Product Code: ICAL05_2103

Theoretical Study of Aerodynamic Behaviour of Assist Gas During Laser Cutting
Authors:
Ruslan Zhuk, NTUU 'KPI'; Kyiv Ukraine
Volodymir Kovalenko, Laser Technology Research Institute; Kyiv Kyiv Region Ukraine
Presented at ICALEO 2005

Cutting is one of the major laser applications which is extensively used nowadays due to its flexibility, accuracy and non-mechanical contact between laser beam and workpiece. Despite numerous experimental and theoretical investigations on dross and striations formation, which are significant factors influencing laser cutting quality, the understanding of these mechanisms leaves much to be desired. Modeling of laser cutting process can shed light on the laser-workpiece interaction and evaluate the influence of process parameters on cutting kerf quality.For this purpose the numerical computations were performed to predict the velocities, configuration and temperature fields of cutting and melting front. Furthermore, the numerical simulations of assist gas flow exiting nozzle at sonic and subsonic speeds were carried out and further interaction of exit jet with melt pool and its behavior within the cut were studied. The reactivity of assist gas was taken into account as well. It was shown that in some cases, when the optimal ratio between assist gas speed and gas nozzle stand-off distance had been found, the cutting quality parameters significantly improve. Various configurations of laser cutting nozzles, means of assist gas delivery and their influence on general cut quality were analyzed.