Rockwell Automation 8520 9/Series CNC Lathe - Manual (Page 589)

Compound Turning Routines
Chapter 24
24-25
G74 Tool Paths, Case 2
If a pocket or multiple pockets are present in a workpiece face, it requires a
Case 2 G74 rough facing routine.
For Case 2, the control cuts each pocket separately, starting with the pocket
closest to the beginning of the operation. Figure 24.20 shows the tool
paths for a typical multiple pocket contour. The retract path used after
each roughing pass is different than for Case 1 rough facing.
Figure 24.20
Tool Paths for Case 2 G74 Rough Facing Routine (with pockets)
Cutting feed
Rapid feed
R
(U+W+I+K)/2
D
Start Point
Important: Figure 24.20 does not show the optional final pass being
made. This is for drawing clarity.
In Figure 24.20, after the roughing passes of one pocket have been
completed, the control does not perform a normal retract move out of the
pocket. Instead the control follows the part contour out of the pocket and
then proceeds on to the next pocket or finishes the routine.