Re-design in AlSi10Mg alloy of an ICE piston for SLM process

The use of components produced with Additive manufacturing (AM) processes has grown significantly over the past decade, finding use in rapid prototyping, rapid manufacturing and functional end-usable products, allowing performance enhancement of lightweight parts. Selective laser melting (SLM), one of the most promising AM technologies, can be applied to build metal parts layer by layer within a powder bed system. In comparison to conventional casting, SLM enables the production of components with customizable shapes, increasing both freedom of design and material usage efficiency. This thesis focuses on the re-design for SLM manufacturing of the piston of a four-stroke engine originally produced with conventional processes and with AlCu4MgSi as constitutive material, with a particular focus on the selection of optimal parameters for the SLM process. As aluminium alloys are widely used in the automotive and aerospace industries due to an exceptional combination of low density and competitive mechanical qualities, AlSi10Mg alloy powder is chosen as the material for this production. Using a design of experiment methodology based on energy density, the influence of process parameters such as scan speed, hatch spacing and laser power on the density and hardness of the final part is experimentally analyzed. The optimized process parameters are selected to maximize the relative density and subsequently used to build samples to assess their mechanical properties under tensile tests at room temperature. Afterwards, topological optimization of the part is carried out by using the Altair Inspire software and three designs of the same piston are obtained. The final design is the one ensuring the same performance as the baseline configuration. Finally, a printing simulation of the building process is carried out in Inspire environment, considering the proper part orientation and support generation in the building chamber volume. The re-designed AM component results in an overall mass reduction of 6.8% with respect to the original piston designed for slush casting.