Analysis of several typical applications of the ho

2022-08-21
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Analysis of several typical applications of laser cutting and welding

the concept of stimulated radiation proposed by Einstein in the 1920s foresaw the generation of laser. 40 years later, in 1960, American scientist Maiman took the lead in developing the first ruby laser, marking the official birth of laser. Subsequently, laser technology developed rapidly. After solid-state lasers, gas lasers, chemical lasers, dye lasers, atomic lasers, ion lasers, semiconductor lasers, X-ray lasers and fiber lasers have come out one after another, and their application fields have also been extended to such industries as electronics, light industry, packaging, gifts, small hardware industry, medical devices, automobiles, machinery manufacturing, steel, metallurgy, petroleum, etc, Provide advanced technical equipment for the technological transformation of traditional industries and the modernization of manufacturing

compared with ordinary light, laser has four characteristics: monochromaticity (single wavelength), coherence, directivity and high light intensity. The laser beam is easy to transmit, and its temporal and spatial characteristics can be controlled separately. After focusing, a very small spot can be obtained. The laser beam with very high power density can melt and vaporize any material, and it can also accurately and quickly process the local area of the material. The heat input to the workpiece during processing is small, and the heat affected zone and thermal deformation are small; High processing efficiency; Easy to automate. Laser technology is a comprehensive high-tech, involving optics, mechanics, electronics and other disciplines. Similarly, laser processing equipment also involves many disciplines, which determines its high-tech and high yield. Throughout the international and domestic laser applications, after years of research, development and improvement, the contemporary laser and laser processing technology and equipment have been quite mature, forming a series of laser processing processes

this paper introduces the application of laser processing technology in metal cutting and welding

1 characteristics and application of laser cutting

laser cutting is the most widely used laser processing technology in various countries. In many foreign fields, such as automobile manufacturing and machine tool manufacturing, laser cutting is used to process sheet metal parts. With the continuous improvement of the beam quality of high-power lasers, the range of laser cutting objects will be more extensive, including almost all metal and non-metallic materials. For example, laser can be used to cut three-dimensional parts with complex shape for materials with high hardness, high brittleness and high melting point, which is the advantage of laser cutting

at present, enterprises that choose laser cutting systems are mainly divided into two categories: one is large and medium-sized manufacturing enterprises, which produce a large number of plates that need cutting and cutting, and have strong economic and technical strength; The other is collectively referred to as processing stations, which are specialized in undertaking laser processing business and have no leading products of their own. On the one hand, its existence can meet the processing needs of some small and medium-sized enterprises, on the other hand, it will bring publicity and demonstration to the promotion and application of laser cutting technology in the initial stage

several key technologies of laser cutting are the integrated technology of light, machine and electricity. The parameters of laser beam, the performance and accuracy of machine and CNC system directly affect the efficiency and quality of laser cutting. The accuracy, efficiency and quality of laser cutting change with different parameters, and the shell is installed on the printed circuit board, which changes with time, such as cutting power, speed, frequency, material thickness and material quality, so the rich experience of operators is particularly important

1.1 main advantages of laser cutting

(1) good cutting quality: narrow incision width (generally 0..5mm), high accuracy (generally hole center distance error 0.1-0.4mm, contour dimension error 0.1-0.5mm), good incision surface roughness (generally RA is 12.5-25 μ m) Generally, the cutting seam can be welded without secondary processing

(2) fast cutting speed, for example, using 2kW laser power, the cutting speed of 8mm thick carbon steel is 1.6m/min; The cutting speed of 2mm thick stainless steel is 3.5m/min, with small heat affected zone and minimal deformation

(3) it is clean, safe and pollution-free, which greatly improves the working environment of operators

laser cutting belongs to non-contact optical thermal processing and is known as "a universal tool that will never wear". The workpiece can be closely arranged or nested in any form to make full use of raw materials. Due to the non-contact processing, the distortion of the processed parts is minimized and the wear is reduced

in fact, laser cutting also has its shortcomings. In terms of accuracy and surface roughness of the incision, laser cutting cannot exceed electrical processing, and it is difficult to reach the level of flame and plasma cutting in terms of cutting thickness. In addition, it cannot be shaped, tapped and folded like a turret punch

1.2 comparison between laser cutting and punch

in the past, the sheet metal processing industry used traditional punch for stamping, and later developed to CNC turret punch and composite machine tools. With the progress of society, laser cutting technology has also been introduced into the metal processing industry. At present, it has become an advanced processing method with rapid development and wide application in industry. According to informal statistics, China has used more than 500 laser cutting systems in industrial production, accounting for about 2% of the total number of systems in operation in the world

in the metal processing industry, laser cutting is widely used in low carbon steel with a thickness of no more than 20mm and stainless steel with a thickness of 8mm. Most of the sheet metal parts have complex contours and small batches, such as automatic elevator structural parts, elevator panels, machine tool and grain machinery covers, various electrical cabinets, switchgear, textile machinery parts, engineering machinery structural parts, large motor silicon steel sheets, etc. In addition, some metal patterns, logos and fonts used in decoration, advertising and service industries can also be made by laser cutting

