The Numerical Control technology in CNC machine tools is a technical method that uses digital signals to control the movement of the machine tool and its processing process. A CNC machine tool is a machine tool that adopts CNC technology, or a machine tool equipped with a CNC system. International Federation of Information Processing, IFIP Fifth Technical Committee, Definition of CNC Machine Tool: A CNC machine tool is a machine tool equipped with a program control system. The control system can logically process programs with control codes or other symbolic instructions, decode them, represent them with coded numbers, and input them into the numerical control system through information carriers. After arithmetic processing, various control signals are issued by the numerical control device to control the action of the machine tool, and the parts are automatically processed according to the requirements.
Compared with traditional manual machine, CNC machines have the following seven advantages:
1. High machining precision and stable quality. Each time the CNC system outputs a pulse, the displacement of the moving parts of the machine tool is called the pulse equivalent. The pulse equivalent of the CNC machine tool is generally 0.001mm, and the high-precision CNC machine tool can reach 0.0001mm, and its motion resolution is much higher than that of ordinary machine tools. In addition, the CNC machine tool has a position detection device, which can feed back the actual displacement of the moving parts or the rotation angle of the lead screw and servo motor to the CNC system and perform compensation. The quality of CNC machined parts is guaranteed by the machine tool, and there is no influence of artificial operation errors, so the same batch of parts has good dimensional consistency and stable quality.
2. It can complete the processing of complex parts that ordinary machine tools are difficult to complete or cannot process at all. For example, CNC machine tools with two-axis linkage or more than two-axis linkage can process rotating body surface parts, cam parts and various complex space surface parts whose busbars are curves.
3. High production efficiency. The spindle speed and feed range of CNC machine tools are larger than those of ordinary machine tools, and the good structural rigidity allows CNC machine tools to use a large amount of cutting, thereby effectively saving manoeuvring time. For the processing of some complex parts, if a CNC machining center with an automatic tool changer is used, continuous processing of multiple processes can be realized under one clamping, which reduces the turnaround time of semi-finished products and improves the productivity more obviously.
4. Strong adaptability to product modification design. When the parts to be processed are modified and designed, it is only necessary to change the processing program of the parts on the CNC machine tool, adjust the tool parameters, etc., to realize the processing of the modified parts, and the production preparation cycle is greatly shortened. Therefore, CNC machine tools can be quickly converted from processing one type of parts to processing another modified design part, which provides a great deal for the processing of single-piece, small-batch new trial products and the frequent update of product structure. convenience.
5. Conducive to the development of manufacturing technology in the direction of comprehensive automation. CNC machine tools are the basic equipment for machining automation. The integrated automation systems such as FMC (Flexible Machine Center), FMS (Flexible manufacturing system), and CIMS (Computer-integrated manufacturing system) established on the basis of CNC machine tools make the integration of machine manufacturing. , intelligence and automation can be realized. This is because the CNC machine tool control system adopts digital information and standardized code input, and has a communication interface, which is easy to realize data communication between CNC machine tools, and is most suitable for the connection between computers to form an industrial control network to realize automatic production process calculation, management and control.
6. Strong monitoring function and fault diagnosis ability. The CNC system not only controls the movement of the machine tool, but also can monitor the machine tool comprehensively. For example, some factors that cause failures can be warned in advance, and fault diagnosis can be carried out, which greatly improves the efficiency of maintenance.
7. Reduce labor costs, reduce labor intensity and improve labor conditions.