Due to the complexity of CNC machine tool failures, while the self-diagnostic capability of the CNC system can not test all parts of the system, often an alarm number indicates a multitude of causes of failure, making it difficult to get started. The following describes the maintenance staff any production practice commonly used troubleshooting methods.

Intuitive inspection method

Intuitive inspection method is based on the maintenance staff to observe the occurrence of faults in a variety of light, sound, smell and other anomalies, to determine the scope of the fault, you can narrow down the scope of the fault to a module or a circuit board, and then troubleshooting.

Initialisation reset method

In general, due to transient faults caused by the system alarm, available hardware reset or switch the system power supply in turn to clear the fault. If the system work storage area due to power down, dial plug circuit board or battery undervoltage caused by confusion, the system must be initialised to clear, clear before the data copy should be noted that good records, if the initialisation of the fault still can not be eliminated, then the hardware diagnosis.

Self-diagnostic method

CNC system has a strong self-diagnostic function, and can monitor the hardware and software of the CNC system at any time the working state. Using the self-diagnosis function, it can show the status of the interface information between the system and the host, so as to judge whether the fault occurs in the mechanical part or the numerical control part, and show the general part of the fault (fault code).

Function programme test method

Function procedure test method is to program the function of the CNC system into a function test procedure and store it on the corresponding media, such as paper tape and magnetic tape. Running this programme during troubleshooting quickly determines the probable cause of a fault. Function program test method is often used in the following occasions: machine tool processing caused by scrap and a moment can not determine whether the programming operation is improper, or CNC system failure caused by; CNC system random faults, it is difficult to distinguish between external interference, or system stability is good; idle for a long time of CNC machine tools in the use of CNC machine tools before or for regular maintenance.

Spare parts replacement method

Replace the diagnosis of bad circuit boards with good spare parts, that is, in the case of analysing the general cause of the failure, maintenance personnel can use the spare printed circuit boards, integrated circuit chips or components to replace the suspected part, thus narrowing down the scope of the failure to the printed circuit board or chip level. And do the corresponding initialisation start, so that the machine tool quickly into normal operation.

For modern CNC maintenance, more and more cases use this method of diagnosis, and then replace the damaged module with spare parts to make the system work normally. As far as possible to shorten the fault downtime, the use of this method in the operation of attention must be carried out in the blackout state, but also carefully check the version of the circuit board, model, various markings, spanning whether the same, if not consistent can not be replaced. Remove the line should be marked and recorded.

Generally do not easily replace the CPU board, memory board and electrical ground, otherwise it may cause the loss of the program and machine parameters, so that the failure to expand.

Parameter inspection method

System parameters are to determine the basis of the system function, parameter setting errors may cause system failure or a function is invalid. Failure should be checked in a timely manner when the system parameters, parameters are generally stored in the magnetic bubble memory or stored in the need to keep the battery MOSRAM, once the battery is insufficient or due to external factors such as interference, so that the individual parameters are lost or changed, confusion occurs, so that the machine tool can not work properly. At this time, you can check and correct the parameters, the fault will be eliminated.

Principle analysis method   

According to the principle of the composition of the CNC system, you can logically analyse the logic level of each point and characteristic parameters, such as voltage values and waveforms, the use of instruments and meters to measure, analyse and compare, so as to determine the fault location.

In addition to the above commonly used fault detection methods, can also be used to pull the plug board method, voltage pull bias method, open loop detection method. In short, according to different fault phenomena, you can choose several methods at the same time, flexible application, comprehensive analysis, in order to gradually narrow the scope of the fault, faster troubleshooting.   

The causes of machine tool failure is multifaceted. For more complex faults, the need for several methods of integrated application, in order to correctly determine the cause of the failure, diagnose the specific parts of the failure, so as to solve the problem in a timely manner, reduce the loss of CNC machine tools to the production, and effectively improve the efficiency of the machine tool.