Application of Laser Processing Technology in Metalworking Processes

Around the current high-quality development goals, the transformation and upgrading of the manufacturing industry is a very urgent need. Manufacturing ushered in the high-end, intelligent and localisation, light manufacturing also ushered in the "best period".

Qian Lao (Qian Xuesen) in 1964 will LASER named "laser". Laser is a beam of photons to stimulate atoms, sending out a beam of photons of the same frequency, and then through the amplification to reach a certain energy level output, which is one of the "four great inventions" in the 20th century, after atomic energy, semiconductors, computers, another major invention. Laser has four major characteristics, namely, high energy (brightness), high directionality, high monochromaticity and high coherence. Since its localisation, the laser has become an advanced tool for a wide range of applications, including industrial, medical, commercial and information technology. The history of laser development can be traced back to 1917, when Einstein put forward the theory of stimulated radiation; in 1960, American scientists discovered the first laser beam in the laboratory; in 1961, China's first ruby laser was born in Changchun Institute of Optical Mechanics; in 1971, Huazhong University of Science and Technology (HUST) set up a laser programme for the first time in a domestic university. The overall industrialisation of laser in China began in 1997, when the Laser Processing Engineering Centre of Huazhong University of Science and Technology was transformed into a corporate operation, and the parent company, Huagong Science and Technology, was established in 1999 and listed on the stock market in 2000, which is also China's "first laser stock". Through nearly 20 years of efforts and breakthroughs in the core light source, through the application in various aspects, especially 3C, automotive, semiconductor, etc., in 2015, through the synergistic development of industry-university-research, led by the school, we won the first prize of the National Scientific and Technological Progress.

At present, the proportion of industrial applications in China's industrial laser industry has reached 60%. The core driving force for the growth of lasers in industrial applications is the continuous penetration and substitution of laser processing for traditional processing. Laser processing is moving towards high energy, with fibre lasers of up to 60,000 watts already commercially available. At the same time, laser processing is developing in two directions around high-efficiency, large-size macro-processing, and high-peak power, narrow pulse widths such as picoseconds and femtoseconds, and other small-size precision micro-nano-processing.

Industrialised production, production and processing of precision requirements are becoming higher and higher. In this case, how to produce precision machined metal composite parts has become one of the key issues that metal composite manufacturing enterprises must address. In the production and processing of many metal composite materials, laser equipment is widely used because of its processing high efficiency and high precision.

I. Principles of the application of laser technology in metal processing

The basic element of the key application of the laser generator in the production of metal composites is the use of the monochromaticity of the laser generator, the properties of the relevant fields and the vertical plane to adjust the focus of the laser generator to fibre laser cutting or arc welding electric welding. At this point, basically, metal composites create a raw material that must be processed. Staff can utilise local industry to accurately produce and process metal composites.

In addition, the operation of the laser generator can be adjusted by means of unique mechanical devices. As a result, the melting of some of the metal composites can be precisely controlled. The key fundamentals of applying lasers in the processing of metallic materials are the utilisation of the linear dispersal characteristics of lasers and the ability to work with high temperature generation. In addition to this, the laser output power and compressive strength can be adjusted during the entire process of processing metallic materials, and the most important elements of the deformation are the compressive strength of the laser's focus point and the machining process.

II. Advantages of laser technology in metal processing

Currently, lasers are coherent light sources, which usually have important characteristics such as coherence and monochromaticity, such as normal directional well, high intensity and high power. In addition, the current laser if focused on a point before the surface treatment material, it has the effect of instantaneous and gradual conversion into thermal and optical energy, and vice versa, heated to tens of thousands of degrees Celsius. At this point, even the strongest materials can withstand high temperatures and melting. At the same time, the temperature in the material will rise, the evaporation phenomenon will produce small holes, the entire production process to remove the part and the remaining material will gradually evaporate and evaporate, leaving no residue. In fact, it is local laser processing materials in the material processing process due to the sharp rise in temperature and rapid liquefaction and evaporation of the continuous process. Laser processing technology can achieve the traditional sheet metal processing methods are difficult to complete parts processing. When the size of steel drilling inside the box is large, the traditional sheet metal processing methods can not be carried out, but the laser processing technology can easily complete the continuous processing, in the same field, the laser processing technology is more accurate than the traditional technology, faster, and more competitive in the market. At the two-dimensional level, laser processing is more flexible.

