Rockwell Automation 8520-GUM 9/Series CNC Grinder Operation and Programming Manual Documentation Set - Manual (Page 596)

Cylindrical Grinding Fixed Cycles
Chapter 17
17-22
The following describes each of the cycle’s parameters.
X -- last plunge point. If in incremental mode (G91 active) then the value
entered here is a signed incremental value indicating the distance from the
start point to the point where the last plunge motion (defined by the Z
parameter) is to be executed. The start point is the coordinate of the X axis
prior to execution of the grinding cycle.
If in absolute mode (G90 active) then the value entered here is the X
coordinate of the last plunge point.
If no value is entered for X, then the plunge move is made from the start
point only. Any Q parameter value programmed is ignored.
I -- dither amount. The value entered here is a signed incremental value
used to indicate the total distance that the X axis is to dither about the start
point. The dither axis oscillates half the incremental distance entered here
on both sides of its plunge point. If no value or a value of zero is entered
for this, then the plunge motion is executed without any X axis dither.
Important: In grinding fixed cycle blocks where changes are made from
absolute to incremental or incremental to absolute modes within the block,
the integrands I, J and K are always in the last mode programmed in the
block, regardless of their position in the block.
Z -- plunge depth. If in incremental mode (G91 active) then the value
entered here is a signed incremental value used to indicate the distance
from the start point to the end of the plunge motion. If in absolute mode
(G90 active) then the value entered here is the Z coordinate of the end
point of the plunge move.
The plunge move with the G84 cycle is made with one continuous motion
until the plunge depth is reached. At that point, any programmed spark-out
passes are made (as defined by the L parameter). After the spark-out
passes are completed, the plunge axis retracts to the start point at its rapid
feedrate.
This parameter is “program modal,” meaning that it needs to be
programmed only once in a part program. Any subsequent cylindrical
grinding blocks (G82 -- G88) use a previously programmed value if a new
value is not programmed.
Q -- plunge shift. The value entered here is an incremental value used to
indicate the distance that the X axis is to shift after the plunge axis has
retracted. This shift takes place after the plunge axis has retracted and is
executed at the rapid feedrate for the X axis.