# NC Programming Slide Show

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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
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 (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
ß Requires two entry parameters in the
command the XYZ end point of the arc and
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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