Analysis of Laser Beam Modulation Effect on Aluminum and Copper Welding

Abstract

Abstract Theoretical and experimental study is conducted to characterize the welding of copper and aluminum at various heat input distributions. Optimal heat inputs and methodologies were derived by analyzing weld cross-sections and tensile strengths as well as computer simulations. To compare the results of weld quality, 3 cases of welding schedules were analyzed. A computer simulation was conducted by using multi-physics finite element analysis to explore heat flows. The inputs were the heat parameters, the welding speeds, the boundary conditions, and the material properties. The laser-beam power was assumed as Gaussian distribution and various shape factors were compared. A comparison of Cases 1, 2 and 3 revealed non-linear relationship between the welding strengths of the low and high heat-input areas. In Case 1, the center-beam output was fixed at 800 W and the ring-beam output was 1,600W–3,000 W. The results showed that higher heat input resulted in better welding strength. In Case 2, the center-beam output was changed in 50W steps from 900 to 1,250 W while the ring-beam output was fixed at 500 W. The heat input was relatively small, but the welding strength remained excellent. In Case 3, the laser output was fixed at 1,100 W and 600 W for center and ring, respectively and the entire beam was repeatedly rotated. The result showed that welding strength varied when the heat input remained constant which lead us to the fact that beam modulation ensures weld reliability.