When the AC servo motor is feeding, the movement phenomenon occurs, and the speed measurement signal is unstable, such as the encoder has cracks; the connection terminals are in poor contact, such as loose screws; is generally caused by the backlash of the feed drive chain or the excessive servo drive gain.
Most of them occur in the starting acceleration section or low-speed feed, generally due to the poor lubrication state of the feed transmission chain, low servo system gain and excessive external load.
In particular, it should be noted that the coupling used for the connection of the AC servo motor and the ball screw, due to the loose connection or the defects of the coupling itself, such as cracks, etc., cause the rotation of the ball screw and the servo motor to be out of synchronization, so that the feed movement is suddenly fast and slow.
When the machine tool is running at high speed, vibration may occur, and an overcurrent alarm will be generated at this time. Machine tool vibration problems are generally speed problems, so we should look for speed loop problems.
As a famous ac servo motor manufacturer, he would manufacture his own series of AC servo motors and servo drives,and constantly improve his products, but these equipments still need to be checked before people use them.When the servo motor runs from the rated locked-rotor torque to high-speed operation, it is found that the torque will suddenly decrease, which is caused by the heat dissipation damage of the motor winding and the heating of the mechanical part. At high speed, the temperature rise of the motor increases, so the load of the motor must be checked before using the servo motor correctly.
When the movement of the servo axis exceeds the position tolerance range, the servo drive will display the position out-of-tolerance alarm of No. 4. The main reasons are: the tolerance range set by the system is small; the gain of the servo system is not set properly; the position detection device is polluted; the cumulative error of the feed transmission chain is too large.
In addition to connecting the pulse + direction signal, the CNC system to the servo driver also has an enabling control signal, which is generally DC+24V relay coil voltage.
If the servo motor does not rotate, the common diagnostic methods are: check whether the numerical control system has pulse signal output; check whether the enable signal is connected; observe whether the input/output status of the system meets the starting conditions of the feed axis through the LCD screen; The servo motor confirms that the brake has been opened; the drive is faulty; the servo motor is faulty; the coupling between the servo motor and the ball screw connection fails or the key is disengaged, etc.