Key Parameters of Laser Welding Machines

Laser Power​

Laser power is a fundamental parameter that directly determines the welding speed and depth. Generally speaking, the higher the laser power, the faster the welding speed, because more energy can melt the material in a shorter time. At the same time, greater power can also penetrate deeper into the material, resulting in a deeper weld. However, it should be noted that excessive power may cause problems such as burning of the material or excessive heat-affected zone, so it is necessary to select the appropriate power according to the thickness and type of the material to be welded.​

Welding Speed​

Welding speed has a significant impact on both welding quality and efficiency. If the speed is too fast, the laser may not have enough time to fully melt the material, leading to discontinuous welds, insufficient fusion, or other defects, which will reduce the strength of the weld. On the contrary, if the speed is too slow, the material will be subjected to prolonged laser irradiation, which will expand the heat-affected zone, cause deformation of the workpiece, and even affect the performance of the material around the weld. Therefore, finding the optimal welding speed according to the material characteristics and welding requirements is the key to balancing quality and efficiency.​

Focal Length​

Focal length affects welding precision and depth. When the focal length is too small, the laser spot acting on the material surface is larger, which may lead to an excessively wide weld, reducing the welding precision. If the focal length is too large, the energy density of the laser at the welding point will decrease, resulting in lower welding power, which may affect the welding depth and penetration effect. In practical applications, the appropriate focal length needs to be set according to the required weld width, depth, and the size of the workpiece to ensure that the laser energy is concentrated at the desired position.​

Pulse Width​

Pulse width mainly affects the distribution of welding energy and heat input. A shorter pulse width means that the laser energy is released in a shorter time, so the energy is more concentrated, and the heat-affected zone (the area around the weld that is affected by heat) is smaller. This is very beneficial for welding materials that are sensitive to heat, as it can reduce material deformation and damage. A longer pulse width will make the heat input more dispersed, which may increase the heat-affected zone, but it is suitable for some materials that require more heat to melt.​

Shielding Gas​

Shielding gas plays a role in preventing oxidation and contamination of the weld. During the welding process, the high-temperature weld is easily oxidized when in contact with air, and may also be contaminated by impurities in the air, which will affect the quality and strength of the weld. Different types of shielding gases have different effects on the welding effect. For example, argon is often used for non-ferrous metals because of its good inertness; helium can provide better penetration; carbon dioxide is sometimes used in combination with other gases for welding steel. The selection of shielding gas should be based on the type of material being welded and the specific welding requirements.​

Summary​

The key parameters of laser welding machines-laser power, welding speed, focal length, pulse width, and shielding gas-are interconnected and collectively determine the quality, efficiency, and stability of the welding process. Laser power sets the foundation for speed and depth, but must be balanced to avoid overheating. Welding speed demands precision to prevent defects or excessive heat impact. Focal length ensures energy is concentrated where needed, directly influencing precision and penetration. Pulse width dictates energy distribution, with shorter pulses ideal for heat-sensitive materials and longer ones suited to materials requiring more heat. Shielding gas safeguards weld integrity by preventing oxidation and contamination, with selection tailored to material type.​

In practice, optimizing these parameters requires a holistic approach, considering material properties, weld specifications, and workpiece characteristics. As laser welding technology advances, more precise control of these parameters will further enhance performance, enabling broader applications across industries and driving innovation in manufacturing processes.

--Rayther Laser Lyra Zhang