1. Substitution comparison method
When it is difficult to determine what kind of fault occurs in the machine tool, the replacement comparison method can be used to determine. A faulty machine tool can be compared with a normal machine tool. Generally speaking, the difference is the fault of the machine tool. When it is difficult to determine whether the technical condition of a part is normal, it can be tested with a good part replacement. If there is no significant change in the working condition of the machine tool, it indicates that the original parts are qualified, and the machine fault has nothing to do with the parts, otherwise, there is a problem with the parts. Horizontal lathe

2. Partial stop method
This method can be used to diagnose the faults of machine tool rotation system. During diagnosis, you can stop or isolate the work of a part or part intermittently to observe the fault phenomenon and confirm the fault location. Such as the C630 headbox rumbling noise, but I do not know which shaft failure. You can connect each shaft of the headstock in turn. When the sound emitted is similar to the fault noise, you can determine which shaft is the problem. This method can diagnose faults of shaft, gear, clutch and other parts.

3. Condition change method
This method is often used when the symptoms of machine fault are not obvious, inadequate or irregular. Such as changing the force of the machine tool, changing the operation conditions of the machine tool, environmental conditions, etc. Sometimes mandatory testing with additional conditions is needed to allow the symptoms of the failure to be more fully exposed. When a part is machined on a lathe, the workpiece vibrates. The three elements of turning can be changed to observe the vibration. If the cutting tool is used for cutting test, if the vibration intensifies, it indicates that the radial clearance of the bearing in front of the spindle is large, and it should be adjusted.

4. Test contradiction
Try to change the working conditions or working state of a part, observe the changes in the phenomenon of the fault, to prove the fault occurred in the site. For example, the common lathe tool phenomenon, dragging plate, tool rest system of many faults can cause the tool. The first step is to select the most likely cause and conduct a tentative investigation. Such as: the positioning mechanism on the tool holder failure or fastening device failure, if there is no problem, then choose another kind of easy to let the knife phenomenon, until the reason is found.

5. Trial, cut and measure method
When the machining accuracy of the parts cannot reach the precision specified by the machine tool, the parts can be measured to diagnose the fault of the machine tool. Such as: according to the direction and frequency of the parts surface vibration grain, to diagnose the vibration of the machine tool; The geometric accuracy of machine tool is diagnosed by the form and position error of parts. For thread processing machine tools, gear processing machine tools, test cutting parts adjacent difference, cumulative error and spread into the tooth shape error, mainly determined by the accuracy of the machine rotation chain, tooth error determines the geometric accuracy of the machine tool, tooth surface roughness determines the vibration of the process system. So measuring the accuracy of the workpiece, can roughly judge the fault location and cause. But when using this method, we should consider the impact of tool, fixture and technology on the machining accuracy of parts.

6. Monitoring and measurement method
Use tools, measuring tools, instruments and meters to monitor or measure the technical parameters of machine tools to diagnose machine faults. If the pressure gauge is observed to monitor the pressure of the hydraulic system of the machine tool, if the pointer of the pressure gauge is unstable or the pressure cannot be reached, it indicates that there is a leak in the oil pipeline or there is gas in the pipeline, which needs to be repaired or replaced.