Common fault diagnosis and maintenance of CNC machining center machine tools

1. Composition of CNC machining center machine tools

Numerical control machine tools generally consist of input and output devices, numerical control devices (or numerical control units), spindle units, servo units, driving devices (or execution mechanisms), programmable controllers (PLC), electrical control devices, auxiliary devices, and measuring devices. In CNC machining centers, the CNC device is the core of the CNC system, directly related to the overall operation quality of the CNC machine tool. Therefore, in the application process of CNC machining center machine tools, emphasis should be placed on strengthening the diagnosis and inspection of these devices, timely discovering vulnerabilities and defects in the system, and adopting targeted maintenance plans.

In the practical application of CNC machining centers, the input and output devices are transmission terminals, and operators can judge the processing information through such devices. At the same time, they can be used for programming, storing, printing, and displaying part machining programs or displaying machining information of the machine tool. The CNC machining center machine tool is a comprehensive system that includes diverse devices. Different devices interact and are interrelated in order to effectively achieve system functions and truly improve system integrity. However, precisely because of this, CNC machining center machines are often prone to various malfunctions in practical applications, resulting in uneven quality of components and seriously affecting the overall operational efficiency of CNC machining center machines.

2. Common types of faults in CNC machine tools

The common faults of CNC machining center machines mainly include the following content.

2.1 System malfunction

In the application process of CNC machining centers, system failures are a common type of failure. The main reason why CNC machine tools experience system failures is due to the influence of their own conditions or related components exceeding the usage standards. For example, if there is a leakage problem in the cooling system, during long-term use, the cooling system will experience severe leakage under high loads and pressures, which will cause serious heating phenomena in the actual operation of the CNC machining center machine tool. The system response will become slow, and the machining accuracy will also be reduced. Under more serious conditions, it is also easy to cause the CNC machining center machine tool system to alarm, and even automatically stop for protection. For example, during the movement of different axes, they may exceed the specified range. In the case of exceeding the motion limit, the CNC machining center machine tool will also display an over travel alarm. Based on this, in the actual application process of CNC machining center machine tools, maintenance and management should be strengthened, various faults in the system should be detected in a timely manner, scientific and effective measures should be taken, faults should be eliminated in a timely manner, and the overall safety and reliability of the system should be guaranteed.

2.2 Random faults

In the practical application process of CNC machining centers, the occurrence of random faults is also quite common. But random failures may not occur as frequently as system failures, nor as inevitably as system failures. The former belongs to accidental failures. It is only possible to occur under certain conditions. Therefore, in the application process of CNC machine tools, it is difficult to analyze and judge the causes of random faults in advance, and take preventive measures. The reason why random failures are prone to occur may be related to the setting of certain key parameters, the quality of the working environment, or the operating procedures and skills of the operators. For example, if connectors and connecting components are not locked due to negligence, relay contacts, and the performance of various switch sockets is reduced, it may cause random failures of CNC machining center machines.

2.3 Alarm display failure

In the application process of CNC machining centers, alarm display faults are also quite common. CNC machine tools are composed of different software and hardware. If there is a software or hardware malfunction, an alarm display will be displayed. Most hardware equipment of CNC machine tools have automatic alarm devices. However, any abnormal situation in the hardware equipment, or exceeding the normal value specified for use, will trigger the alarm device of the CNC machine tool hardware device, causing the warning light to light up. During the operation of CNC machine tools, software equipment will also display alarm prompts. For example, errors in the machining program of the CNC system, incorrect or missing settings of system programs and parameters, errors in computer calculations, and so on. Compared to other faults, this type of fault will provide clear prompts and reminders to attract the attention of operators. When such clear faults occur in the application of CNC machine tools, targeted diagnosis and maintenance can be carried out according to different alarm indicator lights to ensure the stable operation of the CNC machine tool system. In addition, there is a type of fault that is difficult to diagnose during the operation of CNC machine tools. When such faults occur in CNC machine tools, both software and hardware devices within the system may not display clear indicator lights. Once such faults occur, the difficulty of diagnosis is relatively high. In order to quickly determine the fault and quickly locate the area where the fault occurred, it is necessary to combine the actual state of the system before and after the fault to make a judgment and quickly find the fault point.

3. Common fault diagnosis and maintenance of CNC machining center machine tools

When a CNC machine tool malfunctions, maintenance personnel should intervene quickly to avoid the problem from escalating and endangering the overall operation of the CNC machine tool. However, in the process of fault diagnosis, maintenance personnel should seek the cooperation and support of operators, understand the status of CNC machining center machine tools before and after faults through actual investigations, and effectively determine the type and size of faults in CNC machine tools. Scientific and reasonable maintenance measures should be adopted for maintenance management. Taking several common faults as examples, this article scientifically explores the maintenance methods for CNC machining center machine tools.

3.1 Tool drop during tool exchange between spindle tool and tool magazine

In the practical application of CNC machining centers, the occurrence of tool drop is quite common. Once the phenomenon of tool drop occurs, it will seriously affect the efficiency of CNC machining. The common causes of tool loss can be summarized as follows: Firstly, during the tool change process, the spindle box does not return to the position of the tool change, and the tool change is already carried out at a certain distance from the tool change point, which will affect the quality of the tool change. At the same time, during the tool change process, there was an abnormal situation at the tool change point, which deviated from the specified position. The robotic arm had already performed a tool extraction operation before reaching the specified position during operation. In the actual application of CNC machining centers, corresponding measures should be taken once such faults occur. The scientific method is to re select the position of the spindle box, let it move again, and ensure that it can fit with the tool change point. If necessary, the tool change point can also be reset within the system.

3.2 Improper rotation of the tool magazine

In the application process of CNC machining centers, the frequency of such faults is also quite common. The common reasons for such faults include the following: faults in the electric motor, especially the possibility of position deviation during rotation. There may be performance issues with the hydraulic system, and the oil circuit may not be smooth when using the hydraulic system. Of course, it may also be due to the tool magazine itself, such as the load of the tool magazine exceeding its actual capacity. Therefore, when dealing with such faults, corresponding measures should be taken based on the cause of the fault, with a focus on screening the rotation of the motor. If it is found that this is indeed the cause, it should be adjusted in a timely manner, and if necessary, it can be replaced directly. If there are hydraulic issues, it is important to conduct a comprehensive inspection of the system to ensure its overall operational status. If it is due to the tool magazine, it is necessary to check whether the tool installation meets the specifications and ensure the accuracy of the tool installation program and position.

3.3 No display faults of CNC machine tools

In the application process of CNC machining center machine tools, especially during the debugging stage, there is no display of the fault area, and the system is also running continuously, but there is a fault in the display. After restarting, the fault disappeared again. When such faults occur in CNC machine tools, maintenance personnel can make direct judgments based on experience. Determine whether the fault is caused by poor contact by checking the contact performance of various components. Meanwhile, check the display board. During the inspection process, manual mode can be used to diagnose faults by checking one by one.