Fault diagnosis principles of CNC machine tools
1. The CNC machine tool from the outside to the inside is a machine tool integrating machinery, hydraulic pressure and electricity, so its failure will also be comprehensively reflected by these three. Maintenance personnel should check one by one from the outside to the inside, and try to avoid random unsealing and disassembly, otherwise it will expand the fault, make the machine lose accuracy and reduce performance.
2. Generally speaking, mechanical faults are easy to detect, while the diagnosis of CNC system faults is more difficult. Before troubleshooting, first pay attention to eliminating mechanical faults, which can often achieve twice the result with half the effort.
3. First static, then dynamic. In the static state when the machine tool is powered off, the machine tool can be powered on only after it is confirmed as a non-destructive fault through understanding, observation, testing and analysis; Under operating conditions, conduct dynamic observation, inspection and testing to find faults. For destructive faults, the danger must be eliminated before power on.
4. First simple, then complex. When a variety of faults are intertwined and covered up, and there is no way to start at the moment, the easy problems should be solved first, and then the difficult problems should be solved. Often, after simple problems are solved, difficult problems may also become easier.
Common diagnostic methods
1. Intuitive method: (look, hear, ask) ask - the fault phenomenon and processing condition of the machine tool; Look - CRT alarm information, alarm indicator, capacitor and other components are deformed, smoked and charred, protector trips, etc; Listening - abnormal sound; Smell - burnt smell and other peculiar smell of electrical components; Touching - heating, vibration, poor contact, etc.
2. Parameter inspection method: parameters are usually stored in RAM. Sometimes the battery voltage is insufficient, the system will be powered off for a long time or external interference will cause parameter loss or confusion. Relevant parameters should be checked and calibrated according to the fault characteristics.
3. Isolation method: for some faults, it is difficult to distinguish whether they are caused by numerical control part, servo system or mechanical part. Isolation method is often used.