Factors that directly influence laser welding are the welding temperature, the melting point of the material to be welded, the absorption rate of the laser-welded material and the thermal effect. As with the welding process, this can be visualised in terms of material properties, laser power, welding speed, focus position, shielding gas and welding method.

The absorption rate of the laser welding material influences the welding performance. In general, aluminium and copper have a high absorption in the welding laser, while carbon and stainless steel have a low absorption. When welding materials with high absorption, more energy is usually required to melt and produce consistent weld quality.

Laser power is the amount of energy used for laser welding and has a decisive effect on the weld results. The level of laser power also affects the welding speed. The higher the laser power, the better. At a certain laser power, the corresponding weld depth reaches a threshold value. When this threshold is exceeded, the molten pool becomes more unstable, resulting in a lower depth. Therefore, it is particularly important to choose the right laser power level.

Welding speed is inversely proportional to the depth of the melt: the higher the speed, the lower the energy transferred to the weld metal and vice versa. Too fast a speed will not provide enough energy to the weld material to form a perfect weld, while too low a speed will result in a low body temperature, especially for heat-sensitive aluminium.

The position of the focal point directly affects the depth and width of the weld. Laser focus is only on the surface of the weld material, also known as zero focus, where the laser is focused on or below the surface of the weld material. Zero focusing is the smallest, at this time the highest energy density; the use of staggered welding, the specific power is reduced but the spot increases, suitable for welding parts with a large area.

The influence of shielding gas on the weld is not only reflected in the type of blow, but also in different blowing processes. The air jet not only prevents oxidisation of the workpiece surface during the welding process, but also prevents the generation of plasma clouds during the laser welding process. The shielding gas has a direct influence on the appearance and colour of the surface. Welded products requiring both should recognise the importance of shielding gas.

The weld gap of the part to be welded is directly dependent on the fusion depth, the melt depth and the shape of the weld. If the weld gap is too large and the spot is small, the weld is not weldable and difficult to weld; at the same time, the laser irradiation may damage the tool or the part. If the distance is too large, within a certain range, it can be improved by increasing the spot and increasing the variation, but the enhancement is limited.

Welding tests were carried out using a Yaskawa GP25 robot, PRIMA laser, OSPRI weld head (core diameter 100um, focal length 300mm) and Manshunxing wire feeder to test custom welds on 1.5mm thick Q235 carbon steel, SS304 stainless steel and Series 3 aluminium plate. Welding a 1mm thick plate at 1kw power and 30mm /s welding speed, the reference power can be P = a X, where a is a constant factor (a ≥ 0) and X is the plate thickness. In the case of maintaining the welding speed, material and gas and other welding conditions remain unchanged, the value of the a factor decreases with the increase in plate thickness, a factor also affects the welding method.

From the above experimental data, it can be seen that in the backwelding process of carbon steel plate, with the increase of welding speed, the laser power should be increased accordingly. In the case of constant vibration amplitude, the vibration speed must be increased to ensure the welding effect. If the speed is too slow, the welding will be uneven.

In general, the energy required for self-casting carbon steel is less than that required for self-casting carbon steel, and the energy required for self-casting carbon steel is less than that required for welding electrodes. carbon steel. The downward energy is controlled mainly by force and speed. For the same welding power, the higher the power, the faster the speed; the lower the power, the slower the speed. Ideally, weld speed should be the maximum given the quality and efficiency of the weld, but if it&qu39;s too fast, the weld head will vibrate, and you&qu39;ll also be limited by the power of the laser and the properties of the material. That&qu39;s why they usually seek a balance between performance and speed.

A core diameter of 100µm was chosen for the test. if welding highly reflective and heat absorbing materials such as aluminium and copper, higher power densities are required to melt the aluminium. At this stage it was necessary to select zero filler metal. For small welds, this may result in a low power laser producing maximum power density, melting the metal and forming a molten pool, which requires zero focus.