Finite element analysis of single layer forming on metallic powder bed in rapid prototyping by selective laser processing

A method for calculating the distribution of temperature and stress within a single metallic layer formed on the powder bed in rapid prototyping with the selective laser melting method is proposed. The solidified layer is ass umed to be subjected to plane-stress deformation and the two-dimensional fi nite element methods for heat conduction and elastic deformation are combin ed. In the simulation, the finite element mesh is constructed on the surfac e of the powder bed. The heat caused by laser irradiation is given to the e lements under the laser beam. Shrinkage due to solidification is assumed to result in only the change of the. layer thickness. In the elastic finite e lement simulation, the Young's modulus of the solidified part is expressed as a function of temperature. To simplify the calculation, the whole area i s treated to be continuous, and the powder bed and the molten part are assu med to have a very small Young's modulus. The heat conduction and the elast ic finite element calculations are carried out alternately. The obtained re sults of deformation and tensile stress distribution show the possibility a nd places of cracking of the layer during forming. (C) 2001 Elsevier Scienc e Ltd. All rights reserved.