What Is Laser Beam Welding?
Laser welding is an efficient and precise welding method using a laser beam with high energy density as a heat source. Laser welding is one of the important aspects of the application of laser material processing technology. In the 1970s, it was mainly used for welding thin-wall materials and low-speed welding. The welding process is thermally conductive, that is, laser radiation heats the surface of the workpiece. The surface heat is diffused to the inside by thermal conduction. By controlling the width, energy, peak power and repetition frequency of the laser pulse And other parameters to make the workpiece melt and form a specific molten pool. Due to its unique advantages, it has been successfully used in precision welding of micro and small parts.
- Laser welding is an efficient and precise welding method using a laser beam with high energy density as a heat source. Laser welding is one of the important aspects of the application of laser material processing technology. In the 1970s, it was mainly used for welding thin-wall materials and low-speed welding. The welding process is thermally conductive, that is, laser radiation heats the surface of the workpiece. Surface heat is diffused to the inside by thermal conduction. And other parameters to make the workpiece melt and form a specific molten pool. Due to its unique advantages, it has been successfully used in precision welding of micro and small parts.
- China's laser welding is at the advanced level in the world. It has the technology and ability to use laser to form complex titanium alloy components of more than 12 square meters, and has invested in the prototype and product manufacturing of many domestic aviation research projects. In October 2013, Chinese welding experts won the Brooke Prize, the highest academic award in the field of welding, and China's laser welding level has been recognized by the world.
Principles of laser welding technology
- Laser welding can be realized by continuous or pulsed laser beams. The principle of laser welding can be divided into thermal conduction welding and laser deep penetration welding. When the power density is less than 10 4 ~ 10 5 W / cm 2, it is heat conduction welding. At this time, the penetration depth is shallow and the welding speed is slow. When the power density is greater than 10 5 ~ 10 7 W / cm 2 , the metal surface is recessed into "holes" under the action of heat. Form deep penetration welding with fast welding speed and large aspect ratio.
The principle of thermal conduction laser welding is: the laser radiation heats the surface to be processed, and the surface heat is diffused to the inside by thermal conduction. By controlling the laser parameters such as the pulse width, energy, peak power and repetition frequency, the workpiece is melted to form a specific molten pool .
Laser welding machines for gear welding and metallurgical sheet welding mainly involve laser deep-melt welding.
Laser deep fusion welding generally uses continuous laser beams to complete the connection of materials. The metallurgical physical process is very similar to electron beam welding, that is, the energy conversion mechanism is completed through a "key-hole" structure. Under sufficiently high power density laser irradiation, the material evaporates and forms small holes. The small hole filled with steam is like a black body, which absorbs almost all the energy of the incident beam. The equilibrium temperature in the cavity reaches about 2,500 ° C. Heat is transferred from the outer wall of the high-temperature cavity, which melts the metal surrounding the cavity. The small hole is filled with high-temperature steam generated by continuous evaporation of the wall material under the beam. The four walls of the small hole surround the molten metal, and the liquid metal surrounds the solid material. (In most conventional welding processes and laser conduction welding, energy (Deposited on the surface of the workpiece, and then transferred to the interior by transfer). The liquid flow outside the pore wall and the surface tension of the wall layer are consistent with the steam pressure continuously generated in the pore cavity and maintain dynamic equilibrium. The light beam continuously enters the small hole, and the material outside the small hole is continuously flowing. As the light beam moves, the small hole is always in a steady state of flow. That is, the small hole and the molten metal surrounding the hole wall move forward with the forward speed of the leading beam, and the molten metal fills the gap left after the small hole is removed and condenses with it, and a weld is formed. All of this happens so quickly that the welding speed can easily reach several meters per minute.
Laser welding work equipment
- It consists of an optical oscillator and a medium placed between the mirrors at both ends of the cavity of the oscillator. When the medium is excited to a high-energy state, it starts to generate in-phase light waves and reflects back and forth between the mirrors at both ends, forming a photoelectric junction effect, amplifying the light waves, and obtaining enough energy to start emitting laser light.
- Laser can also be interpreted as a device that converts primary energy sources such as electrical energy, chemical energy, thermal energy, light energy, or nuclear energy into a beam of electromagnetic radiation at a specific light frequency (ultraviolet, visible or infrared). The morphology can be easily changed in some solid, liquid or gaseous media. When these media are excited in the form of atoms or molecules, they produce a beam-laser with almost the same phase and nearly a single wavelength. Due to the same phase and single wavelength, the difference angle is very small, and the distance that can be transmitted before being highly concentrated to provide welding, cutting and heat treatment functions is quite long.
