Laser welding technology is a fusion welding technology that uses a laser beam as an energy source to make it impinge on the weldment joint to achieve the purpose of welding.
1. Features of laser welding
First of all, laser welding can reduce the amount of heat input to the minimum, the metallographic change range of the heat-affected zone is small, and the deformation caused by heat conduction is also the lowest. 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 deformation of the machine tool can be minimized. The laser beam is easy to focus, align and be guided by optical instruments. It can be placed at an appropriate distance from the workpiece, and can be guided between tools or obstacles around the workpiece. Other welding methods cannot be used due to the above-mentioned space limitations. . Secondly, the workpiece can be placed in a closed space (vacuumed or the internal gas environment is under control). The laser beam can be focused on a small area, can weld small and closely spaced parts, can weld a wide range of materials, and can also join various heterogeneous materials. In addition, it is easy to automate high-speed welding, and it can also be controlled by digital or computer. When welding thin materials or thin-diameter wires, it is not as easy to be troublesome as arc welding.
2. Advantages of laser welding
(1) The heat input can be reduced to the minimum required amount, the metallographic change range of the heat-affected zone is small, and the deformation caused by heat conduction is also the lowest.
(2) The welding process parameters of 32mm plate thickness single pass welding have been verified and qualified, which can reduce the time required for thick plate welding and even save 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 deformation of the machine tool can be minimized.
(4) The laser beam is easy to focus, align and be guided by optical instruments. It can be placed at an appropriate distance from the workpiece, and can be re-guided between tools or obstacles around the workpiece. Other welding rules are subject to the above-mentioned space limitations. And can't play.
(5) The workpiece can be placed in a closed space (after vacuuming or the internal gas environment is 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 materials that can be welded, and various heterogeneous materials can also be joined to each other.
(8) It is easy to automate high-speed welding, and it can also be controlled by digital or computer.
(9) When welding thin materials or thin-diameter wires, it will not be as easy to be troublesome as arc welding.
(10) It is not affected by the magnetic field (arc welding and electron beam welding are easy), and can accurately align the weldment.
(11) Two metals with different physical properties (such as different resistance) can be welded
(12) No vacuum or X-ray protection is required.
(13) If perforated welding is used, the depth-to-width ratio of the weld bead can reach 10:1
(14) can switch the device to transmit the laser beam to multiple workstations.
3. Advantages and disadvantages
(1) The position of the weldment must be very precise and must be within the focus range of the laser beam.
(2) When a jig is used for the weldment, it must be ensured that the final position of the weldment is aligned with the welding point that the laser beam will impact.
(3) The maximum weldable thickness is restricted to penetrate the workpiece with a thickness far exceeding 19mm. Laser welding is not suitable for the production line.
(4) For materials with high reflectivity and high thermal conductivity, such as aluminum, copper and their alloys, the weldability will be changed by laser.
(5) When performing medium to high energy laser beam welding, a plasma controller must be used to drive out the ionized gas around the molten pool to ensure the reappearance of the weld bead.
(6) The 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) The equipment is expensive.
4. Application
Laser welding machine technology is widely used in high-precision manufacturing fields such as automobiles, ships, airplanes, high-speed rail, etc. It has brought a significant improvement to people's quality of life, and it has also led the home appliance industry into the era of precision manufacturing.
Manufacturing industry, electronics field, medical biology, automobile industry, powder metallurgy and other fields.
5. Foreground
Laser welding is a combination of modern technology and traditional technology. Compared with traditional welding technology, laser welding is particularly unique and has a wider range of applications and applications, which can greatly improve the efficiency and accuracy of welding. Its high power density and fast energy release can better improve work efficiency. At the same time, its own focus point is smaller, which undoubtedly makes the adhesion between stitched materials better, and will not cause material damage and deformation. The emergence of laser welding technology has realized the fields that traditional welding technology cannot apply. It can simply achieve various welding requirements of different materials, metals and non-metals, and because of the penetration and refraction of the laser itself, it can be based on The trajectory of the speed of light itself achieves random focus within 360 degrees, which is undoubtedly unimaginable under the development of traditional welding technology. In addition, because laser welding can release a large amount of heat in a short period of time to achieve rapid welding, it has lower environmental requirements and can be performed under general room temperature conditions, without the need for vacuum or gas protection. After decades of development, people have the highest level of understanding and recognition of laser technology, and it has gradually expanded from the initial military field to the modern civilian field, and the emergence of laser welding technology has further expanded the application range of laser technology. In the future, laser welding technology can not only be used in fields such as automobiles, steel, and instrument manufacturing, but also in military, medical, and other fields, especially in the medical field, with the help of its own high heat and high temperature. The characteristics of integration and hygiene can be better applied in clinical diagnosis and treatment such as neuromedicine and reproductive medicine. And its own precision advantages will also be applied in more precision instrument manufacturing industries, which will continue to benefit the development of mankind and society.