CNC FUNDAMENTALS AND PROGRAMMING

200.00

By P.M.AGRAWAL, DR.V.J.PATEL

2ND Edition 2017 (First Reprint)
ISBN : 9789380358871
292 + 16 = 308 Pages
Size : 17 cm × 23.5 cm × 1.3 cm
Weight : 0.410 kg

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Description

This text-book explains the fundamentals of NC/CNC machine tools, operations and part
programming which form essential portion of course on Computer Aided Manufacturing (CAM).
This book also covers advanced topics such as Macro programming, DNC and Computer Aided
Part Programming (CAPP) in detail.
In this second revised and enlarged edition, all the chapters are reviewed and relevant topics,
examples, part programs, sketches, review questions and exercises have been added to
enhance the utility of the book.
This book is divided into 6 major areas.
Chapter 1 to 4 cover the history, fundamentals and structure of NC/CNC machine tools.
Chapter 5, 6 and 7 cover turning center programming in detail. Various turning canned cycles
are discussed in depth with the help of illustrative examples.
Chapter 8 and 9 are devoted to machining center programming. Drilling canned cycles are
discussed in detail with relevant examples.
Chapter 10 and 11 cover advanced topics of subprogramming and macro programming.
Chapter 12 deals with the communications and networking of NC/CNC machine tools.
Chapter 13 and 14 explain the advanced programming using APT and CAD/CAM based
programming respectively.
The book contains:
* 258 Self explanatory and neatly drawn drawings
* 62 Solved part programming examples
* 37 Part programming exercises
* 173 Review questions at the end of all the chapters
* 101 Multiple choice questions.
It is the fervent hope of the authors that book will satisfy the needs of the Mechanical, Production,
Mechatronics and Automobile Engineering students preparing for the B.Tech/B.E. examinations
of all the Indian Universities, Diploma examinations conducted by various Boards of Technical
Education, Certificate course as well as for the A.M.I.E., U.P.S.C., G.A.T.E., I.E.S. and other
similar competitive and professional examinations. It should also be of an immense help to the
practising Mechanical Engineers.

Additional information

Weight 0.41 kg
Dimensions 17 × 1.3 × 23.5 cm
Author Name

,

Book Edition

ISBN

Content

1 : INTRODUCTION TO NC/CNC MACHINE TOOLS
2 : BASICS OF NC/CNC MACHINE TOOLS
3 : CNC MACHINE TOOLS – STRUCTURE AND ELEMENTS
4 : BASICS OF CNC PROGRAMMING
5 : BASICS OF TURNING CENTER PROGRAMMING
6 : SINGLE PASS CANNED CYCLE FOR TURNING
CENTERS
7 : MULTIPASS CANNED CYCLES IN TURNING
8 : BASICS OF MACHINING CENTER PROGRAMMING
9 : DRILLING CANNED CYCLES IN MACHINING CENTER
10 : SUBPROGRAMMING
11 : MACRO PROGRAMMING
12 : DNC AND DATA COMMUNICATION
13 : APT PROGRAMMING
14 : CAD/CAM INTEGRATION
APPENDIX I : MULTIPLE CHOICE QUESTIONS
APPENDIX II : NC/CNC MANUAL PART PROGRAMMING
CODES
INDEX

