
20.AXIS CONTROL FUNCTIONS PROGRAMMING B-63944EN/02
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A single servo axis is used exclusively so that digital servo can
directly read the rotation position of the master axis. (This axis is
called the EGB dummy axis.)
- Synchronization control
(1) Start of synchronization
If G81 is issued so that the machine enters synchronization mode,
the synch switch of the EGB function is closed, and the
synchronization of the tool and workpiece axes is started.
During synchronization, the rotation about the tool and
workpiece axes is controlled so that the relationship between T
(number of teeth) and L (number of hob threads) is maintained.
During synchronization, the synchronization relationship is
maintained regardless of whether the operation is automatic or
manual.
Specify P and Q to use helical gear compensation.
If only either P or Q is issued, alarm PS1594 is generated.
If, during synchronization, G81 is issued again without
synchronization cancelation, alarm PS1595 is generated if ECN,
bit 3 of parameter No. 7731, is 0. If ECN, bit 3 of parameter No.
7731, is 1, helical gear compensation is conducted with the
synchronization coefficient being changed to the one newly
specified with T and L commands if T and L commands are
issued, and if T and L commands are not issued and only P and Q
commands are issued, helical gear compensation is conducted
with the synchronization coefficient kept intact. This allows
consecutive fabrication of helical gears and super gears.
(2) Start of tool axis rotation
When the rotation of the tool axis starts, the rotation of the
workpiece starts so that the synchronous relationship specified in
the G81 block can be maintained.
The rotation direction of the workpiece axis depends on the
rotation direction of the tool axis. That is, when the rotation
direction of the tool axis is positive, the rotation direction of the
workpiece axis is also positive; when the rotation direction of the
tool axis is negative, the rotation direction of the workpiece axis
is also negative. However, by specifying a negative value for L,
the rotation direction of the workpiece axis can be made opposite
to the rotation direction of the tool axis.
During synchronization, the machine coordinates of the
workpiece axis and EGB axis are updated as synchronous motion
proceeds. On the other hand, a synchronous move command
has no effect on the absolute and relative coordinates.
(3) Termination of tool axis rotation
In synchronism with gradual stop of the tool axis, the workpiece
axis is decelerated and stopped. By specifying the command
below after the spindle stops, synchronization is canceled, and
the EGB synchronization switch is opened.