Second, laser technology and processing materials using laser beams
Although the beam quality of Nd:YAG solid-state lasers with a power of 12 mm×mrad or more is 4 GHz, it is impossible to achieve the application breadth of CO2 lasers. It is because of the low cost of use and maintenance costs of CO2 lasers, so it can be widely used. For example, a 3kW laminar CO2 laser can operate for about 40,000 hours and an operating cost of about 6 marks per hour. When the laser is used at half the power of a conventional CO2 laser, the same weld penetration depth can be achieved almost at the same welding speed of 1.5 m/min. When the welding penetration depth of the steel is 4 mm and the power of the laser beam is the same, the welding speed of the Nd:YAG solid-state laser is only half that of the CO2 laser. The total investment in using a Nd:YAG laser is lower than in a CO2 laser only when using a three-dimensional multi-axis articulated arm robot because the beam transmission through the optical fiber Nd:YAG laser is relatively simple. In the case of long-distance welding, the laser beam of the CO2 laser is focused by the lens, and the optical system of the scanner can freely position the laser beam on the surface of the workpiece. The focusing lens is mounted on an electric slide rail, and the machining point can be determined in a space of 1500 mm × 1500 mm × 400 mm. The mobile mirror unit is used to extend to the solder joint behind the interference edge.
Combining laser beam welding with arc welding can achieve a remarkable welding process: a combination of a CO2 laser beam and a gas-shielded metal arc welding process. This process enables efficient welding of different grades of steel. The purpose of using this process is to determine the maximum gap width amax allowed for welding steel plates of different thicknesses. When the thickness of the steel sheet is t=5 mm, the gap width is 2 mm; when t=8 mm, the width is 1.35 mm; when t=12 mm, the width is 0.7 mm. Welds are machined under gravity without the need for melt support behind any welds. When transversely welding a 20 mm thick steel plate, the gap width asssmax of the overlap can be up to 0.7 mm without any technical problems. Other aspects of the optimum process include setting the speed of the welding and wire feed and selecting the diameter of the wire.
This combined welding process was tested and demonstrated in actual welding work. For example, at Meyer Shipyard, several steel plates of 7.5~12mm thickness and 10m length were successfully welded, and the welding speed reached 2m/min. In the combined welding process described above, the combination of increased arcing can further enhance the advantages of the process, such as minimizing energy per unit length, increasing welding speed and the ability to lap joint gaps.
A robust, easy-to-operate "tool" is a diode-excited Nd:YAG laser and its high-quality laser beam. The thermal lens effect limits the improvement of the beam quality. The goal of the further improvement is to further increase the parameters of the beam and input it into the 100 μm glass fiber, so that the beam quality obtained is comparable to that of the CO2 laser.
The more promising here are disk lasers and laminar lasers. At the 2001 Laser Technology Exhibition, HASS Laser Technologies demonstrated the prototype of a disc laser for the first time. The laser power of the prototype was 1.3 kW, and the diameter of the optical fiber was 0.15 mm. Lamp-excited and diode-excited rod lasers have thermal lens problems caused by laser beam power, while disc lasers do not actually have thermal lens problems. Since the disc laser has a high-quality beam similar to the CO2 laser beam, it can be calibrated to change its power by means of fiber coupling, which is many times greater than the power of the rod laser calibration.
The use of diode-excited solid-state lasers with output powers greater than 4 kW is decisive for the welding of aluminum alloys. The beam quality of these systems is particularly good and can be instantly injected into a fiber with a diameter of 0.4 mm. The focusing power of the laser beam is greatly dependent on the cross-sectional area of ​​the fiber. This shows that the potential of this new generation of solid-state lasers is that the "dot" has a smaller diameter and a higher power density. The high power density allows one to perform welding in a continuous wave mode. For example, it was first used to study various connections to small samples and small parts, such as butt joints, T-welds, and lap joints. The material of the part is AlMgSi0.7 (thickness: 3 mm) and AlMg3 (thickness: 1.6 mm) aluminum alloy. High quality weld bead shapes are only possible in a purely continuous wave state. When welding aluminum with a kilowatt-scale diode-excited Nd:YAG laser, high reliability is achieved over a wide range of parameters.
