bnp-b2365(eng)b.pdf - 第298页
5. Spindle Adjustment 5 - 53 (5) Synchronous tap cutting operation After adjusting the parameters, mount the tap and wo rkpiece, and carry out actual cutting. Vari ous elements affect the tap cutt ing. Even if the synchr…
5. Spindle Adjustment
5 - 52
(4) Adjusting the parameters
Adjust the following parameters while measuring the synchronous error between the servo and
spindle. The servo axis speed loop gain is valid for all control, so adjust the speed loop gain only
on the spindle side. Adjust mainly the lost motion compensation parameters on the servo side.
When these have already been adjusted when measuring the roundness, etc., they do not need to
be adjusted again. If the acceleration/deceleration is delayed for one of the axes, set the
acceleration feed forward gain for the delayed axis to compensate the synchronous delay.
Spindle adjustment parameters
No. Abbr. Parameter name Details
Setting
range
Standard
SP194 VGTP* Synchronized
tapping control
speed loop gain
proportional term
Set the speed loop proportional gain in synchronized tapping
mode.
0 to 1000 63
SP195 VGTI* Synchronized
tapping control
speed loop gain
integral term
Set the speed loop integral gain in synchronized tapping mode.
0 to 1000 60
SP200 FFCI* Synchronized
tapping control
acceleration feed
forward gain (gear 1)
0
SP201 FFC2* (Gear 2) 0
SP202 FFC3* (Gear 3) 0
SP203 FFC4* (Gear 4)
Set the acceleration feed forward gain for selection of gear 000
during synchronized tapping.
This parameter should be used when an error of relative
position to Z-axis servo is large.
0 to 1000
(%)
0
Spindle adjustment parameters
No. Abbr. Parameter name Details Setting range
FEDCBA98765 4 3 2 10
aflt zrn2 afse ovs lmc omr zrn3 vfct upc vcnt
bit Meaning when set to 0 Meaning when set to 1
8
Set the compensation amount with SV016 (LMC1) and SV041 (LMC2).
9
lmc
00: Lost motion compensation stop
01: Lost motion compensation ty pe 1
10: Lost motion compensation ty pe 2
11: Setting prohibited
SV027 SSF1 Servo function
selection 1
SV016 LMC1 Lost motion
compensation 1
Set the compensation amount based on the stall (rated) current of the motor.
The standard setting is double of the friction torque. Setting to "0" means the
compensation amount is zero.
-1 to 200
(Stall [rated]
current %)
SV041 LMC2 Lost motion
compensation 2
Set this with SV016 (LMC1) only when you wish to set the lost motion
compensation amount to be different depending on the command directions.
Normally, set to "0".
-1 to 200
(Stall [rated]
current %)
SV015 FFC Acceleration rate
feed forward gain
When a relative error in the synchronous control is large, apply this parameter
to the axis that is delaying. The standard setting value is "0". For the SHG
control, set to "100".
To adjust a relative error in acceleration/deceleration, increase the value by
50 to 100 at a time.
0 to 999
(%)
POINT
1. Stop the machine error compensation function (backlash comp ensation,
pitch error compensation, etc.) when measuring the synchronous error.
2. The servo's speed loop gain has an effect on all control, so do not adjust it
for synchronous tap. The spindle parameters are dedicated for synchronous
tap control, so improve the synchronization accuracy by adju sting the spindle
parameters when possible.
CAUTION
The above spindle parameters adjusted when adjusting the synchronou s tap
are all validated when the NC p ower is turned ON again.
5. Spindle Adjustment
5 - 53
(5) Synchronous tap cutting operation
After adjusting the parameters, mount the tap and workpiece, and carry out actual cutting. Various
elements affect the tap cutting. Even if the synchronous accuracy (electrical accuracy) is good up
to this point, it may not enable cutting with a sufficient accuracy. Check the items in the following
table and improve the cutting accuracy.
