High-power laser welding

When the power density of the laser spot irradiated on the surface of the workpiece reaches 106W/cm2 or more, the workpiece is rapidly heated under the irradiation of the laser, and its surface temperature rises to the boiling point in a very short time, causing the metal to melt and vaporize. An elongated hole filled with metal vapor is formed in the liquid metal. When the recoil pressure of the metal vapor is balanced with the surface tension and gravity of the liquid metal, the small hole does not continue to deepen, forming a small hole with stable depth around the small hole It is the welding molten pool, the small hole moves with the laser, and the welding seam is formed after the small hole is closed to realize laser self-fusion welding.

Laser self-fusion welding, that is, the welding of two or more parts melts itself and finally cools and condenses into one. This welding method does not require the addition of auxiliary flux or filler, and uses the workpiece itself to weld together. High-power laser self-fusion welding is widely used in different industries, such as airbag gas generators, gears, car seat parts, shock absorbers and other products in the automotive parts industry.

The welding seam of high-power laser self-fusion welding is well formed, and the deformation is small, especially suitable for medium and thin plates. Moreover, the welding equipment configuration is simple, the process is relatively easy to master, and it is widely used.

High-power laser compound welding technology

Laser hybrid welding technology combines the advantages of both laser welding and traditional gas shielded welding (arc). The characteristics of this welding method are:

Laser welding can obtain a large penetration in a small heat input and a small welding heat affected zone;

The attached gas shielded welding can greatly expand the size of the joint root gap, improve the surface condition and the allowable amount of impurities;

Improve the quality of gap filling and forming at the root of the weld and strengthen the control of welding metallurgy.

Compared with pure arc welding, laser composite welding technology has the advantages of laser welding and arc welding, and is suitable for welding aluminum alloy, titanium alloy, magnesium alloy and high alloy steel and other materials. For example, when welding aluminum alloy with pure laser, problems such as high inversion and weld sag are easy to occur. Using the method of laser arc compound welding, the high inversion problem can be solved well.

Laser welding seam tracking technology

Weld seam tracking is an important part of realizing laser welding automation. The principle of laser welding seam tracking system is an optical welding seam tracking system, which is mainly composed of a laser stripe sensor, an analysis unit and one to two linear drives. Advantages of laser welding seam tracking system:

Non-contact type, overcoming the inherent defects of the mechanical probe system, such as the inability to handle butt workpieces, small gaps and spot welds, etc.;

Application of welding seam tracking can ensure welding accuracy, improve welding quality and productivity, and reduce the rate of repairs and scrap;

At the same time, the requirements for assembly and positioning accuracy of welded structural assemblies are reduced, thereby saving tooling fixture costs.

The laser welding seam tracking system can be integrated with both robots and CNC machine tools. Common types of weld joints that are tracked include: butt joints, corner joints, lap joints, T joints, V/Y groove joints, etc., which are widely used in automobiles and auto parts (such as roof laser welding), steel (such as Laser tailored welding plates), aerospace, shipbuilding pipelines and other fields have improved the quality and automation of laser welding.

High-power laser remote welding technology

Remote laser welding technology has become an important welding method to replace traditional resistance spot welding. Compared with traditional laser welding, the main advantages of remote laser welding technology:

High positioning accuracy, short positioning time, fast welding speed and high efficiency;

Long working distance, no interference with welding fixture, less pollution of optical lens;

Flexible programming, tailor-made weld shape, optimized structure, improved strength, etc.

Compared with resistance spot welding, remote laser welding technology fully utilizes the technical and economic advantages of single-sided, non-contact laser welding, and combines it with the advantages of high-speed scanning galvanometer, which improves the overall production efficiency and can be effectively used. It is used to weld more and more automobile covering parts and components.

Application areas include laser connection of body-in-white body welding and its components, such as car seats, doors, hoods, B-pillars, switch cabinets, bumpers, instrument panels, air valves, etc.

(Reprinted from: Laser Manufacturing Network)