In collaboration with CTIF (Centre Techniques des Industries de la Fonderie), we have realized 3 samples of an optimized heat spreader applied to LED cooling. In the first time, we have optimized the thermal behaviour for natural convection using Lattice structures. Open cells materials allow obtaining similar performances whatever the inclination of the dissipator (less than 5% of thermal resistance increase at 90° compared to the horizontal). However, Lattice structure are not easy to materialized except with 3D printing … but at a high price. The Goal of this project to find another way to produce the heat spreader. With a strong collaboration with CITF, we decide to realize the Lattice structure by 2 different casting process. Molds with wax and sand are made by 3D printing. This results to differents quality of parts (surface roughness, porosity, thickness of beams etc) and different production costs : the small part made by direct additive manufacturing costs 3 times the lost wax one and 15 times the sand one ! See the result below exposed at MetalDays in Chaville (France, 92) on November 8th 2018.