Laser welding technology is a technique of fusion welding, which uses a laser beam as an energy source to impact the weldment joint to achieve the purpose of welding.
1. Features of laser welding
First, laser welding can reduce the amount of heat input to a minimum, the metallographic range of the heat affected zone is small, and the deformation due to heat conduction is also the lowest. There is no need to use electrodes, no concerns about electrode contamination or damage. And because it is not a contact welding process, the wear and deformation of the machine can be minimized. The laser beam is easy to focus, align, and guided by the optical instrument. It can be placed at an appropriate distance from the workpiece and can be re-guided between the tools or obstacles around the workpiece. Other welding methods cannot be used due to the above space constraints. . Second, the workpiece can be placed in a closed space (with vacuum or internal gas environment under control). The laser beam can be focused in a small area, and can be welded to small and closely spaced parts. The range of solderable materials is large, and various heterogeneous materials can be bonded to each other. In addition, it is easy to automate high-speed welding, and it can also be digitally or computer controlled. When welding thin or thin wire, it will not be easy to remelt like arc welding.
2. Advantages of
laser welding
(1) The amount of heat input can be minimized, the metallographic range of the heat affected zone is small, and the deformation due to heat conduction is also the lowest.
(2) The welding process parameters of 32mm plate thickness single pass welding have been qualified, 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, no concerns about electrode contamination or damage. And because it is not a contact welding process, the wear and deformation of the machine can be minimized.
(4) The laser beam is easy to focus, align and guided by optical instruments, and can be placed at an appropriate distance from the workpiece and can be redirected between the implements or obstacles around the workpiece. Other welding methods are subject to the above space limitations. Can‘t play.
(5) The workpiece can be placed in a closed space (with vacuum or internal gas environment under control).
(6) The laser beam can be focused in a small area to weld small and closely spaced parts.
(7) The range of weldable materials is large, and various heterogeneous materials can 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 is not as easy to melt 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) Two metals that can weld different physical properties (such as different resistances)
(12) No vacuum is required and X-ray protection is not required.
(13) If the hole is welded, the width of the weld bead can be up to 10:1.
(14) The switching device can transmit the laser beam to a plurality of workstations.
3. Advantages and disadvantages
(1) The position of the weldment must be very precise and must be within the focus of the laser beam.
(2) When the fixture is to be used with a fixture, it must be ensured that the final position of the weldment is aligned with the weld point that the laser beam will impact.
(3) The maximum weldable thickness is limited to workpieces with a penetration thickness of more than 19 mm, and laser welding is not suitable for use on the production line.
(4) Highly reflective and highly thermally conductive materials such as aluminum, copper and alloys thereof, the weldability is changed by the laser.
(5) When performing medium-to-high-energy laser beam welding, a plasma controller is used to drive out the ionized gas around the molten pool to ensure re-emergence of the weld bead.
(6) The energy conversion efficiency is too low, usually less than 10%.
(7) The weld bead is rapidly solidified and may have pores and embrittlement concerns.
(8) The equipment is expensive.
4. Application
Laser welding machine technology has been widely used in high-precision manufacturing fields such as automobiles, ships, airplanes, and high-speed rails, which has brought significant improvements to people‘s quality of life, and has led the home appliance industry into the era of precision.
Manufacturing industry, electronics, medical biology, automotive industry, powder metallurgy and other fields.
5. Prospects
As a combination of modern technology and traditional technology, laser welding is particularly unique compared to traditional welding technology, and its application field and application level are more extensive, which can greatly improve the efficiency and precision of welding. Its high power density and fast energy release improve the working efficiency, and its own focusing point is smaller, which undoubtedly makes the adhesion between the stitched materials better, without causing damage and deformation of the material. The emergence of laser welding technology has enabled the application of traditional welding technology, which can easily realize 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 a free focus in the 360 degree range, 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 time to achieve rapid welding, it is less environmentally demanding and can be carried out under normal room temperature conditions without the need for vacuum or gas protection. After decades of development, people have the highest level of understanding and awareness of laser technology, and it has gradually expanded from the initial military field to the modern civil field, and the emergence of laser welding technology has further expanded the application range of laser technology. Future laser welding technology can not only be used in the fields of automobile, steel, instrument manufacturing, etc., but it can also be applied in more fields such as military, medicine, etc., especially in the medical field, with its own high heat and high. The characteristics of integration, health, etc., are better applied in clinical diagnosis and treatment of neuromedicine and reproductive medicine. And its own precision advantage will also be applied in more precision instrument manufacturing, which will continue to benefit human and social development.
