Fault Diagnosis and Repair of CNC Machine Tool
Computer numerical control (CNC) machine tool has become a necessary tool for many manufacturing processes. It is widely used in the precision machining, parts processing and assembly of electronic, electrical, Mechanical and microelectronic products. As an important part of production equipment, CNC machine tool plays an irreplaceable role in modern production, but because of its complex structure and high demand for accuracy, it often encounters problems in use and requires timely maintenance and repair.
In the case of CNC machine tool, especially in the absence of alarm fault, the fault diagnosis and repair is even more difficult. In order to improve the fault diagnosis and repair technology of CNC machine tool, the repair process must first start from the part testing.
1. Part Testing
Part testing is an important part of fault diagnosis and repair. Through the part testing, the fault is preliminarily judged, and the fault point and working condition are obtained. When testing, pay attention to the test is carried out in the living environment, in order to reduce the interference, pay attention to the grounding.
The fault diagnosis and repair of CNC machine tool is the overall test, the individual fault test and the electro-mechanical system test. When testing, the fault parts to be tested, the test range and order should be determined according to the symptoms, and then the parts in the test range should be tested one by one in order to avoid time waste and wrong decision.
2. Overall Test
In the overall test process, firstly, all the conditions of the machine should be checked, including the power supply and the other control systems connected with the CNC machine tool. The connection sketch should be checked and the power supply indicator should be inspected. Then the printer should be tested. This is because for the fault of CNC machine tool, the printing information output often provides a lot of useful information for fault judgment.
In addition to these, the gears and positioning stops of the machine should also be tested in the overall test process. In general, the lubrication system should also be tested. The good lubrication condition of this part is important for the smooth operation of the CNC machine tool. The last step of the overall test is to check the safety device.
3.Individual Fault Test
When the general working condition of the CNC machine tool is normal and there is no obvious fault, it is necessary to carry out a more detailed Fault test. This is to test the parts and components of the machine individually and confirm the fault parts.
When conducting individual fault tests, the mutual connection between the parts and the correspondence between the parts and the control circuit should be considered first. In addition, when checking the connection between the individual parts and the control system, the correct connection should be checked first, because if the connection is disconnected, some faults can also occur.
Then pay attention to the capacitor, because the capacitor is not involved in the continuous conduction process and its function is to provide a certain amount of energy, and its fault is accompanied by a certain transition process. Therefore, during the inspection process, it is very important to pay attention to the role of the capacitor. The fault of the capacitor will affect the normal operation of the CNC machine tool.
Next is to check the oscillator on the CNC machine tool. If the oscillator is disrupted, some of the components in the main control system will work intermittently or stop; so pay attention to the oscillator when testing.
Then check the logic circuit and memory circuit. These two circuits are important components of the control system and can affect the normal operation of the CNC machine tool. Good maintenance of these two items is also important.
4. Electro-mechanical System Test
The electro-mechanical system test is carried out for the parts requiring mechanical force characteristics in the CNC machine tools. These mechanical parts are quite vulnerable. The electrical signals can be fed back to the control system for judgement, so it is necessary to pay attention to the electromechanical system in the test.
Specifically, it includes testing the position detection device and the various indicators used to detect the mechanical part. If a fault occurs, it will form a conflict between the system and the control signal, resulting in an abnormal operation condition of the CNC machine tool. Then the lubricating oil filter should be checked. If there is too much impurity in the lubricating oil, it will increase the wear of parts, and even cause lubrication failure, thus affecting the normal operation of CNC machine tool.
Finally, if the mechanical components have worn out, the contact parts should be tested. The contact parts are mainly composed of bearings, motor, power and signal lines and other parts. After the above test, the results will be compared with the theoretical value, and the fault can be judged with the deviation.
Through the above comprehensive diagnosis and comprehensive tests, it is possible to accurately locate the fault source and components of the CNC machine tool, and then perform the corresponding fault judgment and repair.
