Gildemeister CTX 400E

[nice-day]

Need help with CNC Gildemeister CTX 400E (year 1994), the main spindle motor is making a horrible noise, so we change the 3 main bearings inside the motor, but we still getting the same noise special when the spindle runs in slow speed 300rpm, we think it’s the main spindle drive, can anyone tell me what that problem and how I can solve it (I tested the motor in a different machine runs good without no noise)

Thanks

[laurensschu]

Does the machine have an automatic chuck?
When not the chuck it's self but the pulling part is even slightly miss aligned it makes a horrible noise or vibration.

[Bill Gorz]

since you have swapped the motor that is eliminated - so its either the drive or the transmission stressing things out. run up the spindle to a couple thousand rpm then shut off the main power to the machine so that the spindle has to coast to a stop. if you still hear the noise the problem is mechanical. If the noise goes away your prob is in the motor controller.