooling. the milling tool has its own motor rotates while spindle is stationary.

I"nn,"I>',..,.., lathe design can be horizontal or more common than the

purpose in for either For

horizontal group can be as a bar type, chucker type or a

to combinations are ac-a CNC lathe an extremely flexible ma-

accessories such as a tailstock, steady rests or fol1ow#up part catchers, pullout-fingers even a third milling attachment are popular compo-nents of the CNC ~ lathe can be very versatile so versatile in that it is often caUed a CNC Turning Center. AU text examples in this handbook use the more tenn CNC lathe, yet still ing aU its rr'ln,('Ip.1m h"",,,,,,h .. u,,,

PERSONN FOR eNC

machine tools have no cannot evaluate a

with skills and

5

control, sk1lls are usually - one doing the

machining. Their depend on the company

as product manufactured is quite distinct, although many

companies the two functions into a one, often called a CNC ProgrammerlOperat01:

CNC Programmer The CNC programmer is the person who the

most responsibility in shop. This person is often responsible for numerical control technology in the plant. is held respon-sible for problems operations. Although duties may vary, the ~ .. ",rr..-.,_ ... ""~ is also responsible for a variety of tasks usage of the CNC machines, In fact, this accountable for the production and quality of operations.

analyze, \"Ullv\"lvU dam into a

the CNC pro-01"1!1 ....... ",..I",. must be to decide upon the best manufactur-

methodology in all respects.

In addition to the machining skills, programmer has to have an understanding of mathematical principles, mainly application of equations. arcs and an-

Equally important is the of trigonometry. with computerized progranuning) knowledge of

manual programming methods is absolutely to the thorough understanding of the control this output.

important quality of a truly "'''''1'">'\''''''P1'" is his or her ability to listen to

the CNC operators, are the first prerequisite to h"""'(lI"'I"""

programmer must be flexible ClllLHll1t);!, quality,

6

CNC Machine Operator The CNe machine tool operator is a complementary po-

sition to the CNe programmer. The programmer and the operator may exist in a single person., as is the case in many small shops. Although the majority of duties performed by a conventional machine operator has been transferred to the CNC programmer, the CNC operator has many unique responsibilities. In typical cases, the operator is responsible for the tool and machine setup, for the changing of the parts, often even for some in-process inspection. Many companies expect quality control at the machine - and the operator of any machine tool, manual or computerized, is also responsible for the quality of the work done on that machine. One of the very important responsibilities of the CNe machine operator is to report fmdings about each pro-gram to the programmer. Even with the best knowledge, skills, attitudes and intentions, the 'fmal' program can al-ways be improved. The CNC operator, being the one who is the closest to the actual machining, knows precisely what extent such improvements can be.

SAFETY RELATED TO CNC WORK

On the wan of many companies is a safety poster with a simple, yet powerful message:

The first rule of safety is to follow all safety rules

The heading of this section does not indicate whether the safety is oriented at the programming or the machining level. The reason is that the safety is totally independent. It stands on its own and it governs behavior of everybody in a machine shop and outside of it. At fIrst sight, it may appear that safety is something related to the machining and the machine operation, perhaps to the setup as well. That is defInitely true but hardly presents a complete picture.

Safety is the most important element in programming, setup, machining, tooling, ftxturing, inspection, shipping. and you-name-it operation within a typical machine shop daily work. Safety can never be overemphasized. Com~

Chapter 1

panies talk about safety, conduct safety meetings, display posters, make speeches, call experts. This mass of informa-tion and instructions is presented to all of us for some very good reasons. Quite a few are based on past tragic occur-rences - many laws, rules and regulations have been written as a result of inquests and inquiries into serious accidents.

At fIrst sight, it may seem that in CNC work, the safety is a secondary issue. 111ere is a lot of automation, a part pro-gram that runs over and over again., tooling that has ben used in the past, u simple setup, etc. All this can lead to complacency and false assumption that safety is taken care of. This is a view that can have serious consequences.

Safety is a large subject but a few points that relate to the CNC work are important. Every machinist should know the hazards of mechanical and electrical devices. The fIrst step towards a safe work place is with a clean work area, where no chips, oil spills and other debris are allowed to accumulate on the floor. Taking care of personal safety is equally important. Loose clothing,jewelry, ties, scarfs, un-protected long hair, improper use of gloves and similar infractions, is dangerous in machining environment. Pro-tection of eyes, ears, hands and feet is strongly recom-mended.

While a machine is operating, protective devices should be in place and no moving parts should be exposed. Special care should be taken around rotating spindles and auto-matic tool changers. Other devices that could pose a hazard are pallet changers, chip conveyors, high voltage areas, hoists, etc. Discollllectillg allY interlocks or other safety features is dangerous - and also illegal, without appropriate skills and authorization.

In programming, observation of safety rules is also im-portant. A tool motion can be programmed in many ways. Speeds and feeds have to be realistic, not just mathemati-cally 'correct'. Depth of cut, width of cut, the tool charac-teristics, all have a profound effect on overall safety.

All these ideas are just a very short summary and a re-minder that safety should always be taken seriously.

