What are the characteristics of laser welding

Update:02 Nov 2020

Spot welding machine Laser welding is one of the greate […]

Spot welding machine Laser welding is one of the greatest inventions of the 20th century. The first device in the world came out in 1960. Laser welding is one of the most advanced manufacturing technologies today. Compared with general welding methods, laser welding has the following characteristics:

1) The power density after focusing can reach 10 to the 5th power to 10 to the 7th power W/CM2. Even higher. The heating is concentrated, and the heat input required to complete the welding of the unit length and unit thickness of the workpiece is low, so the deformation of the workpiece is very small, and the heat affected zone is also very narrow. It is especially suitable for precision welding and micro welding.

2) Welds with a large aspect ratio can be obtained, and thick parts can be formed at one time without grooves. The aspect ratio of laser welding seam has reached 12:1, and the thickness of single-pass welded steel plate without bevel has reached 50mm.

3) It is concerned with the welding of refractory metals, metals with strong heat sensitivity, and large differences in thermophysical properties, differences in size and volume.

4) The spot welding machine can pass through the transparent medium to weld between the workpieces in the closed container.

5) The reflector can be used to make the beam reach the part that cannot be welded by the general welding method. The YAG laser can also be transmitted by the optical fiber, which has good accessibility.

6) The laser beam is not subject to electromagnetic interference and no magnetic bias exists, which is suitable for welding of magnetic materials.

7) No vacuum chamber is required, no X-rays are generated, and observation and alignment are convenient.

The disadvantage of laser welding is the large investment in equipment, and it is difficult to directly weld metals with high reflectivity.
At present, there are two main types of lasers used in spot welding machines for welding, gas lasers and solid-state lasers. The former is represented by CO2 lasers and the latter is represented by YAG lasers. According to the action method of laser, laser welding can be divided into continuous laser welding and pulsed laser welding. With the continuous improvement of equipment performance and the increasingly complex structure, the requirements for joint performance and deformation have become more and more demanding. Many traditional welding methods can no longer meet the requirements. Therefore, laser welding has an irreplaceable role in many occasions.