Fig. 1. Experimental devices for laser cutting. (a) Processing head; (b) fiber laser

Fig. 2. Method for measuring dross height and fraction of oblique striation zone

Fig. 3. Kerf morphologies under different cutting parameters when P=5.4 kW and v=2 m·min-1. (a) f=0 mm, F=1500 kPa; (b) f=-3 mm, F=1500 kPa; (c) f=-4 mm, F=1500 kPa; (d) f=-4 mm, F=1900 kPa

Fig. 4. Effect of laser power on kerf quality. (a) Dross height; (b) fraction of oblique striation zone

Fig. 5. Effect of cutting speed on kerf quality. (a) Dross height; (b) fraction of oblique striation zone

Fig. 6. Effect of defocusing distance on kerf quality. (a) Dross height; (b) fraction of oblique striation zone

Fig. 7. Effect of gas pressure on kerf quality. (a) Dross height; (b) fraction of oblique striation zone

Fig. 8. Simple Laval nozzle. (a) Design drawing; (b) physical map

Fig. 9. Gas flow rate distribution of nozzle. (a) Tapered nozzle; (b) simple Laval nozzle; (c) standard Laval nozzle

Fig. 10. Comparison of kerf morphologies of tapered nozzle and simple Laval nozzle under different cutting speeds. (a)(b) 1.2 m·min-1; (c)(d) 1.6 m·min-1; (e)(f) 2.0 m·min-1

Fig. 11. Effect of cutting speed on kerf quality for tapered nozzle and simple Laval nozzle. (a) Dross height; (b) fraction of oblique striation zone