Rockwell Automation 8520-MUM 9/Series CNC Mill Operation and Programming Manual Documentation Set - Manual (Page 564)

Cutter Diameter Compensation
(G40, G41, G42)
Chapter 21
21-46
Figure 21.43 gives an example of a typical change in tool radius during jog
retract with cutter compensation active.
Figure 21.43
Change in Cutter Radius During a Jog Retract
Original tool
radius
New
tool
radius
Difference in
tool radius
•
R
Programmed path
Compensated path
Jog retract moves
Jog retract
return moves
Tool radius
changed here
90
•
Generated offset block
from difference in
tool radius
•
R
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If exiting automatic mode and either a MDI motion block is executed or a
manual jog motion is made, the cutter compensation feature, if active,
re-initializes when the next motion block is executed in automatic mode.
The compensation feature compensates the cutting tool one tool radius
perpendicular to the tool path of the next motion block that is executed in
automatic mode. In effect, the control generates its own entry move for
compensation with the first compensated block being the next block
executed in automatic operation.
Important: The cutter compensation feature is not available for any
motion blocks that are programmed in MDI mode. The cutter
compensation mode may be altered by programming either G41, G42, or
G40; or the tool radius may be changed in an MDI program. However,
none of the tool paths executed in MDI are compensated. No changes
made to cutter compensation are applied until the next block executed in
automatic mode.
21.6.5
MDI or Manual Motion
During Cutter Compensation