Many types machines are in indus-try, the majority of them are machining centers and CNC lathes. They are by wire EDM, fabricat-ing machines and machines special Although the this handbook is on the two that domi-nate the market, many can be applied to

equipment.

CNC MACHINES - MILLING

The description of CNC milling is so it can fill a thick book all by itself. All machine tools from a

knee lype milling machine up to a five profiler can included in (his They in features, suitability for work, etc., but they do all one common denominator - their primary axes are the X and Y axes - this reason, they are called machines.

the category of the machines are also wire EDM machine tools, laser and water jet cutting name cutters. burners, routers, etc. Although do not qualify as milling type machine tools, we mention them because the majority of programming techniques applicable to the mills is to machines types as well. The example is a contouring operation, a common La many CNC machines.

the purpose this handbook, a milling machine can be defmed:

Milling machine is a machine capable of a simultaneous cutting motion, an end mill as the primary cutting

at least two axes at the same time

This definition eliminates all CNC presses, since covers pOSItioning not profiling. The

nition also eliminates wire EDM machines a of burners, they are capable of a profiling action but not

an end mill. Users these machine tools will still from m:tny covered The

ciples are adaptable to the majority of machine tools. For EDM uses a very small cutter

in the of a A cUlling machine uses beam as its cutter, also having a known diameter bUL

term keifis used The will be concentrated on metal cutting machine of end mills as the primary tool contouring. mill can be in many ways, first look will

or available machines.

CNCMILLING

Types of Milling Machines Milling machines can divided imo Ihree categories: o By the number of axes - two, three or more o By the orientation of axes - vertical or horizontal o By the presence or absence of a tool ... h ..... "',"r

Milling machines where the spindle motion is up and down, are categorized as vertical machines. Milling ma-chines where the spindle motion is in out, are catego-

as horizontal machines - see Figure 2-1 and

Figure 2-/ Schematic representation of a CNC vertical machining center

'I" j'> I

Figure 22 Schematic representation of a CNC horizontal machining center

7

8

simplified not really reflect reality current state of art in .a ...... "' ... tool manufacturing.

machine tool industry is changing. New and more powerful machines are V_'''"",'' __ and produced by

manufacturers worldwide. more features.

The majority of modern machines designed for milling are capable of doing a multitude of machining tasks, not only the traditional milling. machines are also capa-

of many other metal operations, mainly drill-ng, thread cutting

many others. They may with a multi-tool azine (also known as a a fully changer (abbreviated as ATC) a pallet viated as APC). a powerful computerized conlrol unit brevlated as CNC), and so on. Some machine may have additional features, as adaptive control. terface, automatic loading unloading, probing ",,,,,,rpo..,... high speed machining and other mod-ern technology. The is - can machine tools of capabilities be as simpleCNC milling In two words - certainly not. Milling machines that have at

some of built-in. have , .. "u"'''''"" new breed of tools - CNC An/l,r".,,, This lenn is strictly related - a manual machining cel1Jer is a description thal does nul exist.

Machine Axes Milling machines and machining centers have at least

axes - X, Y The machines become more flexi-iflhey usually an

lary axis (the A horizontal models). higher found on with five or more axes. A chine wilh five ;'lxes. he a hnring mill that jor axes, plus a axis (usually the B parallel to the Z (usually the W axis). true complex and flexible five-axis profiling [ling machine is the type used in industry. where a multi-axis. simul-taneous is necessary to complex shapes and and various

At times, three and a the type of of all axes vertical

two and a machine is used.

where simultaneous

machine or a terms refer to

limitations. For a Y and Z axis as primary axes. plus

designated as an A The indexing ta-ble is used posllioning. but il cannot rotate simulta-neously with the motion of primary axes. That type of a

called a 'three and a half axIS ' machine. a more complex but machine Ihal is

a table, is as a four can move simultaneously

with the motion of the axes, is a good example of a true 'four ax.is machine tool.

2

machining center is described by its specifications as provided by the machine tool manufacturer. manu-

lists many as a quick method of comparison between one machine and another. It is not un-usual to find a slightly information in the brochure - after all, it is a tool.

In the area of chine tools are

systems, three most common ma-

Q eNC Vertical Machining Center - VMC Q CNC Horizontal Machining Center HMC Q CNC Horizontal Boring Mill

type, except the major differences will the axes, additional for indexing or full rotary the type of work suitable for individual lion of the most common type of a machining center - the Vertical Machining Center (VMC) - a fairly accu-rate sample other group.

Vertical Machining Centers Vertical

of work, done on

for flat type of machining is

setup.

A vertical machining center can be used with an optional axis. usually a head mounted on the main table. The rotary head can mounted either ver-tically or horizontally, depending on the results and the type. This fourth can either for in-dexing or a full rotary molion. In combination with a

supplied), the fourth in the vertical "nr""",,, can be long parts that

need support at both ends.

maJonty vertical centers most tors work with are those with an empty table and three-axes configuration.

From the programming perspective, there are at least two mentioning:

o ONE programming always takes from the viewpoint spindle, not the means the view is

as if looking straight down, at ninety degrees towards the machine table for development of the tool motion. Programmers always view the top of part!

