CNC Machining

Application Of CNC in The Field Of Hardware Tools

Numerical control generally uses a general-purpose or special-purpose computer to realize digital program control, so numerical control is also called Computerized Numerical Control, or CNC for short. It is generally called CNC in foreign countries, and the concept of NC is rarely used. It usually controls mechanical quantities such as position, angle, speed, and switching quantities related to the flow of mechanical energy. The generation of numerical control depends on the appearance of data carriers and binary data operations. In 1908, the perforated metal sheet interchangeable data carrier came out; at the end of the 19th century, the control system with paper as the data carrier and with auxiliary functions was invented; in 1938, Shannon carried out fast data calculation and transmission at the Massachusetts Institute of Technology, USA. Laid the foundation of modern computers, including computer numerical control systems. Numerical control technology is developed in close combination with machine tool control.

In 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 computer numerical control technology (CNC, Computerized Numerical Control). This technology uses the computer to execute the sequential logic control function of the movement track of the equipment and the operation of the peripherals according to the control program stored in advance. Because the computer is used to replace the numerical control device originally composed of hardware logic circuits, the realization of various control functions such as storage, processing, operation, and logical judgment of input operation instructions can be completed through computer software, and the generated micro-instructions are transmitted. Drive the motor or hydraulic actuator to the servo drive to drive the equipment to run.

Traditional machining is done by manual operation of ordinary machine tools. During machining, the mechanical tool is shaken by hand to cut metal, and the accuracy of the product is measured by eyes with calipers and other tools. Modern industries have already used computer-controlled machine tools for operations, and CNC machine tools can automatically process any product and component directly according to the program pre-programmed by technicians. This is what we call "CNC machining". CNC machining is widely used in any field of machining, and it is also the development trend and important and necessary technical means of mold machining.

"CNC" is the abbreviation of Computerized Numerical Control in English. The CNC machine tool automatically processes the parts to be processed according to the pre-programmed processing program. We put the machining process route of the part, process parameters, tool motion trajectory, displacement, cutting parameters (spindle revolutions, feed, back-feeding amount, etc.) and auxiliary functions (tool change, spindle forward rotation, reverse rotation, The cutting fluid is turned on and off, etc.), according to the instruction code and program format specified by the CNC machine tool to write a processing program list, and then record the content of the program list on the control medium (such as perforated paper tape, magnetic tape, magnetic disk, magnetic bubble memory) ), and then input into the numerical control device of the numerical control machine tool, thereby directing the machine tool to process the parts.

This whole process from the analysis of the part drawing to the production of the control medium is called the compilation of the numerical control program. The difference between CNC machine tools and ordinary machine tools is that the control machine tools process parts automatically according to the program, while the ordinary machine tools are operated by humans. We can achieve the purpose of processing different parts by changing the program that controls the machine tool action. Therefore, CNC machine tools are especially suitable for processing parts with small batches and complex shapes that require high precision.

Since the CNC machine tool must process parts according to the program, after the programmer has compiled the program, it is input into the CNC device to direct the machine tool work. Program input comes through the control medium. Numerical control technology and equipment is the enabling technology and the most basic equipment for the development of emerging high-tech industries and cutting-edge industries. The information industry, biological industry, aviation, aerospace and other national defense industries of various countries in the world widely use numerical control technology to improve the manufacturing capacity and level, and improve the adaptability and competitiveness to the market. The industrialized countries also list CNC technology and CNC equipment as national strategic materials, not only vigorously develop their own CNC technology and its industries, but also implement blockade and restriction policies on my country in terms of "high-precision" CNC key technologies and equipment. Therefore, vigorously developing advanced manufacturing technology with numerical control technology as the core has become an important way for developed countries in the world to accelerate economic development, improve comprehensive national strength and national status.