The causes of abnormal machining accuracy faults are hidden and difficult to diagnose. Five main reasons are summarized: the feed unit of the machine tool is changed or changed; Abnormal zero offset of each axis of the machine tool; Abnormal axial reverse clearance; Abnormal motor operation state, I .e. abnormal electrical and control parts; Mechanical faults, such as screw, bearing, shaft coupling and other components. In addition, the preparation of processing procedures, tool selection and human factors may also lead to abnormal processing accuracy.
Method of Troubleshooting and Fault Diagnosis for Accuracy Reduction of CNC Machine Tools
1. The functional program testing method writes some small programs for all instructions of G,M,S,T and functions, and runs these programs when diagnosing faults to judge the lack of functions.
2. Parameter checking method: Parameters are usually stored in RAM. Sometimes the battery voltage is insufficient, the system is not powered on for a long time or external interference will cause the parameters to be lost or confused. Relevant parameters should be checked and proofread according to the fault characteristics.
3. Intuitive method: (looking at, asking and cutting) asking-machine tool failure phenomena, processing conditions, etc.; Look at-CRT alarm information, alarm indicator lights, capacitors and other components are deformed, smoked and burnt, protectors are tripping, etc. Listening-abnormal sound; Smell-burnt smell and other peculiar smell of electrical components; Touch-fever, vibration, poor contact, etc.
4. The same kind of adjustment method replaces the suspected faulty template with the spare board with the same function, or exchanges the template or unit with the same function.
Isolation method: Some faults, it is difficult to distinguish whether it is caused by the numerical control part, the servo system or the mechanical part, and the isolation method is often used.