
B-65150E/04 3. α SERIES PARAMETER ADJUSTMENT
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3.4.2 Cutting Feed/Rapid Traverse Switchable Function
(1) Overview
For cutting figure improvement, the setting of higher position loop and
velocity loop gains is useful. In general, however, a higher maximum
feedrate and higher acceleration for acceleration/deceleration are used
in rapid traverse, compared with cutting feed. This means that those
settings that achieve stable operation in cutting feed can cause velocity
loop vibration and position loop hunting in rapid traverse. To avoid
such trouble, a function for parameter switching between cutting feed
and rapid traverse for the functions indicated below is available.
Fig. 3.4.2 Parameters switchable between cutting feed and rapid traverse
(2) Setting procedure
<1> Velocity loop gain
If acceleration in rapid traverse causes TCMD saturation, the
velocity loop tends to oscillate at the end of acceleration in rapid
traverse. Some machine systems tend to oscillate at a higher
frequency when a higher feedrate is used. In such cases, gain
switching between cutting feed and rapid traverse is effective.
If the cutting feed/rapid traverse switchable velocity loop gain
function is set, the conventional velocity gain is used for rapid
traverse, and an overridden value is used for cutting feed. Usually,
an override value of 150% to 200% is set. If vibration occurs only
when the machine stops, use the function for changing the
proportional gain in the stop state. (With Series 90A0, the
function for changing the proportional gain in the stop state and
the velocity loop proportional high-speed processing function can
be used at the same time.)
+
+
Fine
acceleration/
deceleration
time constant
Velocity
loop gain
Feed-
forward
coefficient
TCMD
filter
+
Velocity
feed-forward
coefficient
NOTE
1 The TCMD filter and vibration suppression filter can
be used at the same time by parameter setting.
2 The cutting feed/rapid traverse switchable function
is not usable for the vibration suppression filter.
3 With the Series 15-B, the cutting feed/rapid traverse
switchable function is not usable.