The power of green laser pointer is no less than 30mW

Defocus amount of welding quality. Laser welding is usually away from the fuss about because of the high power density of the laser focus at the spot center, easily evaporate into the hole. Leaving the laser focus plane, the power density distribution is relatively uniform. Defocused mode in two ways: positive and negative defocus defocus. Focal plane at the top of the of the workpiece being away from the focus, and vice versa for negative defocus. According to the theory of geometrical optics, when positive and negative away from the focal plane with the welding plane equidistant, corresponding to approximately the same power density on the plane, but the weld pool shape actually. Negative defocus, the availability of greater penetration, which is related with the formation of the molten pool. The power of green laser pointer  is no less than 30mW.
The experiments show that the laser heating 50 to 200us material begins to melt, the formation of liquid metal and asked the sub-vaporization, the formation of city-pressure steam, and at very high speed jet, and a dazzling white. At the same time, high concentrations of vapor liquid metal movement to the weld pool edge, the formation of depression in the weld pool center. When negative defocus, the power density of material internal surface area is also high, easy to form a stronger melting, vaporization, so that the light pass deeper into the material. Therefore, in practical applications, when the requirements of the penetration depth larger, the use of negative defocus; when welding thin materials, Harbin Institute of Technology is preferable to being 12 defocus. Austenitic stainless steels, austenitic stainless steel at room temperature. The specific and detailed requirements of green laser pointer are as follows.