Sometimes we will find that the accuracy of CNC lathes will suddenly decrease. Why?
The causes of abnormal machining accuracy are concealed and difficult to diagnose. Five main reasons are summarized: the feed unit of the machine tool is changed or changed; the zero offset of each axis of the machine tool is abnormal; the axial backlash is abnormal; the motor Abnormal operation status, that is, abnormal electrical and control parts; mechanical failure, such as screw, bearing, shaft coupling and other components. In addition, the preparation of the processing program, the selection of tools and human factors may also cause abnormal processing accuracy.
The method of troubleshooting and fault diagnosis of CNC machine tool accuracy reduction
1. Function program test method: Write some small programs for all the instructions of G, M, S, T and functions, and run these programs when diagnosing faults, and then you can judge the lack of functions.
2. Parameter checking method: The 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. The relevant parameters should be checked and corrected according to the fault characteristics.
3. Intuitive method: (look, hear, ask, cut) ask-machine failure phenomena, processing conditions, etc.; watch-CRT alarm information, alarm indicator lights, capacitors and other components deformed, smoked and burnt, protector tripping, etc.; listen-abnormal sound; smell -Burnt smell of electrical components and other peculiar smells; touch-heat, vibration, poor contact, etc.
4. The same kind of adjustment method replaces the suspected faulty template with the spare board of the same function, or exchanges the same function templates or units with each other.
5. Isolation method: For 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.