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1、略谈特种加工技术激光焊接（On the special processing technology of laser welding）On the special processing technology of laser weldingThis is known as the twenty-first Century universal tool, the laser processing technology, advanced processing technology it is a highly flexible and intelligent. The laser welding
2、 is one of the important aspects of the application of laser material processing technology, it has opened a new era of welding. Laser welding has been widely used in manufacturing industry, the field of powder metallurgy, automobile industry, electronic industry, biomedical and other fields.Welding
3、 technology in the economic and social development of our country has played an important role, but with the progress of science and technology, application of new materials and new technology, the traditional welding technology has been unable to meet the increasingly high requirements and conditio
4、ns, which makes the laser melting of materials science, mechanics, computer science and other related knowledge and technology the welding came into being.Working principle of laser weldingLaser welding is have excellent directivity, high brightness, high strength, high monochromaticity, high cohere
5、nce characteristics of laser beam radiation to the surface area of the workpiece, a laser beam passing through the focusing optical system, the power density of the laser focus is 104-107W/cm2, and the interaction is through the laser welding material, in a very short period the time to be welded to
6、 form a highly concentrated heat source, heat can be welded after zone melting and cooling crystallization form a solid solder joint and weld. According to the laser and the different ways of working, there are two kinds of laser welding method,A pulsed laser welding, mainly for single point and con
7、tinuous fixed material welding book, a circular formation of the solder joints during welding;The other one is continuous laser welding, mainly for large thick pieces of welding and cutting, forming a continuous weld welding process. Speaking in general, the choice of welding material, laser welding
8、 machine, working platform, is the main factor affecting the effect of laser welding. The melting phenomena in the welding process can produce and produce intensity depends mainly on the material surface, laser power density and peak power, good control of the above parameters can be carried out on
9、a variety of different welding by laser processing. In laser welding, laser beam focus position is one of the key control parameters, the laser power and welding speed, focus only in the best position within the weld shape can get the maximum penetration depth and good.The main characteristic of las
10、er welding, twoCompared with other traditional welding technology, laser welding has the following advantages:1, laser welding is a non-contact welding process without compression, high welding speed, high efficiency, large depth, residual stress and deformation is small, can be at room temperature
11、or under special conditions (such as closed space) for welding, welding equipment is simple, does not produce X ray.2, such as welding of refractory material of high melting point metal, and can be used for the welding of ceramics, organic glass and other non-metallic materials, welding of profiled
12、materials, good effect, and has great flexibility for welding inaccessible parts as non-contact remote welding.3, the laser beam can be focused by a small spot, because is not influenced by the magnetic field and precise positioning, therefore, of micro welding, micro, small workpiece is suitable fo
13、r mass production of the automatic welding.4, the laser beam is easy to realize by time and space beam splitter can switch device to transmit a laser beam for a plurality of workstations, therefore, capable of multi beam and processing and multistage process, provide conditions for more precise weld
14、ing.5, because the laser welding is a non-contact processing, no tool wear and tool changing and other issues, at the same time, it does not require the use of electrodes, so no pollution or damage to the electrodes concerns, and easy to automate high speed welding. Can also be digital or computer c
15、ontrol. However, laser welding has some limitations:First, the high cost of laser and its related systems, a large one-time investment in equipment.Secondly, in the process of welding, welding assembly of high precision,Location can not be on the workpiece and beam have significant deviation.In addi
16、tion, the welding thickness ratio of electron beam welding, welding of high reflectivity metal is difficult.Three, laser welding process1, welding between chips and chip. Generally use manual welding and automatic welding, including welding, butt welding, welding end center through hole in the centr
17、e, fusion welding process of four kinds of method.2, welding wire and wire. Generally use manual welding and semi-automatic welding, including wire and wire welding, butt welding, cross parallel welding, T welding and other four kinds of process.3 welding, metal wire and block member. The laser weld
18、ing can be realized successfully connecting wire and block component, block component size can be arbitrary. The welding should be paid attention to in the geometry of filamentous elements.4, different metal welding. Different types of metal welding to solve the weldability and welding parameters of
19、 laser welding between different materials only certain material combination is possible.5, massive object welding. The laser welding by laser melting deposition onto a substrate, generally suitable for products such as mold repair.Four, the quality control of laser weldingWith the development of la
