Since the beginning of the 20th century, manufacturing technologies, especially advanced manufacturing technologies, have continued to develop. As an important part of advanced manufacturing technologies, the role of special processing in manufacturing has become increasingly important. This article outlines what kinds of specialty processing, specialty processing, existing problems and development trends are.
Keywords special processing advanced manufacturing technology
Since the beginning of the 20th century, manufacturing technologies, especially advanced manufacturing technologies, have continued to develop. As an important part of advanced manufacturing technologies, the role of special processing in manufacturing has become increasingly important. He has solved the problems encountered by traditional processing methods and has his own unique characteristics. He has become an indispensable and important processing method and method for modern industry.What is a special processing
Special processing was developed in the 1940s. Due to material science, high-tech development and fierce market competition, and the urgent need for the development of cutting-edge national defense and scientific research, not only new products are being replaced by new generations, but also their product requirements are of high strength. Weight ratio and cost performance ratio, and is moving toward the direction of high speed, high precision, high reliability, corrosion resistance, high temperature and high pressure, high power, size polarization. For this reason, a large number of new materials, new structures, and complex-shaped precision mechanical parts have emerged, raising a series of urgent problems that need to be resolved in the machinery manufacturing industry. For example, the processing of various difficult-to-cut materials; the complex shapes of various structures, the size of small or extra large, the processing of precision parts; the rigidity of thin-walled, elastic components, and the processing of special parts. In this regard, the use of traditional processing methods is very difficult and even impossible to process. Therefore, on the one hand, through the study of highly efficient machining tools and tool materials, automatic optimization of cutting parameters, improved tool reliability and online tool monitoring systems, the development of new cutting fluids, the development of new types of automatic machine tools, etc., to further improve the cutting status and improve the cutting process. Level, and to solve some problems; on the other hand, break through the shackles of traditional processing methods, continue to explore and seek new processing methods, so a kind of special processing that is essentially different from the traditional processing came into being, and continue to obtain development of. Later, due to the further development of novel manufacturing technology, people defined special processing in a broad sense, that is, electrical, magnetic, acoustic, optical, chemical, and other energy or combinations thereof were applied to the processed parts of the workpiece so that the material was removed and deformed. Non-traditional processing methods such as changing properties or being plated are collectively referred to as special processing.Two special processing features
1. Without mechanical energy, it has nothing to do with the mechanical properties of the processing object. Some processing methods, such as laser processing, EDM, plasma arc machining, electrochemical machining, etc., are the use of thermal energy, chemical energy, electrochemical energy, etc. These processing methods are The hardness of the workpiece is not related to the mechanical properties, it can be processed a variety of hard, soft, brittle, heat-sensitive, corrosion-resistant, high melting point, high strength, special properties of metal and non-metallic materials.2. Non-contact processing does not necessarily require tools. Some tools are used but do not contact the workpiece. Therefore, the workpiece does not receive large forces. The hardness of the tool can be lower than the hardness of the workpiece, so that the rigidity is extremely low and the elastic elements are not To be processed.
3. Micro-fabrication, high quality workpiece surface, some special processing, such as ultrasonic, electrochemical, water jet, abrasive flow, etc., the machining allowance is all fine, so it can not only process tiny holes or slits, but also can obtain High-precision, extremely low-roughness machined surfaces.4. There is no mechanical strain in processing or thermal strain in a large area, and a low surface roughness can be obtained. The thermal stress, residual stress, and cold work hardening are relatively small, and the dimensional stability is good.
5. Two or more different types of energy can be combined with each other to form a new composite processing, the comprehensive processing effect is obvious, and it is easy to promote the use.6. The special processing has a positive impact on the simplification of the processing technology, the transformation of the design of new products, and the structural design of parts.
Classification of three special processingAs with other advanced manufacturing technologies, special processing is being researched, developed and applied, and has very good development potential and application prospects. According to the sources and forms of processing energy, various commonly used special processing methods are listed.
EDM is a process that removes the material of the workpiece in a controlled manner through the discharge between the workpiece and the tool electrode, and deforms, changes properties, or is plated. Among them, the forming process is applicable to various hole and groove molds, and can also be used for engraving, surface strengthening, and coating; the cutting process can be applied to various punches, powder metallurgy molds and workpieces, punching pieces of various types of templates, magnetic steels, and silicon steel sheets. Molybdenum, tungsten, semiconductor or precious metal.
