An
`Introduction
`toCNC
`Machining
`and Pro-
`gramming
`
`David Gibbs and
`
`Thomas M. Crandell
`
`1010
`
`Page 1 of 74
`
`RA v. AMS
`Ex. 1010
`
`

`

`An Introduction To
`
`CNC Machining
`and
`Programming
`David Gibbs
`
`I. Eng., MIED
`Senior Lecturer in the Department of Technology
`Reading College of Technology
`England
`
`Thomas M. Crandell
`
`Computer Integrated Manufacturing Coordinator
`Associate Professor
`Manufacturing Engineering Technologies Department
`Ferris State University
`
`Industrial Press Inc.
`
`Page 2 of 74
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`RA v. AMS
`Ex. 1010
`
`

`

`DEDICATION
`
`I would like to dedicate my work on this textbook in loving memory of my grandfather,
`Edgar L. Crandell. I also dedicate my work to my parents Gale and Beverly Crandell. It
`was these three individuals who taught me to work hard to complete a task and to do it
`to the best of my ability. I thank them for their time and patience during my upbringing.
`My thanks goes to the following: My family — Linda, Chad, and Todd—for time spent
`away from them; Ferris-State University for equipment support; and Ferris Faculty and
`Staff that provided assistance.
`
`Thomas M. Crandell
`
`Portions of this text were originally published in Great Britain by Cassell Publishers Limited
`as An Introduction to CNC Machining, 2nd edition, © 1987 by David Gibbs and CNC
`1987 by David Gibbs.
`Part Programming, (cid:9)
`
`
`Library of Congress Cataloging-in-Publication Data (cid:9)
`
`Gibbs, David.
`An introduction to CNC machining and programming/David Gibbs, Thomas M. Crandell. (cid:9)
`552 p. 15.6 x 23.5 cm. Includes index. ISBN 0-8311-3009-1
`1. Machine-tools—Numerical control—Programming. I. Crandell, Thomas M. II. (cid:9)
`Title.
`TJ1189.G53 1991
`621.9'023 — dc20 (cid:9)
`
`90-23499 (cid:9)
`CIP
`
`INDUSTRIAL PRESS INC.
`200 Madison Avenue
`New York, New York 1 001 6-401 8
`Copyright © 1991 by Industrial Press Inc., New York, New York. Printed in
`the United States of America. All rights reserved. This book, or parts thereof,
`may not be reproduced, stored in a retrieval system, or transmitted in any form
`without the permission of the publishers.
`
`6 8 9 7
`
`CONTENTS
`
`Preface
`
`1
`
`An Introduction to the Concept of Computer Numerical Control 1
`
`2
`Machine Design 16
`
`3
`Tooling for Computer Numerically Controlled Machining 41
`
`4
`Work Holding and Loading for Computer Numerically Controlled
`Machining 78
`
`5
`Data Preparation and Input to Machine Control Units 95
`
`6
`Terms and Definitions Associated with Part Programming and
`Machine Control 116
`
`7
`Speeds and Feeds for Numerically Controlled Machining 152
`
`8
`Part Programming for Computer Numerically Controlled
`Machining 162
`
`Page 3 of 74
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`(cid:9)
`(cid:9)
`

