With the advantages of high efficiency, high precision, good results, easy automation integration, laser welding is widely used in various industries, playing a pivotal role in industrial production and manufacturing, including in the military, medical, aerospace, 3C auto parts, mechanical sheet metal, new energy, sanitary ware hardware and other industries.
However, any processing method if you do not have a good grasp of its principles and processes, will produce certain defects or defective products, laser welding is no exception. Only a good understanding of these defects, and learn how to avoid producing these defects, in order to better utilize the value of laser welding, processing the appearance of fine, high-quality products.
1. Cracks
Cracks produced in laser continuous welding is mainly thermal cracks, such as crystallization cracks, liquefaction cracks, etc., the reason is mainly caused by the weld in the fully solidified before the production of large contraction force, filler wire, preheating and other measures can reduce or eliminate cracks.
2. Porosity
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 speed 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 porosity. However, the laser welding cooling fast, resulting in porosity is generally smaller than the traditional welding. Cleaning the surface of the workpiece before welding can reduce the tendency of porosity, and the direction of blowing also affects the generation of porosity.
3. Spatter
The spatter generated by laser welding seriously affects the surface quality of the weld, and will contaminate and damage the lens. Spatter and power density has a direct relationship, appropriate reduction of welding energy can reduce spatter. If the depth of fusion is insufficient, reduce the welding speed.
4. Bite edge
If the welding speed is too fast, the liquid metal at the back of the hole pointing to the center of the weld can not be redistributed in time, and solidification on both sides of the weld will form a biting edge. Joint assembly gap is too large, filler melted metal is reduced, also prone to bite edge. Laser welding end, if the energy drop time is too fast, the hole is easy to collapse, resulting in localized biting, control power and speed matching can be a good solution to the generation of biting.
5. Collapse
If the welding speed is slow, the melt pool is large and wide, the amount of molten metal increases, the surface tension is difficult to maintain the heavier liquid metal, the center of the weld will sink, the formation of collapses and craters, at this time it is necessary to appropriately reduce the energy density to avoid the collapse of the melt pool.
