The control system of CNC lathes is very intelligent, and all of them are designed with fault self-diagnosis. Under normal circumstances, alarm information appears when a fault occurs. According to the fault handling method in the manual, most faults can find a solution. There are some faults in the use of the machine tool, that is, no alarm, and the phenomenon is not obvious. In this case, it is not as simple as it is well documented. Some machine tools are more difficult to handle after a failure in use, if the workpiece is scrapped in batches if it is not noticed. For such fault handling, when the maintenance personnel lack certain work experience, the handling often makes a wrong judgment, causing unnecessary economic loss or prolonging the repair time. In order to find out the cause of such failures, we must first find out the real phenomenon from the various surface phenomena that are criss-crossed (this "phenomenon" is the real situation of the fault), and then find out the occurrence from the confirmed fault phenomenon. s reason.
1. The fault occurs when it appears in normal work or just after booting.
2. The number of occurrences is the first time or has occurred many times.
3. Confirm that the machining program of the machine tool is not wrong.
4. Has the other personnel repaired or adjusted the machine tool?
The following are some of the processing analysis methods that we encounter in the maintenance without alarm failure, for reference.
Fault 1: In the use of the CNC lathe, the manual movement is normal, and the automatic movement returns to zero after moving a certain distance, and the manual movement is normal again. The lathe uses economical numerical control, stepping motor, manual movement, because the speed is slightly slower, and the automatic moving back to zero, the fast moving distance is long, and the mechanical jam occurs. Analysis based on failures, mainly for mechanical reasons. Such failures often occur without paying attention to the repairs, so attention should be paid to the work to avoid this phenomenon.
Fault 2: The machine screen is not displayed after booting. To eliminate this type of fault, the first thing is to make the screen work properly. Sometimes it's just the reason for the display part. But in many cases, there may be multiple failures. The power switch on the operation panel of a FANUC SERIESO-TD system has been pressed. The red and green lights are on. Check that the switches and main parts of the cabinet are not abnormal. All the control circuits have no problem. Re-open after shutdown and the fault is the same. After investigation, due to the poor working environment, the ground wire of the machine tool was loose, causing static electricity to cause this failure. After the ground wire is connected, press the MODE1 mode to start the system is normal.
Fault 3: The same lathe is controlled by FANUC SERIESO-TD system. No matter the normal startup, the default data is activated or the stored data is started. After power-on, the normal operation screen display cannot be displayed. The reason for the failure is that the plc user appears after downloading. When the ECU has not written the PLC program from the static memory to the FLASH, the ECU is powered off, and the PLC user program cannot be started by the power-off method. The CPU user program in the plc programming software must be used to start the downloaded PLC user program to destroy the ECU. After replacing the ECU module, the system is in normal condition.
Fault 4: In the numerical control equipment, the most error-free machine tool error or size error occurs. For example, when a CNC lathe appears in the diameter direction, it is more likely to be small. The cause of this failure is generally that the coupling structure of the lead screw and the motor has different frequency and possibility of failure, and the phenomenon is different after the failure. Some sizes will only increase in the negative direction, but some are positive and negative. The possibility of change in direction will occur. According to experience, the elastic coupling in the middle of the coupling is basically a negative increase, and both faults in the middle using the key connection will occur.
Fault five JBNC320B teaching CNC lathe, in the process of turning the thread, the thread is deducted. I thought it was a problem with the system software. After the original software is deleted, the system is reinstalled, and the system failure is still not eliminated. The post-analysis may be a mechanical failure. After opening the cover, it is found that the mechanical connection between the spindle and the spindle encoder is loose. After re-correcting and fixing, the fault is eliminated.
Fault six FANUC SERIESO-TD system controls a lathe. After the system is started, the stepper motor does not work, but the screen display position is changing, and the green LED marked with RDY is driven on the drive. By analyzing the search, it is an operation error, and the system also works in the program test PRT mode one. After canceling this mode, the fault is eliminated. This type of failure is sometimes caused by a drive failure. Therefore, we must carefully analyze and treat it correctly.
In short, the no-alarm failure in CNC lathes is mostly caused by some comprehensive factors. In the repair of CNC lathes, the experience of judging the faults in this aspect can only be adapted to the maintenance work of modern industrial new equipments by groping in practice, continuously summarizing and continuously improving.
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