the YAG laser welding device

When the metal begins to melt or vaporize the surface, its reflectivity decreased rapidly. Two metallic materials at room temperature laser absorption rate is generally below 20 ℃; when the metal temperature reaches the melting and vaporization produces branded point of the absorption rate of up to 40 ~ 50%; when close to the boiling point of up to 90% absorption rate. The working condition of laser pointer is good enough.
The absorption rate of the laser material and the material is proportional to the square root of the DC resistivity, and the laser wavelength is inversely proportional to the square root relationship. Angle of incidence greater the absorption rate is smaller. When the laser light perpendicular to the metal surface, the metal absorption maximum of the laser. But usually to protect the laser exit lens, the need to maintain a certain angle of incidence. For low reflectivity can be coated with a thin metal surface layer of metal powder, but both must be able to form alloys. Such as copper, gold, silver can cover the sharp thin layer, then the same penetration in the case of welding the energy required is about the original copper, gold, silver and required a quarter. Quality of the YAG laser welding device, the focus of the (spot size) is the optical path through the device itself precision coaxial output fiber and outgoing head of the imaging ratio to be guaranteed. Laser emitted when the focus falls just above the location of the work is zero. Defocus amount is zero distance from the focus away from this amount. Focus position than the position is called a negative zero defocus (focus down to internal parts), the distance is negative defocus amount. Instead, the focus distance value is less than zero is the amount of defocus. To obtain a larger penetration depth, focus position can be selected within a certain location on the workpiece, that is, using the negative defocus amount of welding. The fault status of laser pointer is the important reference index.
Pulsed laser welding, mainly heat melting manner. Laser beam directly on the metal itself, the depth of penetration is limited, and its conductivity depends on the material temperature coefficient (conductivity temperature coefficient of the penetration depth is large) rather than the size of the laser power. Arc welding is the most widely used welding method. It includes: manual arc welding, submerged arc welding, gas tungsten arc welding, plasma arc welding, MIG welding and other gases.