`

`vi (cid:9)
`
`CONTENTS
`
`9
`Part Programming Calculations 309
`
`10
`Computer-Aided Part Programming 334
`
`11
`
`Advanced Techniques 436
`
`Appendix A
`EIA Specifications 460
`
`Appendix B
`Cutting Speed and Feed Information, Carbide Grades,
`and Power Requirements Formulas 461
`
`Appendix C
`Programming Exercises 493
`
`Appendix D
`GDT Symbols 522
`
`Appendix E
`Formulas 525
`
`Index 531
`
`PREFACE
`
`An Introduction to CNC Machining and Programming is intended to support
`the essentially practical activity of preparing and proving computer numerical
`control (CNC) part programs for turning, milling, and drilling. It will be of
`value to students in a wide range of courses dealing with CNC programming
`and calculations of all forms, tooling for CNC, and fixturing for CNC whether
`in a major or related course in a college, university, or industrial organization.
`The preparation and proving of CNC part programs requires access to ma-
`chinery and computer installations in order to obtain the necessary practical
`experience. Using such equipment, and understanding particular programming
`languages and techniques, requires instruction, examples, and exercises from
`a competent instructor. Students undertaking a course of study devoted to part
`programming will therefore find it necessary to attend an adequately resourced
`college or training center. The student must also have a good understanding of
`basic machining techniques, and should ideally have previous experience in
`turning, milling, and drilling operations. In preparing this text, these funda-
`mental requirements have been borne in mind.
`CNC part programming is an absorbing and time-consuming activity—it is
`one of the few areas of study where students complain that time has passed
`too quickly! Thus a primary objective of this book is to ensure that limited
`course time can be used to the best advantage by providing the opportunity to
`devote as much time as possible to preparing programs and using the associated
`equipment. Accordingly, an attempt has been made to include sufficient in-
`formation to provide the student with much of the theoretical knowledge needed
`to support the more practical elements of study, thereby reducing the time spent
`on formal lectures and unnecessary note taking. The text also provides the
`student with the opportunity to study specific aspects of interest or needs.
`This text is essentially practical in nature and is intended to provide adequate
`material for course work. It contains a series of assignments that provide the
`student with a practical understanding of CNC tooling, processing, and pro-
`gramming by various means. Throughout the book there are numerous fully
`detailed drawings of components in inch and metric units that, while primarily
`included to complement the text, may also be used as programming exercises
`in the early stages of a course. An additional series of projects, of varying
`degrees of complexity and intended for later use, should satisfy most levels of
`ability.
`It is the author's experience that many mature people returning to college
`
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`

`PREFACE
`
`for retraining, also many younger students, are hampered in their programming
`work by never being taught how to apply their calculation skills in algebra,
`geometry, and trigonometry. It is generally outside the scope of a course of
`study devoted to part programming to spend much time rectifying this state of
`affairs, and yet it cannot be ignored. To assist both instructors and students
`there is a chapter devoted entirely to the type of calculations that will be en-
`countered when preparing part programs manually; it is hoped that the com-
`pletion of this material, supported by on-the-spot tutoring by faculty, will be
`of value.
`This text will be of on going value to students, faculty, and industrial pro-
`grammers alike.
`
`D.A.W. Gibbs
`Workingham
`
`Thomas M. Crandell
`Ferris State University
`
`1
`
`AN INTRODUCTION TO THE CONCEPT
`OF COMPUTER NUMERICAL CONTROL
`
`DEFINITION OF NUMERICAL CONTROL
`
`Numerical control (NC) is the term used to describe the control of machine
`movements and various other functions by instructions expressed as a series of
`numbers and initiated via an electronic control system.
`Computerized numerical control (CNC) is the term used when the control
`system utilizes an internal computer. The internal computer allows for the fol-
`lowing: storage of additional programs, program editing, running of programs
`from memory, machine and control diagnostics, special routines, and inch/
`metric—incremental/absolute switchability.
`The two systems are shown diagrammatically in Figure 1.1. The control units
`may be free-standing or built into the main structure of the machine. The op-
`erating panel of an integrated control unit is shown in Figure 1.2.
`
`THE APPLICATION OF COMPUTER NUMERICAL CONTROL
`
`Computer numerical control is applied to a wide range of manufacturing pro-
`cesses such as metal cutting, woodworking, welding, flame cutting, sheet metal
`forming, sheet metal punching, water jet cutting, electrical discharge machin-
`ing and laser cutting. The text that follows is restricted to its application to
`common machine-shop engineering processes, namely, turning, milling, and
`drilling, where it has been particularly successful.
`
`THE ADVANTAGES OF COMPUTER NUMERICAL CONTROL
`
`Computer numerical control is economical for mass, batch, and, in many cases,
`single-item production. Many factors contribute to this economic viability, the
`most important of these being as follows:
`
`(a) high productivity rates
`(b) uniformity of the product
`(c) reduced component rejection
`
`1
`
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`

