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Cncprogramming

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Cncprogramming

  1. 1. Computer Numerical Control<br />
  2. 2. Types of Automation<br />Manufacturing<br />Automation<br />Hard/ Rigid/ Mechanized<br />Automation<br />Soft/ Flexible/ Programmable<br />Automation<br />Copy milling machines <br />Automats<br />Special purpose machines<br />CNC Machines <br />Robots<br />Automatically Guided Vehicles (AGVs) <br />Reconfigurable conveyors <br />Unlimited muscle power<br />Speed<br />Accuracy<br />Unmanned operation<br />Flexibility<br />Simplified generic tooling even for the most complex jobs<br />Advantages of Soft Automation<br />
  3. 3. Introduction to CNC<br />Conventionally, an operator decides and adjusts various machines parameters like feed , depth of cut etc depending on type of job , and controls the slide movements by hand. <br />In a CNC Machine functions and slide movements are controlled by motors using computer programs. <br />The most basic function of any CNC machine is automatic, precise, and consistent motion control.<br />The two most common axis types are linear (driven along a straight path) and rotary (driven along a circular path). <br />
  4. 4. Introduction to CNC<br />Conventionally, an operator decides and adjusts various machines parameters like feed , depth of cut etc depending on type of job , and controls the slide movements by hand. <br />In a CNC Machine functions and slide movements are controlled by motors using computer programs. <br />The most basic function of any CNC machine is automatic, precise, and consistent motion control.<br />The two most common axis types are linear (driven along a straight path) and rotary (driven along a circular path). <br />
  5. 5. Why CNC is Accurate?<br />
  6. 6. Defining Axes<br />
  7. 7. Defining Axes<br />Lathe<br />Vertical Machining Center<br />
  8. 8. Important G Codes<br />G00 Rapid Transverse<br />G01 Linear Interpolation<br />G02 Circular Interpolation, CW<br />G03 Circular Interpolation, CCW<br />G17 XY Plane,G18 XZ Plane,G19 YZ Plane<br />G20/G70 Inch units<br />G21/G71 Metric Units<br />G40 Cutter compensation cancel<br />G41 Cutter compensation left<br />G42 Cutter compensation right<br />G43 Tool length compensation (plus)<br />G43 Tool length compensation (plus)<br />G44 Tool length compensation (minus)<br />G49 Tool length compensation cancel<br />G80 Cancel canned cycles<br />G81 Drilling cycle<br />G82 Counter boring cycle<br />G83 Deep hole drilling cycle<br />G90 Absolute positioning<br />G91 Incremental positioning<br />
  9. 9. Important M Codes<br />M00 Program stop<br />M01 Optional program stop<br />M02 Program end<br />M03 Spindle on clockwise<br />M04 Spindle on counterclockwise<br />M05 Spindle stop<br />M06 Tool change<br />M08 Coolant on<br />M09 Coolant off<br />M10 Clamps on<br />M11 Clamps off<br />M30 Program stop, reset to start<br />
  10. 10. Modal and Non-Modal Commands<br />Modal commands: Commands issued in the NC program that will stay in effect until it is changed by some other command, like, feed rate selection, coolant selection, etc.<br />Nonmodal commands: Commands that are effective only when issued and whose effects are lost for subsequent commands, like, a dwell command which instructs the tool to remain in a given configuration for a given amount of time.<br />
  11. 11. Open Loop and Closed Loop System<br />
  12. 12. Tape Preparation<br />
  13. 13. Programming : Absolute and Incremental<br />5 – Parity check<br />6 – Zero<br />7- Minus<br />8 – End of info<br />EIA<br />ASCII<br />
  14. 14. Features of a CNC Systems<br />The tool or material moves.<br />Tools can operate in 1-5 axes.<br />Larger machines have a machine control unit (MCU) which manages operations.<br />Movement is controlled by a motors (actuators).<br />Feedback is provided by sensors (transducers)<br />Tool magazines are used to change tools automatically.<br />
  15. 15. Types of Interpolations<br />Point to Point - No contouring capability <br />Straight cut control - one axis motion at a time is controlled for machining<br />Contouring - multiple axis’s controlled simultaneously<br />
