When the spindle servo system fails, there are usually three forms of expression:
One is to display alarm information or alarm content on the CRT or operation panel;
The second is to display the fault of the spindle drive device with the alarm light digital tube on the spindle drive device;
Third, the spindle does not work properly, but there is no alarm information. The common faults of the spindle servo system are:
1. External interference Due to electromagnetic interference, poor shielding and grounding measures, the spindle speed command signal or feedback signal is disturbed, causing random and irregular fluctuations in the spindle drive. The method for discriminating whether there is interference is: when the spindle speed command is zero, the spindle still reciprocates, and adjusting the zero speed balance and drift compensation cannot eliminate the fault.
2, overload cutting usage is too large, frequent positive, reverse, etc. can cause overload alarm. The specific performance is that the spindle motor is overheated, the spindle drive is displayed, and the overcurrent alarm is displayed.
3, spindle positioning jitter spindle quasi-stop for tool exchange, fine retraction and gear shifting, etc., there are three ways to achieve:
(1) Mechanical quasi-stop control (2) Electrical quasi-stop control of magnetic sensor (3) Encoder type quasi-stop control
4. Spindle speed and feed mismatch When performing thread cutting or cutting with the feed per revolution command, there will be a failure to stop the feed and the spindle continues to run. To execute the feed per revolution command, the spindle must have a feedback signal for one revolution per revolution. In general, there is a problem with the spindle encoder.
This can be determined by the following methods:
1. The CRT screen has an alarm display.
2. Call the machine data or I/O status through the CRT to observe the signal status of the encoder.
3. Execute the program with the feed command per minute instead of the feed per revolution to see if the fault disappears.
5. Deviation from the command value When the spindle speed exceeds the range specified by the technical requirements, consider:
1. The motor is overloaded.
2. The spindle speed analog output (usually 0-+-10V) output by the CNC system does not reach the value corresponding to the speed command.
3. The speed measuring device has a fault or the speed feedback signal is broken.
4. The spindle drive unit is faulty.
6. The abnormal noise and vibration of the main shaft must first distinguish between abnormal noise and vibration occurring in the mechanical part of the main shaft or in the electric drive part.
1. The occurrence of the deceleration process is generally caused by the drive device, such as the regenerative circuit failure in the AC drive.
2. Produced at constant speed, can be distinguished by observing whether there is noise and vibration during the free stop of the spindle motor. If it exists, there is a problem with the mechanical part of the spindle.
3. Check if the vibration period is related to the speed. If it is not relevant, generally the spindle drive unit is not adjusted; if relevant, it should be checked whether the mechanical part of the spindle is good and the speed measuring device is defective.
7, the spindle motor does not turn
In addition to the speed analog control signal, the CNC system to the spindle drive has an enable control signal, typically a DC+24V relay coil voltage.
1. Check if the CNC system has a speed control signal output.
2. Check if the signal can be turned on. Observe the I/O status through the CRT and analyze the machine tool plc graph (or flow chart) to determine whether the spindle start conditions, such as lubrication, cooling, etc., are met.
3. The spindle drive unit is faulty.
4. The spindle motor is faulty.
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