`

`2
`
`THE CONCEPT OF COMPUTER NUMERICAL CONTROL
`
`3
`
`Machine tool
`
`Data flow
`
`Control unit
`
`(a)
`
`(b)
`
`1....____ Machine tool
`
`Memory
`
`Microcomputer
`
`— Control unit
`
`Combined unit
`
`Figure 1.1 Basic control systems: (a) numerical control and (b) computerized numerical con-
`trol.
`
`Figure 1.2 Integrated control unit.
`
`(d) reduced tooling costs
`(e) less operator involvement
`(f) complex shapes machined easily
`
`It is also the case that fewer employees will be required as conventional ma-
`chines are replaced by modern technology, but those employees that remain
`will of necessity be high caliber technicians with considerable knowledge of
`metal-cutting methods, cutting speeds and feeds, work-holding, and tool-set-
`ting techniques and who are familiar with the control systems and programming
`for numerical control.
`
`THE CAPABILITY OF COMPUTER NUMERICAL CONTROL
`
`The dramatic effect computer numerical control has already had on traditional
`engineering production techniques is now well appreciated. Machines con-
`trolled in this way are capable of working for many hours every day virtually
`unsupervised. They are readily adaptable to facilitate production of a wide range
`
`Page 6 of 74
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`

`4
`
`of components. Every function traditionally performed by the operator of a
`standard machine tool can be achieved via a computer numerical control ma-
`chining program.
`To appreciate just how versatile computer numerical control can be, it is
`only necessary to examine very briefly the human involvement in the produc-
`tion of a simple component such as the one shown in Figure 1.3. The hole
`only is to be produced by drilling on a conventional vertical milling machine.
`The activities of the operator in producing the component would be as follows:
`
`1. Select a suitable cutting tool.
`2. Locate the cutting tool in the machine spindle.
`3. kcure-tItcutting tool.
`4. rocatAhe component in the work-holding device.
`5. Clamp the component.
`6. Establish a datum in relation to face A.
`7. Determine the amount of slide movement required.
`8. Determine the direction of slide movement required.
`9. Move the slide, monitoring the movement on the graduated dial allow-
`ing for leadscrew backlash, or digital readout if available.
`10. Lock the slide in position.
`11. Establish a second datum in relation to face B.
`
`25
`(1.0)
`
`1.50 (0.60)
`Face A
`
`25
`(1.0)
`
`Face B
`
`50 (2.0)
`
`10 (0.4)
`
`THE CONCEPT OF COMPUTER NUMERICAL CONTROL (cid:9)
`
`5
`
`12. Determine the amount of slide movement required.
`13. Determine the direction of slide movement required.
`14. Move the slide, monitoring the movement on the graduated dial allow-
`ing for leadscrew backlash, or digital readout if available.
`15. Lock the slide in position.
`16. Select a suitable spindle speed.
`17. Determine the direction of spindle rotation.
`18. Select a suitable feed rate.
`19. Switch on the spindle motor.
`20. Switch on the coolant supply motor.
`21. Engage the feed and machine the hole.
`22. Disengage feed and withdraw tool.
`23. Switch off the coolant supply motor.
`24. Switch off the spindle motor.
`25. Remove the component.
`26. Verify the accuracy of the machine movement by measuring the compo-
`nent.
`
`From this list it can be seen that even the simplest of machining operations
`involves making a considerable number of decisions that influence the resulting
`physical activity. A skilled machinist operating a conventional machine makes
`such decisions and takes the necessary action almost without thinking. Never-
`theless, the decisions are made and the action is taken.
`It is not possible to remove the human involvement totally from a machining
`process. No automatic control system is yet capable of making a decision in
`the true sense of the word. Its capability is restricted to responding to a man-
`ually or computer-prepared program, and it is during the preparation of the
`program that the decisions are made. Via that program the machine controller
`is fed with instructions that give effect to the decisions. In this way all the
`functions listed above, and many others not required in such a simple example
`of machining, may be automatically and repeatedly controlled. Figure 1.4 lists
`the elements of total machine control.
`
`Machine
`tool control
`
`50 (2.0)
`
`Slide
`movement
`
`Spindle
`rotation
`
`Tooling
`
`Work
`holding
`
`Supporting
`functions
`
`Figure 1.3 Component detail. (Inch units are given in parentheses.)
`
`Figure 1.4 Elements of machine control.
`
`Page 7 of 74
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`

