On the thermal response of a surface deposited laser-irradiated powder particle

This paper provides a basic analysis of the temperature rise of a particle in a powder that is being irradiated by a laser and simultaneously conducting heat with its surroundings. The work is motivated by the widespread use of laser post-processing of deposited particles in additive manufacturing technologies. The study focuses on one of the "building blocks'' of additive, powder-based, technologies, namely the controlled irradiation of a single particle. The analysis employs two models: (a) a classical model, based on a balance of energy in conjunction with Fourier-type conduction and (b) a thermally relaxed model, based on a balance of energy in conjunction with thermally relaxed conduction, which is important when using fast-pulsing lasers. Analytical and numerical results are generated to qualitatively ascertain the time-transient trends as a function of particle size, heat capacity, material density, laser irradiance, conductivity and the thermal relaxation. The objective is to provide researchers with methods to quickly determine the required laser input to bring the particle to a desired temperature, which is an essential step in powder-based additive manufacturing. (C) 2015 CIRP.