# FANUC Series 16/18/160/180-Model C for Lathe Operator Manual PROGRAMMING
B–62754EN/01
4. INTERPOLATION FUNCTIONS
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In the cylindrical interpolation mode, circular interpolation is possible
with the rotation axis and another linear axis. Radius R is used in
commands in the same way as described in Section 4.4.
The unit for a radius is not degrees but millimeters (for metric input) or
inches (for inch input).
< Example Circular interpolation between the Z axis and C axis >
For the C axis of parameter No. 1022, 5 (axis parallel with the X axis)
is to be set. In this case, the command for circular interpolation is
G18 Z__C__;
G02 (G03) Z__C__R__;
For the C axis of parameter No. 1022, 6 (axis parallel with the Y axis)
may be specified instead. In this case, however, the command for
circular interpolation is
G19 C__Z__;
G02 (G03) Z__C__R__;
To perform cutter compensation in the cylindrical interpolation mode,
cancel any ongoing cutter compensation mode before entering the
cylindrical interpolation mode. Then, start and terminate cutter
compensation within the cylindrical interpolation mode.
In the cylindrical interpolation mode, the amount of travel of a rotary axis
specified by an angle is once internally converted to a distance of a linear
axis on the outer surface so that linear interpolation or circular
interpolation can be performed with another axis. After interpolation,
such a distance is converted back to an angle. For this conversion, the
amount of travel is rounded to a least input increment.
So when the radius of a cylinder is small, the actual amount of travel can
differ from a specified amount of travel. Note, however, that such an error
is not accumulative.
If manual operation is performed in the cylindrical interpolation mode
with manual absolute on, an error can occur for the reason described
above.
Specified value
The actual amount
of travel
2×2πR
MOTION REV
MOTION REV
MOTION REV
:
The amount of travel per rotation of the rotation axis (Set-
ting value of parameter No. 1260)
R
:
:Rounded to the least input increment
=
2×2πR
In the cylindrical interpolation mode, an arc radius cannot be specified
with word address I, J, or K.
If the cylindrical interpolation mode is started when tool nose radius
compensation is already applied, circular interpolation is not correctly
performed in the cylindrical interpolation mode.
D Circular interpolation
(G02,G03)
D Cutter compensation
D Cylindrical interpolation
accuracy
Restrictions 