A new method for influencing the geometry and quality of welds is also presented in the literature. This is based on the influence of the electromagnetic force in the molten pool, resulting in different molten pool flow and heat input. This selectively changes the shape of the weld, the depth of penetration, the shape of the weld bead and the formation of voids.
When the inner surfaces of pipes, cylinders and bushings are treated with a laser beam, the properties of the material can be changed even on very limited specific surfaces. The laser beam provides a precisely controlled source of energy that is applied at a specific location and time, usually with minimal error, so no or only a small amount of post-processing is required. In industrial applications, such tools are equipped with protective equipment, such as pressure. The chamber and the cross-jet (Cross-Jet) protect the optical system and dissipate the absorbed laser radiation, plasma radiation and incidental heat radiation by cooling.
The laser includes the following components: a laser adapter, a substrate, and a laser head. The substrate allows the laser to be mechanically coupled to a defined processing system and to the media to be processed. Within the matrix, laser radiation is provided to the laser head optically. If necessary, a device that moves with the media brush can be mounted to rotate the laser head. The laser head is equipped with a central beam forming element (coated copper mirror) and a protective gas or process gas nozzle. A 2kW kW Nd:YAG laser is also connected to a hardening unit for long rails. The integrated mirror set focuses the beam to 3mm x 5mm at a working distance of approximately 60 mm. A solid-state laser with a power of 3 kW can harden a high-alloy steel bushing of φ60 mm and a depth of 600 mm. In addition, the development of an optical system for internal hardening of the pipe has a rotating laser head that can be used on a fixed engine block to harden the cylinder bearing surface of the gray cast iron engine block of the truck diesel engine.
Although the beam quality of Nd:YAG solid-state lasers with a power of 12 mm×mrad or more is 4 GHz, it is impossible to achieve the application breadth of CO2 lasers. It is because of the low cost of use and maintenance costs of CO2 lasers, so it can be widely used. For example, a 3kW laminar CO2 laser can operate for about 40,000 hours and an operating cost of about 6 marks per hour. When the laser is used at half the power of a conventional CO2 laser, the same weld penetration depth can be achieved almost at the same welding speed of 1.5 m/min. When the welding penetration depth of the steel is 4 mm and the power of the laser beam is the same, the welding speed of the Nd:YAG solid-state laser is only half that of the CO2 laser. The total investment in using a Nd:YAG laser is lower than in a CO2 laser only when using a three-dimensional multi-axis articulated arm robot because the beam transmission through the optical fiber Nd:YAG laser is relatively simple. In the case of long-distance welding, the laser beam of the CO2 laser is focused by the lens, and the optical system of the scanner can freely position the laser beam on the surface of the workpiece. The focusing lens is mounted on an electric slide rail, and the machining point can be determined in a space of 1500 mm × 1500 mm × 400 mm. The mobile mirror unit is used to extend to the solder joint behind the interference edge.
Combining laser beam welding with arc welding can achieve a remarkable welding process: a combination of a CO2 laser beam and a gas-shielded metal arc welding process. This process enables efficient welding of different grades of steel. The purpose of using this process is to determine the maximum gap width amax allowed for welding steel plates of different thicknesses. When the thickness of the steel sheet is t=5 mm, the gap width is 2 mm; when t=8 mm, the width is 1.35 mm; when t=12 mm, the width is 0.7 mm. Welds are machined under gravity without the need for melt support behind any welds. When transversely welding a 20 mm thick steel plate, the gap width asssmax of the overlap can be up to 0.7 mm without any technical problems. Other aspects of the optimum process include setting the speed of the welding and wire feed and selecting the diameter of the wire.
This combined welding process was tested and demonstrated in actual welding work. For example, at Meyer Shipyard, several steel plates of 7.5~12mm thickness and 10m length were successfully welded, and the welding speed reached 2m/min. In the combined welding process described above, the combination of increased arcing can further enhance the advantages of the process, such as minimizing energy per unit length, increasing welding speed and the ability to lap joint gaps.
