The thesis investigates the influence of process parameters in laser welding of copper hairpin conductors used in electric motor windings, where achieving high mechanical strength and low electrical resistance of the welded joints is crucial. An experimental methodology was employed, including electrical resistance measurements using the Kelvin four-point method, quantitative CT analysis of porosity, and destructive tensile testing. Three key parameters were systematically varied during the experiments: the geometry of the laser beam path (ellipse, Lissajous curve with a frequency ratio of 3:1, and Lissajous curve with a ratio of 3:2), welding speed (200, 400, and 600 mm/s), and the power distribution between the central and ring-shaped beams (75/25% and 50/50%). The results showed that higher welding speeds lead to improved joint quality and mechanical properties. Furthermore, beam path geometries that provide greater coverage of the weld area result in better weld integrity, while overly complex geometries introduce process instabilities. A balanced power distribution of 50/50% between the central and ring beams effectively reduces both the number and volume of internal porosities. The optimal combination of parameters in terms of strength and electrical resistance was found to be Lissajous curve with a frequency ratio of 3:1 with the highest tested welding speed of 600 mm/s, whereas the combination with the lowest porosity volume was ellipse at a welding speed of 600 mm/s.
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