1. External fault
As the reliability of modern CNC systems is getting higher and higher, the failure rate is getting lower and lower, and failures rarely occur. Most of the failures are non-system failures and are caused by external causes.
2. NC system failure
The external faults of CNC cutting machines can be divided into soft faults and hard faults caused by external hardware damage.
(1) Hardware failure: Sometimes due to hardware damage in the NC system, the machine stops. For the diagnosis of this type of fault, you must first understand the working principle of the CNC system and the functions of each circuit board, and then analyze the fault phenomenon, and use the switching method to accurately locate the fault point under conditions.
(2) Soft failure: Some failures are caused by NC system parameters, sometimes due to improper settings, sometimes due to accidental changes or confusion of parameters, such failures will naturally disappear as long as the parameters are adjusted. There are also some failures that cause the NC system to be in an infinite loop due to accidental reasons. Such failures sometimes must be forced to start to restore the system.
Sometimes the diagnosis process is more complicated, but once the problem is found, it is easier to solve. The following two principles should be followed for external fault diagnosis. First of all, we must be proficient in the working principle and action sequence of the CNC cutting machine. Secondly, we must use PLC ladder diagram.
The status display function of the NC system or the external programmer monitors the running status of the PLC. Generally, as long as you follow the above principles and be careful, the general CNC cutting machine faults will be eliminated in time.
Three, the failure of the servo system
Because the control core of the CNC system is to digitally control the feed part of the cutting machine, and the feed is realized by the servo unit controlling the servo motor and driving the ball screw. The rotary encoder is used as the position feedback element to form a semi-closed loop. Position control system. Therefore, the role of the servo system on the CNC machine tool is very important. Servo system failures are generally caused by problems with the servo control unit, servo motor, tachometer motor, encoder, etc.