Shielding gas supply fixture for improvement in weld quality of laser welded fuel cell bipolar plates

Owing to the complex clamping requirements, accurate positioning and limited available area for processing, welding can be classified as a critical process in manufacturing of metallic bipolar plates. A shielding gas assisted welding process is used for isolating oxygen from process zone and to help reduce weld spatter. The gas flow rate can influence the dynamics of melt pool and material solidification which may aid to improve the seam quality. A system was developed for local provision of the gas during the laser welding of bipolar plates. The system can be attached to the clamping fixture to ensure even distribution of the gas in targeted locations and allows the adjustment of the gas flow rate as per requirement. Various shielding gas supply configurations were tested to verify the most effective design for optimal distribution of the gas and cross-sections of weld seams were compared.