(i) Fast processing speed

Compared with traditional production and processing expertise, the most important professional advantage of laser cutting equipment in the production and processing of metal composite materials is faster production and processing. Compared with fibre laser cutting, the professional production and processing speed advantage is more obvious. According to the scientific research on the processing of parts in the processing of metal materials can be found, in the parts processing, the power of the laser generator is directly proportional to the speed of fibre laser cutting of metal composite materials. In the whole production process, the application of fibre laser cutting machinery and equipment can quickly produce a variety of metal composite materials and non-metallic materials, fibre laser cutting machinery and equipment can quickly produce complex parts, basically guaranteeing the accuracy of production.

(B) laser technology processing high precision

In the application of laser technology processing of metal materials in the whole process, metal material parts of the laser cutting or welding process of processing precision provisions are very high. After the laser generator irradiates the surface of the part, the surface of the part is partially melted. The compressive strength and relative density can be adjusted according to a precise management programme to compare the partially melted part of the surface of the metallic part with the melting temperature. Compared to conventional welding processes, laser welding offers greater selectivity. In the whole process of metal welding and metal material composite fibre optic line fibre laser cutting, the application of laser generator will reduce the harmful substances produced in the whole process of argon arc welding and arc welding. And basically maintain the health and life safety of employees. In addition, because the local melting of metal substances can be precisely controlled, the properties of other parts of the metal workpiece will not change due to the temperature increase. On this basis, the welding precision and performance of metal materials can be ensured more stably.

(iii) Good processing quality

On the basis of high processing precision, laser technology can improve the processing quality of metal materials, and cut and weld high melting point metal materials quickly and accurately. On this basis, some metal materials with high melting point can be processed with higher precision and quality. Secondly, the use of laser technology to process metal materials can manipulate the scale of partial melting operation of metal materials at a larger level. As a result, after laser cutting or electric welding and soldering, the surface of the metal material product workpiece produces less convex and uneven surface. From this perspective, laser cutting equipment can not only improve the production quality of metal composite materials, but also improve the production efficiency of metal composite materials.

III. Application of laser technology in the processing of metal materials

Due to its range of advantages such as good laser directionality, high power and monochromaticity, this task has been common worldwide since the early 1960s, and high priority has been given to scientific research in this field. Laser technology has fuelled the rapid development of many fields, in particular the results of processing in any field of application.

Laser processing is the process of laser light on a surface causing a change in the shape of an object or in the properties of an object. Based on the mechanism of light-matter interaction, laser processing can be broadly classified into two categories: laser heat treatment and photochemical reaction processing. Laser heat treatment refers to various treatments of the body due to the rapid heating effect of the laser on the material, and photochemical reaction processing refers to the process of using a high-intensity, high-brightness laser to act on the body in a controlled manner and cause a photochemical reaction, which is also known as cold processing. Cutting, drilling, boring and sweeping of hot and cold metallic and non-metallic materials, such as welding, surface strengthening and reduction of heat-treated metallic materials are very favourable.

(i) Application of laser technology in the cutting of metal materials

Laser cutting can effectively use the advantages of programming software, greatly improve the utilization of the plate, reduce the use of materials and waste, while reducing labour intensity and labour force, to achieve the desired results, improvements, on the other hand, the unloading function can be omitted from the cutting process and plate cutting, effectively reducing the clamping material, reducing additional processing time. Therefore, it promotes the most reasonable arrangement of the cutting procedure, effectively improves the processing efficiency and saves materials; in the growing market environment, rapid product development means market. The application of laser cutting machine can effectively reduce the number of times the moulds are used, save the development cycle of new products, and enhance the speed and pace of their development.

