Mitsubishi MELDAS HS Series Specifications And Instruction Manual page 89

No. Abbrev. Parameter name
SV039 LMCD Lost motion
compensation timing
When the LMCD is gradually raised, a two-peaked contour may occur at the motor FB position
DBB measurement. However, due to the influence of the cutter diameter in cutting such as end
milling, the actual cutting surface becomes smooth.
Because satisfactory cutting can be achieved even if this two-peaked contour occurs, consider
the point where the protrusion becomes the smallest and finest possible without over
compensating (bite-in) as the optimum setting.
Cutter center path
Actual cutting surface
(4) Adjusting for feed forward control
In LMC compensation, a model position considering the position loop gain is calculated based on
the position command sent from the CNC, and compensation is carried out when the feed
changes to that direction. When the CNC carries out feed forward (fwd) control, overshooting
equivalent to the operation fraction unit occurs in the position commands, and the timing of the
model position direction change may be mistaken. As a result, the LMC compensation timing
may deviate, or compensation may be carried out twice.
If feed forward control is carried out and the compensation does not operate correctly, adjust with
the non-sensitive band (SV040: LMCT) during feed forward control. In this non-sensitive band
control, overshooting of a set width or less is ignored. The model position direction change point
is correctly recognized, and the LMC compensation is correctly executed.
This parameter is meaningless when feed forward control is not being carried out.
<Adjustment method>
If the compensation timing deviates during feed forward control, increase the LMCT setting by
1µm at a time.
Note that 2µm are set even when the LMCT is set to 0.
No. Abbrev. Parameter name
SV040 LMCT Non-sensitive band
during feed forward
control
POINT
Chapter 8 Adjustment
Unit
Set this when the lost motion compensation timing does not
msec
match. Adjust while increasing the value by 10 at a time.
Quadrant changeover point
Cutter diameter
Cutting direction
Unit
µm
This setting is valid only during feed forward control.
2 µm is set when this is set to 0. Adjust by increasing the value
by 1 µm at a time.
Setting of the non-sensitive band (SV040: LMCT) during feed forward control
is effective for improving overshooting compensation mis-operation during
feed forward control.
Explanation
Point of LMC compensation execution
Explanation
8–22
Setting range
0 to 2000
Setting range
0 to 100