`

`6
`
`SLIDE MOVEMENT
`
`The success of any manual machining exercise is dependent on many factors,
`not least of which is the experienced worker's practical skills. These skills are
`most in evidence when they affect the accuracy of the finished product, such
`as when they are involved in positioning, via the machine slides, the cutting
`tool and workpiece in the correct relationship to each other. This aspect of
`machining skill is also the crucial factor when the machine is electronically
`controlled.
`Slide movement on computer numerically controlled machines is achieved
`by:
`
`(a) hydraulically operated pistons
`(b) electric servo motors.
`
`The use of electric motors is by far the most common technique. The motor
`is either directly coupled, or connected via a toothed belt drive, to the slide
`leadscrew. The servo motor, in effect, replaces the conventional handwheel
`and this is illustrated in Figure 1.5, which shows conventional machines, a
`center lathe and a vertical milling machine, fitted with servo motors. A few
`
`THE CONCEPT OF COMPUTER NUMERICAL CONTROL (cid:9)
`
`7
`
`machine designs have retained handwheels as an aid to setup or to provide for
`both numerical and manual control.
`Machine tools have more than one slide and so the slide required to move
`will have to be identified. The plane in which movement can take place may
`be longitudinal, transverse, or vertical. These planes are referred to as axes
`and are designated by the letters X, Y, Z, and sometimes U, V, W. Rotary
`axes A, B, and C can also be applied to a machine around a center axis men-
`tioned previously. A rotary axis has as its centerline one of the three standard
`axes (X to A, Y to B, and Z to C). Their location on common machine tools
`is shown in Figure 1.6. Note that the Z axis always relates to a sliding motion
`parallel to the spindle axis.
`The direction in which a slide moves is achieved by the direction of rotation
`of the motor, either clockwise or counterclockwise, and the movement would
`be designated as plus or minus in relation to a given datum. Figure 1.6 also
`shows how the direction of travel is designated on common machine tools.
`Slide movement and relative tool and work movement are discussed in more
`detail in Chapter 6.
`The rate or speed at which slide movement takes place, expressed in feet/
`meters per minute or inches/millimeters per revolution of the machine spindle,
`
`Figure 1.5 (a) Conventional center lathe fitted with servo motors.
`
`Figure 1.5 (b) Conventional milling machine fitted with servo motors.
`
`Page 8 of 74
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`

`8
`
`THE CONCEPT OF COMPUTER NUMERICAL CONTROL
`
`9
`
`Figure 1.7 Cogged belt drive from servo motor to leadscrew.
`
`there may be reduction pulleys or gears between the motor and the leadscrew,
`as shown in Figure 1.7, in which case the linear movement obtained in relation
`to the motor revolutions would be proportionally reduced. The length of travel
`made, or required to be made, by a slide is referred to as a coordinate dimen-
`sion.
`Since the slide movement is caused by the servo motor, control of that motor
`will in turn control the slide movement. The motor is controlled electronically
`via the machine control unit. All the relevant information, that -is the axis,
`direction, feed rate, and length of movement, has to be supplied to the control
`unit in an acceptable numerical form. The input of information to the machine
`controller is achieved in a variety of ways: perforated tape, magnetic tape, via
`a computer link, computer disk, and manually. Data input is covered in more
`detail in Chapter 5.
`
`Complex Slide Movement
`So far, consideration has been given to simple linear movement involving one
`slide. There are, however, many instances when two or more slides have to
`be moving at the same time. It is possible to produce a 45° angle as shown in
`
`Knee movement
`
`Knee movement
`
`_c c a)
`o E
`-o 0
`c E
`cn
`
`(a)
`
`(b)
`
`(c)
`
`Figure 1.6 Identification of slides and direction of the slide movement on common machine
`tools: (a) center lathe (turning center); (b) horizontal milling machine (horizontal machining
`center); (c) vertical milling machine (vertical machining center).
`
`will be proportional to the revolutions per minute of the servo motor; the higher
`the revolutions per minute, the faster the rate of slide travel.
`The length of slide movement is controlled by either the number of revo-
`lutions or the number of part revolutions the motor is permitted to make, one
`complete revolution being equal to the lead of the leadscrew, in the same way
`as one turn of a handwheel is equal to the lead of a leadscrew. In some cases
`
`Page 9 of 74
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`

