Rockwell Automation 8520-MUM 9/Series CNC Mill Operation and Programming Manual Documentation Set - Manual (Page 538)

Cutter Diameter Compensation
(G40, G41, G42)
Chapter 21
21-20
The easiest way to demonstrate the actual tool paths taken by the cutting
tool when using cutter compensation type B 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. The
following figure gives an example of a typical entry move:
Figure 21.17
Cutter Compensation Entry Move
Programmed tool path
Cutting tool center path
G42 cutter compensation right
Cutting tool
Compensation entry move
Workpiece
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.
The entry move of the cutting tool for type B cutter compensation can
generate extra motion blocks to attempt to prevent gouging of the part as
may sometimes occur using compensation type A. Type B cutter
compensation keeps the cutting tool at least one radius away from the
start-point of the next block at all times during an entry move. The final
end-point of the entry move is a position at right angles to and on the left
or right side of the next programmed move in the currently defined plane.
21.4
Cutter Compensation
(Type B)
21.4.1
Cutter Compensation
Type B Entry Moves