Analytical model for geometrical characteristics control of laser sintered surfaces

Abstract

Selective laser sintering (SLS) is an additive rapid manufacturing technique where a high-power laser is used to fuse micro- and nano-particles into a specified three-dimensional geometry. The goal of this work was to develop an analytical model for the SLS manufacturing process in order to control the geometrical characteristics of the sintered areas when iron/copper (Fe/Cu) powder alloy is used on a flat substrate. Powder particles are subject to melting by the laser energy and form a liquid globule that solidifies as the laser beam spot moves along the substrate. The model is developed by considering lumped mass and energy balances and fluid dynamic equilibrium of the sintered material. It is assumed that the process is two-dimensional and axisymmetric. It is further assumed that the energy delivered by the laser is used to sinter the material rising its temperature up the melting point, while the energy lost due to conduction in the metal substrate is very small. The sintered area geometry is parameterised and the parameters are obtained by solving a system of nonlinear algebraic equations.