  16. 16. Sample Programming<br />Preparatory Information: units, incremental orabsolute positioning<br />Coordinates: X,Y,Z, RX,RY,RZ<br />Machining Parameters: Feed rate and spindlespeed<br />Coolant Control: On/Off, Flood, Mist<br />Tool Control: Tool and tool parameters<br />Cycle Functions: Type of action required<br />Miscellaneous Control: Spindle on/off, directionof rotation, stops forpart movement<br />This information is conveyed to the machine through a set of instructions arranged in a desired sequence – Program<br />
  17. 17. Sample Programming<br />Manual Part Programming: Manual programming of the machines<br />Computer Aided Programming (CAP): Programming done by a computer<br />Manual Data Input (MDI): A manual program is entered into the machine’s controller via its own keyboard<br />
  18. 18. Sample Programming<br />Tool size = 0.25 inch,<br />Feed rate = 6 inch per minute,<br />Cutting speed = 300 rpm,<br />Tool start position: 2.0, 2.0<br />Programming in inches<br />Motion of tool:<br />p0  p1  p2  p3  p4  p5  p1  p0<br />
  19. 19. Sample Programming<br />Set up the programming parameters<br />Programming in inches<br />Use absolute coordinates<br />Feed in ipm<br />N010 G70 G90 G94 G97 M04 <br />Spindle speed in rpm<br />Spindle CCW<br />
  20. 20. Sample Programming<br />Set up the machining <br />conditions<br />Machine moves in XY-plane<br />Use full-circle interpolation<br />Feed rate<br />Spindle speed<br />N020 G17 G75 F6.0 S300 T1001 M08 <br />Tool no.<br />Flood coolant ON<br />
  21. 21. Sample Programming<br />Move tool from p0 to p1 in straight line <br />Linear interpolation<br />target coordinates<br />N030 G01 X3.875 Y3.698 <br />
  22. 22. Sample Programming<br />Cut profile from p1 to p2<br />Linear interpolation<br />target coordinates<br />N040 G01 X3.875 Y9.125 <br />or<br />N040 G01 Y9.125 <br />X-coordinate does not change  no need to program it<br />
  23. 23. Sample Programming<br />Cut profile from p2 to p3<br />Linear interpolation<br />target coordinates<br />N050 G01 X5.634 Y9.125 <br />
  24. 24. Sample Programming<br />Cut along circle from p3 to p4<br />circular interpolation, CCW motion<br />target coordinates<br />N060 G03 X7.366 Y9.125 I0.866 J-0.125 <br />coordinates of center of circle <br />(always in incremental )<br />
  25. 25. Sample Programming<br />Complete Programming<br />N010 G70 G90 G94 G97 M04 <br />N020 G17 G75 F6.0 S300 T1001 M08 <br />N030 G01 X3.875 Y3.698 <br />N040 G01 X3.875 Y9.125 <br />N050 G01 X5.634 Y9.125 <br />N060 G03 X7.366 Y9.125 I0.866 J-0.125 <br />N070 G01 X9.302 <br />N080 G01 X3.875 Y3.698 <br />N090 G01 X2.0 Y2.0 M30 <br />
  26. 26. Adaptive Control<br />Adaptive control with constraints<br />Adaptive control with optimization<br />
  27. 27. Advantage of NC<br />Increased productivity<br /> Reduced tool/fixture storage and cost<br /> Faster setup time<br /> Reduced parts inventory<br /> Flexibility that speeds changes in design<br /> Better accuracy of parts<br />Reduction in parts handling<br /> Better uniformity of parts<br /> Better quality control<br /> Improvement in manufacturing control<br />
  28. 28. Disadvantages<br />Increase in electrical maintenance<br />High initial investment<br />Higher per-hour operating cost than traditional machine tools<br />Retraining of existing personnel<br />NC is a general term used for Numerical Control. CNC refers specifically to COMPUTER NUMERICAL CONTROL. CNC machines are all NC machines but not all NC machines are CNC machine. <br />
  29. 29. Applications<br /><ul><li>Traditional machining
  30. 30. Turning, boring, milling, grinding etc.
  31. 31. Sheet metal manufacture
  32. 32. Turret punch press, pipe bending, flow forming etc.
  33. 33. Non-traditional machining
  34. 34. Wire-EDM, water-jet cutting, electron beam machining, laser beam machining, plasma cutting etc.
  35. 35. Coordinate Measuring Machines
  36. 36. Drafting machines
  37. 37. Robots
  38. 38. Rapid Prototyping (RP) machines</li></ul>NC is a control technique; not a process<br />
  39. 39. END<br />

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