Q TWO various markers located somewhere on the machine show the positive and the motion of the machine axes. For programming, markers should be ignored! These indicate operating directions, not programming directions. As a matter of fact, typically the programming directions are exactly the opposite of the markers on the

tooL

CNC MILLING 9

Vertical and Horizontal Machining - Typical Specifications . - ...... _- ...

m __ ,

Description Vertical Machining Center Horizontal Machining Center 1= I~

Number of axes 3 axes IXYZ) 4 axes IXYZB} 780 x 400 mm 500 x 500 mm Table dimensions 31 x 16 inches 20 )( 20 inches

Number of tools 20 36

575 mm 725mm Maximum travel- X axis 22.5 inches 28.5 inches

380 mm 560mm Maximum travel- Y axis 15 inches 22 inches

470 mm 560 mm Maximum travel- Z axis 18.5 inches 22 inches

Table indexing angle N/A 0.001 degree

Spindle speed 60-8000 rpm 40 - 4000 rpm

AC 7.5/5.5 kW AC 11/8 kW Spindle output AC 10/7 HP AC15/11HP

Spindle nu:>t:-tlJ-t~1.1 distan ... ", - Z axis 150 - 625 mm 150 - 710 mm 6 - inches 6 - 28 inches

430mm 30 560 mm Spindle center-to-column distance Y axis 17 inches 1.2 inches

Spindle taper No. 40 No. 50

Tool shank CAT50

2 - 10000 mm/min 1 - 10000 mmlmin 0.100 - 393 in/min 0.04 - 393 in/min

Rapid traverse rate 30000 mm/min (XY) - mm/min IZl 30000 mm/min (XYI - 24000 (2)

Tool selection ...

Maximum tool diameter

Maximum length

Maximum tool weight

Horizontal Machining Centers Horizontal CNC Machining Centers are also

as multi-tool and versatile machines. and are

1181 in/min IXY) 945 in/min (Z) 1181 in/min (XV)- 945 iI\Imin memory Random memory

80 mm (150 w/empty pockets) 1 mm 3.15 inches (5.9 w/empty pockets) 4.1 inches

300mm 350 mm 11.8 13.75 inches

6 kg 20 131bs 44

There arc many applicaions in lhis area. Common exam-are large as pump housings, cases,

manifolds, blocks and so on. machining bieal paris, where majority of machining has to centers always include a special ing table and arc

equipped with a pallet and other on more than one in a single setup.

10

Because their flexibility and complexity, CNC zonlal machining centers are priced significantly than vertical CNC machining centers.

the programming point view, there are several eli mainly relating to the Automatic Tool

the indexing table, - in some cases - to the ad-ditional for example, the changer. All differences are relatively minor. Wriling a program for horizontal machining centers is no different than writing a

for venical machining center!'..

Horizontal Boring Mill Horizontal boring mill is another machine. It

closely resembles a CNC horizontal machining center, but have its own Iy, a horizontal mill is by the lack some common fea-

tures, such as Automatic Changer. As Ihe name of the machine its primary purpose is boring opera-tions, mainly lengthy that reason, the reach of the is extended by a specially designed quill. An-other typical feature is an axis parallel to the Z axis, called Ihe W axis. Although is, in the fifth nation (X, y, W), a horizontal boring mill cannot be called a true axis machine. Z axis (quill) and the W axis (table) work in the (awards other. so Ihey can be used large parts and hard-to-reach areas. It means, that during drilling, the machine table moves an quill. quill is a physical part of the spmdle. It is in the spindle where the culling 1001 ro-"'lies - but in-nnd-out motions are done by the table. Think of the method offered on horizontal mills - if the quill were to be very it would lose strength and rigidity. belter way was to split the tradI-tional single Z axis movement into two - the quill extension

the Z axis will move only of the way Owards lhe and the table itself, the new axis, will move another

Chapter 2

parl of the way towards area the part Ihal chine tool resources.

spindle. bOlh meet in the be machined using all the ma-

Horizontal boring mill may be called a machine, but certainly nol as-axis CNC the count of the axes is Programming CNC mills are similar to Ihe horizontal and

machining centers.

Typical Specifications On the preceding page is a comprehensive chart showi

the typical specifications a CNC Vertical Machining Cellterand a CNC Horizontal Machining Centel: ifications are side by side in two

not for any comparison are two different types and comparison is no\ possible all features. In order to compare individual machine tools within a category, machine tool prov-ided by the machine manufacturer serve as the basis for comparison. specifications are contained a of verifiable data, mainly technical in nature, describes lhe individual machine by main features. Machine tool buyers frequently compare many brochures of several fcrcnt machines as parr of the pre process. agers process planners compare individual machines in the machine shop and assign the available workload 10 the most suitable machine.

A fair and accurate comparison can be made between two vertical ining centers or between two horizontal ma-chining centers, but cannOI be done to compare (ween two differenl types.

In 11 typical sped chart, additional dala may be listed, not included in earlier chart In this hand-book, the focus is on only those specifications Ihat are interest \0 the CNC and the CNC operator.