Content Details

Chapter 1 INTRODUCTION TO NC/CNC MACHINE TOOLS

1-1. History of NC machines
1-2. Introduction to numerical control (NC) machine tools
Definition
1-3. CNC (Computer Numerical Control)
Machine control unit
1-4. Differences between NC and conventional machine tools
(1) Spindle drives
(2) Guideways
(3) Motion transmission
(4) Feed drives
(5) Machine tool structure
(6) Control unit
(7) Feedback unit
(8) Automatic tool changer (ATC)
(9) Automatic pallet changer (APC)
1-5. Advantages of CNC over NC
(1) Controller
(2) Memory
(3) Part program editing
(4) Cutter compensation
(5) Multipass canned cycles
(6) Advance part programming
(7) Tool path simulation
(8) Conversational programming
(9) Diagnostic
1-6. Advantages of NC and CNC over Conventional machine tools
(1) Increased flexibility
(2) More complex geometry
(3) Higher production rate
(i) Reduced set-ups
(ii) Reduced lead time
(iii) Reduced non-machining time
(4) Higher accuracy and repeatability
(5) Reduced inspection
(6) Reduced operator skill
(7) Reduced scrap
(8) Reduced work-in-process inventory
(9) Elimination of profile tools
(10) Simpler fixtures
(11) Optimum cutting conditions
1-7. Limitations of NC/CNC machine tools
(1) Cost
(2) High maintenance costs
(3) Not cost effective for low production levels
(4) Programming skill
1-8. Specifications of a typical turning center
(1) Axes system
(2) Main spindle
(3) Tool turret
(4) Tail stock (with hydraulic quill)
(5) Other Features
1-9. Specifications of a typical vertical machining center (VMC)
(1) Axes system
(2) Table
(3) Headstock
(4) ATC system
(5) Special features
1-10. Role of NC/CNC technology in modern manufacturing
(1) Machining
(2) Unconventional machining
(3) Fabrication and welding
(4) Press work
(5) Material handling and assembly
(6) Inspection and measurement
(7) Wood working
1-11. Multi-tasking machine tools
Review questions 1

Chapter 2 BASICS OF NC/CNC MACHINE TOOLS

2-1. Axes designation
2-1-1. Coordinate system
2-1-2. Designating the axes
2-2. Axes system of different machine tools
2-2-1. Turning center
2-2-2. Vertical machining center (VMC)
2-2-3. Horizontal machining center
2-2-4. Turn mill center
2-2-5. Three axes planer
2-2-6. Four axes machining center
2-2-7. Five axes horizontal boring machine
2-2-8. Five axes vertical machining center
2-3. Reference points
2-3-1. The grid system
2-3-2. Machine origin or machine zero
2-3-3. Part origin or part zero
2-3-4. Tool reference point
2-4. CNC control systems
2-4-1. Point-to-Point control (P-type)
(1) Axial path
(2) 45° path
(3) Linear Path
2-4-2. Line control/straight cut control (L-type)
2-4-3. Continuous path control (C-type)
(1) 2-D contouring control
(2) 2 1
2 -D contouring control
(3) 3-D contouring control
(4) 4-D contouring control
2-4-4. Example of P, L and C type controls
2-5. Automatic tool changer (ATC)
2-6. Automatic pallet changer
Review questions 2

Chapter 3 CNC MACHINE TOOLS – STRUCTURE AND
ELEMENTS

3-1. Machine tool structure
3-2. Machine tool spindle
(1) Belt driven spindle
(2) Integral motor-spindle
3-3. Spindle bearings
3-4. Guideways
3-5. Transmission system
3-5-1. Recirculating ballscrews
(1) Double nut preloading
(2) Single nut preloading
3-5-2. Roller screw
3-6. Drives
3-6-1. Stepper motor
3-6-2. AC/DC rotary servo motor
3-6-3. Linear motor
3-7. Open loop and closed loop control systems
3-7-1. Open loop control system
3-7-2. Closed loop control system
3-8. Feedback devices
3-8-1. Incremental optical encoders
3-8-2. Absolute optical encoders
(1) Pure binary code
(2) Gray code
(3) Gray excess code
3-9. CNC Tooling
3-9-1. Qualified tool
3-9-2. Preset tools/semi-qualified tools
3-9-3. Tool presetters
3-9-4. Tool holders
Review questions 3
Exercise 3

Chapter 4 BASICS OF CNC PROGRAMMING
4-1. Coding systems
(1) Fixed sequential format
(2) Tab sequential format
(3) Word address format
(i) Alphabet
(ii) Digits
(iii) Operators
(iv) Special characters
4-2. Punched paper tapes
(1) ISO code
(2) EIA code
4-3. Punched tape readers
(1) Electromechanical tape reader
(2) Photoelectric tape reader
(3) Pneumatic tape reader
(4) Magnetic tapes
4-4. Types of codes
(1) Sequence or block number
(2) Preparatory code
(3) Miscellaneous code
(4) Axis words
(5) Feed word
(6) Speed word
(7) Tool number
4-4-1. Preparatory codes
4-4-2. Miscellaneous codes
4-4-3. Modal and Non-modal codes
4-5. Decimal point programming
4-6. Absolute and incremental positioning
4-6-1. Absolute programming or positioning
4-6-2. Incremental/relative programming or positioning
4-7. Diameter and radius programming
4-8. Programming functions
4-8-1. Data input units
4-8-2. Spindle speed control
(1) Direction
(2) Spindle speed
4-8-3. Feedrate control
4-8-4. Coordinate system preset
4-8-5. Tool and tool offset
4-8-6. Program control
(1) M00: Program stop
(2) M01: Optional stop
(3) M02: End of program
(4) M30: Program stop and rewind
Review questions 4

