(1) The intuitive method

When a CNC lathe fails, the operator can analyze the failure through preliminary observations, determine the abnormal situation of the lathe when the failure occurs, try to reduce the failure point to a certain range, and the brake equipment maintenance personnel can perform professional repairs.

(2) Parameter detection method

The various parameters of the CNC lathe are the basic conditions to ensure the stable operation of the lathe. Various parameter information is usually stored in the memory. When encountering interference from external factors, it is likely that the CNC parameters will change, causing the lathe to not work properly. Especially for those continuously placed lathes, this phenomenon is more obvious, so professional maintenance personnel to check the lathe parameters is the main way to find some system failures.

(3) Functional test method

The function test method is to run a manual function test program on the lathe where the fault occurs to detect the fault. Professional maintenance personnel can determine the cause of the failure of the CNC lathe by checking the effectiveness of the various functions of the lathe.

(4) Parts exchange method

When the general failure of the lathe is determined, professional maintenance personnel can take the parts exchange method to repair it. Under the condition of good external factors, use the same type of electronic components to replace the suspected faulty parts, so as to determine and eliminate the fault location.

（5） Principle analysis

Principle analysis method is based on the working principle of CNC lathe, using oscilloscope or multimeter and other instruments to analyze and compare the parameters and levels of each point, so as to judge and eliminate the fault. This method has higher requirements for the professional ability of the equipment maintenance personnel and the mastery of the circuit principle and technology. In the process of fault diagnosis, it is necessary to draw the control circuit diagram of the fault location for the convenience of troubleshooting.