Laser welded metal sandwich panel
2022-09-07 12:04:10
Lightweight aluminum sandwich panels are used in a wide variety of vehicles with different speeds: from buses to racing cars; from cargo planes to flights; from ferries to rowing. The hardness and strength of these materials are very important properties. Honeycomb sandwich panels are often used as skeletons and bonded together using high performance adhesives. This structure is problematic for many engineers, especially when exposed to flame or when immersed in water. In order to solve these problems, the British Welding Research Institute (TWI) has developed a laser welded metal sandwich panel structure using extruded aluminum as the core material. >> Into the colorful world of laser welding  Â
According to the institute, in the experimental study, the aluminum sandwich plate with the trademark Ex-StructTM was composed of a 2 mm thick 5083 aluminum alloy plate and a 6060 aluminum alloy extruded tube. The extrusion die is designed to form an interlocking connection of the outer circumference of the tube. The tube has a diameter of 30 mm and a wall thickness of 2 mm. The tolerance of the bump interface is strictly controlled. According to the Welding Research Institute, they have used laser spot welding and laser strut welding to demonstrate the feasibility of sandwich panel fabrication and to identify key factors affecting weld quality and deformation. It is said that the use of a 4047 alloy (Al-13% Si) filled wire having a diameter of 1.2 mm can reduce weld solidification cracks and obtain a smooth beaded surface.
An exemplary panel of the Ex-StructTM sandwich panel was fabricated by positioning at the mechanical joint of the tube and using Nd:NAG laser spot welding. Laser spot welding is performed one by one in a horizontal direction from one side of the sandwich panel. A continuous welding operation is performed at the spot weld of each row by controlling the on/off time of the grating. In order to avoid welding cracks, the spot mode is used, and the power ramp is used at the end of the pulse to reduce the cooling rate. The controlled ramping of the laser power reduces the crack sensitivity of the weld. The same welding operation as described above is then started on the other side of the sandwich panel.
Another demonstration of the Ex-StructTM sandwich panel was made by Nd:NAG laser strut welding. The degreased tube is first placed on the bottom plate and made up as a whole. The welding proceeds linearly from one edge of the surface to the other and along the mechanical joint between the welded tubes. This operation is repeated until the welding of the other edge is completed. The same welding operation as described above is then performed on the other side of the sandwich panel. The weld is relatively smooth and has no surface defects, the welding speed can reach 2.6mm/min, the laser power is 3kW, and the feeding speed is 3mm/min.
Over the years, the British Welding Institute has been providing solutions for a wide range of materials for the civil and military shipbuilding industries worldwide. With the increasingly fierce international competition and the demand for high-speed ferry users to reduce the weight of aluminum ships, it is now under great pressure not only to reduce overall life cost and innovation, but also to increase the cost-effectiveness of manufacturing. The UK Welding Institute's strategy is therefore to provide added value for thin plates, extruded materials, castings or prefabricated panels for aluminium or aluminium companies, as well as technical solutions to reduce material costs or increase material functionality. The new vision of connectivity technology will be the focus of the hospital's work to meet current and future markets. In addition to developing connection technology, the British Welding Institute is now working on material development, cladding technology, distortion prediction, simulation work, and ship structure performance and reliability prediction.
According to the institute, in the experimental study, the aluminum sandwich plate with the trademark Ex-StructTM was composed of a 2 mm thick 5083 aluminum alloy plate and a 6060 aluminum alloy extruded tube. The extrusion die is designed to form an interlocking connection of the outer circumference of the tube. The tube has a diameter of 30 mm and a wall thickness of 2 mm. The tolerance of the bump interface is strictly controlled. According to the Welding Research Institute, they have used laser spot welding and laser strut welding to demonstrate the feasibility of sandwich panel fabrication and to identify key factors affecting weld quality and deformation. It is said that the use of a 4047 alloy (Al-13% Si) filled wire having a diameter of 1.2 mm can reduce weld solidification cracks and obtain a smooth beaded surface.
An exemplary panel of the Ex-StructTM sandwich panel was fabricated by positioning at the mechanical joint of the tube and using Nd:NAG laser spot welding. Laser spot welding is performed one by one in a horizontal direction from one side of the sandwich panel. A continuous welding operation is performed at the spot weld of each row by controlling the on/off time of the grating. In order to avoid welding cracks, the spot mode is used, and the power ramp is used at the end of the pulse to reduce the cooling rate. The controlled ramping of the laser power reduces the crack sensitivity of the weld. The same welding operation as described above is then started on the other side of the sandwich panel.
Another demonstration of the Ex-StructTM sandwich panel was made by Nd:NAG laser strut welding. The degreased tube is first placed on the bottom plate and made up as a whole. The welding proceeds linearly from one edge of the surface to the other and along the mechanical joint between the welded tubes. This operation is repeated until the welding of the other edge is completed. The same welding operation as described above is then performed on the other side of the sandwich panel. The weld is relatively smooth and has no surface defects, the welding speed can reach 2.6mm/min, the laser power is 3kW, and the feeding speed is 3mm/min.
Over the years, the British Welding Institute has been providing solutions for a wide range of materials for the civil and military shipbuilding industries worldwide. With the increasingly fierce international competition and the demand for high-speed ferry users to reduce the weight of aluminum ships, it is now under great pressure not only to reduce overall life cost and innovation, but also to increase the cost-effectiveness of manufacturing. The UK Welding Institute's strategy is therefore to provide added value for thin plates, extruded materials, castings or prefabricated panels for aluminium or aluminium companies, as well as technical solutions to reduce material costs or increase material functionality. The new vision of connectivity technology will be the focus of the hospital's work to meet current and future markets. In addition to developing connection technology, the British Welding Institute is now working on material development, cladding technology, distortion prediction, simulation work, and ship structure performance and reliability prediction.
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