CNC MACHIN TURNING

or it turret IS a common In machine shop. A lathe is used

machimng or conical work, as shafts. wheels, bores, threads, etc. The most common lathe

operation is removal material from a round Illrning tool for external culling. A lathe can ror internal operations such as boring, as well as for

threading, etc., if a cutting tool is are usually in machining power

lathes, hutlhey do have a carousel that holds cutting tools. An lathe has often one

or two CUlling tools at a lime, but has more ma-chining power.

Typical lathe work controlled by a CNC system uses ma-known in industry as the CNC Turning - or

more commonly - the CNC

term 'turning is curate overall descnption of a

can be used for a number of machining op-during a example, in addition to

lathe as turning and a lathe can be used for drilling, grooving,

knurting and even burn It can also be used in ent modes, such as chuck work,

centers. Many other combinations also exist are designed to hold tools in special

can have a milling indexable chuck, a sub a tailstock, a steadyrest many other features

associated with a lathe design. more than four axes ore common. With

constant advances in machine technologies, more CNC appear on the market that are designed to do a number of operations in a many of them (tonally reserved for a mill or a center.

Types of eNC lathes lathes can by the type of

the number of a xes. two types are lathe and the horizontal CNC lathe. Of

the two, horizontal type is by the most common in manufacturing and machine shops. A CNC lathe (incorrectly called a vertical boring mill) is somewhat less common but is irreplaceable for a work. For a CNC there are no differences in the approach between two lathe types.

CNC TURNING

of Axes The most common distinction CNC lathes is

by the number of programmable axes. Vertical CNC lathes have two axes in almost all The much more common CNC horizontal commonly designed with two programmable axes, are available wilh three, four or axes, adding extra to manufactur-ing of more complex parts.

A type

lathe can funhcr described by the

o FRONT lathe oREAR

... an engine lathe type

... a unique slant bed

SIan! bed type is very popular its design allows chips to operator and, in case an accident, down a area, towards the chip

Between the of flat bed and type lathes, front and rear lathes, horizontal and venicallalhe designs, there is another variety of a lathe. This describes CNC lathes by number of axis, which probably the simplesl and most common method identification.

AXES DESIGNATION

A typical CNC is designed with two standard axes -one axis is the X other axis is lhe Z axis. Both axes are perpendicular to other and represent the two-axis lathe motions. X axis also represents I ravel of the cutting tool, Z represents nal morion. All varieties of tools are

can be or turret (a special too) Because of this lurret loaded with all CUI-

Z axes, which means all

Following the established and machining

of making a hole by or punching, is the Z

of the milling ma~ the only machine

of drilling, boring.

CNC lathe work, the oriemation a type of lathe is downwards motion

axis, and left and motion for the Z axis, when looking from the machinist's position. This view is shown . following three illustrations Figure 3-1, Figure

3-3.

11

12

HEADSTOCK

I

I . !

Figure 3-1

CHUCK /

/ JAWS ! ----". TOOL

X+ TAILSTOCK t

.....

" x- QUILL

Typical configuration of a two axis slant bed eNG lathe - rear type

x+

t Z- ..... Z+

" X-X-

t .....

" X+

Figure 3-2 Typical configuration of a CNC lathe with two turrets

Figure 3-3 Schematic representation of a vertical eNC lathe

is true for both the front and rear lathes and for lathes with or more axes. The chuck is verti-cally to the horizontal spindle center line for all horizontal lathes. Vertical lathes, due to their design, are rotated 90, where the chuck face is oriented horizontally to the vertical spindle center line.

Chapter 3

In addition to the X and Z primary axes, the lathes have individual of each additional axis,

example, the C axis is usually third axis, for milling operations, using so called live tooling. More tails on the subject of coordinate system and machine ge-ometry are available ill Ihe next

Two-axis Lathe This is the most common type of CNC The work

holding u!\ually a chuck, is on the left of machine (as viewed by the operator). The rear type, with slant bed, is most popular design for general work. some special for in the petroleum industry (where turning tube ends is a common work). a

bed is usually more suitable. The CUlling lools are held in a specially designed indexing turret that can hold six, eight, len, more tools. Many such lathes also have two turrets.

Advanced 1001 designs incorporate tool storage away from the work area, similar to the design of machin-ing centers. 'even hundreds, of cutting tools may stored and used a single CNC program. Many lathes also incorporate a quick changing tooling system.

Three-axis Lathe Three~axls lathe is essentially a two-axis lathe with an

ditional This has own usually as a C in absolute mode (H in incremental mode), and is fully programmable. Normnlly, the third axis is used for cross-milling slot CUlling. bolt circle holes drill-ing, helical slots, etc. axis can re-place some simple operations on a milling machine, reduc-ing setup time for the job. Some limitations apply (0 many models, example, the milling or drilling opera-tions can (ake place only at positions projecting from the tool center La the spindle center line (within a machin-

plane), although adjustments. The third has own power source but the power raL-

is relatively lower when compared with the majority of machining centers. Another limitation may the smallest increment of the third axis, particularly on the three axis lathes. Smallest increment of one degree is certainly more useful an increment of two or five (j"'l'rf"'~ better is an increment of 0.1'\ 0.01 0, and commonly 0.00 1 on the models. Usually the lathes with three axes of-

a fine radial increment that allows a simultaneous rotary motion, with low increment values are usually designed with an oriented spindle stop only.

