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					        IE 447
 COMPUTER INTEGRATED
   MANUFACTURING

NC Programming Fundamentals
or how to put the “GO” in your G-
               codes
          NC Part Programming




   Linear tool motion (Milling) relative to the part
      Example: A Milling Operation
                                    SPINDLE
NC CODE (Word Address Format)
                                    STOP !
N50   G00   X15 Y12.5 Z0 F0         SPINDLE
N55   M03   S2000                   STARTED !
N60   G01   Z-2.5 F500 M08
N65   G01   X50
N70   G01   Y45
N75   G01   X15
N80   G01   Y12.5
N85   G00   Z0 M09
N90   G79   M04
                         Z      Y
                                X
                    (0,0,0)
    Basics of NC Part Programming
   it is always assumed that the tool moves
    relative to the work piece no matter what the
    real situation is.
   The position of the tool is described by using a
    Cartesian coordinate system.
   If (0,0,0) position can be described by the
    operator, then it is called floating zero.
             NC Part Program
ß Code that is read by the controller and results
  in various machine functions.
ß Five categories of Commands
  ß   Preparatory Functions
  ß   Axis Motion Function
  ß   Feed and Speed Commands
  ß   Identification Commands
  ß   Miscellaneous Commands

                       G-codes                      5
Preparatory Functions (G Codes)
ß Tool motion
  ß Rapid traverse G00
     ß Positioning command
     ß Moves the tool at a rapid feed rate to a specific XYZ
       coordinate
     ß Takes the shortest route to reach the specified point
  ß Format
     ß G00 Xx Yy Zz



                           G-codes                             6
          Linear Interpolation
ß Moves the tool from its current position to a
  specific XYZ coordinate at a specified feed
  rate
ß Format
  ß G01 Xx Yy Zz ff




                      G-codes                     7
Linear Interpolation




        G-codes        8
         Circular Interpolations
ß Moves a tool around a circular arc to a
  specific XYZ coordinate
  ß Requires 5 pieces of information
     ß Plane selection
     ß Arc start point
     ß Rotation direction
     ß Arc end point
     ß Arc center or arc radius



                          G-codes           9
        Circular Interpolations
ß G02 circular interpolation clockwise around
  an arc G03 circular interpolation counter
  clockwise around an arc




                     G-codes                    10
      How You Tell Directions
ß The direction for G02 can be determined
  by rotating from the positive axes
  towards the negative axes. The direction
  for a G03 is exactly opposite




                   G-codes               11
          Still Going in Circles
ß Two basic methods
  ß I. J. K. Method
     ß (G02,G03) Xx Yy Ii Jj Ff (on the XY plane)
  ß Radius method
     ß (G02,G03) Xx Yy Rr Ff (on the XY plane)




                          G-codes                   12
               IJK Method
ß The I, J, K addresses are used to specify
  the distances from the start of the arc to
  the arc center coordinates in XYZ
  directions.




                    G-codes                    13
What Vectors Are IJK?




         G-codes        14
            Radius Method
ß Requires two entry parameters in the
  command the XYZ end point of the arc and
  the radius R
ß G02/G03 Xx Yy Zz Rr




                   G-codes               15
Code This!!!




    G-codes    16
             Plane Selection
ß Determines the plane that machining will take
  place
  ß G17 XY plane selection
  ß G18 ZX plane selection
  ß G19 YZ plane selection




                       G-codes                17
           Positioning Systems
ß G90 (modal)
  ß Use to specify the absolute positioning system
     ß All coordinates are based off a single origin in the
       work coordinates system
ß G91 (modal)
  ß Use to specify the incremental positioning system
     ß The current tool position is taken as a reference point
       in the tool moves the incremental distance given in the
       command

                            G-codes                           18
                      Units
ß G70
  ß Used to specify inches as the unit of measurement
ß G71
  ß Use to specify millimeters as the unit of
    measurement
ß These cannot be used in the same part
  program


                        G-codes                    19
         Absolute Zero Setting
ß G92
  ß Sets the absolute zero for the coordinates system
ß G92 Xx Yy Zz
ß Does not cause any tool motion
ß Specifies the distance of the cutter in XYZ to
  the origin
ß Ties the coordinates of the machine tool to the
  coordinates of the program
                        G-codes                     20
G92 Example




    G-codes   21
       Stop and End Functions
ß M00 unconditional stop shuts down all drive
  motors until re-started by the machinist
ß M01 optional stop will stop the program if
  the optional stop button is pressed
ß M02/M30 end of program statement




                     G-codes                22

				
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