Common defects of laser welding and their solutions
Posted by： Hangao Time：5/21/2025 11:28:19 AM
Laser welding is a highly efficient and precise welding method that uses a high-energy-density laser beam as a heat source. It boasts advantages such as high efficiency, precision, and ease of use. Today, laser welding is widely used in various industries, including electronic components, automotive manufacturing, and industrial pipe welding.
However, laser welding is not infallible. Sometimes, processing errors can occur due to operational or parameter setting errors. Only by fully understanding these defects and learning how to avoid them can the full potential of laser welding be realized.
Welding Spatter
The spatter produced by laser welding seriously affects the surface quality of the weld and can contaminate and damage the lens. It typically manifests as numerous metal particles adhering to the surface of the material or workpiece after laser welding.
Cause of spatter: The surface of the material or workpiece is not cleaned properly, and is contaminated with oil or contaminants.
Solution: A. Ensure that the material or workpiece is clean before laser welding. B. Spatter is directly related to power density. Appropriately reducing the welding energy can reduce spatter.
Cracks
Cracks produced by continuous laser welding are primarily thermal cracks, such as crystal cracks and liquefaction cracks.
Causes of cracking: Mainly due to excessive shrinkage forces before the weld is fully solidified.
Solution: Preheating measures can reduce or eliminate cracking.
Porosity
Porosity on the weld surface is a common defect in laser welding.
Causes of Porosity: A. The laser weld pool is deep and narrow, leading to rapid cooling. Gases generated in the liquid pool do not have time to escape, easily leading to pore formation. B. The weld surface is not cleaned thoroughly.
Solution: Clean the workpiece and weld surfaces before welding. Additionally, the direction of the gas blow can affect the formation of pores.
Undercut
Undercut refers to a poor bond between the weld and the base material, resulting in a groove with a depth greater than 0.5mm and a total length greater than 10% of the weld length, or exceeding the length required by the acceptance criteria.
Causes of Undercut: A. Excessive welding speed prevents the liquid metal in the weld from redistributing behind the keyhole, resulting in undercuts on both sides of the weld. B. If the energy decreases too quickly at the end of laser welding, the keyhole can collapse, also causing localized undercuts. Solution: A. Match the laser welding machine's processing power and speed to avoid undercutting.
Weld Bead Buildup
The weld is significantly too high.
Cause of weld bead buildup: Welding speed is too slow.
Solution: Increase welding speed or reduce laser power.
Weld Bead Concavity
Weld bead concavity refers to a depression on the weld metal surface.
Cause of Concavity: During continuous welding, the weld center is poor. The laser spot center is close to the lower plate, offset from the weld center, causing partial melting of the base material.
Solution: Adjust the laser spot size to match.
