Understanding the Influence of Beam Shape on the Laser Welding of Copper Hairpins with Core/Ring Configurations

Several beam sources have been proposed for use in laser welding of hairpin couples in electric drive manufacturing. Contemporary laser sources provide several options in terms of temporal and spatial beam intensity variations as well as novel wavelengths. Benchmarking studies are fundamental for providing comparative analysis in order to point out the most suitable laser solution for the given hairpin configuration in terms of size, material, and position in the electric drive. Simulation tools can be of aid to test out new laser solution especially prior to extensive experimental testing in a wider range of process parameters involving new beam shapes. This work describes the development of computer fluid dynamics simulations to understand the influence of the core and ring beam shapes in laser welding of copper hairpin couples. The work provides a view of simulation setting, calibration, and validation stages. In the experimental work, a 5 kW fiber laser source with core and double coaxial ring configuration is tested. The experiments were assisted by high-speed imaging to assess the possibility of defining proxy parameters for spatter generation. The parameters related to the melt pool motion and energy extracted the process simulations were found to be in good accordance with the observed spatter and plume emission behaviour in the high speed videos.