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4. Servo Adjustment
4 - 27
(5) Setting and adjusting LMC compensation type 3
LCM compensation type 3 can be used to accommodate quadrant projection changes that
accompany feed rate and circular radius changes which could not be accommodated by LCM
compensation type 2. In this case, on a machine model where the travel direction is reversed, the
viscosity component is also considered in addition to the friction, with compensation occurring in
accordance with the changes in the cutting conditions.
Adjust Compensation parameter (SV016, SV041), a basis of compensation, while measuring
roundness at low speed. Then adjust viscous coefficient (SV086) while measuring roundness at
high speed.
LMC compensation type 3 parameter adjustments should be made while performing a machine
end roundness measurement such as a DDB measurement, etc.
<Adjustment method>
[1] Set the bit1=1 to servo function selection 5 (SV082). (The LMC compensation type 3 will start).
[2] Set a value double the friction torque to the lost motion compensation 1 (SV016). The SV016 setting
value will be used for compensation in the positive and negative directions when the lost motion
compensation 2 (SV041) is 0.
[3] Set the initial value, 1000 to the lost motion compensation viscous coefficient (SV086).
[4] Perform a roundness measurement at such speed as radius R=100mm and feedrate F=1000mm/min
and adjust SV016 value.
[5] Set SV041, when changing the compensation amount in the direction for compensation. The setting
of the compensation direction is shown below with the setting of CW/CCW in the NC parameter. If
compensating only one direction, set –1 to the side not to be compensated.
Compensation
point
CW CCW
A X axis: SV041 X axis: SV016
B Y axis: SV016 Y axis: SV041
C X axis: SV016 X axis: SV041
D Y axis: SV041 Y axis: SV016
[6] Perform a roundness measurement at such speed as radius, R=100mm and feedrate,
F=5000mm/min. (Select a condition to be used for the actual cutting according to the machine's
specification.) Adjust viscous coefficient (SV086) by reducing it gradually to have minimum quadrant
protrusion.
[7] After adjusting SV086, verify its accuracy by performing roundness measurement at low speed again.
POINT
1. As the acceleration of circular feed increases, the quadrant protrusion tends to
get larger. Therefore, the quadrant protrusion gets larger as the circular feedrate
increases for the same radius and as radius gets smaller for the same feedrate.
2. Torque offset (SV032) does not work for LMC compensation type 3.
3. Always set 0 to the lost motion compensation timing (SV039:LMCD).
+Y
-Y
+X
-X
A
The X axis command direction
chan
g
es from + to -.
D
The Y axis command direction
changes from + to -.
B
The Y axis command direction
changes from - to +.
C
The X axis command direction
changes from - to +.