Analysis of the effects of supersonic assist gas for laser cutting using normal shock theory

초록

The behavior of the assist gas in a laser cutting process affects the cutting quality. In this study, numerical analysis was conducted to analyze the trend in cutting quality with respect to the nozzle design and stand-off distance. For this purpose, a supersonic nozzle was designed based on the method of characteristics to maintain the cutting quality regardless of the stand-off distance. For a simplified laser cutting process with a minimum length nozzle or conical nozzle, numerical simulations were performed for a set of stand-off distances using a Reynolds-averaged Navier–Stokes model. Finally, based on the structural similarity between flows, the normal shock theory was examined to predict the trend in cutting quality from a free jet simulation. © 2019 The Korean Society of Mechanical Engineers

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