From the perspective ofCNC part programming, the ditional knowledge required is a subject not difficult to learn. General principles of milling apply and many pro-gramming features are also available, for fixed

and other

CNC TURNING

four-axis lathe

a four-axis CNC lathe is a a three-axis lathe. As a matter of to pro-

lathe is nothing more than programming lathes at the same time. That may sound

the principle of a CNC lathe

are actually two controls one each pair (set) axes.

used to do the external - or (OD) and another program to do the

- roughing (ID). Since a pair of axes independently, and can be at the same time, doing two different operations

simultaneously. The main keys to a 4-axis lathe programming is coordination of the (ools and their opera-tions, liming of the tool motions a sense of

compromise.

reasons, both Kf':.c.ml

It is very important to understand the specifications and of the CNC machine lools in shop. Many fea-

to the control system, many others to the ma-tool itself. In CNC programming, many imponanl

are based on one or of features, for example number of tool stations available, maximum spin-

others.

Control Features in understanding the description of a

lathe is the look at some control unique 10 how they differ form a typical control.

of control features is described in more detail 5,

At some fealures and codes nOI make sense - they are included for ,,,r,"'''''1> only. Com-

mon typical features are listed: Q X a diameter, nat a radius Q Constant surface speed leSS) is standard control

(G96 for CSS and G97 for r/min) Q Absolute programming mode is X or Z or C Q nr:rl~m,.'ntlll nrn"'''"rnnllnn mode is U or War H

3

Q of various forms (including taper and circular) can performed, depending on the control model

Q Dwell can use the p. U or X address (G04) Q Tool

Q

uses 4-digit identification 1=,,,,,1.,,.,,, s~!lection (normal) in mm/rev or in/rev

a Feedrate (special) in mlmin or inlmin a Rapid traverse rate different for X and Z axes Q Multiple repetitive cycles for turning, boring, facing, contour

repeat, grooving, and threading are available a Feedrate is common from 0 to 200% in 10%

increments (on some lathes only from 0 to 150%) o X axis can Q Tailstock can be programmable a Automatic 2m" .. "rv, and corner rounding

R and II Kin a Thread available with six-decimal

place accuracy (for inch units) a Least input increment in X is 0.001 mm or .0001

inches on diameter one half of that value per side

COORDINATE GEOMETRY

a in /lates. System of coordinates is mathematical principles dating

most important of

on a over four

are those that today. In various

these princi-the rea/number sys-

can be applied to Ihe CNC technology publications on mathematics and pies nrc lisled under the headings (ell! and the rec/angular coordinates.

REAL NUMBER SYSTEM

key to understanding (he knowledge of arithmetic. key knowledge in this area is /lumber system. Within ten llvuiluble numerals ,_'",,"'vl can be used in any of the

o Zero integer.. . 0 r:J Positive integers ...

(with or without sign) L 2, 10,12943, +45

o Negative integers ... (minus sign required)

-381, 25,-77

o Fractions ... 1/8, 3/16. 9/32, 35/64 o Decimal fractions 0.1 .546875. 3.5

At! groups are used the mainstream of just modern life. In CNC programming, primary goal is to usc the numbers to 'Iranslate' the drawing, based on its menslons, into t). cutter

Computerized Numerical Control means control by the numbers using a All information in a drawing has to be translated into a program, using primarily numbers. are used Lo describe commands, functions, comments, so on. The mathematical rn.,r,'n. of a real number can he expressed graphically on a straight line, scale, where all divisions have the same 4-1.

Figure 41 Graphical representation of the Number Scale

The length of division on the scale re[>re~,e unit of measurement in a convenient and ceptcd It may come as a surprise that used day. example, a simpJe ruler used in

on the number scale concept, regardless of mea-Weight scales using lons, pounds,

of mass are other uses the same

as

RECTANGULAR COORDINATE M

coordimlte system IS a to 2D point, using the XY coordinates, or a spa-

point, using the XYZ coordinates. [t was first 17th century by a French and

......... ,"'" Rene Descartes (I I us an alternative to the rectangular

called Coordinate System

T " ..

T

-, ..

-;

Figure 4-2 Rectangular coordinate system

The concepts used in design, and in numerical control are over 400 years old. A point can be mathe-matically defined on a plane (two coordinate values) or in space (three coordinate values). defin ition of one point IS !O another poinl as a distance parallcl with one of

axes that are perpendicular to each olher. In a plane, only two axes are required, in the space, all three axes must

specified. In programming, represents an exacllo-If such a location is on a the point is defined

as a 20 point, along two axes. the location is in a space, lhe poilH is defilled as a three axes,

15

16

When two number scales that intersect at right angles are used, mathematical for a recTangular coordinate sys-tem is terms from tion, and all have an important role in CNC programming.

understanding is very important for further

Axes and Planes of number an axis.