Investigation items for improving cutting accuracy
Investigation item Remedy
Use a spiral tape (recommended) with good cutting chip discharge
performance
1. The cutting chip discharge is poor (cutting
chips get caught)
Adjust the cutting speed to an appropriate value
2. The tap cutting performance is poor Replace the tap
3. The tap hole diameter is too large Set the tap hole diameter to an appropriate size
4. The spindle PLG waveform adjustment is
insufficient
Readjust the offset and gain
5. The servo axis backlash compensation
amount is incorrect
Adjust the backlash compensation amount
6. The servo axis pitch error compensation
amount is incorrect
Adjust the pitch error compensation amount
7. The acceleration/deceleration time constant is
short
Increase the acceleration/deceleration time constant to improve the
accuracy
8. The tap depth is too deep for the tap diameter Set the tap depth to up to 3-times the tap diameter
9. The spindle center deviates Check the tap mounting state
10. The spindle backlash is too large Improve the machine side
11. The spindle load inertia is too large (3-times or
more)
Try using fixed position loop excitation (SP193/bit3 = 1)
Note that vibration noise will be generated easily
12. The cutting load is large (50% or more)
The tap hole is too small → Check the tap mounting state
The spindle center deviates → Check the tap mounting state
The tap cutting performance is poor → Replace the tap
Try using fixed position loop excitation (SP193/bit3 = 1)
If the tap breaks, investigate the following items.
Investigation items when tap breaks
Investigation item Remedy
1. The program's screw pitch and tap pitch do not
match.
Set the program to the tap.
2. The tap center deviation is large Check the accuracy of the spindle and the tap mounting state
3. The tap hole is too shallow Drill the tap hole to an appropriate depth
4. The tap hole is too small Drill the tap hole to an appropriate size
5. Spindle Adjustment
5 - 54
5-3-5 Adjusting the C-axis control
(1) Confirming the default parameters
Confirm that the parameters are correctly set according to the machine specifications. When
carrying out interpolation control with the servo axis, set the following parameters according to the
servo axis specifications.
(a) Position loop gain
When carrying out interpolation control with the servo axis using C-axis control, the C-axis
control and position loop gain for each mode must be set to match the servo axis used for
interpolation control. During C-axis control in this case, the operation is always controlled with
the same position loop gain.
C-axis non-cutting position loop gain SP003 = SV003
First position loop gain for cutting on C-axis SP130 = SV003
Second position loop gain for cutting on C-axi s SP131 = SV003
Third position loop gain for cutting on C-axis SP132 = SV003
Stop position loop gain for cutting on C-axis SP133 = SV003
C-axis position loop gain 2 SP165 = SV004
C-axis position loop gain 3 SP166 = SV057
(b) High-gain servo synchronous compensation
Set C-axis control specification SP129/bit3 according to the specifications of the servo drive
unit used for interpolation control with C-axis control.
Synchronous compensation valid = High-gain servo:
MDS-C1-V1/V2 (for high-gain setting), MDS-B-V14/V24
Synchronous compensation invalid = Standard servo:
MDS-C1-V1/V2 (for st andard setting), MDS-B-V1/V2, MDS-B-SVJ2
(2) Gain parameters
The position loop gain and speed loop gain can be set according to each control state. Note that
when using SHG cont rol for C-axis control, or when carryin g out interpolation control with the servo
axis, the same value must be set in the position loop gain (SP003, SP130, SP131, SP132, SP133)
for each control state.
Gain parameter settings for C-axis control
Control state
Parameter
During
non-cutting
(rapid traverse)
No.1 gain
selection for
cutting control
No.2 gain
selection for
cutting control
No.3 gain
selection for
cutting control
When cutting
is stopped
Speed loop proportional gain SP134 SP137 SP140 SP143 SP146
Speed loop integral gain SP135 SP138 SP141 SP144 SP147
Speed loop delay compensation SP136 SP139 SP142 SP145 SP148
Position loop gain SP003 SP130 SP131 SP132 SP133
Position loop gain 2 SP165
Position loop gain 3 SP166
POINT
In order to perform C-axis interpolation with the servo axis, the position loop gain
settings for e a ch C-axis control mode must match that of the servo axis where
interpolation occurs. If the servo axis is performing SHG control, the SP165 and
SP166 settings apply to all control modes. Therefore, the position loop gain values
for each control mode (SP003, SP130, SP131, SP132 and SP133) must be th e same
as the position loop gain (SV003) for all the servo axes.