The Influence of Surface Roughness on Laser Beam Welding of Aluminium Alloys

A laser beam is the light that is subject to the laws of physics. Surface roughness can cause that the light can be reflected in different angles. Therefore, the surface roughness may influence the amount of light to be reflected so the power of the laser could be lowered. Present paper analyses the influence of different surface roughness on porosity and geometry of weld joint using design of experiment. Surface roughness monitored during the experiment was in the range from Ra 0.8 to Ra 15 achieved and by machining on aluminium-lithium alloy AW2099. In order to keep the same condition for welding the bead on plate welds were realised. Porosity was analysed using computer tomography. Surface roughness proved to have minor influence on porosity as well as the shape of the weld joint