Laser welding laser classification
- There are two main types of lasers used for welding, namely CO2 lasers and Nd: YAG lasers. Both the CO2 laser and the Nd: YAG laser are invisible infrared light to the naked eye. The Nd: YAG laser beam is mainly near-infrared light with a wavelength of 1.06 Lm. The thermal conductor has a high light absorption at this wavelength. For most metals, its reflectivity is 20% to 30%. 25 mm As long as the use of standard optical mirrors can make the near-infrared light beam to a diameter of 0. 25 mm. The CO2 laser beam is far-infrared light, with a wavelength of 10.6Lm. Most metals reflect 80% to 90% of this light. A special optical mirror is required to focus the beam to a diameter of 0.75-0.1mm. . Nd: YAG laser power can generally reach about 4 ~ 6 000W, and now the maximum power has reached 10 000W. The CO2 laser power can easily reach 20 000W or more.
- The high-power CO2 laser solves the problem of high reflectivity through the pinhole effect. When the surface of the material illuminated by the light spot melts, a pinhole is formed. This small hole filled with steam is like a black body, which absorbs almost all the energy of the incident light. The equilibrium temperature reaches about 25 000 e, and the reflectance decreases rapidly within a few microseconds. Although the development focus of CO2 lasers is still focused on the development of equipment, it is no longer about increasing the maximum output power, but how to improve the beam quality and focusing performance. In addition, in the case of high-power welding with a CO2 laser of more than 10 kW, if an argon shielding gas is used, a strong plasma is often induced to make the penetration shallow. Therefore, for high-power welding of CO2 lasers, helium gas that does not generate plasma is often used as a protective gas.
- The application of a diode laser combination to excite high power Nd: YAG crystals is an important development topic, which will greatly improve the quality of the laser beam and form more efficient laser processing. The direct diode array is used to excite the laser with an output wavelength in the near-infrared region. Its average power has reached 1 kW, and the photoelectric conversion efficiency is close to 50%. The diode also has a longer service life (10 000 h), which is conducive to reducing the maintenance costs of laser equipment. Development of a diode-pumped solid-state laser device (DPSSL). [1]
Laser welding process parameters
- (1) Power density. Power density is one of the most critical parameters in laser processing. With a high power density, the surface layer can be heated to the boiling point within a microsecond time range, resulting in a large amount of vaporization. Therefore, high power density is advantageous for material removal processes such as punching, cutting, and engraving. For lower power density, it takes several milliseconds for the surface temperature to reach the boiling point. Before the surface layer vaporizes, the bottom layer reaches the melting point, which is easy to form a good fusion weld. Therefore, in conductive laser welding, the power density is in the range of 10 ^ 4 ~ 10 ^ 6W / CM ^ 2.
- (2) Laser pulse waveform. Laser pulse waveform is an important problem in laser welding, especially for thin-plate welding. When a high-intensity laser beam is irradiated to the surface of the material, 60 to 98% of the laser energy is reflected and lost on the metal surface, and the reflectance changes with the surface temperature. During a laser pulse, the reflectivity of the metal varies greatly.
- (3) Laser pulse width. Pulse width is one of the important parameters of pulse laser welding. It is not only an important parameter different from material removal and material melting, but also a key parameter that determines the cost and volume of processing equipment.
- (4) The influence of defocus amount on welding quality. Laser welding usually requires a certain amount of defocus, because the power density in the center of the spot at the laser focus is too high, and it is easy to evaporate into holes. The power density distribution is relatively uniform across the planes away from the focal point of the laser. There are two ways of defocusing: positive defocus and negative defocus. The focal plane is above the workpiece for positive defocus, otherwise it is negative. According to geometrical optics theory, when the positive and negative defocus planes are equal to the welding plane, the power density on the corresponding planes is approximately the same, but the shape of the molten pool obtained is actually different. With negative defocus, greater penetration can be obtained, which is related to the formation of the molten pool. Experiments show that laser heating of 50 ~ 200us material begins to melt, forming liquid metal and partial vaporization, forming high-pressure steam, and ejecting at extremely high speed, emitting dazzling white light. At the same time, the high-concentration vapor moves the liquid metal to the edge of the molten pool, forming a depression in the center of the molten pool. When negative defocusing, the internal power density of the material is higher than the surface, and it is easy to form stronger melting and vaporization, so that the light energy is transmitted deeper into the material. Therefore, in practical applications, when large penetration depth is required, negative defocus is used; when welding thin materials, positive defocus should be used.
