A new temperature index for build orientation optimization in powder bed fusion additive manufacturing

Abstract

In Additive Manufacturing (AM) technology, part orientation holds a significant influence on various aspects including manufacturing time, support requirements and thermo-mechanical properties. The research specifically examines the crucial role of temperature in determining metallic part orientation for AM. With the aim of optimizing part orientation while temperatures are minimized even so, we introduced a novel thermal index. This index is able to quantify temperature changes upon rotating the part and comprises multiple sub-indices (area ground, circle, height and angle) derived from geometrical information extracted from STL (Standard Triangle Language) files. In order to assess the effectiveness of the thermal index, a combination of finite element method (FEM) and genetic algorithm (GA) techniques to solve the orientation problem is here performed. In this frame, a 360° rotation of the part for comparative analysis was conducted between the solutions obtained from the thermal index and those from FEM simulations. This contribution comprises two cases studies: a cone and a sand clock. The obtained results demonstrate a correlation between the thermal index and FEM-calculated temperature during the AM process. Notably, the highest thermal index (1.8 for the cone and 2.0 for the sand clock) corresponds to the lowest part temperatures (54°C for the cone and 53°C for the sand clock). Due to the simplifications of using this index, the time required to locate the part was significantly reduced by 96 % for the cone (to 4 minutes) and by 53 % for the sand clock (to 21 minutes) compared to the FEM. Furthermore, we validated the thermal index solving the part orientation problem for an industrial part and a foot orthosis.