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  1. 1. 1 GEETANJALI INSTITUTE OF TECHNICAL STUDIES Presentation on DEPARTMENT OF MECHANICAL ENGINEERING CNC (Computer Numerical Control) machine GITS IN-HOUSE TRANING Approved by :- Prof. Vishnu Agarwal HOD,Mechanical Submitted By :- Kapil vadiyar
  3. 3. CONTENT • 1. Introduction • 2. What is CNC? • 3. History of CNC • 4. Classification of CNC machine • 5. Basic element of CNC machine • 6. Process of CNC • 7. CAD/CAM • 8. Part programming • 9. Basic G-codes • 10. Basic M-codes • 11. Process of program • 12. Advantages • 13. Challenges 3
  4. 4. INTRODUCTION • In Industry it is not efficient or profitable to make everyday products by hand. • CNC machines can have several axes of movement, and these movements can be either linear or rotary. Many machines have both types. • We use Siemens 802D CNC Lathe machine in our college. 4
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  6. 6. WHAT IS CNC? • CNC Machining is a process used in the manufacturing sector that involves the use of computers to control machine tools. • This means a computer converts the design into numbers which the computer uses to control the cutting and shaping of the material. • CNC machine works like the Robot, which has to be fed with the program and it follows all your instructions. 6 Computer Numerical Control
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  8. 8. CLASSIFICATION OF CNC MACHINE Classification of CNC Based on Motion Point-to- point Straight line Continuous path Based on Feedback Closed loop Open loop 8
  9. 9. HISTORY OF CNC • 1949:US Air Force asks MIT to develop a "numerically controlled" machine. • 1952:Prototype NC machine demonstrated (punched tape input). • 1980:CNC machines (computer used to link directly to controller) • 1990:DNC: external computer “drip feeds” control programmer to machine tool controller 9
  10. 10. BASIC ELEMENTS OF CNC MACHINE A CNC machine consist of following 6 major elements:- 1. Input Device 2. Machine control unit 3. Machine tools 4. Driving system 5. Feedback devices 6. Display unit. 10
  12. 12. PROCESS OF CNC • The computer is used to draw the design. However, the design is only a picture and the CNC machine cannot use this to manufacture the product. The computer software must also convert the drawing into numbers (coordinates) . A Computer • A computer cannot be directly connected to a CNC machine. The computer is connected to an interface. This converts the signals from the computer to a form that the CNC machine understands. An Interface • The signals from the interface control the motors on the CNC machine. CNC machine 12
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  14. 14. CAD/CAM • CAM – Computer Aided Machining or Manufacturing – Refers to the use of various software packages to create tool paths and NC code to run a CNC controlled machine, based on 3D computer model (CAD) data. When the two are used together, this is generally referred to as CAD/CAM. • Note: CAM does not actually run the CNC machine, but just creates code for it to follow. 14
  15. 15. PART PROGRAMMING Prepare the process plan Identify the machine tool Select the drive axis Choose the tool Determining the machining parameter Make job and tool set-up plan Decide the tool path Write the part program Test the part program Document the program 15
  16. 16. PROGRAMMING FUNCTION Preparatory function G- code 16 Miscellaneous function M- code Speed function S- code Feed rate F- code Tool function T- code
  17. 17. BASIC G-CODES Codes Functions GOO Linear interpolation at rapid motion GO1 Linear interpolation at feed rate GO2 Circular interpolation(clockwise ) G03 Circular interpolation(anti-clockwise) GO4 Dwell time G70 Inch mode G71 Millimeter mode G75 Reference position(home position) G94 mm per minute G95 mm per revolution 17
  18. 18. BASIC M-CODES Codes Function M00 Program stop M01 Optional stop M02 End of program M03 Spindle clockwise M04 Spindle anti clockwise M05 Spindle OFF M06 Tool change M08 Coolant ON M09 Coolant OFF M10 Chuck open M11 Chuck close M16 Auto tool change M30 End of tape/ tape rewind 18
  19. 19. PROCESS OF PROGRAM Start up program Tool position Profile program End of program 19
  20. 20. EXAMPLE G71 G95 G75 X0Z0 M16 T1 M03 S1000 G00 X32Z2 G00 X29 G01 Z-10 F0.1 G01 X30 G00 Z2 G00 X28 G01 Z-10 F0.1 G01 X30 G00 Z2 G75 X0Z0 M05 M30 20 RPM = CUTTING SPEED(V.C) X 1000 ∏ X D
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  23. 23. ADVANTAGES OF CNC • Increase production throughput • Improve the quality and accuracy of manufactured parts • Stabilize manufacturing costs • Manufacture complex or otherwise impossible jobs -2D and 3D contours • Less skilled/trained people can operate CNC’s 23
  24. 24. CHALLENGES • Costly setup • Skilled operators required • Programming knowledge required • Maintenance is difficult. 24
  25. 25. REFERENCES • • • CAD/CAM books • Training report. 25
  26. 26. Any Questions? THANKS! 26