Rockwell Automation 8520-MUM 9/Series CNC Mill Operation and Programming Manual Documentation Set - Manual (Page 528)

Cutter Diameter Compensation
(G40, G41, G42)
Chapter 21
21-10
The easiest way to demonstrate the actual tool paths taken by the cutting
tool when using cutter compensation type A is by pictorial representation.
The following subsections give a brief description of the cutter path, along
with a figure to clarify the description.
An entry move is defined as the path that the cutting tool takes when the
cutter compensation function first becomes activated in a program.
Figure 21.8 gives an example of a typical entry move.
Important: Any entry move into cutter compensation must be a linear
move. Initial activation of cutter compensation by designation of either the
G41 or G42 commands in a circular cutting mode (G02 or G03) is not
allowed. The G41 or G42 commands may be designated in a circular
block to change cutter compensation direction, as long as cutter
compensation is already active.
Figure 21.8
Cutter Compensation Entry Move
Programmed tool path
Cutting tool center path
G42 cutter compensation right
Cutting tool
Compensation entry move
Workpiece
The entry move of the cutting tool for type A cutter compensation takes the
shortest possible path to its offset position. This position is at right angles
to and on the left or right side of the next programmed move in the
currently defined plane.
21.3
Cutter Compensation
(Type A)
21.3.1
Cutter Compensation
Type A Entry Moves