Rockwell Automation 8520 9/Series CNC Lathe - Manual (Page 420)

Spindles
Chapter 17
17-22
When end face milling is activated, the circle plane is set to XY. The X
axis becomes the primary axis of the circle plane and remains so, as long
as the G16.2 mode is active. If the active plane is changed, the change
does not become effective until the G16.2 mode is cancelled, and is
superseded if the G16.2 plane is reactivated.
End Face Milling Operation
When virtual C axis end face milling is activated, the control terminates
any primary spindle operations and defines the current primary spindle
position as zero degrees. If the AMP parameter Automatic Home on
Virtual C Entry is set to “YES,” a homing operation was performed prior
to this. The control then switches primary spindle operation from an
open-loop spindle to a closed-loop positioning axis.
Important: If orientation of the part is important, or if you expect to leave
G16.2 mode and then return and continue work on a specific area of the
part, the primary spindle should be homed each time you enter the G16.2
mode. If the AMP parameter Automatic Home on Virtual C Entry is
set to “NO” (refer to the documentation provided by your system installer),
you need to home the virtual C axis, typically by programming a M19S0.
The blocks following the G16.2 block determine the contour to be
machined on the end face of the cylindrical workpiece. The moves of the
virtual C axis and the machine axes are interpolated to provide the
programmed contours on the workpiece face.
Example 17.3 generates a square cut in the face of a part similar to that
show in Figure 17.5.
Example 17.3
Virtual C Axis, End Face Milling
N1 G91 M05 X-20.;
N2 G16.2 Z-5.;
N3 Y10.;
N4 X-20.;
N5 Y-20.;
N6 X20.;
N7 Y-10.;
N8 Z5.;
N9 G15;