CNC tool holder fault resolution analysis

The phenomenon of the continuous operation of the tool holder or the failure of a certain tool position and its causes

The following is an example of a lathe equipped with a DTM system (Titma CNC system):

Occasionally, during the automatic operation of the lathe, the continuous operation of the tool holder or the non-stop of a certain position sometimes run continuously for 2~3 positions and then stop and lock. When continuous operation or a certain tool position does not stop, the “301” alarm appears on the display (tool holder failure). The machine automatically stops. When the continuous operation is 2~3 positions, the alarm number is not displayed and the machine automatically runs. normal.

Since the fault is random and random, it is not convenient to find the maintenance personnel to check that it belongs to the electrical control fault. After the output voltage measurement result of the tool holder control system is normal, the tool holder control system relay is also normal. Finally, the protective cover at the top of the tool holder was taken out and the input voltage of the Hall element signal line was measured one by one. It was found that the middle copper core of one signal line was broken temporarily by the wire protection rubber skin. When the tool holder was turned to a certain position, the wire protection rubber skin was affected. Forced tension copper core wire can not be normally connected to the program control system can not find the corresponding tool number, the "301" alarm will appear. When the machine tool is reset and the tool holder is rotated to a certain position by manual mode, the wire protection rubber skin is loosened. Both ends of the copper core wire are turned on. The tool holder rotates normally and no alarm number appears.

Troubleshooting

After the maintenance personnel replace the Hall element connection signal line and replace the test drive, the machine is running normally.

Comprehensive analysis of the above two cases of fault finding and elimination process, we can be clear that CNC machine tool failures not only occur in the electrical part but also in the mechanical part. For the CNC lathe equipped with the above two systems, the semi-closed loop control system does not have the mechanical fault feedback function. In the operation and use, it is necessary to strengthen the daily maintenance and maintenance. If the "alarm number" is not displayed after the failure, it is likely to be a mechanical fault. Checking the mechanical part will make it more accurate and timely for the maintenance personnel to troubleshoot.