First, the generation of numerical control
Usually control mechanical quantities such as position, angle and speed, as well as switching quantities related to the flow direction of mechanical energy. The appearance of numerical control depends on the appearance of data carrier and binary data operation.
1908, perforated metal foil interchangeable data carrier came out; At the end of 19, a control system with auxiliary functions was invented with paper as the data carrier. During the period of 1938, Shannon carried out rapid data calculation and transmission at MIT, which laid the foundation for modern computers, including computer numerical control systems.
Numerical control technology is closely combined with machine tool control and developed. 1952, the first CNC machine tool came out, which became an epoch-making event in the history of the world machinery industry and promoted the development of automation.
Now numerical control technology is also called CNC (Computerized Numerical Control). At present, it is a technology to realize digital program control by computer. This technology uses a computer to perform the logical control functions of the equipment motion trajectory and the peripheral equipment operation sequence according to the pre-stored control program.
Because the computer is used to replace the original numerical control device composed of hardware logic circuits, various control functions such as storage, processing, calculation and logical judgment of input operation instructions can be realized through computer software, and the micro-instructions generated by processing are transmitted to the servo drive device to drive the motor or hydraulic actuator to drive the equipment to run.
Second, composition
Computer numerical control system consists of hardware and software, and the understanding of the architecture of numerical control system should be carried out from both hardware and software. Its core is computer digital control device.
Through the system control software and system hardware, it reasonably organizes and manages the input, data processing, interpolation and output information of the numerical control system, controls the executive parts, and makes the numerical control machine tool automatically process according to the requirements of the operator.
The CNC system takes the computer as the control component, and usually some or all CNC functions are realized by the CNC system software residing in it, so as to control the movement of the machine tool in real time.
As long as the control software of computer numerical control system is changed, a brand-new control mode can be realized. There are many types of CNC systems, including lathes, milling machines and machining centers.
The CNC system of various CNC machine tools generally includes the following parts: CPU, memory, I/O equipment, operation panel, display and keyboard, paper tape punch, programmable controller, etc.
With the rapid decline in the cost performance of computer hardware and the popularization and application of graphic display, modern numerical control system no longer needs perforated paper tape, but is directly controlled by computer. It uses a small general-purpose computer or personal computer to directly control a machine tool, and the control program of the machine tool is stored in the memory of the computer, which is easy to modify and expand its functions and has good flexibility.