Aerotech UNIDEX 600 Series, Руководство пользователя

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Parameters U600 User’s Guide
C-72
Aerotech, Inc.
Version 1.4
C.4.24. CutterToleranceDeg
This task parameter may be used to avoid short circular arc segments known as link
moves when operating in cutter compensation, around “outside corners” between nearly
parallel moves. These short link moves may cause Motion Queue Starvation, or the error
message, “Link Arc Degenerates to Line”, usually due to the Imprecision of Target
Values.
If during cutter compensation, the angle between two moves on an outside corner will be
less than the angle specified by this parameter, then, instead of generating a link move
between points A and C, around the angle
θ
, the controller will instead execute an offset
move, and follow that path. For example travel through point A to point B, then through
point C, as illustrated in the picture.
Large values of CutterToleranceDeg can be dangerous. The offset method is
desirable when the angle between move 1 and move 2 is small, as discussed above.
However, the “offset method”, is less desirable, the larger the angle between the
moves, because it will also cause the tool to leave the part temporarily (at point b the
tool will not contact the part). This departure increases dramatically with move angle,
and in fact if the angle between move 1 and move 2 is 180 degrees, the offset method
yields an infinite departure, and the controller reverts to the link method regardless of
the value of the value of CutterToleranceDeg.
Figure C-17. Cutter Compensation Illustration
WARNING
•
CutterY
a
Programmed Path
θ
Actual Path
c
•
•
b
CutterX
Move 1
Move 2