G92 or G32 for screw thread not working

The CNC controller is not working on G92 or G32, the X and Z axis are even not moving, but G99 is normal to turn the end face and excircle of the workpiece under AUTO mode.

It could be several causes:

1-      Encoder wiring problem of the AC servo motors.

2-      Encoder hardware problem of the AC servo motors.

3-      I/O board problem of the CNC controller.

4-      Clutch slipping.

In this case we found there is a cold solder joint on Zero signal cable of the Z axis encoder, fix it then everything is fine.