PROGRAMMING
G and M code operations or
lines are entered in the ISO variable line format. An operation is a line
of text containing the operation code and any information needed to do
that operation. Multiple G and M code operations cannot be placed on one
line, they must occupy separate lines, although one G and one M code may
appear in the same program line.
The text necessary to execute
an operation is composed of a sequence of letters A..Z, digits 0..9, signs
(+ and -) and spaces.
EXAMPLE: If a G operation
for linear interpolation is to be coded then the text line will include
the string G01, "G" for a G operation and "01" because linear interpolation
is operation 1. If further information is to be specified such as
an X coordinate of 0.5 inches, a Z coordinate of 1.5 inches and a feed
rate of 4 inches per minute then further strings can be added with spaces
as separators:
G1 X0.5 Z2.5 F4
G code Functions
A G code is command in the program specifying
the mode on which a CNC machine moves along programming lines. The mode
of movement is indicated by the numerical value following the G address.
A G code is usually placed at the beginning of a block so it can set the
control for a particular mode when acting on the words in the block
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Preparatory
function descriptions
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G00-Rapid
positioning
G01-linear
interpolation
G02-Circular
interpolation clockwise
G03-Circular
interpolation counterclockwise
G04-Dwell
G12-Circle
cutting clockwise
G13-Circle
cutting counterclockwise
G17-X
and Y plane designation
G18-X
and Z plane designation
G19-Y
and Z plane designation
G25-Program
copy
G28-Return
to reference position
G29-Return
from reference position
G40-Cancel
cutter radius compensation
G41-Cutter
radius compensation left side of profile
G42-Cutter
radius compensation right side of profile
G43-Tool
position offset Z axis
G49-Cancel
tool position offset Z axis
G73-Canned
cycle for high speed deep hole drilling
G76-Canned
cycle for boring, shift to side for rapid withdraw
G80-Cancel
canned all canned cycles
G81-Canned
cycle for standard drilling
G82-Canned
cycle for spot facing
G83-Canned
cycle for deep hole drilling
G84-Canned
cycle for tapping
G85-Canned
cycle for boring, feed both ways
G86-Canned
cycle for boring, rapid withdraw
G87-Canned
cycle for boring, manual withdraw
G88-Canned
cycle for boring with dwell, manual withdraw
G89-Canned
cycle for boring with dwell, feed both ways
G90-Absolute
positioning/programming
G91-Incremental
positioning/programming
G92-Programming
of absolute Zero point (distance to X0 Y0)
G94-Feed
rate in inches per minute (IPM)
G95-Feed
rate in inches per revolution (IPR)
G98-Return
to initial Z level, canned cycles
G99-Return
to initial Z point, canned cycles
Miscellaneous Functions
(M-codes)
The miscellaneous functions
use the address letter M followed by up to two digits to perform various
instructions that do not involve dimensional movements of the machine.
They are also referred to as machine functions, or simply M codes. They
include stopping the program, starting or stopping the spindle, tool change,
coolant flow, and others. Some M codes are standardized and are common
to most CNC controllers; others have special assignment for particular
controllers. Only one M function can be used in any one block of information.
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Miscellaneous
function descriptions
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M00-Program
stop, start program again by pressing button
M01-Optional
stop, operator can switch (/) on or off
M02-Program
end
M03-Spindle
on clockwise rotation
M04-Spindle
on counterclockwise rotation
M05-Spindle
stop rotation
M06-Command
to change tools, automatic tool changer (ATC)
M08-Coolant
on
M09-Coolant
off
M30-Program
end, all functions stop, memory/tape rewinds
M94-Mirror
image off
M95-Mirror
image on
M98-Subroutine
call
M99-Subroutine
return