Rockwell Automation 8520-MUM 9/Series CNC Mill Operation and Programming Manual Documentation Set - Manual (Page 620)

Irregular Pocket Milling Cycles
Chapter 25
25-2
Use the irregular pocket milling roughing cycle (G89.1) to rough out an
irregular pocket in a workpiece. This cycle makes multiple cuts at a
programmed depth, one cutter radius in width.
The G89.1 block used to rough out an irregular pocket has this format:
G89.1 X__Y__Z__P__Q__H__E__F__L__;
Where : Is :
X Y The coordinates that specify the start/end corner of the irregular pocket in the
selected plane. These parameters must be programmed.
Z The coordinate (along the plunging axis) that specifies the bottom of the irregular
pocket. In incremental mode this parameter specifies the depth of the pocket as
measured from the start-point to the pocket bottom. This parameter must be
programmed.
P The sequence number of the first block in the set of blocks that define the pocket
shape. The coordinates in this block specify the end-point of the pocket’s first
wall.
Q The sequence number of the last block in the set of blocks that define the pocket
shape. The coordinates in this block specify the end-point of the pocket’s last
wall. This endpoint must correspond to the start/end corner specified by the X
and Y coordinates. This parameter must be programmed.
Important: The set of blocks specified by P and Q must be at least 5
blocks long to qualify as an irregular pocket.
The set of blocks specified by P and Q may be located anywhere in the same
program as the G89.1 block. These blocks can not be called from a subprogram
or a macro unless the G89.1 block is in that subprogram or macro.
H The finish allowance that will be left on the sides of the irregular pocket. This
finish allowance can be removed later using a G89.2 finishing cycle.
To leave a finish allowance on the pocket bottom, program a pocket depth (Z
parameter) that is at the desired finish allowance above the actual pocket bottom.
This finish allowance can be removed later using a G89.1 roughing cycle
programmed with the actual pocket bottom.
E Plunge feedrate. This parameter determines the feedrate of any Z axis moves. If
not programmed the roughing feedrate (F parameter) will be used.
F Roughing feedrate. This parameter determines the feedrate of any XY axis
cutting moves. If not programmed the existing (modal) cutting feedrate will be
used.
L Incremental plunge depth of each cutting pass along the Z axis. If not
programmed, the plunge amount will be equal to the programmed depth of the
pocket.
Before invoking the G89.1 cycle, the programmer must activate cutter
compensation left or right by programming G41 or G42. This allows the
control to begin interpreting the blocks that define the contour of the
pocket as they are encountered.
25.1.1
Irregular Pocket Roughing
(G89.1)