
B-64663EN/01 LASER FUNCTION 7.THREE-DIMENSIONAL MACHINING SYSTEM
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Cautions
Consider the length of the arm when specifying overtravel because
overtravel is monitored with the machine coordinates.
In the nozzle head fixing mode, the distances of movement along the
X, Y, and Z axes caused by the rotation about the α and β axes are
added to those of the X, Y, and Z axis move commands. The speed on
each axis may, therefore, be higher than the actually specified speed.
For this reason, upper limits must be sets on the rapid traverse rates
and machining feedrates on the α and β axes so that the speeds in head
fixing operation do not exceed the upper speed limits of the motors.
The maximum speeds on the X, Y, and Z axes that can be generated
due to the rotation about the α and β axes can be determined with the
following formula:
Fmax=L×Fr
Fmax : Maximum speed on the X, Y, or Z axis
L : Length of the first or second arm
Fr : Speed on the α or β axis
Example)
For rapid traverse
Parameter No. 1420, α axis (Fα): 8000 deg/min
β axis (Fβ): 10000 deg/min
Parameter No. 15615, first arm (L1): 120mm
Parameter No. 15616, second arm (L2): 100mm
Fxy = L1×α
= 120×2π/360×8000=16755mm/min
Fyz = L2×Fβ
= 100×2π/360×10000=17453mm/min
Due to the rotation about the α axis, move commands with up to 16.8
mm/min can be issued for the X and Y axes, and due to the rotation
about the β axis, move commands with up to 17.5 mm/min can be
issued for the Y and Z axes.
It is, therefore, necessary to determine the rapid traverse rates on the α
and β axes so that the rapid traverse rates on the individual axes plus
the maximum speeds do not exceed the speed limits for the motors.
With attitude control B, consider this thoroughly when selecting
motors.
To operate the machine tool in the nozzle head fixing mode, specify
the same gain and time constant for the X, Y, Z, α, and β axes. If
different gain and time constants are specified, the axes may not work
well together.
Due to attitude control, the compensation pulses output for the X, Y,
and Z axes change from block to block. Only acceleration/deceleration
after interpolation is effective to these interpolation pulses. It is
necessary to specify a post-interpolation time constant that can
accommodate sufficiently any abrupt compensation pulse changes
between blocks.