The parameters that directly affect the quality of hand-held laser welding machine include: laser pulse energy, laser beam spot diameter, laser pulse width, excited laser pulse frequency, light pulse waveform, relative light absorption coefficient of welding materials, welding speed, shielding gas, etc.
Laser pulse frequency of laser welding machine
This is the ability to reflect how many pulses a laser can hit in one second, in hertz. First of all, it needs to be explained that the welding metal uses laser energy. When the laser power is constant, the higher the frequency, the smaller the energy output of each laser. Therefore, we need to ensure that the laser energy is sufficient to melt the metal, and consider the processing speed to determine the output frequency of the laser. In the case of laser grinding tools, 15Hz has been able to meet the needs of welding. Excessive frequency will inevitably lead to low laser pulse energy, leading to welding failure.
Handheld laser pulse energy
Refers to the energy output of a single laser pulse in the joule. This is a main parameter of laser, which determines the energy generated by laser welding machine. According to the purpose of mold repair, no matter how much energy is wasted or can not be used, the laser energy below 70J can meet the needs of any occasion, resulting in an increase in the volume of the laser power supply and radiator, thus reducing the power efficiency.
Laser pulse waveform
Laser pulse waveform is an important problem in pulsed laser welding for laser welding machine using pulsed laser for welding processing. When the high intensity laser is incident on the surface of the material, the metal surface will reflect 60%~98% of the laser energy, and the reflectivity changes with the surface temperature. Therefore, different metals have different reflectivity and utilization rate of laser. To conduct effective welding, laser with different waveforms must be input, so that the metal structure at the weld can be crystallized in a way that is consistent with that of the base metal, and high-quality weld can be formed. Generally, domestic machines use cheap single waveform laser power supply. Therefore, its welding flexibility is low, and it is difficult to adapt to the welding of a variety of mold materials. In addition, it often needs to be reworked, which greatly wastes the time of welding materials and may lead to the scrapping of molds. Different metal material surfaces have different degrees of reflection and absorption of laser, while the same laser beam will produce different welding effects on different metals, and affect their penetration, laser welding machine welding speed, crystallization speed and hardness. Therefore, a single rectangular wave welding cannot meet the requirements of different mold metal welding.
