The electrical fault diagnosis of CNC deep hole drilling machine has three stages: fault detection, fault judgment, fault isolation and fault location.
The first stage of fault detection is to test the CNC deep hole drilling machine to determine whether there is a fault.
The second stage is to determine the nature of the fault and isolate the fault components or modules.
The third stage is to locate the fault to the replaceable module or printed circuit board to shorten the repair time.
In order to find out the faults of the system immediately, quickly determine the fault location and eliminate it immediately.
It is required that the fault diagnosis should be as small and simple as possible, and the time required for fault diagnosis should be as short as possible.
To do this, the following 8 diagnostic methods you must know to troubleshoot common problems of CNC deep hole drilling machine:
1.Intuitive method
Using the sensory organs, pay attention to various phenomena in case of failure, such as whether there is spark or light, abnormal noise, abnormal heat and smell.
It is a basic and common method to carefully observe the surface condition of each printed circuit board which may be in failure, and if there is any burning or damage trace to further reduce the inspection scope.
2. Self-diagnosis of CNC system
Depending on the ability of the CNC system to process data quickly, multi-channel and fast signal acquisition and processing are carried out for the fault location.
Then, the diagnosis program makes logical analysis and judgment to determine whether the system has any fault and locate the fault immediately.
The self-diagnosis function of the modern CNC system can be divided into two categories:
(1) Startup self-diagnosis and start-up self-diagnosis refers to the function test of the internal diagnosis program of the system before the operation of CPU, memory, bus, i/o unit and other modules, printed circuit board, CRT unit, photoelectric reading machine and floppy disk driver from each power on to the normal operation preparation state, Confirm whether the main hardware of the system can work normally.
(2) The fault information indicates that when the machine tool is in operation, the number and content will be displayed on CRT display. According to the prompt, consult the relevant maintenance manual to confirm the cause of the fault and the troubleshooting method. Generally speaking, the more information of the fault is prompted by the diagnosis function of the NC machine tool, the more convenient it can be to diagnose the fault. However, it should be noted that some faults can directly confirm the cause of the fault according to the prompt of fault content and consulting manual; However, the real cause of some faults is inconsistent with the prompt of fault content, or there are multiple fault reasons in a fault display. This requires the maintenance personnel to find out the internal relationship between them and confirm the cause indirectly.
3.Data and status check
The self-diagnosis of CNC system can not only display fault alarm information on CRT display but also provide machine parameter and status information in the form of multi-page “diagnosis address” and “diagnosis data”.
Common data and status checks include parameter checks and interface checks.
(1) Parameter checking of the machine tool data is an important parameter obtained by a series of tests and adjustments, and it is the guarantee of the normal operation of the machine tool.
These data include gain, acceleration, contour monitoring tolerance, reverse clearance compensation value and screw pitch compensation value. When disturbed by external, data loss or chaos will occur, and the machine tool can not work normally.
(2) Interface check the input/output interface signal between CNC system and deep hole drilling machine, including input/output signal of CNC system and PLC, PLC and machine tool.
The input/output interface diagnosis of the CNC system can display the status of all switch signals on CRT display, and use “1” or “0” to indicate whether the signal is present.
The status display can check whether the CNC system has output the signal to the machine side, whether the switch quantity on the machine side has been input to the CNC system, so that the fault can be located on the machine tool side or in the CNC system.
4.Alarm indicator light display failure
In the CNC system of modern CNC deep hole drilling machine, in addition to the above-mentioned “software” alarm such as self-diagnosis function and status display, there are many “hardware” alarm indicator lights, which are distributed on power supply, servo drive, input/output and other devices.
According to the indication of these alarm lights, the cause of the fault can be judged.
5.Replace the spare plate
It is a quick and simple method to replace the template with the spare circuit board.
It is often used in the function modules of CNC system, such as CRT module and memory module. It is important to note that before replacement of standby board, check the relevant circuit to avoid the damage of the board due to short circuit.
At the same time, check whether the selection switch and jumper wire on the test board are consistent with the original template. Some templates should pay attention to the adjustment of potentiometer on the template. After replacing the memory board, the memory shall be initialized according to the requirements of the system, otherwise the system will not work normally.
6.Exchange method
In CNC deep hole drilling machine, there are modules or units with the same function.
The same modules or units are exchanged with each other, and the fault location can be determined quickly by observing the situation of fault transfer. This method is often used for fault checking of servo feed drive devices, and can also be used for the exchange of the same modules in the CNC system.
7.Percussion method
CNC system consists of various circuit boards, and there will be many welding points on each circuit board.
Any false welding or poor contact may cause failure. When the circuit board, connector or electrical component with the fault point is gently knocked with insulation, if the fault occurs, the fault is likely to be at the knocking part.
8.Measurement comparison
In order to detect conveniently, the module or unit is equipped with detection terminals.
By using a multimeter, oscilloscope, and other instruments, the level or waveform detected by these terminals can be compared with the value of the fault, and the cause and location of the fault can be analyzed.
Because of the comprehensive and complex characteristics of CNC deep hole drilling machines, the factors causing the failure are various.
Sometimes, the above methods should be applied at the same time, and the fault is analyzed comprehensively, and the fault location can be quickly diagnosed, so as to eliminate the fault.
At the same time, some faults are electrical, but the cause is mechanical;
On the contrary, it may be mechanical, but the cause is electrical; Or both.
Therefore, methods of troubleshoot CNC deep hole drilling machines should not only attributed to the electrical or mechanical aspects but also must be considered comprehensively from all aspects.