Direct Metal Laser Melting process optimization: Laser Powder Bed Fusion process simulation, component optimization for DMLM process, numerical-experimental correlation

Additive manufacturing is a technology that in recent years has been evolving very rapidly and is revolutionizing the design and production concept of the manufacturing industry, but there are still several problems that prevent its rapid spread. The design of components with the aid of this technology is still based on a "trial and error" approach, which makes additive manufacturing a too expensive process, especially for small-medium industries. The Direct Metal Laser Melting which is a Laser Powder Bed Fusion process is characterized by a multitude of variables such as material, machine parameters and component geometry, so it is very difficult to know what the successful parameters is to adopt. In this regard, using software for thermo-mechanical printing process simulation can help to reduce costs and design times. The master thesis aim is to study the “Compensation by Simulation” technique to optimize the DMLM printing process. First, a sensitivity was performed on two software for the printing process simulation, to establish which one offers the best results in terms of deformation predictions. Then, with the help of the software chosen in the first step, we move on to the generation of the compensated geometries. Compensated geometry is a component that has a pre-deformation on the nominal STL file. This pre-deformation has an opposite direction compared with process simulation prediction, or respect to those that occurred during the printing process. The compensated geometries taken in analysis were then printed, to evaluate the effects of the compensation based on the simulation parameters set. The compensation purpose is to obtain printed components within tolerance, as the distortions that occur during the printing process bring the compensated geometry into nominal conditions. Finally, the printed components were analyzed in order to validate both the simulation, that is the expected deformations and the “Compensation by Simulation” technique. The case study examined is a low-pressure turbine blade of the rear frame turbine, whose thickness and material used make it achievable only with the DMLM. The master thesis work has been developed in collaboration with Polytechnic of Turin and GE Avio Aero. GE Avio Aero, in the last years, has become an important reference of innovative technological solutions, especially in AM. For example, Cameri (No) plant is one of the largest factories in the world entirely dedicated to additive manufacturing and in 2017 Avio Aero created, in collaboration with Polytechnic Institute of Turin, the Turin Additive Laboratory (TAL).