Selective laser sintering (SLS) of metal powder is an emerging technology by which metal parts can be fabricated in a layer by layer fashion. SLS of the first layer is modeled as melting and resolidification of a metal powder layer subject to a moving heat source on top, while the bottom is adiabatic. SLS of the consecutive layer is modeled as melting and resolidification of a metal powder layer on top of the existing multiple resolidified layers.The results indicate that the thicknesses of the loose metal powder layer, the moving heat source intensity, and the scanning velocity have significant effects on the sintering process in both the first layer and each subsequent layer. A parametric study is performed, and the best combination of processing parameters is recommended.

No abstract

Laser sintering of a metal powder mixture that contains two kinds of metal powders with significantly different melting points under a moving Gaussian laser beam is investigated numerically. The continuous-wave laser-induced melting accompanied by shrinkage and resolidification of the metal powder layer are modeled using a temperature-transforming model. The liquid flow of the melted low-melting-point metal driven by capillary and gravity forces is also included in the physical model. The numerical results are validated by experimental results, and a detailed parametric study is performed. The effects of the moving heat source intensity, the scanning velocity, and the thickness of the powder layer on the sintering depth, the configuration of the heat affected zone, and the temperature distribution are discussed.

A three-dimensional model of selective laser sintering of a two-component loose metal powder layer on top of previously sintered layers by a single-line laser scanning is presented. A temperature-transforming model is employed to model melting and resolidification accompanied by partial shrinkage during laser sintering. The heat losses at the top surface due to natural convection and radiation are taken into account. The liquid flow of the molten low-melting-point metal powders, which is driven by capillary and gravity forces, is also considered and formulated by using Darcy’s law. The effects of the dominant processing parameters, such as laser-beam intensity, scanning velocity, and number of the existing sintered layers underneath, are investigated.

No abstract