Common Faults and Troubleshooting Methods for Machining Centers

1. Machine Tool Cannot Return to Zero Point

Causes:

1. The contact of the origin switch is stuck and cannot move;

2. The origin stop dog cannot press the origin switch to the operating position;

3. Water entering the origin switch causes rust on the switch contacts and poor contact;

4. Disconnection of the origin switch circuit or failure of the input signal source;

5. Burned-out PLC input point.

Countermeasures:

Clean the stuck parts to ensure smooth movement of movable parts, or replace the travel switch; adjust the mounting position of the travel switch so that the contact of the zero point switch can be smoothly pressed to the operating position by the stop dog; replace the travel switch and take good waterproof measures; check the switch circuit for open circuit or short circuit and confirm the availability of signal source (+24V DC power supply); replace the input point on the I/O board, complete parameter setting and modify the PLC program.

2. Positive and Negative Hard Limit Alarm of Machine Tool

This alarm does not occur under normal conditions. It may appear if the machine tool is operated before returning to zero. Before zero return, the system has no fixed mechanical coordinate system and is positioned randomly, and the soft limit is invalid. Therefore, it is necessary to return to zero point first before operating the machine tool.

Causes:

1. The travel switch contact is pressed or stuck (over travel);

2. Damaged travel switch;

3. Open circuit, short circuit or missing signal source in the travel switch circuit;

4. The limit stop dog cannot press the switch contact to the operating position;

5. Burned-out PLC input point;

Corresponding Countermeasures:

Move the machine manually or by handwheel back to a safe position, or clean the switch contact; replace the travel switch; check the travel switch circuit for short circuit and reprocess if any short circuit exists; check the signal source (+24V DC power supply); adjust the mounting position of the travel switch so that the switch contact can be normally pressed to the operating position; replace the input point on the I/O board, complete parameter setting and modify the PLC program.