Chapter 5 BASICS OF TURNING CENTER PROGRAMMING

Chapter 5 BASICS OF TURNING CENTER PROGRAMMING
5-1. Rapid traverse (G00)
5-2. Linear interpolation (G01)
5-3. Circular interpolation (G02/G03)
(1) Cutting direction (G02 or G03)
(2) Arc end point coordinates
(3) Radius of arc or center of arc
5-4. Tool compensations
(1) Geometry offsets
(2) Wear offsets
(3) Tool nose radius compensation
5-4-1. Geometry offsets
5-4-2. Wear offset
5-4-3. Tool nose radius compensation
5-5. Automatic reference point return (G28)
5-6. Dwell
Review questions 5
Exercise 5

Chapter 6 SINGLE PASS CANNED CYCLE FOR TURNING
CENTERS

6-1. Rectangular turning cycle (G90)
6-2. Thread cutting cycle (G92)
6-3. Face turning cycle (G94)
Review questions 6
Exercise 6

Chapter 7 MULTIPASS CANNED CYCLES IN TURNING
7-1. Rough turning cycle (G71)
7-2. Face roughing cycle (G72)
7-3. Pattern repeating cycle (G73)
7-4. End face peck drilling cycle (G74)
7-5. Outer diameter grooving cycle (G75)
7-6. Multi-pass thread cutting cycle (G76)
Review questions 7
Exercise 7

Chapter 8 BASICS OF MACHINING CENTER PROGRAMMING
8-1. Rapid traverse (G00)
8-2. Linear interpolation (G01)
8-3. Circular interpolation (G02/G03)
8-3-1. Circular interpolation for arcs greater than 180°
8-3-2. Programming of full circle in one block
(1) Radius of arc programming
(2) Center of arc programming
8-4. Profile milling
8-5. Cutter compensations
8-5-1. Cutter radius compensation
(1) Offset plane selection and offset vector
(2) Cutter radius compensation to the left (G41)
(3) Cutter radius compensation to the right (G42)
(4) Ramp on move
(5) Ramp off move
(6) Tool movements in offset mode
(7) Change of the cutter compensation value
8-5-2. Tool length compensation
8-5-3. Tool wear compensation
8-6. Automatic reference point return (G28)
Review questions 8
Exercise 8

Chapter 9 DRILLING CANNED CYCLES IN MACHINING CENTER
9-1. Syntax of drilling canned cycles
(1) Return to the initial level (G98)
(2) Return to R level (G99)
9-2. Cancel the drilling canned cycle (G80)
9-3. Spot drilling cycle (G81)
9-4. Counter boring cycle (G82)
9-5. Deep hole peck drilling cycle (G83)
9-6. High speed peck drilling cyc le (G73)
9-7. Right-hand tapping cycle (G84)
9-8. Left-hand tapping cycle (G74)
9-9. Boring cycles (G85,G86)
9-10. Back boring cycle (G87)
9-11. Boring cycle with manual retraction (G88)
9-12. Boring cycle with dwell (G89)
9-13. Fine boring cycle (G76)
9-14. Polar coordinate system
9-15. Local coordinate system using datum shift (G52)
Review questions 9
Exercise 9

Chapter 10 SUBPROGRAMMING
10-1. Writing a subprogram
10-2. Multiple operations on specific set of hole locations
10-3. Pattern repeating
10-4. Coordinate system mirroring
10-5. Coordinate system rotation
10-6. Scaling
Review questions 10
Exercise 10

Chapter 11 MACRO PROGRAMMING

11-1. Applications of macros
(1) Part family
(2) Development of canned cycles
(3) Complex interpolations
(4) Controlling optional devices
11-2. Variables
(1) As arguments
(2) In calculations
(1) Local variables [#1 – #33]
(2) Common variables [#100 – #149] [#500 – #532]
(3) System variables [#1000 onwards]
CNC FUNDAMENTALS AND PROGRAMMING

