Laser welding is an important aspect of laser material processing technology. It can be categorized by its working method into laser spot welders (manual welders), automatic laser welders, laser beam welders, and fiber-optic transmission laser welders. Laser welding involves using high-energy laser pulses to heat small areas of the material locally. The energy of the laser radiation is then transferred and diffused into the material through heat conduction, causing it to melt and form a specific molten pool, thereby achieving the welding objective.
The principle of laser welding machines is essentially to complete welding through pulsed laser beams. This principle can be divided into thermal conduction and laser deep penetration. The thermal conduction principle involves heating the area to be welded through radiation. As surface heat gradually penetrates into the material interior through conduction, melting the workpiece can be achieved by relative energy, repetition frequency, and relevant laser parameters. For laser deep penetration, a continuous laser beam is required to perform the task, thus achieving material interconnection and welding depth. With technological advancement (categorized as pulsed laser welding and continuous laser welding), pulsed laser welding has less than or equal to 100 spots per second, while continuous laser welding can reach less than or equal to 5,000 spots per second. This welding principle, under sufficient high-density laser irradiation, allows the welding material to rapidly absorb the energy of the laser beam at a point, resulting in complete melting and penetration of the metallic material.
Compared to other traditional welding techniques, the main advantages of laser welding are:
1. The laser beam has a small laser focus spot with high power density, capable of welding high melting point and high-strength alloy materials.
2. Laser welding is a contactless processing method, eliminating tool wear and tool change issues. The laser beam energy and movement speed are adjustable, allowing for various welding processes.
3. Laser welding offers high automation, controllable by computer, with fast welding speed and high efficiency, allowing for convenient welding of any complex shapes.
4. Laser welding results in a small heat-affected zone and minimal material deformation, eliminating the need for further processing.
5. Lasers can weld workpieces inside vacuum chambers and within intricate structural interiors.
6. Laser beams are easy to direct and focus, enabling transformations in all directions.
7. Laser welding compares favorably to electron beam processing, as it does not require a stringent vacuum equipment system and is easy to operate.
8. Laser welding offers high production efficiency, stable and reliable processing quality, and good economic and social benefits.
Application:
Laser welding technology is suitable for welding metals such as gold, silver, titanium, nickel, tin, copper, aluminum, stainless steel, galvanized steel, and their alloys. It enables precise welding between the same type of metal and different types of metals, and has been widely applied in industries such as aerospace equipment, shipbuilding, instruments and meters, electromechanical products, hardware accessories, kitchenware, digital accessories, fitness equipment, precision machinery, and automotive manufacturing.
