1. Power supply is the energy source of the maintenance system and the normal work of the whole CNC machine. Its failure or light fault will lose data and cause shutdown. The worst can destroy part or all of the system.

In China, the power supply network with large fluctuation and high harmonics is slightly insufficient, and some artificial factors inevitably cause the failure of power supply. When we design the power supply system of NUMERICAL control, we should try to do:

(1) Provide independent distribution box and not with other equipment in series;

(2) The beginning of the power supply has good grounding;

(3) The area with poor power supply quality should be equipped with three-phase AC voltage regulator;

④ The layout of electrical components in the electric cabinet and the laying of AC and DC wires should be isolated from each other.

⑤ Into the CNC go three-phase power supply should use three-phase five-wire system, the middle line (N) and grounding (PE) strictly separated;

2. Position ring of nc walking system is faulty

① Position ring alarm. The position measurement loop may be open; Measuring element damage; The interface signal established by position control does not exist.

② Coordinate axes move without instructions. It could be too much drift; Position loop or velocity loop is connected to form positive feedback; Feedback wiring open; The measuring element is damaged.

3, NC go coordinates can not find zero. It could be that the zero direction is moving away from zero; Encoder damaged or wiring open; Grating zero mark shift; Return to zero reduction switch fails.

4, the dynamic characteristics of the NC machine become worse, the workpiece processing quality decreases, and even the vibration of the machine occurs at a certain speed. There is a big possibility that the clearance of the mechanical transmission system is too large or even serious wear or the lubrication of the guide rail is insufficient or even wear; For the electrical control system, it may be that the speed ring, position ring and related parameters are not in the matching state, and should be re-adjusted after the mechanical fault is basically eliminated.

5. Accidental shutdown failure. There are two possible cases: one case is caused by problems in the related software design as mentioned above in some specific operation and function combination of shutdown failure, under normal circumstances, nc go power off after re-energized will disappear; The other is caused by environmental conditions, such as external interference (power grid or peripheral equipment), high temperature, excessive humidity, etc. This environmental factor is often ignored by people, such as the southern area of the NUMERICAL control machine in the ordinary factory building or even close to the open door near the electric cabinet for a long time to open the door operation, there is a large number of dust, metal chips or water mist equipment and so on. These factors will not only cause failure, serious will damage the system, be sure to pay attention to improve.