Laser welding has been widely used in various industries due to its high efficiency, high precision, good effect, good compatibility, and easy automation integration. It plays a pivotal role in industrial production and manufacturing, including new energy, mechanical sheet metal, 3C auto parts, military, medical, aerospace, bathroom hardware and other industries.

However, any processing method will produce certain defects or defective products if its principles and processes are not mastered, and laser welding is no exception. Only by having a good understanding of these defects and learning how to avoid them can we better utilize the value of laser welding and process products with beautiful appearance and high quality. Through long-term experience accumulation, SHINHOP welding application engineers have summarized solutions to some common welding defects for reference by industry colleagues!

1. Cracks

The cracks produced in continuous laser welding are mainly thermal cracks, such as crystal cracks, liquefaction cracks, etc. The main cause is the shrinkage force generated before the weld is completely solidified. Measures such as wire filling and preheating can reduce or eliminate it. Crack.

2. Stomata

Porosity is a defect that is more likely to occur in laser welding. The molten pool of laser welding is deep and narrow, and the cooling rate is very fast. The gas generated in the liquid molten pool does not have enough time to escape, which can easily lead to the formation of pores. However, laser welding cools quickly and the pores produced are generally smaller than traditional fusion welding. Cleaning the work piece surface before welding can reduce the tendency of pores, and the direction of blowing will also affect the occurrence of pores.

3. Splash

The spatter produced by laser welding seriously affects the surface quality of the weld and can contaminate and damage the lens. Spatter is directly related to power density, and appropriately reducing welding energy can reduce spatter. If penetration is insufficient, the welding speed can be reduced.

4. Undercut

If the welding speed is too fast, the liquid metal from the back of the small hole pointing toward the center of the weld will not have time to redistribute, and will solidify on both sides of the weld to form undercuts. If the joint assembly gap is too large, the melted metal in the joints will be reduced, and undercuts will easily occur. At the end of laser welding, if the energy decrease time is too fast, the small hole will easily collapse, resulting in local undercut. Matching control efficiency and speed can effectively solve the problem of undercut.

5. Collapse

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 the heavier liquid metal, and the center of the weld will sink, forming collapses and pits. At this time, the energy density needs to be appropriately reduced to avoid the molten pool collapsed.

Aluminum alloy weld seam collapse

By correctly understanding the defects produced during the welding process and understanding the causes of different defects, we can more specifically solve the problem of abnormal weld seams in laser welding.

SHINHOP laser equipment engineers remind everyone:

No matter what kind of laser welding defect it is, it can actually be overcome in many practical applications. In addition to the technical performance of the laser equipment, it also has a great relationship with the characteristics of the welding material and the welding experience of the operator, so we have to solve it. For welding problems, we must first have a good set of welding equipment that is suitable for the material characteristics of the product. In this regard, we need to contact manufacturers with advanced and rich laser equipment and choose the right manufacturer to cooperate. Only in this way can we provide solutions for problems that arise during actual welding. Good solution!