96-8000
CUTTER COMPENSATION
155
June 1999
ENTRY AND E XIT FROM C UTTER C OMPENSATION
When entering and exiting cutter compensation or when changing from left side to right side compensation,
there are special considerations to be aware of. Cutting should not be performed during any of these three type
of moves. In a block that turns on cutter compensation, the starting position of the move is the same as the
programmed position but the ending position of the move will be offset by the cutter compensation size. In a
block that turns off cutter compensation, the starting point is offset and the ending point is not offset. Similarly,
when a block changes from left to right compensation, the starting point is shifted in one direction and the
ending point is shifted in the other direction. The result of all of this is that the tool is moved through a path that
may not be the same as the intended path or direction.
If cutter compensation is turned on or off in a block without any X-Y move, there is no change made to cutter
compensation until the next X or Y move is encountered. To enter cutter compensation, a nonzero D code
must be specified and either G41 or G42 specified. To exit from cutter compensation, you may either specify
D0 or G40, or both.
You should always turn off cutter compensation in a move which clears the tool away from the part being cut. If
a program is terminated with cutter compensation still active, an alarm is generated. In addition, you cannot
turn on or off cutter compensation during a circular move (G02 or G03); otherwise an alarm will be generated.
An offset selection of D0 will use zero as the offset size and have the same effect as turning off cutter compen-
sation. If a new value from offset memory is selected while cutter compensation is active, the starting point of
a move will reflect the old value and the ending point will reflect the new value. This will also have the effect of
shifting the motion to something other than what was intended by the programmer. You cannot change the
offset code or side during a circular motion block.
When turning on cutter compensation in a move followed by a second move at an angle of less than 90 de-
grees, there are two common ways of computing the first motion. They are called cutter compensation type A
and B. Type A will not stay on the programmed side of the first cut but will go directly to the starting point for
the second cut. Type B will remain clear of the first line and follow it with the same motions as described in the
previous section to position for the second cut. Types A and B are selected with Setting 43.
Setting 58 also changes the way the entry and exit to cutter compensation works. There is still a type A or B
but the type of moves used to clear the tool from the beginning of the cut change as described in the previous
section. The following two diagrams describe how this works.
FEED A DJUSTMENTS IN C UTTER C OMPENSATION
When using cutter compensation in circular moves, there is the possibility of speed adjustments to what has
been programmed. If the intended finish cut is on the outside of a circular motion, the tool should be slowed
down to ensure that the surface feed does not exceed what was intended by the programmer. There are
problems, however, when the speed is slowed by too much. For this reason, Setting 44 is used to limit the
amount by which the feed is adjusted in this case. It can be set between 1% and 100%. If set to 100%, there
will be no speed changes. If set to 1% the speed can be slowed to 1% of the programmed feed.
When the cut is on the inside of circular motion, there is no speedup adjustment made to the feed rate.
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