Abstract

Selection of process parameters is an important step in Powder-Based Additive Manufacturing (PBAM) of metals.Inorderto achieve an optimal parameterset,current literature ismainlyfocusedonthe understanding of powderdynamics by analysing the aerodynamic forces. In this letter, however, we show the importance of the laser in-duced force (radiation pressure) on the powder dynamics. Generalised Lorenz-Mie theory has been employedto accurately estimate the radiation pressure and it is shown that its magnitude is significant in comparison tovarious aerodynamic forces and the grains weight, hence, can significantly contribute to denudation and spatterobserved in the manufacturing process. Furthermore, the importance of compressibility and rarefaction effectson the magnitude of drag and lift forces that a particle experiences is demonstrated by estimating theMaandKnnumbers under process conditions, which directly impact the powder dynamics.