A simulation for the effect of substrate on temperature distribution and thermal gradients in selective laser melting

Selective laser melting (SLM) is an additive manufacturing technique in which functional, complex parts can be created directly by selectively melting layers of powder. This process is characterized by highly localized high heat inputs during very short interaction times and will therefore significantly affect the microstructure. For the successful production of parts with Laser Beam Melting technology support structures are essential. Their main functions are to support overhanging structures, dissipate the heat generated during the process, and minimizing geometrical distortions caused by internal stresses. If we want to produce a part that is overhanging feature, by the process of selective laser melting without the use of support structures, in some areas where thepart is hung, scanning is performed on the previous layer which is powder and if a support structure is used, the scan is performed on a layer that is solid. In this study, the effect of powder and solid properties of the substrate as well as the effect of changing the substrate material on temperature distribution, thermal gradient and cooling rate were investigated. The results of the simulation show that the changing the substrate material from AlSi۱۰Mg to Al۲۰۲۴ and change the properties of the substrate from powder to solid reduces the temperature and increases the cooling rate. This is because the thermal conductivity of Al۲۰۲۴ is higher than AlSi۱۰Mg and the heat transfer through the thermal conductivity in the solid is more than the powder.

Keywords:

Selective Laser melting , Support , Finite Element , Temperature distribution , Cooling rate , Temperature gradient.