`THE CONCEPT OF COMPUTER NUMERICAL CONTROL (cid:9)
`
`11
`
`Curve produced by series
`of angular moves
`
`y —axis co-ordinates
`
`Figure 1.11 Designation of a curved profile by a series of coordinate dimensions.
`
`x—axis co-ordinates
`
`in Figure 1.11, and, providing the machine were capable of responding to the
`minute variations in size, a satisfactory result would be obtained, but the cal-
`culations necessary to approach the task in this way would be considerable.
`Complex slide movements such as those required to produce the curve can
`readily be achieved by the inclusion in the system of a computer capable of
`making the necessary calculations from the minimum of input data. Of course,
`the calculation of slide movements to produce complex profiles is not the only
`function of a computer. The other facilities it provides, in particular its ability
`to store data that can be used as and when required, will be considered later.
`
`Verification of Slide Movement
`An important function of the skilled worker operating a conventional machine
`is to monitor the slide movement and verify its accuracy by measuring the
`component. A similar facility is desirable on computer numerically controlled
`machines.
`Control systems without a facility to verify slide movements are referred to
`as "open-loop" systems, while those with this facility are called "closed-loop"
`systems. A closed-loop system is shown diagramatically in Figures 1.12 and
`1 13.
`The exact position of the slide is monitored by a transducer and the infor-
`mation is fed back to the control unit, which in turn will, via the feed motor,
`make any necessary corrections.
`In addition to positional feedback some machines are equipped with "in-
`process measurement." This consists of probes that touch the machined surface
`and respond to any unacceptable size variation. The data thus gathered are fed
`back to the control system and corrections to the slide movement are made
`automatically.
`
`10
`
`Figure 1.8 by synchronizing the slide movements in two axes, but to produce
`the 30° angle in Figure 1.9 would require a different rate of movement in each
`axis, and this may be outside the scope of a simple NC system unless it is
`capable of accurately responding to two precalculated feed rates.
`Similarly, the curve shown in Figure 1.10 would present problems, since
`ideally its production would require constantly changing feed rates in two axes.
`The curve could be designated by a series of coordinate dimensions as shown
`
`Cutter path
`
`Slide
`movements
`
`a
`Slide movement
`lengths equal
`
`Cutter
`
`Figure 1.8 Effect of equal rates of slide movement.
`
`Slide
`movements
`
`Cutter path
`
`Cutter
`
`..Z1b
`a
`Slide movement
`lengths unequal
`
`Figure 1.9 Effect of unequal rates of slide movement.
`
`Cutter path
`
`Slide
`movements
`
`( t
`
`Cutter
`
`Figure 1.10 Profile requiring constantly changing rates of slide movement. (Inch units are
`given in parentheses.)
`
`Page 10 of 74
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`

