Wei Shun: How to Maintain the Relay Contactor Control System of CNC Lathe?

In addition to CNC devices, the electrical control system also includes the machine tool power control system. The high-power control system of NC lathe is mainly composed of the drive of common AC motor, the logic control device of machine tool electrical appliances, PLC and operation panel. This paper briefly introduces the maintenance and maintenance of common relay contactor control system and PLC programmable controller in machine tool power control system.

1.Maintenance of Common Relay Contactor Control System

In addition to CNC system, there are general relay contactor control systems for economical CNC lathes. Its maintenance and maintenance work is mainly how to take measures to prevent strong electromagnetic interference of contactors and relays in strong cabinets. Contactors, relays and other electromagnetic components in the strong cabinet of CNC machine tools are the interference sources of CNC system. Because of AC contactor, when AC motor starts and stops frequently, its electromagnetic induction phenomenon will cause noise such as spikes or surges in the control circuit of CNC system and interfere with the normal operation of the system. Therefore, we must take measures to eliminate these electromagnetic interference. For example, for AC contactor coils, RC networks are connected in parallel at both ends or three-phase input terminals of AC motors to suppress the interference noise generated by these appliances. In addition, attention should be paid to preventing the oxidation of contactors and relay contacts and poor contact of contacts.

2.Maintenance of PLC Programmable Controller

Programmable controller is also an important electrical control part of NC lathe. In addition to the control of auxiliary movement and action, the high-power control system of NC machine tools also includes the control of protective switches, various stroke and limit switches. In the above process, the PLC programmable controller can replace most of the machine tools and electrical appliances in the high-power control system of NC machine tools, thus realizing the logical control of spindle, tool change, lubrication, cooling, hydraulic and pneumatic systems. When the PLC programmable controller is integrated with the NC device, it constitutes the built-in PLC, while when it is located outside the NC device, it constitutes the type PLC. Because the structure of PLC is similar to that of NC device, the maintenance and maintenance of PLC can refer to that of NC device.