Executing Organisation: AiF Projekt GmbH, Program: ZIM – Central Innovation Program SME of the Federal Ministry of Economic Affairs and Energy
The aim of this project was to develop a new smoke suction system for welding fumes generated during laser beam welding of high-alloyed lightweight materials. These materials contain a high percentage of carcinogenic Manganese, Magnesium and Zinc and hence, the observance of fume limits is of special interest. Due to weld seam defects of mentioned materials, laser beam welding is often performed with beam oscillation. The effects of laser beam oscillation on particle sizes and emission directions have been investigated, which was needed for the development of a novel fume suction and filter system.
One approach was to measure welding fumes for reference materials and high alloyed materials like TWIP-steel and AA-7075 during laser beam welding with and without beam oscillation. In order to enable these investigations, a measuring camber was constructed. The aim was to clarify the effect of beam oscillation on particle size, distribution and total amount of weld fume. Furthermore a new filter system with fume suction system for welding with beam oscillation has been developed and built up, which was characterized afterwards.
It was shown that the energy per unit length significantly influences the total amount of weld fume emissions during laser beam welding. Measurement results from fume extraction setup show different amounts of particles and colors for the detected oxidation products (picture left). Quantitative increases of up to 80 % were determined. The evaluation of the weld fume trajectory from high-speed videos showed a broader spreading of the emissions in space (up to 3 times) for oscillation welding, which sometimes has been observed periodically. The findings were used to develop an efficient weld fume suction (capture efficiency > 95%, picture right) for the filter system.