This old principle, when applied to programming, means that at least two axes nvo number scales - will be

mathematical definition of an

definition can enhanced a statement thaI an axis can also be a line of reference. In CNC programming, an as a reference all the lime. The definition contains word '. A plane is a term in 2D ap-plications, while a solid object is used in 3D applications. Mathematical definition of a plane is:

the top viewpoint of the looking straight down on the illustration Figure 4-3, a viewing direction is established. This is often called viewing a plane.

A plane is a 2D entity - letter X identifies horizon-

Yaxis

I I- 1- '1--1-" I -I -I 1 +-1- X axis

Figure 4-3 Axis designation viewing plane Mathematical is fully implemented in CNC

lal the Jetter Y identifies its vertical axis. 111is plane IS called XY plane. Defined mathematically, (he horizon-tal axis is always listed as the first of the pair. In

and CNC programming. this plane is also known as the Top View or a Plan View. Other planes arc in CNC, but not to the same extent as in CAD/CAM work.

4

Point of Origin Another term that emerged from the rectangular

nate is called poil11 of origin, or just origin. 11 is the point where lhe two perpendicular axes intersect. is point a zero coordinate value in each {lxis, fled a.

GEOMETRY

counting starts at the positive of the horizontal 4-5 illustrates the definitions.

... Yaxis

II _ Quadrant I X+Y+

" I 1--1'- -+ -I -u'+ -1--1-+ --i--I-JiIo. X

Quadrant III - Quadrant IV x-y- X+Y-

Figure 45 Quadrants in the

Any point zero. Any cation of the distance

and their identification

value can be positive, is determined solely

point in a particular quadrant and its relative to the origin - Figure

COORDI POINT ON X AXIS Y AXIS

, """"""""~,--"--

QUADRANT I + , ,-""""", .. ,,--"""""""""""""''''''

QUADRANT II QUADRANT III

+ Figure 46 Algebraic signs for a point location in plane quadrants

o IMPORTANT: ... If the defined point lies exactly on the X axis,

it has the Yvalue to zero (YO). o 0 If the point on the Y axis,

it has the X value to zero (XO). ... If the point lies on both X and Yaxes,

both X and Yvalues are zero IXO YO). XOYOZO is the point In part programmmg,

itive values are written W",UlIlI the plus sign - Figure

Right Hand Coordinate System In {he illustrations of the number scale, quadrallfs and

axes, the origin into two portions. The zero point - the point of origin - separates the positive sec-tion of the axis from the section. In the right-hand coordinate system, the at the origin and is directed towards rig III upwards for the Y axis and towards lhe viewpoint for Z

Opposite directions are

Y+ .,

P2+

t

x- -r--I-~1~~I-~-r-I--~ .. I- x+ ..,.. P1

P1 ::: XQ.Q P2 ::: XQ.Q

- - ---""""

P3 ::: X5.5 YS.O Figure 4-7

+ .. I

T

- ---- .....

P4

::: X4.0 Y-3.0 ::: X-S.O Y-4.S

P6 ::: X-5.0 YO.Q

Coordinate definition of points within the rectangular coordinate system (point PI = Origin XOYO)

over a

17

If these directions were hand, they would "",..r"''', ... ' '" from root of thumb or finger in the X direction,

middle

would point the Y direction and

majority of CNC are programmed using the so called absolute method, that is based on the point of origin XOYOZO. This absolute method of gramming follows very of rectangular co-ordinate geometry and aU covered in this chapter.

MACHINE GEOMETRY

Machine geometry is the tween the fixed point of the TTlU,' TlU,,",

a/the part. TypicaJ machine uses hand coordinate system. and negative

UH'"",,,,'VlI is determined by an VIewing con-vention. The basic rule for the Z it is always the

along which a simple hole can machined Wilh a sin-point tool, such as a drill, reamer, or a laser beam.

Figure 4-8 illustrates the standard orientation of an type machine tools.

Axis Orientation - Milling A typical 3-axis machine uses controlled axes of

motion. They are defined as and the Z X to of the

is parallel to dimension the Z axis is the spindle movement. On a

machining center, the X axis is longitudi-the Y axis is the saddle cross direction and

Figure 4-8 Standard orientation of planes and eNe machine tool axes

the Z axis is the spindle direction. horizontal machining centers, the terminology is changed due to the design of these machines. The X axis is table longitudinal direc-tion, the Y is the column direction the Z axis is the spindle direction. Horizontal machine can be as a

machine rotnted in space by ninety degrees. The additional feature of a horizontal machining center is the indexing B axis. Typical machine axes applied to CNC ver-tical machines are illustrated in 4-9.

r~~"'-""""

TOP VIEW ISOMETRIC VIEW Figure 4-9 Typical machine axes of a vertical eNe machining center Axis Orientation Turning Most CNC lathes have two axes, X and Z. More axes are

available, but they are not important at this point. A special third axis, the C axis. is designed for milling operations (live tooling) and is an option on typical CNC lathe.

What is more common for CNC lathes in industry, is the double orientation of axes. Lathes are distinguished as front and a rear lathes. An example of a lathe is similar to the conventional engine lathe. All the slant bed types a lathe are the rear kind. Identification of the axes have often not followed principles.