A robust, easy-to-operate "tool" is a diode-excited Nd:YAG laser and its high-quality laser beam. The thermal lens effect limits the improvement of the beam quality. The goal of the further improvement is to further increase the parameters of the beam and input it into the 100 μm glass fiber, so that the beam quality obtained is comparable to that of the CO2 laser.
The more promising here are disk lasers and laminar lasers. At the 2001 Laser Technology Exhibition, HASS Laser Technologies demonstrated the prototype of a disc laser for the first time. The laser power of the prototype was 1.3 kW, and the diameter of the optical fiber was 0.15 mm. Lamp-excited and diode-excited rod lasers have thermal lens problems caused by laser beam power, while disc lasers do not actually have thermal lens problems. Since the disc laser has a high-quality beam similar to the CO2 laser beam, it can be calibrated to change its power by means of fiber coupling, which is many times greater than the power of the rod laser calibration.
The use of diode-excited solid-state lasers with output powers greater than 4 kW is decisive for the welding of aluminum alloys. The beam quality of these systems is particularly good and can be instantly injected into a fiber with a diameter of 0.4 mm. The focusing power of the laser beam is greatly dependent on the cross-sectional area of ​​the fiber. This shows that the potential of this new generation of solid-state lasers is that the "dot" has a smaller diameter and a higher power density. The high power density allows one to perform welding in a continuous wave mode. For example, it was first used to study various connections to small samples and small parts, such as butt joints, T-welds, and lap joints. The material of the part is AlMgSi0.7 (thickness: 3 mm) and AlMg3 (thickness: 1.6 mm) aluminum alloy. High quality weld bead shapes are only possible in a purely continuous wave state. When welding aluminum with a kilowatt-scale diode-excited Nd:YAG laser, high reliability is achieved over a wide range of parameters.
A new method for influencing the geometry and quality of welds is also presented in the literature. This is based on the influence of the electromagnetic force in the molten pool, resulting in different molten pool flow and heat input. This selectively changes the shape of the weld, the depth of penetration, the shape of the weld bead and the formation of voids.
When the inner surfaces of pipes, cylinders and bushings are treated with a laser beam, the properties of the material can be changed even on very limited specific surfaces. The laser beam provides a precisely controlled source of energy that is applied at a specific location and time, usually with minimal error, so no or only a small amount of post-processing is required. In industrial applications, such tools are equipped with protective equipment, such as pressure. The chamber and the cross-jet (Cross-Jet) protect the optical system and dissipate the absorbed laser radiation, plasma radiation and incidental heat radiation by cooling.
The laser includes the following components: a laser adapter, a substrate, and a laser head. The substrate allows the laser to be mechanically coupled to a defined processing system and to the media to be processed. Within the matrix, laser radiation is provided to the laser head optically. If necessary, a device that moves with the media brush can be mounted to rotate the laser head. The laser head is equipped with a central beam forming element (coated copper mirror) and a protective gas or process gas nozzle. A 2kW kW Nd:YAG laser is also connected to a hardening unit for long rails. The integrated mirror set focuses the beam to 3mm x 5mm at a working distance of approximately 60 mm. A solid-state laser with a power of 3 kW can harden a high-alloy steel bushing of φ60 mm and a depth of 600 mm. In addition, the development of an optical system for internal hardening of the pipe has a rotating laser head that can be used on a fixed engine block to harden the cylinder bearing surface of the gray cast iron engine block of the truck diesel engine.
Our LED Emergency Batten Light is perfect for commercial and industrial use, made from solid polycarbonate with a thick poly carbonate diffuser the unit is very durable this fitting has an IP rating of 65 and is anti corrosive. Interal lithium battery pack to make emergency time rating from 60-180mins. The fitting gives off an impressive 5850 lumens using only 65 watts of energy making it a great energy saving light fitting. The batten uses high quality LED chips giving off a great array of light to any indoor and outdoor area.
Emergency Batten Light,Emergency Led Batten,Emergency Light Batten,Led Emergency Batten Light
Foshan Nai An Lighting Electric Co.,ltd , https://www.naipslighting.com