`12
`
`THE CONCEPT OF COMPUTER NUMERICAL CONTROL (cid:9)
`
`13
`
`+ Y
`
`Machine tool
`
`Positional feedback
`
`4
`
`Data
`flow
`Comparing
`unit
`
`Memory
`
`— Data flow
`
`Computer
`
`Control unit
`
`One unit
`
`Figure 1.12 Closed-loop control system. (cid:9)
`
`(Courtesy of AIMTECH.) (cid:9)
`
`Machine attached here
`
`Figure 1.13 Basic NC hardware concept.
`
`Figure 1.14 Identification of rotary movements.
`
`+Z (cid:9)
`
`+ X
`
`ROTARY MOVEMENTS
`
`Sometimes the production of a component requires rotary movement in addition
`to the linear movement of the machine-tool slides. This movement is provided
`by ancillary equipment such as rotary tables and indexers. These movements
`are controllable via the machining program. They are identified by the letters
`A, B, and C as indicated in Figure 1.14.
`
`CONTROL OF MACHINE SPINDLES
`
`Machine spindles are driven directly or indirectly by electric motors, and a few
`by hydraulic drive. The degree of automatic control over this motion usually
`includes stopping and starting, and the direction and speed of rotation. Some
`very early systems, and perhaps a few inexpensive modern systems, do not
`include control of the spindle motions at all, switching on and off and gear
`selection being a totally manual operation. On the other hand, on some very
`modern control systems the torque or horsepower necessary to carry out the
`machining operation can be monitored and compared with a predetermined value
`included in the machining program; when necessary, the spindle speed will be
`varied automatically to provide optimum cutting conditions. (See "Adaptive
`Control," Chapter 9.)
`The speed of the spindle is often infinitely variable, and may automatically
`change as cutting is taking place to maintain a programmed surface speed.
`Thus, when facing the end of a bar on a lathe as the tool nears the work center,
`the spindle speed will increase. In this way material removal is achieved at the
`fastest possible rate with due regard to tool life and the surface finish required.
`The direction of spindle rotation required can be determined as follows:
`
`1. Clockwise (CW). When the spindle rotates a right-handed screw would
`
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`

`14 (cid:9)
`
`advance into the workpiece, or if the machine operator looked through
`the tool toward the workpiece, he would see it moving clockwise.
`2. Counterclockwise (CCW). When the spindle rotates a right-handed screw
`would retract from the workpiece, or if the machine operator looked
`through the tool toward the workpiece, he would see it moving coun-
`terclockwise.
`
`CONTROL OF TOOLING
`
`Computer numerically controlled machines may incorporate in their design tur-
`rets or magazines that hold a number of cutting tools. The machine controller
`can be programmed to cause indexing of the turret or magazine to present a
`new cutting tool to the work or to facilitate tool removal and replacement where
`automatic tool-changing devices are involved.
`Simpler machines rely on manual intervention to effect tool changes. In these
`cases the control unit is programmed to stop the automatic sequence at the
`appropriate time and the operator will make the change. There is sometimes a
`connection between the control unit and the tool-storage rack and the correct
`tool to be used is indicated by an illuminated lamp.
`Tooling is dealt with in more detail in Chapter 3.
`
`CONTROL OF WORK HOLDING
`
`Work holding is another aspect of computer numerically controlled machining
`that can include manual intervention or be totally automatic. The work-holding
`devices themselves can be fairly conventional: vices, chucks, collets, and fix-
`tures are all used. The computer numerical control can extend to loading the
`workpiece by the use of robots and securely clamping it by activating hydraulic
`or pneumatic clamping systems.
`Again, as with tool changing, on simpler machines, a programmed break in
`a machining cycle can facilitate manual intervention as and when required.
`Work holding is dealt with in detail in Chapter 4.
`
`SUPPORTING FUNCTIONS
`
`The various supplementary functions a skilled worker would perform during a
`manually controlled machining operation are, of course, vital to the success of
`the operation. For example, it may be necessary to clamp a slide, apply cool-
`ant, clear away swarf before locating a component, monitor the condition of
`tooling, and so on. Slide clamping is usually hydraulic, and hydraulic pressure
`provided by an electrically driven pump with the fluid flow controlled by so-
`
`THE CONCEPT OF COMPUTER NUMERICAL CONTROL (cid:9)
`
`15
`
`lenoid valves has long been a feature of machine tool design. With the new
`technology the control of the electrical elements of such a system is included
`in the machining program. Similarly, it is a simple matter to control the on—
`off switching of a coolant pump and the opening or closing of an air valve to
`supply a blast of cleaning air. Tool monitoring, however, is more complex and
`is the subject of much research and innovation ranging from monitoring the
`loads exerted on spindle motors to recording variations in the sound the cutting
`tool makes. Some of these more advanced features of computer numerical con-
`trol are discussed further in Chapter 9.
`
`QUESTIONS
`
`1 Explain with the aid of a simple block diagram the difference between an
`NC and a CNC machining system.
`
`2 State two advantages of CNC over NC control systems.
`
`3 The common axes of slide movement are X, Y, and Z. What is significant
`about the Z axis?
`
`4 How are rotary movements about a given axis identified and when are they
`likely to be used?
`
`5 What data are required io initiate a controlled slide movement?
`
`6 On a vertical machining center the downward movement of the spindle is
`designated as a Z minus. From a safety aspect this is significant. Why
`is this so?
`
`7 How is an angular tool path achieved?
`
`8 With the aid of simple block diagrams to show data flow, explain the dif-
`ference between an open-loop and a closed-loop control system.
`
`9 How would a manual tool change be accommodated in a machine program?
`
`10 Explain what is meant by "constant cutting speed" and how this is achieved
`on CNC machines.
`
`Page 12 of 74
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`