Chapter 4

, X+ REAR LATHE

FRONT LATHE ,

VERTICAL

~--I"""- X+ Figure 4-10 Typical machine axes of a eNe lathe (turning

Another variety. a venical CNC lathe, is basicaHy a hori-zan tal lathe rotated 900 Typical axes for the and vertical machine axes, as applied to turning, are illustrated in Figure 4-10.

Additional Axes A CNC machine of any type can designed with one or

more additional axes. normally designated as second-ary axes using the U, V and W letters. These axes are nor-mally parallel to primary X, Y and Z axes respectively. For a or an indexing applications, additional axes are defined as A, B and C axes, as rotated about the X, Y and Z axes, in their respective order. Positive di-rection of a rotary an indexing) is direction re-quired to advance a right handed screw in the positive X. Y or Z axis. The relationship of the primary and the second-ary (or supplementary) axes is shown 1.

Primary axes

__ Secondary axes Arc center

1..\--+---+--+--+--+ -- vectors

X axis related

4-11

Yaxis related

,

I Zaxis related

Relationship of the primary and the sec:oncfarv

Rotary axes

axes

center modifiers (sometimes the arc center vectors) are not true axes, yet they are also to the primary axes This subject will described in the section on Circular Interpolation, in Chapter

A unit equipped witn a control system is commonly known as a an analogy of the machine tool as the

system, control unit is its are no levers, no knobs and no

machine the way they function on COniVCr1lIIO and lathes. All the machine

and hundreds of other tasks are by a programmer and controlled by a computer that is ma-

of the CNC unit To make a program for a CNC ma-chine tool means to make a program for system.

the machine tool is a major as well, but it is the unit thai of the pro-

structure and its syntax.

GE Fanuc Series 16-M

(OFF I I

1--1 \

ON I OFF BUTTONS,

Figure 51

\

HELP KEY \.

OPERATION MENU

CONTROL SYSTEM

In order to fully understand CNC programming pro-cess, it is important to understand not only the intricacies of

to machine a pan, what tools to select, what speeds to use, how to many other fea-

tures. It is equally the computer, the CNC unit, actually to be an expert in electronics or a I shows an actual Fanuc control

The machine own panel, with all the and button needed to operate the CNC machine and all its features. A typical operation panel is illustrated in Another item required the system. the handle, will be described as well.

A typical example of 8 Fanuc control panel. actual layout and features will vary on different models (Fanuc 16M)

19

20

GENERAL DESCRIPTION

a brief look at any reveals that there are two basic components - one is operation paJlel, full rotary switches, toggle and push buttons. The other component is the display screen with a keyboard or a keypad. The programmer who does not normally work on

CNC machine will if ever, have a reason to use

control unit - the work in conjunction

anything useful on its own. if the program itself tons and keys are by control over the program "''''''''''''''.'''

Operation Panel Depending on CNC machine,

ing table covers most typical and common found on the modern operation panel. There are some

5

the operation panel or the display screen. They are at the machine to the machine operator. and the as well as to control the activi-

of the machine. differences for the of a machining center a

Should the CNC interested in ma- but both operation are similar. As with any chine operation? Is for the to reference book, it always a good idea to double know and understand all of the conlIol system? with specifications and recommen-

is only one answer to both questions - definizely dations. It is common machines In

x y o 0

OPTIONAL STOP ON @ OFF

Y X

z

ID

Z

4

BLOCK SKIP ON @ OFF

MDI

CYCLE D

MOO M01 M30 o 0

have some special

ERRORS

ALARM o

M-S-T MACHINE DRY LOCK LOCK RUN

ON ON ON @ @ @ OFF OFF OFF OFF

TAPE 175 150 125 1

EDIT 80 400 60

MODE 40 600 30 - 800 20 1000 15 1200 10 1500 5 2000 0 4000

EDIT ...! ,-_._-

80 90

110 0

80 90 70 60

50 40-30

20 10 0

120 CYCLE START FEEDHOLD OVERRIDE %, N OVERRIDE % AUTO

Figure 52 A typical operation panel of a CNC macnmlllO center actual features wiN vary on different models

OFF AUTO

ccw D

EMGSTOP

CONTROL

Feature

ONI switch

Start

Emergency Stop

Feedhold

Single Block

Optional Stop

Block Skip

Dry Run

Spindle Override

Feedrate Override

Chuck Clamp

Clamp

Coolant Switch

Gear Selection

Spindle Rotation

Spindle Orientation

Tool Change

Position

Handle

Tailstock Switch

Indexing Table Switch

MOl Mode

Description

Power and control switch for the main power and the control unit

Starts program execution Or MDT command

all machine and turns off power to the control unit

motion of all axes

Allows program run one block at a time

Temporarily stops the program execution (MOl required in program) Ignores blocks preceded with a forward slash (I) in the program

Enables program testing at fast feedrales (without a mounted part) Overrides the programmed spindle usually within 50-120% range

Overrides the programmed feedrate, usually within 0200% range

Shows current status of the chuck (Outside I Inside

Shows current status of table

Coolant control ON I I AUTO

Shows current status of working gear range selection

Indicates spindle rotation direction or counterclockwise)

