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Modelling of Laser Beam Distribution Effects for Metal Laser Cutting
E.H. Amara, K. Kheloufi, T. Tamsaout and S. Aggoune

We develop a study on laser cutting of metals with assist gas jet, the aim is to investigate the effect of the beam shape spatial distribution when a top-hat or a Gaussian beam distributions are considered. A three-dimensional (3-D) numerical model is developed for assumed normal atmospheric conditions, where the treated metallic sample is subjected to irradiation with a continuous wave (CW) Nd:YAG laser beam. The finite volume method (FVM) is used to discretize the differential governing conservation equations, which are numerically solved. The solid-air and liquid-air interfaces are tracked by implementation of the volume of fluid (VOF) method, whereas an enthalpy approach allows to take into account the melting and re-solidification phenomena. The cut formation is simulated by inserting the related laser deposited energy, for the considered beam distribution, as a volumetric source term in the energy conservation equation, the results show that the used beam distribution may play an important role in reducing the striation formation.

Keywords: Nd:YAG laser, laser beam, laser cutting, top-hat, Gaussian, numerical model, finite volume method (FVM), volume of fluid (VOF) method, enthalpy approach, interface tracking, kerf formation, striation

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