- (5) Welding speed. The speed of the welding speed will affect the heat input per unit time. If the welding speed is too slow, the heat input will be too large, which will cause the workpiece to burn through. If the welding speed is too fast, the heat input will be too small, which will cause the workpiece to be opaque.
Laser welding welding characteristics
- It belongs to fusion welding, which uses laser beam as energy source and impacts on the welding joint.
- The laser beam can be guided by a planar optical element (such as a mirror), and then the beam is projected on the weld seam by a reflective focusing element or a lens.
- Laser welding is a non-contact welding. It does not require pressurization during the operation, but inert gas is required to prevent the oxidation of the molten pool. The filler metal is occasionally used.
- Laser welding equipment and products (17 photos)
- Laser welding can be combined with MIG welding to form a laser MIG composite welding to achieve large penetration welding, while the heat input is greatly reduced compared to MIG welding.
Comparison of laser welding processes
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- Sensor sealing welding methods include: resistance welding, argon arc welding, electron beam welding, plasma welding and so on.
- 1. Resistance welding: It is used to weld thin metal parts, and clamp the workpiece to be welded between two electrodes to melt the surface contacted by the electrode with a large current, that is, to perform welding by resistance heating of the workpiece. The workpiece is easily deformed. Resistance welding is welded on both sides of the joint, while laser welding is performed from only one side. The electrodes used for resistance welding need to be maintained frequently to remove oxides and metal stuck from the workpiece. In contact with the workpiece, the beam can also enter areas that are difficult to reach by conventional welding, and the welding speed is fast.
- 2. TIG welding: Non-consumable electrodes and shielding gas are used to weld thin workpieces, but the welding speed is slower, and the heat input is much larger than laser welding, which is prone to deformation.
- 3. Plasma arc welding: Similar to argon arc, but its welding torch will generate a compression arc to increase the arc temperature and energy density. It is faster than argon arc welding and has a deeper penetration, but is inferior to laser welding.
- 4. Electron beam welding: It relies on a beam of accelerated high-energy density electrons to impinge on the workpiece, which generates huge heat in a small dense surface of the workpiece, forming a "small hole" effect, thereby implementing deep-fusion welding. The main disadvantages of electron beam welding are the need for a high vacuum environment to prevent electron scattering, the equipment is complex, the size and shape of the weldment are limited by the vacuum chamber, and the quality of the weldment assembly is strict. Non-vacuum electron beam welding can also be implemented. Scattering and focusing do not affect the effect. Electron beam welding also has magnetic offset and X-ray problems. Because the electrons are charged, they will be affected by magnetic field deflection, so it is required to demagnetize the workpiece before welding. X-rays are particularly strong under high pressure and need to protect operators. Laser welding does not require a vacuum chamber and demagnetization before welding the workpiece. It can be performed in the atmosphere and has no X-ray prevention problems. Therefore, it can be operated online in the production line and can also weld magnetic materials.
Laser welding development process
- The world's first laser beam was produced in 1960 by using a flash bulb to excite ruby crystals. Due to the limited thermal capacity of the crystal, it can only produce a very short pulsed beam with a low frequency. Although the instantaneous pulse peak energy can be as high as 10 ^ 6 watts, it still belongs to low energy output.
- The yttrium aluminum garnet crystal rod (Nd: YAG) using neodymium (ND) as the excitation element can generate a continuous single wavelength beam of 1--8KW. YAG laser, with a wavelength of 1.06uM, can be connected to the laser processing head through a flexible optical fiber. The equipment layout is flexible and suitable for welding thickness of 0.5-6mm.
- Using CO2 laser (wavelength 10.6uM) with CO2 as exciter, the output energy can reach 25KW, and it can make single-pass total penetration welding with 2mm plate thickness. The industry has been widely used in metal processing.
- In the mid-1980s, laser welding, as a new technology, received widespread attention in Europe, the United States, and Japan. In 1985, the German company Thyssen Steel and Volkswagen Co., Ltd. successfully adopted the world's first laser tailored welding plate on the Audi100 body. In the 1990s, major automobile manufacturers in Europe, North America, and Japan began to use laser tailored welding technology in large-scale body manufacturing. The practical experience of both laboratories and automobile manufacturers has proved that tailor-welded plates can be successfully applied to the manufacture of automobile bodies.
