A Model of Laser-Powder Interaction in Direct Selective Laser Sintering of Metals

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Date

2001

Authors

Das, Suman
Chung, Haseung

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Abstract

We present a simple one-dimensional model that describes the physical mechanisms of heat transfer, melting and resolidification taking place during and after the interaction of a laser beam with a bed of pure metal powder. The physical model describing this situation is based on the classical Stefan problem with appropriately chosen boundary conditions to reflect direct selective laser sintering of metals. A numerical model based on the finite volume method is developed to perform computations for two beam diameters, three beam speeds and for constant, step and ramp laser power input profiles. The results of these computations show the influence of laser beam diameter, laser power input rate and input duration on the melt interface velocity and location, and temperature. Scaling laws for time to reach maximum melt depth and total meltresolidification time are derived. Comparisons of the temperature histories for the three power input profiles are described.

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