20、ser, laser welding technology matures. However, in the actual welding production process, but also because of various reasons and problems. How to identify the causes of problems, how to solve the quality problem, this is a very important process in the process of management.First of all, to inspect
21、 the welding quality of the welding quality inspection. There are two kinds of methods of visual inspection and destructive inspection. Visual inspection as the name suggests, is the staff according to their rich experience in welding to determine whether the product is qualified, but if by this tes
22、t and as a result, is not sufficient, which requires destructive testing, which ripped the weldments for confirmation. In addition, the inspection can also be carried out using the tensile strength tensile tester.Secondly, according to the phenomenon of reason analysis. In general, if the welding pr
23、ocess is bad, may be a problem with the material, material or change the laser welding machine set waveform conditions were replaced in the material quality inspection solution; if the same parts of the welding products for poor welding, is likely to be the work table and the fixture problems; if th
24、e occasional welding and weld the phenomenon, can check the welding machine energy stability or table and fixture if there is a problem.Thirdly, strengthen the welding quality assurance management. In the welding process, often with a pressure test instrument to test the welding pressure, so that th
25、e pressure remains constant, at the same time, to carry out regular inspection of welding head movement condition; two to strengthen the monitoring of the current, avoid the fluctuations of the supply voltage, overload operation of welding machine caused by overheating causes current output reductio
26、n the workpiece, the bad result in the decrease in current, welding machine performance problems; three to consider the change of workpiece thickness, coating thickness, metal components, avoid bad welding products.Note five, laser weldingThe laser with the general light has biological effects (ripe
27、 effect, optical effect, pressure effect and electromagnetic effect), the biological efficiency in the benefits to the society, if there is no door or door will not on as the eyes, skin and nervous system of human tissue such as a direct or indirect damage. In order to ensure the safety and protecti
28、on of laser welding, it is necessary to strictly control the laser damage, good project control, personal protection and safety management.1, engineering controlEngineering control refers to the safety measures, laser or laser processing system adopted in the structure mainly includes: - to prevent
29、staff accept exceed the maximum permissible exposure guard; safety interlock means connected with the protective cover, remove the protective cover can be avoided when the automatic device radiation; eecure - on irradiation may cause light burning or secondary radiation to be closed; the key switch,
30、 remove the key to,Laser beam; termination - in order to make the laser beam beyond the controlled processing area, can use the beam stop or attenuator.2, personal protectionMainly refers to the laser protection and heat-resistant refractory wear clothes, wearing protective glasses, the laser can be
31、 selectively attenuated specific laser wavelength wear for ultraviolet laser source of laser protective masks, wearing protective gloves can prevent the laser reflection or scattering of laser damage.3, safety managementSafety management including set up specialized agencies or personnel, clear resp
32、onsibilities and rights: including safety training and medical supervision.Six, the development trend of laser weldingPeople in the application of laser welding technology at the same time, also continue to conduct in-depth research, aiming at its shortcomings, heating and other heat sources to impr
33、ove the performance of the laser heating of the workpiece, while maintaining the advantages of laser heating, the laser and other heat source for hybrid welding, the main laser with the arc, laser and plasma arc welding, laser composite and induction and dual laser beam welding. Composite welding ca
34、n increase welding penetration, improve joint performance, reduce the cost of equipment, improve the welding speed and productivity. In short, laser welding has high production efficiency, processing quality is stable and reliable, good economic and social benefits. In the new equipment, new materia
35、ls, new technology and new technology emerge in an endless stream, constantly updated era, producers not only to understand the characteristics, advantages and requirements of laser welding, we must know many innovations in this field and the future trend, the only way to grasp the technical trend,
36、can always walk in the forefront of the times.This is the authorized reprint articles, any person without the consent of the Licensor shall not be copied, reproduced excerpts or any other means of use, e-works will not bear any legal responsibility resulting! If any please inform me in time, in orde
37、r to carry out timely treatment. Contact: editore- tel:027-87592219/20/21.This is the authorized reprint articles, any person without the consent of the Licensor shall not be copied, reproduced excerpts or any other means of use, e-works will not bear any legal responsibility resulting! If any please inform me in time, in order to carry out timely treatment. Contact: editore- tel:027-87592219/20/21.