Manual orientation of [he spindle

Switch allowing a manual tool

Switches and relating to setup of the machine from reference position

Manual Generator (MPG). used for Axis Select and Handle Increment switches

Tailstock and/or IJUOUI'v"1 the tails!ock

switch to manually

Manually indexes machine table setup

mode

Feature

AUTO Mode

MEMORY mode

mode

EDlT

MANUAL Mode

JOG Mode

RAPID Mode

Memory Access

Error lights

Description

automatic operations

Allows program execution from the memory of the CNC unit

Allows program execution from an external device, such as a desktop computer or a punched tape

Allows to bt: made to a program stored in the CNC memory

Allows manual

Selects

mode for setup

(switch) to allow program editing

Red an error

21

is some may not be listed, vinual\y all of those in table are somewhat related to the CNC pro-

Many control systems unique of their own. These features must known to The program supplied to the machine should not rigid - it should 'user friendly'.

Screen Display and Keyboard The screen display is 'window' to the computer. Any

program can be viewed, including the status the control, current tool position, various offsets, parameters, even a graphic representation of the Tool Path. On all CNC units, individual monochrome or color screens can be se-lected to have the desired display at any time, using the in-

keys (keyboard pads and soft keys). Setting for interna-tionallanguages is also possible.

The keyboard pads and soft keys are used to input in-structions to control. can modi-fied or deleted, new programs can Using key-board input, not only the machine axes motion can be controlled, but the spindle speed and feed rate as well Changing internal evaluating various diagnostics are more specific means of control, often re-stricted to service people. Keyboard and screen are used to set program origin and to hook up to devices,

as a connection with another computer. There are many other options. keyboard allows use of fers, digits and symbols for data entry. Not every keyboard allows the use of all the alphabet letters or all available symbols. Some control panel keys have a description of an operatiol1, rather than a letter, digit or symbol, example, Read Punch or the Offset

22

Handle machine has a rotary

handle that can move one by as little as the least increment of the control system. The official Fanuc name for the handle is Manual Pulse Gen.erator. Associ-

with the handle is the Axis Select switch dupli-cated on the operation as well as on the handle) and the range of increment is the least increment X I, X 10

X I (0). The X in this case is the multiplier and stRnds for limes'. One handle division will move the se-

axis by X times the minimum increment of the active of measurement. In Figure and the following table

are the details a typical handle.

y Z X ...... AXIS

SELECT

x1

5~3

x10 x100

An example of a detached handle, called the Manual Pulse Generator (MPG), With a typical fayout and features. Layout and features may vory on different machine models.

II

Handle One handle division motion is ... Multiplier Metric units for English units

" Xl 0.001 mm .0001 inch " Xl0 0.010 mm .0010

Xl00 : 0.100 mm .0100 inch

Chapter 5

SYSTEM fEATURES

The CNC unit is more than a sophisticated spe-purpose computer. 'special purpose' in this case is

a computer capabll' of controlling the of a ma-tool, such as a lathe or a machining center. It means

the computer to designed a company has ex-pertise in Ihis type of special purpose computers. Unlike many business types each CNC unit is made

a particular customer. customer is typically ma-chine manufacturer, not the end user. The manufacturer

certain requirements that the control system to requirements that reflect the uniqueness of the ma-

chines they build. The basic conlrol does not change, but some customized features may added taken away) for a specific the system IS to the manufacturer, more features are added to the system. They mainly relate to the design capabilities of the machine.

A example is a CNC unit for two machines that are the same in all except one. One a manual lool changer, the other an automatic 1001 changer. order to support the automatic tool changer, the CNC unit must have special features . that are not

for a machine without Ihe rool changer. The more complex the CNC system is, the more expensive it Users that do not require all sophisticated features, do not pay a for they do not need.

Parameter Settings infonnalion that establishes the built-in connection

between the control and machine tool is stored as special data in called the system parame-ters. Some of the in this handbook is quite ~pe-cialized listed for reference only. Programmers with limited experience not to know parameters in a great depth. The original factory are sufficient for most machining jobs.

When (he parameter screen is displayed, it shows the rameler number with some data in a row. Each row num-

one bYle, digit in the is called a word bit is the Binary digiT

is smal unit of a parameter input. Numbering starts with O. from the to the left:

The Fanuc control system parameters belong to one of three groups, specified within an allowed range:

o codes o Units inputs o Setting values

CONTROL SYSTEM

The groups use different input values. binary input can only have an input of a 0 or I for the bit data format, 0 10 + 127 for byte type. Units inpur has a broader scope -the unit can in mm, mmimin, in/min, milliseconds, etc. A value can also be specified within a given range, for example, a number within the of 0-99, or 0-99999, or + 127 to -127, etc ..

A typical example of a binary input is a selection be-tween two options, instance, a feature called dry run can set only as effective or ineffective. To select a ence, an arbitrary bit number of a parameter has be set to 0 to make the dry run effective and to I to make it ineffective,

UniTs inpur, for example, is used to selthe increment sys-tem - the dimensional units, Computers in general do no! distinguish between inch and metric, just numbers, It is up to the user and the setting, whether the control will 0