Polyamide 12 (PA 22000) is a well-known material and one of the most biocompatible materials tested and used to manufacture customized medical implants by selective laser sintering technology. To optimize the implants, several research activities were considered, starting with the design and manufacture of test samples made of PA 2200 by selective laser sintering (SLS) technology, with different processing parameters and part orientations. The obtained samples were subjected to compression tests and later to SEM analyses of the fractured zones, in which we determined the microstructural properties of the analyzed samples. Finally, an evaluation of the surface roughness of the material and the possibility of improving the surface roughness of the realized parts using finite element analysis to determine the optimum contact pressure between the component made of PA 2200 by SLS and the component made of TiAl6V4 by SLM was performed.

Abstract. This paper presents a series of research that have been made by the authors in the field of medical implants realized from PA 2200 powder material using the Selective Laser Sintering (SLS) method. Several sets of samples differently oriented into the working area of the machine were manufactured from PA 2200 by SLS, in order to determine which is the recommended orientation to be used during the manufacturing process, in such a way that at the end the mechanical properties (e.g. Compressive strength, Young's modulus, etc.) will be as closed as possible to the ones of the human bones. The obtained results were further on used in the case of a medical implant (Acetabular liner) that was manufactured at the Technical University of Cluj-Napoca (TUCN) from PA 2200 material using the DTM Sinterstation 2000 SLS equipment.

Within this article, there are presented a series of researches that were developed for the first time in Romania, in the field of customized medical implants made by using the Selective Laser Melting (SLM) technology. Finite Element Method (FEM) has been successfully used in order to analyze the fatigue and to determine the durability of a customized medical implant that has been selected for the made analysis. The material characteristics taken into consideration within the Finite Element Analysis (FEA) that has been performed were the ones of two types of dedicated metallic powders which are commercially available (TiAl6Nb7 and TiAl6V4 material) and suitable for the SLM 250 HL equipment from the SLM Solutions GmbH Company from Lubeck, Germany. The Finite Element Analysis made in the case of these two types of SLM titanium alloyed materials, proved that the modified characteristics, such as the yield strength and hardness of the material are significantly influencing the durability of the medical implants made by SLM technology.

Within this article, there are presented a series of researches that are related to the field of customized medical implants made by Additive Manufacturing techniques, such as Selective Laser Melting (SLM) technology. Lattice structures are required in this case for a better osteointegration of the medical implant in the contact area of the bone. But the consequence of using such structures is important also by the mechanical resistance point of view. The shape and size of the cells that are connected within the lattice structure to be manufactured by SLM is critical in this case. There are also few limitations related to the possibilities and performances of the SLM equipment, as well. This is the reason why, several types of lattice structures were designed as having different geometric features, with the aim of analyzing by using finite element method, how the admissible stress and strain will be varied in these cases and what would be the optimum size and shape of the cells that confers the optimum mechanical behavior of lattice structures used within the SLM process of the customized medical implant manufactured from titanium-alloyed materials.

Abstract. The article presents a case study that was realized at the Technical University of Cluj-Napoca (TUC-N) in the field of customized medical implants made by using different additive manufacturing (AM) technologies, such as the Selective Laser Sintering (SLS) and the Selective Laser Melting (SLM). Finite element analysis was successfully used to determine the mechanical behavior of an acetabular liner that was made from PA 2200 powder material by SLS and to determine the optimum technological parameters required to be used in the manufacturing process of the acetabular liner by SLS, so as the contact pressure between the acetabular liner made from PA 2200 material by SLS and the femoral head made from TiAl6V4 material by SLM will be optimum at the end and the displacement between the components will remain in the admissible limits