
4.INTERPOLATION FUNCTIONS PROGRAMMING B-63784EN/01
- 60 -
WARNING
1 Consider lines L1, L2, and L3. ∆X is the distance the
tool moves per time unit at the feedrate specified
with address F in the Cartesian coordinate system.
As the tool moves from L1 to L2 to L3, the angle at
which the tool moves per time unit corresponding to
∆X in the Cartesian coordinate system increases
from θ1 to θ2 to θ3.
In other words, the C-axis component of the feedrate
becomes larger as the tool moves closer to the
center of the workpiece. The C component of the
feedrate may exceed the maximum cutting feedrate
for the C-axis because the tool movement in the
Cartesian coordinate system has been converted to
the tool movement for the C-axis and the X-axis.
L1
L2
L3
θ3
θ2
θ1
∆X
L : Distance (in mm) between the tool center and
workpiece center when the tool center is the
nearest to the workpiece center
R : Maximum cutting feedrate (deg/min) of the C axis
Then, a speed specifiable with address F in polar
coordinate interpolation can be given by the
formula below.
Specify a speed allowed by the formula. The
formula provides a theoretical value; in practice, a
value slightly smaller than a theoretical value may
need to be used due to a calculation error.
F<L×R×
180
(mm/min)
The speed can be controlled so as to prevent the
issue of alarm OT512 (excessive speed). See II-
5.5.2 for details.
2 The following functions cannot be used for the
rotation axis for polar coordinate interpolation.
Using any of these functions results in abnormal
operation.
- Roll-over function
- Multiple-rotary axis control
- Index table indexing function