Cutting Whistle – An Original Approach for Nozzle Design in Fiber Laser Cutting of Stainless Steel

Instabilities of the melt flow dynamics at the laser cutting front lead to quality losses, due to the formation of striations at the cut flank, especially when using cost-efficient 1 µm laser radiation. This paper summarizes fundamental studies of the subproject A8 of the SFB 1120 using the concepts of a whistle-like structure as basis for the nozzle design. This approach is an innovative strategy for quality enhancement of cut flanks. The nozzle was designed for the stimulation of resonance between the acoustic waves generated by the gas flow through the nozzle with characteristic melt wave frequencies at the cutting front. The cutting experiments reveal an improvement of cut flank quality, while reducing the assist gas consumption compared to a standard nozzle with diameter of 5 mm.