11-3. Arithmetic expressions
11-4. Flow control statements
11-4-1. Unconditional branching
11-4-2. Conditional branching
11-4-3. Looping
11-5. Calling a macro
Review questions 11
Exercise 11

Chapter 12 DNC AND DATA COMMUNICATION

12-1. History
12-2. Direct numerical control
12-3. Distributed numerical control
12-4. DNC software features
(1) File transfer
(2) File management
(3) NC editor
(4) Report generation
(5) Access control
12-5. Advantages of DNC
12-6. DNC communications
12-6-1. Parallel communications
12-6-2. Serial communications
(1) Synchronous serial communication
(2) Asynchronous serial communication
12-7. Networking
12-7-1. Networking components
(1) Coaxial cables
(2) Twisted pair cables
(3) Optical fiber cables
12-7-2. Network topologies
(1) Physical topology
(2) Logical topology
(1) Bus network topology
(2) Ring network topology
(3) Star network topology
(4) Mesh network topology
(5) Tree network topology
12-8. Networking of CNC machine tools
(1) Wired DNC Networks
(i) RS232 DNC system
(ii) Ethernet DNC system
(2) Wireless DNC networks
(i) Ethernet wireless DNC system
(ii) Bluetooth wireless DNC system
Review questions 12

Chapter 13 APT PROGRAMMING

13-1. Introduction
(1) Arithmetic calculations
(2) Cutter offset computation
(3) Postprocessing
13-2. Coordinate system
13-3. Language features
13-3-1. Keywords
(1) Major words
(2) Minor words
13-3-2. Symbols
Subscripted symbols
13-3-3. Other features
(1) Numbers
(2) Angles
(3) Arithmetic operators
(4) Library functions
13-4. APT statements
13-4-1. Postprocessor statements
13-4-2. Auxiliary statements
13-4-3. Geometry statements
(1) Point
(2) Line
(3) Circle
(4) Plane
(5) Patern
(6) Vector
(7) Zsurf
13-4-4. Motion statements

(1) Tolerance specifications
(2) Startup and positioning statements
(3) Part, drive and check surfaces
(4) Startup statements
(5) Point to point motion statements
13-5. Machining center canned cycles
13-6. Macro programming
13-7. Repetitive programming
(1) Tracut
(2) Looping and branching
Review questions 13
Exercise 13

Chapter 13 APT PROGRAMMING
Chapter 14 CAD/CAM INTEGRATION
14-1. CAD/CAM systems
(1) Standalone CAD/CAM systems
(2) Integrated CAD/CAM/CAE systems
(1) Input of geometrical and technological data
(2) Calculation of the tool path and creation of the
tool paths
(3) Translation of the tool paths to a part program
Step 1: Create the manufacturing model
Step 2: Setup the manufacturing data base and operations
(1) Tooling data
(2) Machine tools/work cells
(3) Fixture setups
(4) Operation setup
Step 3: Define the NC-sequences
(1) Defining the machining features
(2) Define the sequence of machining features
Step 4: Create the toolpath (cutter location files)
Step 5: Post-processing
14-2. Evaluation of CAM software
14-2-1. Turning
(1) 2-axis turning
(i) Contouring
(ii) Hole making
(iii) Roughing
(iv) Copy roughing
(v) Grooving
(vi) Threading
(2) Multi-spindle and multi-turret turning
14-2-2. Milling
(1) Simple milling
(i) Pocketing
(ii) Facing
(iii) Hole making
(iv) Profiling
(v) Thread milling
(2) Advanced milling
(i) Rotary axis
(ii) Machining using 4th and 5th axis
(3) Machining of 3D freeform shapes
14-3. Conversational programming
(1) Initialization module
(2) Machining cycle module
(3) Contour module
(4) Tool module
(5) Toolpath simulation module
(6) Utility module
14-4. Part program verification
14-4-1. The purposes of part program verification
(1) To detect geometric errors of the cutter path
(2) To detect potential tool interference
(3) To detect incorrect cutting conditions
14-4-2. Part program verification methods
(1) Dry run
(2) Machine a prototype
(3) CAD-based verification software
Review questions 14

Appendix I MULTIPLE CHOICE QUESTIONS

Appendix II NC/CNC MANUAL PART PROGRAMMING CODES

Index

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