The solution to the tool change failure in the machining center spindle
Tool change failures, which account for more than 80% of machining center failures. The main problems are poor signal and poor actuators. Although the structure of the tool change mechanism is different due to different types of machining centers, it is only necessary to analyze carefully. PLC ladder diagram, check the signal flow, this kind of problem is relatively easy to solve. Take a Japanese vertical machining center used in a factory in Hubei as an example. The vertical machining center cannot change the tool normally during the machining process, and the tool magazine is always in the standby state without reporting an error. This is a common problem of the machining center. The position deviation of the z-spindle is directly related. Through the inspection of the PLC ladder diagram, the engineering equipment maintenance personnel of the factory found that the root cause of the tool magazine standby is the excessive accumulated error of the z-axis servo system. Adjust the stop error of DGN802. Make the value below 10, the problem can be solved.
The precision of the structure of the machining center is high. The environment temperature and cleanliness should be controlled during the use process to avoid the burning of the drive module and the seizure of the spindle bearing caused by pollutants such as dust due to excessive temperature.
Orientation failure, the spindle orientation device is another important device of the CNC center. It is a prerequisite for tool exchange and empty finishing. During the machining process, the tool can be placed at a specific position on a circle and can be used as the next step for finishing. The positioning point has a great influence on the machining accuracy and error accumulation.
The main reasons for positioning problems include: PLC output signal is invalid, positioning solenoid valve failure, proximity switch failure and positioning hydraulic cylinder failure, etc. Through the PLC ladder diagram analysis to determine the scope of the fault, one by one inspection and elimination can effectively solve the problem. In addition, the orientation problem may also be on the circuit board and the CNC original. When the original is burned out and the control fails, the position control cannot be achieved. At this time, the mechanical positioning device and the digital circuit of the spindle need to be checked separately to test the validity of the digital circuit. If the signal output and return to normal, it can be judged as a mechanical failure, otherwise it is a circuit failure. Orientation issues mostly involve three aspects, such as hydraulic pressure, position detection, and circuit boards, and more attention should be paid to this.