CNC brick tower punch is suitable for mass production of products with simple shape. The finished products include electrical cabinets, communication system exchange cabinets, elevator door panels and handrail panels, steel furniture, etc. Compared with the same cutting and stamping conditions, the price of laser cutting machine is generally higher than that of CNC brick tower punch, but due to its flexibility and other advantages (for example, laser cutting only needs to cut according to the drawing shape, and there is no need to manufacture molds, which will shorten the production cycle in the future). In recent years, some manufacturers are gradually aware of the high benefits it brings. In order to enhance market competitiveness, enterprises purchase laser cutting machines while owning multiple CNC brick tower punches to adapt to various types of products. Therefore, it is more appropriate to complement each other than to say that there is competition between laser cutting machine and CNC brick tower punch

2 typical applications of laser cutting

2.1 applications in the automotive field

advanced three-dimensional laser equipment can not only cut car body parts, but also cut, weld, heat treat, melt the whole car body. In view of the new changes in EU regulations, even three-dimensional measurement, so as to achieve the technical requirements that conventional processing cannot achieve. German tongkuai's three-dimensional laser equipment has been successfully applied in Mercedes Benz, Audi, BMW, Volkswagen, general motors, Ford, Renault, Skoda, Opel, Saab, Volvo and Daimler Chrysler for many years

2.2 wide application in the aviation field

many international aero-engine enterprises use three-dimensional laser equipment to cut and punch high-temperature alloy materials in the burner section, and have achieved success in laser cutting of aluminum alloy materials or special materials in military and civil aircraft

3 characteristics and application of laser welding

laser welding is a high-speed, non-contact and minimal deformation welding method, which is very suitable for large and continuous processing. With the development of laser equipment and processing technology, the ability of laser welding is also increasing. At present, 4kw C02 laser is used to weld 1mm plates, and the welding speed is as high as 20m/min. for example, the splicing and welding of large plates at the bottom of car boxes in the automotive industry. There are mainly two ways of laser welding: conduction welding and penetration welding. At present, penetration welding is the main laser application in the world. In recent years, high-power 10000 watt laser has been widely used in machinery, automobile, steel and other industrial sectors

compared with other welding technologies, the main advantages of laser welding machine are:

(1) laser welding speed is fast, the weld depth width ratio is large (up to 5 ~ 10), and the deformation is small

(2) suitable for processing precision parts, box parts and weldments with sealing requirements. After the laser beam is gathered, a small spot can be obtained, which can be accurately positioned, and can be applied to large-scale automatic production. Not only the production efficiency is greatly improved, but also the heat affected zone is small, and the solder joint is pollution-free, which greatly improves the quality of welding

(3) the mechanical properties of laser welds are good. Generally, the mechanical properties of welds are stronger than that of base metal

(4) when welding, there is no need for shielding or vacuum environment, which is of great significance for industrial scale production

(we often confuse the wire change experimental machine with the material change experimental machine. 5) through new technology such as laser wire feeding welding and laser powder feeding welding, the industrialized application of laser has been realized, and a new application field of laser welding has been opened up

(6) inaccessible parts can be welded, and non-contact long-distance welding can be implemented. Especially in recent years, optical fiber transmission technology has been used in YAG laser processing technology, which makes laser welding technology more widely promoted and applied

in a word, laser welding has the following advantages: high strength, ultra long service life; High welding speed and efficiency; The lap joint process is simple and the scrap rate is low; Low positioning accuracy is suitable for industrial production. It is mainly used in military enterprises, food industry, chemical industry and petrochemical industry

4 typical application of laser welding

4.1 application of laser welding large plate splicing for automobile

in order to meet the needs of the automotive industry for wide steel plates and special functional steel plates, large plate splicing is carried out by laser welding to meet the requirements of large three-dimensional functional stamping parts in automobile factories. Automobile manufacturers all over the world have realized the application of laser welding of such components. For example, Mercedes Benz, BMW Volkswagen, general motors, Toyota, Opel Saab, Daimler Chrysler and many other companies have already applied it. Cold rolled steel plates with a width of 1m can be assembled into steel plates with a width of 2m by laser welding

4.2 application of laser welding in gear processing

the process of laser welding gear has fundamentally changed the traditional design and manufacturing concept, and provided better economy and more compact structure for the processing of gear box components. Using the laser welding gear process, the whole ring gear ring needs to be processed first, then cut into several gear rings, and then welded on the transmission shaft according to the requirements of the gearbox

5 Conclusion

laser processing technology has been widely used in many fields. With the continuous deepening of the research on laser processing technology, equipment and technology, it will have a broader application prospect

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