Rockwell Automation 8520 9/Series CNC Lathe - Manual (Page 514)

Tool Tip Radius Compensation (TTRC)
Function
Chapter 21
21-30
Except for entry and exit moves, the basic tool path generated during
TTRC is the same for types A and B TTRC. Whether tool left or tool right
is specified, the path taken is a function of the angle between tool paths
(G41 or G42) and the radius of the cutting tool.
Important: If at any time during the execution of TTRC blocks a block
reset is performed, the TTRC function re-initializes and the next move acts
as an entry move as described in an earlier section.
Important: When cutting arcs with TTRC active, the control may need to
adjust the programmed feedrate to maintain cutting speed. See chapter 18
for details on feedrates during TTRC.
The control generates extra motion blocks to keep the cutting tool in
tolerance of the desired tool path. This becomes necessary when the
intersection of tool paths is an outside tool path (as defined in section 22.1)
that has an angle as follows:
between 0°and 90°during TTRC left (G41)
between 270°and 360°during TTRC right (G42)
21.5
Tool Path During TTRC