
PROGRAMMING
B–63534EN/02
22. RISC PROCESSOR
659
The machine–specific length from the rotation center of the tool rotation
axes (A– and B–axes, A– and C–axes, and B– and C–axes) to the tool
mounting position is referred to as the tool holder offset. Unlike a tool
length offset value, a tool holder offset value is set in parameter No.
19666. When tool length compensation in tool axis direction is applied,
the sum of the tool holder offset and tool length offset is handled as a tool
length for compensation calculation.
Tool length offset
Tool holder
offset
Rotation
center
Tool
length
Fig. 22.4 (b) Tool Holder Offset
A tool compensation vector is found from the coordinates on the rotation
axes for controlling the tool axis direction. However, the configuration
of some machines is such that the tool axis is inclined using a fixed
attachment. In such a case, the rotation angles of the rotation axes can be
set using parameters.
Set bit 1 (RAP) of parameter No. 19650 to 1, and set the coordinates in
parameter No. 19658.
This function compensates for a slight shift of the rotation axis origin
caused, for example, by thermal displacement. Specify a compensation
value in parameter No. 19660.
When the tool axis is on the Z–axis, and the rotation axes are the B–axis
and C–axis, a compensation vector is calculated as follows :
Xp = Lc * sin(B–Bz) * cos(C–Cz)
Yp = Lc * sin(B–Bz) * sin(C–Cz)
Zp = Lc * cos(B–Bz)
Xp,Yp,Zp : Compensation pulse on each axis after origin shift
compensation
Lc : Offset value
B,C : Machine position on B–axis and C–axis
Bz,Cz : Origin compensation value on B–axis and C–axis
Set offsets relative to the rotation angles of the rotation axes in parameter
No. 19659. The compensation vector calculation formula is the same as
that used for rotation axis origin compensation, except that Bp and Cp are
changed to rotation axis offsets.
When rotation axis origin compensation and rotation offsetting are set at
the same time, both compensations are performed.
When the tool axis is on the Z–axis, and the rotation axes are the B–axis
and C–axis, compensation vector calculation is performed as follows :
D Tool holder offset
D Parameter–based
rotation angle
specification
D Rotation axis origin
compensation
D Rotation axis offset