Mitsubishi MELDAS MDS-C1 Instruction Manual page 239

(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
1. The cutting chip discharge is poor (cutting
chips get caught)
2. The tap cutting performance is poor
3. The tap hole diameter is too large
4. The spindle PLG waveform adjustment is
insufficient
5. The servo axis backlash compensation
amount is incorrect
6. The servo axis pitch error compensation
amount is incorrect
7. The acceleration/deceleration time constant is
short
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
10. The spindle backlash is too large
11. The spindle load inertia is too large (3-times or
more)
12. The cutting load is large (50% or more)
If the tap breaks, investigate the following items.
Investigation item
1. The program's screw pitch and tap pitch do not
match.
2. The tap center deviation is large
3. The tap hole is too shallow
4. The tap hole is too small
5. Spindle Adjustment
Use a spiral tape (recommended) with good cutting chip discharge
performance
Adjust the cutting speed to an appropriate value
Replace the tap
Set the tap hole diameter to an appropriate size
Readjust the offset and gain
Adjust the backlash compensation amount
Adjust the pitch error compensation amount
Increase the acceleration/deceleration time constant to improve the
accuracy
Check the tap mounting state
Improve the machine side
Try using fixed position loop excitation (SP193.bit3 = 1)
Note that vibration noise will be generated easily
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)
Investigation items when tap breaks
Set the program to the tap.
Check the accuracy of the spindle and the tap mounting state
Drill the tap hole to an appropriate depth
Drill the tap hole to an appropriate size
5 - 29
Remedy
Remedy