`6
`
`TERMS AND DEFINITIONS
`ASSOCIATED WITH PART
`PROGRAMMING AND
`MACHINE CONTROL
`
`PART PROGRAMMING
`
`The expression "part programming" causes some confusion, since "part" is
`often thought to mean something that is incomplete. In numerical control terms
`a part program is, in fact, a complete program. The word "part" means com-
`ponent.
`
`PREPARATORY FUNCTIONS
`
`Preparatory functions are used to inform the machine control unit of the fa-
`cilities required for the machining that is to be carried out. For example, the
`control unit will need to know if the axis movements stated dimensionally in
`the program are to be made in inch or metric units, and whether the spindle
`is to rotate in a clockwise or counterclockwise direction.
`The way in which machine controllers are provided with such information
`depends on the type of control unit. On conversational MDI systems, it may
`simply involve pressing the appropriate button on the control panel. For sys-
`tems using the word address programming method, the various preparatory
`functions were originally standardized (ANSI/EIA RS274-D:1979; BS 3635:1972),
`each function being identified by the address letter G followed by two digits. Thus
`preparatory functions came to be referred to generally as "G codes." The Standard
`has been adopted and is widely used, although variations in the allocation of special
`G codes will be encountered.
`The preparatory functions, as they appear in the Standard, are shown in Ta-
`ble 6.1. The codes used for any particular control system will depend on the
`machine type and the sophistication of the system and, although a complete
`list such as the original standard is rather extensive, it should be appreciated
`that the number of codes included in any one system will be considerably fewer
`in number.
`
`116
`
`PART PROGRAMMING AND MACHINE CONTROL
`
`117
`
`Table 6.1 Preparatory functions codes (M = modal).
`Code Number (cid:9)
`
`Function
`
`GOO
`001
`G02
`G03
`G04
`G05
`
`GO6
`GO7
`
`GO8
`G09
`G1C}
`G11
`G12
`G13—G16
`G17
`G18
`G19
`G20
`G21
`G22
`G23
`G24
`G25—G29
`
`G30
`G31
`G32
`G33
`G34
`G35
`G36—G39
`
`G40
`G41
`G42
`G43
`G44
`G45}
`G46
`G47
`G48
`G49
`G50
`G51
`G52
`G53
`G54
`
`Rapid positioning, point to point
`Linear positioning at controlled feed rate
`Circular interpolation CW—two dimensional
`Circular interpolation CCW—two dimensional
`Dwell for programmed duration
`Unassigned EIA code may be used as hold.
`Cancelled by operator
`Parabolic interpolation
`Unassigned EIA code reserved for future
`standarization
`Programmed slide acceleration
`Programmed slide deceleration
`
`Unassigned EIA code sometimes used for
`machine lock and unlock devices
`Axis selection
`XY plane selection
`ZX plane selection
`YZ plane selection
`Unassigned EIA code
`
`Unassigned EIA code sometimes used for
`nonstop blended interpolation movements
`Unassigned EIA code
`Permanently unassigned. Available for indi-
`vidual use
`
`Unassigned EIA code
`
`Thread cutting, constant lead
`Thread cutting, increasing lead
`Thread cutting, decreasing lead
`Permanently unassigned. Available for indi-
`vidual use
`Cutter compensation/offset, cancel
`Cutter compensation, left
`Cutter compensation, right
`Cutter offset inside corner
`Cutter offset outside corner
`
`Unassigned EIA code
`
`Reserved for adaptive control
`Cutter compensation +/0
`Cutter compensation —/0
`Linear shift cancel
`Linear shift X
`
`Moder
`
`(M)
`(M)
`(M)
`(M)
`
`(M)
`
`(M)
`(M)
`(M)
`(M)
`
`(M)
`(M)
`(M)
`
`(M)
`(M)
`(M)
`(M)
`(M)
`
`(M)
`(M)
`
`Page 13 of 74
`
`RA v. AMS
`Ex. 1010
`
`

