1, temperature
At room temperature, the absorption rate of metal materials is two at 20, when the metal temperature reaches the melting point and the absorption rate is 40~50%, the absorption rate can be as high as 90% when it is close to the boiling point.
The square root of the direct current resistivity of the material to the laser absorption rate is proportional to the square root of the direct current resistivity of the material, and is inversely proportional to the square root of the laser.
2, the incident angle of laser beam
The larger the incident angle, the smaller the absorption rate. When the laser is perpendicular to the surface of the metal, the absorption rate of the metal to the laser is the highest. But usually in order to protect the laser out of the lens, the need to maintain a fixed angle of incidence.
The surface state of the village is in order to lower reflectance, which can be coated with a thin layer of the metal surface, but they must be able to form the alloy. Such as rice, gold and silver thin covering layer. At this time under the same penetration, welding energy required is about original copper, gold, silver, and the fourth one.
3, focus and focus
Excellent quality of YAG laser welding device, the poly (pyrogallol (spot size) is the device itself optical coaxial precision, output optical fiber and head shot imaging than to ensure.
In order to shoot the focus of the laser beam is located at the top of the job is zero.
The distance from the focal point is the distance from the zero. When the focus position is more than zero position, it is called the negative focus (the focal depth to the workpiece), and the distance value is negative. On the other hand, the distance from the focus is less than zero. To obtain a large depth of penetration, the focus position can be selected at one position in the inner part of the workpiece, that is, the negative off focus amount is used for welding.
4, the welding penetration depth
Pulse laser welding is mainly based on the heat transfer and melting mode. Laser beam itself on the metal direct penetration depth is limited, it is mainly determined in material thermal conductivity (guide large temperature coefficient of penetration depth), and not laser power size.