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First, CNC machining center for spindle maintenance before preparation
The spindle speed is not normal, that is, after the spindle is given the speed instruction, the CNC machining center machine tool feedback speed is not consistent with the speed of the instruction (generally less than the instruction speed) or the spindle is not smooth, there is an abnormal "squeak" sound, when fast and slow, and in some cases, the motor may even appear overcurrent alarm.
In the case of encoder feedback, the speed instruction "S" given by the CNC machining center machine tool is followed by a number, that is, the value that will be fed back to the system display is consistent. The main shaft drive can be belt drive or gear drive, now most of them are synchronous belt drive, the speed is not normal, it may be because the synchronous installation is too long, so the belt slip lost step.
At the same time, the connection between the spindle and the spindle encoder is also made with a synchronization belt, and there is also the possibility of losing steps in this link. The lubrication of the main shaft is not good or any bearing on the main shaft is burned out, resulting in excessive machine resistance and making the main shaft not rotate smoothly. And external signal interference can also cause this phenomenon.
Second, CNC machining center repair survey.
The machining center runs in empty, only goes in one direction or reverses at a low spindle speed, and the loss of the spindle speed is not obvious, but it is more obvious when the reversing movement of the spindle shaft is fast or when the cutting material is cut, especially when the loss of step is large.
Third, analyze the reasons
1. The signal sent from the CNC machining center system to the spindle servo amplifier (inverter) is dried during transmission;
2. The circuit voltage is unstable;
3. The synchronization belt to transmit to the spindle must be too long or worn to cause sliding;
4. The synchronization belt between the connecting spindle and the spindle encoder is too long or worn to cause sliding;
5. The signal line between the encoder and the servo amplifier or the system is subjected to the signal external dry;
6. The two groups of bearings supporting the main shaft are burnt out;
7. CNC machining center spindle lubrication is poor.
4, determine the steps, check the CNC machining center spindle failure
1. Use a multimeter to measure the power voltage of the CNC machining center, and find that the voltage is normal, and the other machine tools next to the same power grid work normally, you can eliminate the cause of voltage instability;
2. Check that the amount of lubricating oil of the CNC machining center machine tool is within the normal working range, the lubrication system works normally, the oil circuit has no oil leakage and other faults, and the fault of lubrication is eliminated;
3. There is no problem with lubrication, which may be caused by poor bearing movement, when the spindle of the CNC machining center is running, a long rod (usually a screw) is leaned on the approximate position of the spindle box installation bearing, and a (large one) is leaned on the ears of the maintenance personnel to listen to the sound of the bearing running. It sounds that there is no abnormal sound, and the possibility of the bearing causing the fault can be ruled out. ;
4. If there is no problem with the lubrication of the CNC machining center, the problem may be in the interior of the headstock. Open the interior of the headstock, check the synchronization belt connection between the spindle motor and the spindle, and press the belt between the two belt wheels by hand. ;
5. There is no problem in the synchronous belt connection between the motor and the spindle. When checking the synchronous belt between the spindle and the encoder, it is found that the synchronous belt has been seriously worn. After replacing the new synchronous belt, the system shows that the spindle speed is normal. In the process of machining, the spindle speed has an abnormal phenomenon, the speed displayed by the system is unstable, and the time is fast and the time is slow.