`

`118
`
`Table 6.1 (Continued)
`
`Code Number
`
`Function
`
`Modal'
`
`G55
`G56
`G57
`G58
`G59
`G60—G69
`G70
`G71
`G72
`G73
`
`G74
`G75
`G76—G79
`G80
`G81
`G82
`G83
`G84
`G85
`G86
`G87
`G88
`G89
`G90
`G91
`G92
`G93
`G94
`G95
`G96
`
`G97
`
`G99
`G98}
`
`Linear shift Y
`Linear shift Z
`Linear shift XY
`Linear shift XZ
`Linear shift YZ
`Unassigned EIA codes
`Inch programming
`Metric programming
`Circular interpolation—CW (three dimensional)
`Circular interpolation—CCW (three
`dimensional)
`Cancel multiquadrant circular interpolation
`Multiquadrant circular interpolation
`Unassigned EIA code
`Fixed cycle cancel
`Fixed cycle 1
`Fixed cycle 2
`Fixed cycle 3
`Fixed cycle 4
`Fixed cycle 5
`Fixed cycle 6
`Fixed cycle 7
`Fixed cycle 8
`Fixed cycle 9
`Absolute dimension input
`Incremental dimension input
`Preload registers
`Inverse time feedrate (V/D)
`Inches (millimeters) per minute feedrate
`Inches (millimeters) per revolution feedrate
`Constant surface speed, feet (meters) per
`minute
`Revolutions per minute
`
`Unassigned EIA code
`
`(M)
`(M)
`(M)
`(M)
`(M)
`
`(M)
`(M)
`(M)
`(M)
`
`(M)
`(M)
`
`(M)
`(M)
`(M)
`(M)
`(M)
`(M)
`(M)
`(M)
`(M)
`(M)
`(M)
`(M)
`
`(M)
`(M)
`(M)
`(M)
`
`(M)
`
`Function retained until cancelled or superceded by subsequent command of same
`letter.
`
`Many preparatory functions are modal, that is, they stay in operation until
`changed or cancelled.
`
`MISCELLANEOUS FUNCTIONS
`
`In addition to preparatory functions there are a number of other functions that
`are required from time to time throughout the machining program. For ex-
`ample, coolant may be required while metal cutting is actually under way but
`
`PART PROGRAMMING AND MACHINE CONTROL (cid:9)
`
`119
`
`will need to be turned off during a tool-changing sequence. Operations such
`as this are called "miscellaneous functions."
`Conversational MDI control systems will, as with preparatory functions, have
`their own particular way of initiating miscellaneous functions, but for word
`address systems the EIA standards have been adopted except for special options
`on particular machine tools. The functions are referred to as "M functions"
`and are identified by the address letter M followed by two digits.
`The original standardized miscellaneous functions are listed in Ta