System information

SECTION FOUR - PREPARATORY FUNCTIONS (G CODES)
Note 5: Cutter compensation is shut off at the start of each program.
How To Compensate for a Cavity
If the part is a cavity, then the start and end points will have to change. Simply changing the G41
to G42 (right cut) will not help. This is because the tool will still come down on the part. The
reason for that is as explained earlier: the system uses the previous, current, and the next
programmed points to calculate its compensation. This procedure does not occur at point 1 and
point 5.
Relocation of Points 1, 2, 10, and 11 for a Cavity
In the above figure, the tool should be brought down at point 1 and taken back up at 5.
The purpose of adding point 1a is to give advance information to the system about line 4 to 5.
The length of 1a to 1 can be as small as 00.0001". It is important to note that for the correct
advance information the slope of 1a to 1 has to be the same as the slope of 4 to 5. In this case
the slope is zero.
Similarly, the purpose of adding point 5a is to give past information to the system about line 1 to
2. Again, the slope of 5 to 5a has to be the same as the slope of 1 to 2.
Regardless of the cutter radius, the tool can now be brought down on the corner at (2) and
brought back up at 5.
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