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CNC fault and fault classification(cnc machining)

Dec 30,20

CNC fault and fault classificationcnc machining)

CNC lathe is the product of mechatronics, advanced technology and complex structure. The faults of CNC machine tools are various, each of which is different. The causes of faults are generally complex, which brings many difficulties to the fault diagnosis and maintenance of CNC machine tools. In order to facilitate the fault analysis and diagnosis of machine tools, according to the nature of the fault, the cause of the fault and the location of the fault and other factors, the faults of CNC machine tools are roughly divided into the following categories.
1. According to the nature of CNC machine failure classification
(1) Systemic failure
This kind of fault means that as long as certain conditions are met, the machine tool or CNC system will inevitably appear. For example, if the grid voltage is too high or too low, the system will give an alarm of too high or too low voltage; if the cutting amount is too large, it will give an overload alarm.
For example, the CNC machine tool in the processing process, the system sometimes automatically power off, restart, can also work normally. According to the working principle and fault phenomenon of the system, it is suspected that the fault is caused by the fluctuation of the system power supply voltage. Measuring the 24 V input power supply on the system power supply module, it is found that it is about 22.3 v. when the machine tool is processing, the voltage also fluctuates downward, especially when the cutting amount is large, the voltage drops greatly, sometimes close to 21 v. at this time, the system automatically turns off. In order to solve this problem, change the capacity A large 24 V power transformer eliminates this fault.
(2) Random failure
This kind of fault refers to the fault that only happens once or twice occasionally under the same conditions. It is not easy to copy the same fault artificially, sometimes it takes a long time and is difficult to encounter again. It is difficult to analyze and diagnose such faults. Usually, this kind of fault is related to the looseness and dislocation of mechanical structure, the drift of working characteristics of some components in CNC system and the decline of reliability of electrical components of machine tool.
For example, a CNC groove grinder, in the process of occasional problems, groove position changes, resulting in waste. The working principle of the machine is analyzed. In the grinding process, the measuring arm first swings down to the clamping position of the workpiece, and then the workpiece starts to move. When the reference end face of the workpiece contacts the measuring head, the numerical control device records the position data at this time, then the measuring arm is raised, and the machining program continues to run. According to the position data of the end face, CNC equipment grinds the groove at a certain distance from the end face. The position of the groove is not accurate, which has a lot to do with the measurement. Because it doesn't happen very often, it's hard to see the fault. Therefore, according to the working principle of the machine tool, no problem was found in the inspection of the measuring head. When checking the rotation of the measuring arm, it is found that the rotation axis is a little tight, sometimes the measuring arm may not be placed in place accurately, resulting in measurement error. After removing the rotating shaft, it was found that it had been severely worn. A new spare part was made, and the failure did not occur after replacement.