Electrochemical machining is a special process for removing a workpiece material or coating a metal material thereon by an electrochemical reaction. Among them, electrolytic machining is applicable to deep holes, holes, cavities, profiles, chamfers, deburring and polishing. Electroforming processing is applicable to hollow parts with complex shapes and high precision, such as waveguides; molds for injection molding, thin-walled parts; replicating precise surface profiles; surface roughness models, mirrors, dials, and other parts. The coating process can be applied to surface worn, scratched, and rusted parts to restore size; coating oversize products can be remedied. The surface of large, complex, small batches of parts is coated with an anti-corrosion layer and a corrosion-resistant layer to improve the surface properties.
High-energy beam processing is a general term for a special processing method that uses a laser beam, an electron beam, or an ion beam with a high energy density to remove a workpiece material. Among them, laser beam processing is mainly applied to punching, cutting, welding, laser surface strengthening, trimming, and storage. There are two types of electron beam processing, thermal type and non-thermal type. The thermal type processing is the use of electron beam to heat the material locally to the melting or gasification point for processing, suitable for drilling, cutting slots, welding and other deep structure of fine Processing; non-thermal processing is the use of electron beam chemical effects of etching, large-area thin layer and other micro-processing. Ion beam processing is mainly used in microfabrication, sputtering processing and injection processing. Plasma arc machining is suitable for cutting, welding, and heat treatment of various metal materials. It can also produce high-purity alumina, silicon oxide, and workpiece surface strengthening. Plasma arc welding and spraying can also be performed.
Ultrasonic machining is the use of ultrasonic vibration tools in abrasive liquid media or in dry abrasives to produce abrasive impacts, polishing, hydraulic impact, and the resulting cavitation effects to remove material, and ultrasonic vibrations to bond workpieces together. method. It is suitable for forming, cutting, welding and ultrasonic cleaning.
Liquid jet processing is the use of water or additives in the water liquid, the high-speed liquid beam generated by the pump and booster, sprayed to the surface of the workpiece, so as to achieve the purpose of removing material. It can process thin and soft metal and non-metal materials, remove internal burrs of cavity parts, and make plastic deformation of metal surfaces. Abrasive blasting is suitable for deburring, surface cleaning, cutting, engraving, blanking and punching.
Chemical processing makes use of a chemical reaction between a chemical solution and a metal to cause the metal to corrode and dissolve and change the shape and size of the workpiece. Used to remove surface layers of materials to reduce weight; selectively process shallower or deeper cavities and grooves; and taper holes for plates, sheets, formed parts and extruded parts.
Composite machining refers to the special processing that combines two or more different types of energy to remove the workpiece material at the same time on the processing site. Problems in the four special processing
Although special processing has solved many problems that traditional cutting processing is difficult to process, it shows great advantages in improving product quality, production efficiency and economic benefits, but at present it still has many problems to be solved.
1. The mechanism of many special processing (such as ultrasonic, laser and other processing) is not very clear, and the selection of process parameters and the stability of the processing process need to be further improved.
2. Some special processing (such as electrochemical machining) in the process of waste residue, waste gas if improper housing, will produce environmental pollution, affecting the health of workers.
3. The processing accuracy and productivity of some special processing (such as rapid prototyping, plasma arc machining, etc.) need to be improved.
4. Some special processing (such as laser processing) requires large investment in equipment, high maintenance costs, but also to be further resolved.
The development trend of five special processing
1. In accordance with the perspective of system engineering, intensify the in-depth research on the basic principles, processing mechanisms, process rules, and processing stability of special processing. At the same time, it fully integrates high-tech based on modern electronic technology, computer technology, information technology, and precision manufacturing technology to make processing equipment more automated and flexible.
2. Starting from the actual situation, we will vigorously develop new methods in the field of special machining, including micro-machining and compound machining, especially high-quality, high-efficiency, and economic-type composite machining, and match the appropriate manufacturing mode to give full play to it. Features.
3. The pollution problem is a serious obstacle to the influence and restriction of some special processing applications and developments. We must make great efforts to use waste gas, liquid waste, and waste residues to develop in the direction of "green" processing.
It can be foreseen that with the development of science and technology and modern industry, special processing will continue to improve and develop rapidly, which in turn will promote the development of science and technology and modern industry, and will play an increasingly important role.
references
1. Kong Qinghua, Special Processing, Tongji University Press, 1997
2. Special processing manual,