Topology optimization of lattice support structures for heat conduction in selective laser melting

Abstract

Support structures are required in selective laser melting process to support overhanging surfaces in order to remove heat away from the process and to reduce geometrical distortions. Heat stress and warping may occur due to heat accumulation in overhangs. These ultimately affect the dimensional and geometrical accuracy of the part. Therefore, this work introduces an approach to mitigate heat stress by maximizing the heat conduction of support structures. The minimum thermal compliance is set as an objective function to use a method of three-dimensional topology optimization to generate lattice support structures. In addition, fabrication experiments were conducted to investigate the warpage and levelness of the final built cantilever parts supported by our support structures and the three conventional support structures including pillar, wall, and “IY” support structures. The experiment results revealed that the warpage deformation of the cantilever part supported by our support structures is the lowest. Compared with the pillar, wall, and “IY” support structures, the top surface warp deformation of the cantilever supported by our support structures is reduced by 25.4, 31.75, and 17.65%, respectively. Moreover, the experiment results also indicated that the collapse and cracking of the built cantilever part supported by our support structures is significantly reduced compared with the conventional support structures.