
20. FUNCTIONS FOR HIGH SPEED
CUTTING
B–63002EN/01
NC FUNCTION
236
This function pre-reads 15 blocks, and automatically controls the
feedrate.
The feedrate is determined on the basis of the following items. If the
command speed exceeds the feedrate, acceleration/deceleration before
interpolation is executed to reduce the speed.
Change in speed for each axis at the corner, and allowable speed
change specified
Acceleration expected for each axis, and allowable acceleration
specified
Change in cutting load estimated by direction of Z-axis movement
In the automatic velocity control mode, acceleration/deceleration is
executed before interpolation. The speed is then reduced automatically so
that the machine is not shocked much.
Therefore, the time constant for automatic velocity control should be
reduced, and the feed-forward coefficient should be increased. The
machining error caused by delay of acceleration/deceleration or the servo
system is then reduced.
20.6.2
Automatic Velocity
Control Function