With the advantages of high efficiency, good effect, high precision and easy automation integration, laser welding machine is widely used in various industries and plays a decisive role in industrial production and manufacturing. At present, it has been fully utilized in aerospace, health care, 3C digital, auto parts, mechanical food, new energy, bathroom hardware and other industries.
However, any processing method without mastering its principle and process will produce certain defects, and laser welding machine is no exception. Only by better understanding these defects, can we avoid these defects, give better play to the value of laser welding, and process products with exquisite appearance and high quality. Below, Qingyuan laser summarizes some solutions to common welding defects for your reference!
1. Cracks appear during welding
The cracks produced in laser continuous welding are mainly thermal cracks, such as crystallization cracks, liquefaction cracks, etc., which are mainly caused by the large shrinkage force of the weld before complete solidification. Wire filling, preheating and other measures can reduce or eliminate the cracks.
2. Pores appear during welding
Porosity is a relatively easy defect in laser welding. The molten pool of laser welding is deep and narrow, and the cooling speed is very fast. The gas produced in the liquid molten pool does not have enough time to escape, which is easy to lead to the formation of pores. However, the cooling speed of laser welding is fast, and the pores produced are generally smaller than those of traditional fusion welding. Cleaning the workpiece surface before welding can reduce the tendency of pores, and the direction of blowing will also affect the generation of pores.
3. Undercut during welding
If the welding speed is too fast, the liquid metal at the back of the small hole pointing to the center of the weld cannot be redistributed, and the undercut will be formed by solidification on both sides of the weld. The joint assembly gap is too large, the caulking molten metal is reduced, and undercut is easy to occur. At the end of laser welding, if the energy decreases too fast, the small hole is easy to collapse, resulting in local undercut. Controlling the power and speed to match can well solve the generation of undercut. If the welding speed is slow, the molten pool is large and wide, the amount of molten metal increases, and the surface tension is difficult to maintain heavy liquid metal, the weld center will sink, forming collapse and pits. At this time, it is necessary to reduce the energy density appropriately to avoid the collapse of the molten pool.