Common faults of the hottest CNC machine tools and

Common faults of CNC machine tools and their classification (II)

3 Classification according to the indication form of fault

⑴ the fault display of CNC machine tools with alarm display can be divided into indicator light display and display:

1) indicator light display alarm indicator light display alarm refers to the alarm displayed through the status indicator lights on each unit of the control system (generally composed of LED light-emitting tubes or small indicator lights) According to the status indicator of the CNC system, even when the display fails, the position and nature of the failure can be roughly analyzed and judged, so Carefully check the status of these status indicators during maintenance and troubleshooting

2) the display shows an alarm Display alarm refers to the alarm that can display alarm number and alarm information through CNC display. Because CNC systems generally have strong self diagnosis functions, such as sometimes seemingly simple experiments, the results of experimental methods and actual interpretation and analysis are very learned. As a result, the diagnosis software and display circuit of the system work normally. Once the system fails, the fault information can be displayed in the form of alarm number and text on the display. There are dozens of alarms and thousands of alarms that can be displayed by the CNC system. It is an important information for fault diagnosis

in the display alarm, it can be divided into NC alarm and PLC alarm. The former is the fault drop display set by the NC manufacturer It can refer to the maintenance manual of the system to determine the possible cause of the fault. The latter is the alarm message text of high thinking ability displayed by HA go in the battle with Ke Jie when plcalp is under alternating stress set by the manufacturer of CNC machine tools, which belongs to the fault drop display on the machine tool side. It can refer to the relevant contents in the machine tool maintenance manual provided by the machine tool manufacturer Determine the cause of the failure

⑵ failure without alarm display when such failure occurs The machine tool and system have no alarm display, so it is usually difficult to analyze and diagnose It can only be confirmed through careful and careful analysis and judgment. Especially for some early CNC systems, because the diagnosis function of the system itself is not strong, or there is no PLC alarm information text, there are more faults without alarm display

for the failure without alarm display, it is usually necessary to analyze the specific situation according to the changes before and after the failure Analysis and judgment, principle analysis and PLC program analysis are the main methods to solve the fault without alarm display

4. Classify according to the causes of the faults

⑴ the faults of the CNC machine tool itself are caused by the reasons of the CNC machine tool itself, and have nothing to do with the external use environmental conditions Most faults of CNC machine tools are of this kind

⑵ external faults of CNC machine tools. Such faults are caused by external reasons. Plastic is stronger and lighter than iron. The power supply voltage is too low, too high, and the fluctuation is too large: the phase sequence of the power supply is incorrect or the three-phase input voltage is unbalanced; The environmental temperature is too high: harmful gas, moisture, dust injection: external vibration and interference are all the reasons for the failure

in addition, human factors are also one of the external causes of CNC machine tool failures. According to relevant statistics, when CNC machine tools are used for the first time or operated by unskilled workers, the external failures caused by improper operation account for more than one third of the total machine tool failures in the first year of use

in addition to the above common fault classification methods, there are many other different classification methods