- Laser tailor welding is the use of laser energy to automatically splice and weld several different materials, different thicknesses, different coatings of steel, stainless steel, aluminum alloy, etc. to form a whole plate, profile, sandwich panel, etc. Different components have different requirements for material properties, and use the lightest weight, optimal structure and optimal performance to achieve lightweight equipment. In developed countries such as Europe and the United States, laser tailor welding is not only used in transportation equipment manufacturing, but also in fields such as construction industry, bridges, home appliance plate welding production, rolled steel plate welding (steel connection in continuous rolling) and other fields. use.
- World-renowned laser welding companies include Swiss Soudonic, French Arcelor Steel Group, German ThyssenKrupp Group TWB, Canadian Servo-Robot, and German Precitec.
- The application of laser tailored welding technology in China has just started. On October 25, 2002, China's first professional commercial production line for laser tailored welding plates was officially put into operation. Introduction of Krupp Group TWB. Since then, Shanghai Baosteel Arcelor Laser Tailor Welding Co., Ltd., FAW Baoyou Laser Tailor Welding Co., Ltd. have been put into production one after another.
- In 2003, double beam C02 laser wire filler welding and YAG laser wire filler welding of the A318 aluminum alloy lower wall structure were realized abroad. It replaced the traditional riveting structure by reducing the weight of the aircraft fuselage by 20% and saving 20% of the cost. . Gong Shuili believes that laser welding technology will have great significance for the transformation and upgrading of China's traditional aviation manufacturing industry. Later, he immediately applied for a number of related pre-research topics, organized a research team, and took the lead in introducing the "dual beam laser welding" technology into the topic research in China. From the beginning, he was planning to use this technology in aircraft manufacturing. A team of Chinese experts presented preliminary technology to an aircraft design firm and introduced them to the superiority and feasibility of dual-beam laser welding. After many studies and evaluations, the design firm decided to apply this technology to the manufacture of ribbed siding of an aircraft, achieving the goal of initially applying the "dual-beam laser welding" technology to aircraft manufacturing, breaking through the lightweight alloy laser Key technologies such as welding wire filling precision control, integrated and innovatively developed a dual-beam laser wire-filling composite welding device, established the first domestic high-power double-beam laser wire-filling welding platform, and realized large-wall thin-walled T-joints with double-beam sides Synchronous welding, which was successfully applied for the first time in the welding and manufacturing of key structural parts of aviation stiffened siding, played an important role in the development of new aircraft in China.
- In 2003, China's first large-scale strip online welding complete equipment provided by Huagong Laser passed offline acceptance. The equipment integrates laser cutting, welding and heat treatment, making China Huagong Laser the fourth company in the world capable of producing such equipment.
- In 2004, the "High Power Laser Cutting, Welding and Cutting Welding Combined Processing Technology and Equipment" project of Huagong Laser Farley won the second prize of National Science and Technology Progress, and became the only laser enterprise in China with the technology and equipment research and development capabilities.
- With the rapid development of the industrial laser industry, the market requires more and more laser processing technology. Laser technology has gradually shifted from a single application to a variety of applications. Laser processing is no longer a single cutting or welding. The market requires laser processing. The demand for integrated cutting and welding is also increasing, and integrated cutting and welding laser processing equipment for laser cutting and laser welding has come into being.
- Huagong Laser Farley research and development of Walc9030 cutting and welding integrated machine, 9 × 3 meters ultra-large format, is currently the world's largest format laser cutting and welding integrated equipment. Walc9030 is a large-format cutting and welding device that integrates laser cutting and laser welding functions. The device has professional cutting heads and welding heads. The two processing heads share a beam. Numerical control technology ensures that they will not interfere with each other. The equipment can complete Cutting and welding are required at the same time. Cut before welding, welding after cutting, laser cutting, welding can be easily switched. One device, two functions, without adding new equipment, saves equipment costs for application manufacturers, improves processing efficiency and processing scope, And because of the integrated welding and cutting, the machining accuracy is completely guaranteed, and the equipment performance is efficient and stable. In addition, it overcomes the difficulties of easily deforming the plate during the tailor welding of super-large plates and how to maintain the stability of the ultra-long flying light path. Two flat plates of 6 meters long and 1.5 meters wide can be welded at one time, and the surface is smooth after welding. It is flat and does not require other subsequent processing. At the same time, it can cut 3 meters wide and 6 meters long and less than 20mm. It can be formed in one time without secondary position.
- The Shenyang Institute of Automation of the Chinese Academy of Sciences has conducted international cooperation with Ishikawajima Harima Heavy Industries Co., Ltd., following the national technology development strategy of introducing digestion and innovation, conquering several key technologies of laser tailor welding, and developed the first domestic laser in September 2006. Tailor-welded complete production line, and successfully developed a robot laser welding system, realizing laser welding of plane and space curves.
