Automatic CNC Machine is composed of machine, electrical and hydraulic three parts, the operation needs the basis of relevant technology and knowledge, master the common fault diagnosis and maintenance technology of CNC lathe can reduce daily maintenance costs. Avoid the occurrence of serious mechanical accidents, but also to extend the service life of the lathe. CNC lathe PLC in the operation process has the following common failures, in the work for the failure to take the following corresponding measures to avoid the occurrence of serious mechanical accidents, but also to extend the service life of the lathe.
1, the power grid fluctuation is too large PLC does not work
The PLC has no output. First check the input signal (power signal, interference signal, command signal and feedback signal). The observation method is used to check the voltage waveform of the power grid with an oscilloscope, and it is found that the voltage fluctuation of the power grid is too large, and the duration of the under-voltage noise jump is greater than 1s. Since the Automatic CNC Machine is in the debugging stage, the formation faults in the unit system should be excluded, which can be seen from the interference measures of the internal power grid (filtering, isolation, voltage regulation). The conventional power supply system has been unable to cut off or filter out the undervoltage noise of the grid for a long time, which is caused by insufficient anti-grid measures (internal causes), resulting in PLC not working normally.
2. Electromagnetic interference
Electromagnetic interference failure often occurs in the new machine tool debugging stage frequent machine shutdown, but can work, can exclude the parameter confusion and components caused by internal causes, the possible cause is the electromagnetic interference of the power grid or the environment, resulting in system instability, the external cause is the frequency conversion inductive interference source. This is the capacity of the selected components is too small, too large grid interference pulse, so that the inductor inside the filter appears magnetic saturation, can not filter the high-frequency interference pulse. A 2.2mF capacitor is connected in parallel between the system power input lines, that is, an absorption network is added, and the fault is removed.
3. PLC-MD parameter failure
The fault occurs in the debugging stage, when the Automatic CNC Machine returns to zero operation, it can only move in the negative direction along the rail axis, and the overrange alarm will appear when it moves normally. First check whether the parameter setting table is out of order, and then use the parameter modification method.
Treatment method:
① Turn OFF the alarm soft key (OFF), and restore the alarm soft key ON after the operation is returned to zero;
② Temporarily change the soft limit parameter (143) to +999999 and restore the original value after the operation is returned to zero. Both processing methods can be removed after restarting the machine.
Note: In the actual zero return operation, the overrange alarm is generated by hitting the stroke switch, and the "reset method" is not allowed to be used, in order to prevent the accuracy of the Automatic CNC Machine from being damaged by hitting again.
Automatic CNC Machine https://www.zjshuangzheng.com/Fully-Automatic-CNC-Machine-Category
