Industry News

Methods for determining the cause of CNC machine failure

2020-03-07
First, the intuitive method
It is to use human senses to pay attention to the phenomenon when a failure occurs and determine the possible parts of the failure. If there are any abnormal sounds, sparks, burnt spots, and abnormal heat when there is a fault, then further observe the surface condition of each circuit board that may fail, such as Burned, blackened or cracked electronic components to further reduce the scope of inspection. This is a basic and simple method, but it requires machine tool maintenance personnel to have some maintenance experience.
Second, use the hardware alarm function of the CNC system
The alarm indicator can judge the fault location. There are many alarm indicators on the hardware circuit board of the numerical control system, which can roughly determine the location of the fault.
Third, make full use of the software alarm function of the CNC system
The CNC system has self-diagnostic function. The system can be quickly diagnosed with self-diagnostic programs during system operation. Once a fault is detected, the fault is immediately displayed on the form screen in an alarm mode or each alarm light is lit. During maintenance, you can find the fault of the machine tool according to the alarm content prompt.
Ⅳ.Using the diagnostic function of status display
The CNC system can not only display the fault diagnosis information, but also provide various statuses of machine tool diagnosis in the form of diagnosis address and diagnosis data, for example, the input / output signal status of the interface between the system and the machine tool, or PC and CNC The status of the input / output signals at the interface between the device and the PC and the machine tool can be used to check whether the CNC system has input signals to the machine tool or whether the switch information of the machine tool has been input to the CNC system. . In short, the fault can be distinguished whether it is on the machine tool side or the CNC system side, so that the inspection range of the CNC machine tool fault can be reduced.
5. Check the CNC system parameters in time when a failure occurs
Changes in system parameters will directly affect the performance of the machine tool, and even cause the machine tool to fail, and the entire machine tool will not work. And external interference may cause changes in individual parameters in the memory. It seems that when the machine tool has some inexplicable failure, the parameters of the CNC system can be checked.
6. Replacement of spare parts
When the failure of the machine tool is analyzed and it is found that the circuit board may be faulty, it can be replaced with a spare part board, and the faulty circuit board can be quickly identified. However, you need to pay attention to the following two points when using this method: ① Pay attention to the positions of the adjustable switches on the circuit board. When changing the board, pay attention to make the setting status of the two circuit boards that are exchanged exactly the same, otherwise it will cause The system is unstable or not in good condition, and even an alarm occurs. ② After replacing some circuit boards (such as CCU board), it is necessary to reset or input the parameters and programs of the machine tool.
VII.Using the detection terminal on the circuit board
There are detection terminals on the circuit board for measuring the voltage and waveform of the circuit, so as to determine whether the part of the circuit works normally during debugging and maintenance. But when testing this part of the circuit, you should be familiar with the circuit principle and the logical relationship of the circuit. In the case of unfamiliar logical relationships, two identical circuit boards can be used for comparison to detect the failure of the circuit board.
In short, when a CNC machine fails, following the above detection steps and methods can correctly determine the cause and location of the fault.

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