- In October 2013, Chinese welding experts won the Brooke Prize, the highest academic award in the field of welding. The British Welding Institute (TWI) recommends nominations from more than 4,000 member units from more than 120 countries each year, and finally awards the award to an expert in recognition of its outstanding contribution in the field of welding or connecting science and technology with industrial applications . This award is not only a recognition of Gongshui and his team, but also an affirmation of AVIC's advancement in material connection technology.
Advantages and disadvantages of laser welding
Laser welding advantages
- (1) The required amount of heat can be reduced to a minimum, the metallographic range of the heat affected zone is small, and the deformation caused by heat conduction is also the lowest;
- (2) The welding process parameters for single-pass welding of 32mm plate thickness have passed the verification, which can reduce the time required for thick plate welding and even eliminate the use of filler metal;
- (3) There is no need to use electrodes, and there is no concern about electrode contamination or damage. And because it is not a contact welding process, the wear and tear of the machine can be minimized;
- (4) The laser beam is easy to focus, align and guided by optical instruments. It can be placed at a proper distance from the workpiece and can be re-guided between the tools or obstacles around the workpiece. Other welding laws are limited by the above-mentioned space And cannot play
- (5) The workpiece can be placed in a closed space (under vacuum control or internal gas environment under control);
- (6) The laser beam can be focused on a small area, and small and closely spaced parts can be welded;
- (7) A wide range of weldable materials can also be used to join various heterogeneous materials;
- (8) It is easy to perform high-speed welding by automation, and it can also be controlled by digital or computer;
- (9) When welding thin materials or small diameter wires, it will not be as easy to be melted back as arc welding;
- (10) It is not affected by the magnetic field (easy for arc welding and electron beam welding), and can accurately align the weldment;
- (11) Welding two metals with different physical properties (such as different resistance);
- (12) No vacuum or X-ray protection is required;
- (13) If through-hole welding is used, the bead depth-to-width ratio can reach 10: 1;
- (14) The switching device can be used to transmit the laser beam to multiple workstations.
Disadvantages of laser welding
- (1) The position of the weldment must be very accurate, and it must be within the focus range of the laser beam;
- (2) When welding fixtures are required, the final position of the welding fixture must be aligned with the welding spot where the laser beam will impact;
- (3) The maximum weldable thickness is limited. For workpieces with a penetration thickness exceeding 19mm, laser welding is not suitable for the production line;
- (4) For highly reflective and highly thermally conductive materials such as aluminum, copper and their alloys, the weldability will be changed by the laser;
- (5) When laser beam welding with medium to high energy is performed, the plasma controller needs to be used to drive off the ionized gas around the molten pool to ensure the reappearance of the weld bead;
- (6) Energy conversion efficiency is too low, usually less than 10%;
- (7) The weld bead solidifies rapidly, and there may be concerns about porosity and embrittlement;
- (8) Equipment is expensive.
- In order to eliminate or reduce the defects of laser welding and make better use of this excellent welding method, some composite welding processes using other heat sources and lasers are proposed, mainly laser and arc, laser and plasma arc, and laser and induction heat sources. Welding, dual laser beam welding, and multi-beam laser welding. In addition, various auxiliary process measures have been proposed, such as laser filler wire welding (can be subdivided into cold wire welding and hot wire welding), external magnetic field to enhance enhanced laser welding, shielding gas to control deep welding of the weld pool, and laser-assisted friction stir welding Wait.
Laser welding applications
Laser welding manufacturing
- TailoredBlandLaserWelding technology has been widely used in foreign car manufacturing. According to statistics, there were more than 100 laser tailored welding production lines for cutting blanks worldwide in 2000, with an annual output of 70 million tailored blanks for passenger car components, and continued Grow at a higher rate. The domestically produced imported models Passat, Buick, Audi, etc. also use some tailored blank structure. In Japan, CO2 laser welding is used instead of flash butt welding to connect steel rolling coils. Research on ultra-thin plate welding, such as foils with a thickness of 100 microns or less, cannot be welded, but by using a special output power waveform The success of YAG laser welding shows the broad future of laser welding. Japan also successfully developed YAG laser welding for the first time in the world to repair the thin tubes of steam generators in nuclear reactors. In Japan, Su Baorong also carried out gear laser welding technology.
