Evaluations of effective thermal conductivity of support structures in selective laser melting

Simulations capable of predicting the complex thermal behavior which occurs in a selective laser melting (SLM) process would help design and manufacturing engineers build more optimum designs in a reliable manner. A multiscale feed forward adaptive refinement and de-refinement (FFD-AMRD) finite element framework has been developed in response to this need. Support structures fabricated during SLM to overcome residual stress induced part distortion are a key part of the process, and a representation of these support structures in a finite element framework must be considered. If support structures could be designed with minimal material usage while still maintaining an ability to withstand the residual stresses generated during the part fabrication, this would significantly impact industrial use of SLM. In this work, the effective thermal properties of support structures are represented using thermal homogenization. The effective thermal properties of the support structures have been found to be a function of their geometry, anisotropy and constituent independent thermal properties. The results from this study have been compared against standard models and a good match has been found. The objective of this work is to derive effective thermal property functions which could be directly incorporated in the FFD-AMRD framework mentioned above to enhance computational speed. (C) 2015 Elsevier B.V. All rights reserved.