The spatter generated by laser welding seriously affects the surface quality of the weld seam, and will pollute and damage the lens. The automotive industry in particular requires extensive use of laser welding for certain materials such as galvanized steel, copper and aluminum. The way to eliminate spatter is to sacrifice the inherent advantages of fiber lasers, but this will reduce the processing efficiency. Therefore, it is necessary to understand the reasons for the spatter of the laser welding machine during welding, so as to find a way to maximize the elimination of the impact of spatter. The following introduces the solution to the spatter of laser welding technology in welding.
First, what is a splash?
Splash is the molten metal that flies out of the molten pool. After the metal material reaches the melting temperature, it changes from a solid state to a liquid state, and continues to heat up and will transform into a gaseous state. When the laser beam is continuously heated, the solid metal turns into a liquid state, forming a molten pool; then, the liquid metal in the molten pool is heated and "boils"; finally, the material absorbs heat to vaporize, and the boiling changes the internal pressure, bringing out the surrounding package of liquid metal, eventually producing a "splash".
How to control spatter has become a link that cannot be ignored in the laser welding process. Enterprises at home and abroad have long started research on reducing spatter laser processing technology. By comparing the low spatter technologies introduced by several mainstream laser manufacturers, we can understand and distinguish their respective principles. Stainless steel industrial steel pipes are used more and more widely. Therefore, steel pipe manufacturers must ensure high-quality welds while improving production efficiency. Therefore, laser welding technology has received more and more attention in the field of industrial welded pipe production, and has been increasingly widely used. In recent years, Hangao Tech (SEKO Machiner) has focused on exploring the field of laser welding industrial tube forming machine pipe making line, and has officially put into production in the customer's workshop, and the products have been recognized and affirmed by customers. Although laser welding is in its infancy in the field of stainless steel welded pipe production, Hangao Tech (SEKO Machiner) believes that with such extensive customer data accumulation, it will definitely be able to further develop in this area.
Laser welding technology has a solution to spatter in welding:
Method 1: Change the energy distribution of the laser spot to avoid boiling, and try not to use Gaussian beam distribution.
Changing the single Gaussian distribution laser beam to a more complex ring + center beam can reduce the high temperature vaporization of the center material and reduce the generation of metal gas.
Method 2: Change the scanning mode and swing welding.
The laser head swing method can improve the temperature uniformity of the weld seam and avoid boiling due to excessive local temperature. It only needs to control the X and Y axes of the motion mechanism to complete the swing of various trajectories.
Method 3: Use short wavelengths, increase absorption rate, and use blue light to reduce splashing.
Since low-absorption wavelength and high-power lasers cannot cure spatter, how about changing to short wavelengths? The laser absorptivity of traditional metals has an obvious downward trend with the increase of wavelength. High reflectivity non-ferrous metals such as copper, gold and nickel are more obvious.
The above is the solution to the spatter of laser welding technology in welding. The inevitable spatter problem is one of the biggest pain points in the welding process. A narrow keyhole is formed by ordinary laser welding. Such a keyhole is unstable and is very prone to spatter and even air holes, which affects the shape and appearance of the weld. The beam can be adjusted with high-power fiber laser for welding, and the ring core beam is used to open the keyhole. At the same time, the center beam is used to increase the penetration depth to form a large and stable keyhole, which can effectively suppress the generation of spatter.