The quality of laser cut parts is very good, significantly improve production efficiency, conducive to small batch production, effectively ensuring the shortening of the product development cycle, the market atmosphere, the application of laser cutting, the size of the drop moulds are positioned accurately, can be widely used in the future of mass production. Sheet metal processing work, almost all types of acne need finishing surgery, laser cutting machine and direct welding junction assembly, so the application of laser cutting machine to reduce the process and duration of work, effectively improve work efficiency, can achieve the labour intensity and double increase in the reduction of processing costs, and promote the improvement of the working environment, and greatly accelerate the development of the progress of the speed of reducing the investment in moulds, and effectively reduce the cost of; Laser Cutting Machine in Sheet Metal Processing and drying in a wide range of applications, can greatly shorten the processing and production cycle of new products, greatly reducing the investment in moulds and other aspects; significantly improve the processing speed of workers, saving unnecessary processing procedures; at the same time, widely used in industrial processing, laser cutting machine can effectively process a variety of complex parts, improve accuracy, help to shorten the processing cycle, improve the accuracy of the processing, and directly eliminating the need for stamping moulds to replace the process, the Improve labour productivity.

(ii) Laser welding

Laser welding technology is very popular in modern times. There are two main forms of expression, namely, deep melt welding and conductive welding.

Deep solution welding is widely used in the machinery and equipment manufacturing industry. In use, the laser power must generally be adjusted to the appropriate level before electric welding. At the corresponding power standard, the laser output power input far exceeds the heat transfer rate. At this point, the laser is aimed at the surface of the metal material product, which will vaporise the surface of the material and produce a corresponding small hole. At this point, the laser will continue to move down the small aperture diameter. During this process, the metal part of the metal workpiece will continue to melt, producing the corresponding molten metal. At this point, the welding process is complete. Conduction welding, also known as heat transfer welding technology, is a traditional laser welding technique. In the application, the laser is directed onto the surface of the metal workpiece to raise its temperature. At this point, due to the principle of heat conduction, the surface temperature will gradually penetrate and spread to the interior. When the surface and internal temperatures rise to a certain melting point level, a molten pool appears, at which point the welding is completed. Conductive welding is more commonly used because it is suitable for conventional welding with shallow melt depths and small width requirements. In addition, compared with conventional welding technology, laser welding technology has the advantages of low labour costs and good welding quality. Therefore, the use of laser welding technology in welding work of modern metal processing technology is favourable, but the type of laser welding technology should be selected according to the actual requirements.

From the current development situation, laser welding technology has been continuously penetrated into the automotive industry, providing the necessary technical support for the development of the industry. At present, laser welding technology can meet the welding requirements of 70% of the parts in the automotive transmission system. Compared with other welding processes, laser welding can not only increase the service life of parts, but also reduce the cost of use, reflecting the unique value of the application.

Simply put, welding and stamping assembly scattered for flat workpieces. Through welding and assembly, the number of workpieces can be reduced, but also can improve the performance of parts, reduce weight, and thus improve the overall performance of the vehicle.

(iii) Laser perforation

Laser perforation is a traditional laser engraving and material processing technology. Compared with other technologies, laser engraving has the advantages of high precision, high efficiency, high efficiency, and has become an indispensable part of the current manufacturing technology. Since the end of the twentieth century, the pace of development of laser engraving technology has accelerated, and the trend of diversification has greatly increased. In addition, with the continuous progress of technology, the aperture is getting smaller and smaller, and the performance is getting higher and higher. Rough calculation, if we open a hole with a radius of 0.032 mm on the wings of 50,000 aircraft, we can save 40% of the oil due to the reduced flow resistance. In China, laser engraving technology has a relatively long history. in the early 1960s, China used this technology to manufacture watches, and the cumulative output has now exceeded 2.3 billion yuan. However, compared with developed countries, China still has a certain gap. At present, the laser engraving technology in developed countries is widely used in medicine manufacturing, food processing, aircraft manufacturing and other industries, bringing great material wealth and spiritual wealth.

(D) laser marking

Laser marking technology is a powerful laser material processing technology. The plant part consists of high-intensity, high-power laser, localised radiation and various types of chemical reactions, such as evaporation and liquefaction, which will be permanently retained on the MOL surface. Currently, metal products are the most widely used industry for laser marking technology. In recent years, laser systems have been continuously improved.The average maximum intensity of 250yag significantly deepens the label depth and improves the quality of the label. In addition, laser marking technology as a new type of anti-counterfeiting means, more and more attention from all walks of life.

Laser technology can reflect the modernisation degree of a country to some extent. Laser processing technology is basically a kind of technology that uses the characteristics of laser beams interacting with materials to cut, weld, stamp and engrave materials. With the continuous development of industry and the progress of laser processing technology, laser processing technology is bound to become an important processing technology in the application of metal processing technology.