Views: 2 Author: Site Editor Publish Time: 2021-02-15 Origin: Site
Laser welding is one of the most advanced welding forms. Its application spans a range of different industries from aerospace to high-end jewelry manufacturing. However, there have been several welding methods before laser welding, which introduce the question: since we have other options, why do we need a laser welding machine? We will study it after briefly reviewing the origin of this technology.
The following knowledge points are listed below:
The working process of laser welding machine
The use of processing gas in laser welding
The types of laser welding machine
Laser welding machine uses a highly concentrated beam at a very small spot, so the area under the laser beam absorbs the light and becomes very energetic. When a powerful laser beam is used, the electrons in this area are excited to the point where the material melts, which is the result of atoms breaking chemical bonds with each other.
Laser welding can also be used to connect plastics.
The melting of these two materials at the seam fuses them into a joint. Surprisingly, the power of light can turn metal into metal within a few milliseconds. In order to achieve such a powerful laser beam, the laser welding machine uses several parts to guide and amplify the laser.
Gas lasers, solid-state lasers and fiber lasers are the three most commonly used lasers in laser welding machines.
Usually, the laser beam is supplied to the laser welding machine through the optical fiber. There are a single optical fiber welding machine and multiple optical fiber welding machines. Multiple fiber welding machines have a laser connected to each fiber. As each fiber increases, the intensity of the laser increases.
In order to focus the beam to a point before leaving the machine, collimator and focusing mirrors are usually used.
If you have been studying laser welding, you may notice that laser nozzles are constantly accompanied. This is another nozzle that provides a gas called process gas or cutting gas.
Basically, this is the flow of gas, the most common is carbon dioxide, which is also directed to the location of the weld, the purpose is to prevent the welding surface from contacting the atmosphere.
Without the use of cutting gas, the welding atmosphere has only two options: ordinary atmosphere and vacuum atmosphere. Vacuum laser welding is certainly possible, but this is not possible due to the high cost and requirements of professional settings.
In a normal atmospheric environment, laser welding machine without gas treatment will have an adverse effect. Because the nitrogen concentration in the air is very high, it can mix with the molten metal, causing voids or holes in the weld. This situation will lead to welding failure.
The humidity in the air and other factors can cause hydrogen to be generated during welding. The diffusion of hydrogen in metals can also lead to weak welded joints. Therefore, laser welding in a normal environment without shielding is not allowed.
The welding machine is equipped with a cutting gas attachment to spray gas onto the welding surface to ensure that no impurities are mixed into the weld.
Laser welding has two methods of heat conduction welding and keyhole welding.
Heat conduction welding: In this process, the metal surface is heated above the melting point of the metal, but it will not evaporate. This process is used for welds that do not require high welding strength.
The advantage of heat conduction welding is that the final weld will be very smooth and beautiful. Heat conduction welding uses low power laser less than 500W.
Keyhole welding: In this process, the laser beam heats the metal to evaporate its contact surface and penetrate deep into the metal. This creates a keyhole, and when the temperature rises well above 10,000 degrees Celsius, a plasma-like state is created.
This process requires a high-power laser with a power exceeding 105 W / mm2.
Now you know the technology of laser welding machine, uv laser marking machine, co2 laser marking machine.
