Effect of nozzle orientation on the gas dynamics of inert-gas laser cutting of mild steel
- Penn State Univ., University Park, PA (United States)
This investigation applies sonic and supersonic coaxial and off-axis nozzles to the cutting of mild steel sheet of 1 to 4 mm thickness. A 1 kW CW CO{sub 2} laser is used with nitrogen as the assist gas. Sonic coaxial cutting is compared to that of off-axis nozzles which vary in orientation from 20-60{degrees} behind the laser axis, and in exit Mach number from 1 to 2.4. Results show a 50% increase in maximum cutting speed at about a 40{degrees} nozzle angle. In comparison, variations in nozzle exit Mach number have little effect. A scale-model kerf was used to visualize the kerf gas dynamics, revealing that nozzle angles of 0-20{degrees} cause a shock wave/boundary layer interaction with flow separation inside the kerf. Angles of 20-45{degrees} alleviate this interaction, producing a uniform supersonic flow throughout the kerf which yields high cutting speeds due to high shear forces. For nozzle angles greater than 45{degrees} the assist gas is diverted away from the kerf, reducing cutting speed. Compared to nozzle angle, exit Mach number was found to be of secondary importance.
- OSTI ID:
- 539313
- Report Number(s):
- CONF-961073-; CNN: Grant DMI-9400119; TRN: 97:003387-0039
- Resource Relation:
- Conference: ICALEO `96: 15. international congress on applications of lasers and electro-optics, Detroit, MI (United States), 14-17 Oct 1996; Other Information: PBD: 1996; Related Information: Is Part Of Proceedings of the laser materials processing conference - ICALEO `96. Volume 81; PB: 971 p.
- Country of Publication:
- United States
- Language:
- English
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