Laser welding powder metallurgy
- With the continuous development of science and technology, many industrial technologies have special requirements on materials, and materials manufactured by smelting methods can no longer meet the needs. Due to the special properties and manufacturing advantages of powder metallurgy materials, traditional metallurgy materials are being replaced in some fields such as automotive, aircraft, tool and cutting tool manufacturing. With the increasing development of powder metallurgy materials, the problem of its connection with other parts It appears increasingly prominent, which limits the application of powder metallurgy materials. In the early 1980s, laser welding entered the field of powder metallurgy material processing with its unique advantages, opening up new prospects for the application of powder metallurgy materials, such as welding diamond using the brazing method commonly used in powder metallurgy material connection. Low strength, wide heat-affected zone, especially inability to adapt to high temperature and high strength requirements that cause the solder to melt and fall off. Laser welding can improve welding strength and high temperature resistance.
Laser welding automotive industry
- In the late 1980s, kilowatt-level lasers were successfully used in industrial production, and today laser welding production lines have appeared in the automotive industry on a large scale, becoming one of the outstanding achievements of the automotive industry. European automobile manufacturers such as Audi, Mercedes-Benz, Volkswagen, and Volvo in Sweden took the lead in using sheet metal welding such as roof, body, and side frames in the 1980s. In the 1990s, GM, Ford, and Chrysler competed. Introducing laser welding into automobile manufacturing, although it started late, it has developed rapidly. Fiat in Italy uses laser welding in the welding assembly of most steel plate components. Japan's Nissan, Honda and Toyota Motors have used laser welding and cutting processes in the manufacture of body cover parts. High-strength steel laser welding assemblies have excellent performance due to their excellent performance. It is used more and more in automobile body manufacturing. According to the statistics of the US metal market, by the end of 2002, the consumption of laser welded steel structures will reach 70,000 tons, which is three times that of 1998. According to the characteristics of large volume and high degree of automation in the automotive industry, laser welding equipment is developing towards high power and multi-path. In terms of technology, the Sandia National Laboratory of the United States and PrattWitney have jointly researched the addition of powder metal and wire in the laser welding process, and the Institute of Applied Beam Technology of Bremen, Germany has conducted a lot of research on the use of laser welding of aluminum alloy body frames. It is believed that the addition of filler metal to the weld seam will help eliminate hot cracks, increase welding speed, and solve tolerance problems. The developed production line has been put into production at Mercedes-Benz's factory.
Laser welding electronics industry
- Laser welding has been widely used in the electronics industry, especially in the microelectronics industry. Because laser welding has a small heat-affected zone, rapid heating concentration, and low thermal stress, it has shown unique advantages in the packaging of integrated circuit and semiconductor device housings. Laser welding has also been applied in the development of vacuum devices, such as Molybdenum focus pole and stainless steel support ring, fast hot cathode filament assembly, etc. The thickness of the elastic thin-wall corrugated sheet in the sensor or the temperature controller is 0.05-0.1mm, which is difficult to solve by traditional welding methods, TIG welding is easy to weld through, and the plasma stability is poor. There are many influencing factors, and laser welding has a good effect and is widely used. Applications.
- In recent years, laser welding has gradually been applied to the assembly process of printed circuit boards. As circuits become more integrated, component sizes are getting smaller, and lead pitches are becoming smaller, it has been difficult for previous tools to operate in small spaces. The laser can solve the problem because it can be welded without touching the parts. It is valued by circuit board manufacturers.
Laser welding biomedicine
- Laser welding of biological tissues began in the 1970s. Klink et al. And Jain [13] successfully welded fallopian tubes and blood vessels with lasers and showed superiority, which led more researchers to try to weld various biological tissues and popularize them. Welding of other tissues. The domestic and foreign research on the nerve of laser welding mainly focuses on the research of laser wavelength, dose and its function recovery and the choice of laser solder. Liu Tongjun conducted basic research on laser welding of small blood vessels and skin. The common bile duct of rats was welded. Compared with the traditional suture method, the laser welding method has the advantages of fast anastomosis, no foreign body reaction during the healing process, maintaining the mechanical properties of the welded part, and the growth of the repaired tissue according to its original biomechanical properties. It will be used in future biomedicine. Get more widely used.
Laser welding other
- In other industries, laser welding has also gradually increased, especially in special materials welding. Many studies have been conducted in China, such as laser welding of BT20 titanium alloy, HEl30 alloy, Li-ion battery, etc. German glass machinery manufacturer GlamacoCoswig and IFW joined Technology and Materials Experimental Research Institute has developed a new laser welding technology for flat glass.