The structure of the control part of the CNC machine tool
The specific composition and work flow of CNC machine tools
The composition of CNC machine tools includes the following parts: the main part, the control part, the execution part, and the auxiliary device. The following takes the commonly used CNC lathe as an example to introduce the structure of the CNC machine tool in detail.
The brain of the entire CNC lathe, all components of the control part communicate with the CNC device, and all resources are uniformly distributed through the CNC device. Through this centralized management mode, the CNC device effectively organizes the components of the control part together.
1) User program
The user program refers to the part processing program, which is generally compiled by the numerical control engineer of the user unit according to the part drawing, and stored on an information carrier, which can be input into the CNC device for processing through an input device.
2) Input/output equipment
The popular input devices now mainly include:
·Disk drive. Mainly read the processing program stored on the disk.
·Press H on the operation panel. The user program can be entered through the panel.
·DNC interface. Programs can be input to CNC machine tools through DNC (distributed numerical control control system) interface and host computer communication.
·Operation switch, hand wheel. The coordinate axes can be manually controlled through these input interfaces.
The output devices mainly include printers, monitors and output interfaces. The main function of the output device is to display and print.
3) CNC device
The CNC device is composed of hardware and software. The hardware is mainly an industrial control computer or a microcomputer, which is the material basis for the realization of numerical control technology. The software relies on the hardware, is stored on the hardware, and drives and controls the hardware. It can be said that the stalk is equivalent to the human body, and the software is the human soul.
The CNC device is the core of the CNC machine tool. Under the function of the system software, the CNC device can automatically process the part processing program input by the user and issue corresponding control commands to the actuator to achieve the function of driving the entire machine tool.
PLC can program the controller to complete the logical sequence control of various actuators of CNC machine tools. Before the PLC came out and promoted, the logic sequence control function of the actuator was mainly completed by the relay circuit. PLC is mainly used to control spindle speed, tool change and realize auxiliary functions of CNC machine tools.
5) Drive system
The drive system mainly has two parts: spindle drive and feed drive. The function of the drive system is to receive instructions from the CNC device, perform operations such as comparison and signal amplification, and then directly drive the execution motor. It can be said that the drive system is a middleware that serves as a link between the previous and the next.