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This article presents a bridge between topology optimization (TO) and additive manufacturing. On the one hand, it presents an algorithm that considers the design variables as binary and then solves the problem by binary linear programming to optimize a ferromagnetic core. On the other hand, a 3-D printing process is developed to manufacture the shapes obtained by TO. Finally, these magnetic parts are characterized through electrical measurements.

The performance and energy efficiency of electro-mechanical converters are strongly bound to the properties of their magnetic cores. The latter are mostly made from stacked laminations of soft magnetic materials, such as Fe3%Si, which limits the core geometry design. However, when complex geometries are required, usually forging processes may be employed but with very low silicon steels (<0.5%) to be able to forge the steel. In that case, the low silicon content yields to higher electrical conductivity and then to higher eddy current loss. In this work, an additive manufacturing technique allowing to build complex geometries is studied with Fe3%Si magnetic materials. The fabrication process allows to obtain green parts which are then densified through debinding and sintering steps. The magnetic characterization is performed on toroidal cores and allows to observe a high level of magnetic induction and relative permeability. Finally, the impact of the printing strategy on the magnetic performances is investigated.

Nowadays, additive manufacturing of metallic materials is most often carried out using expensive and complex tools that leave the user with limited control and no possibility of modification. In order to make the printing of metal parts more accessible to small structures but also better suited for academic research, the use of a mixture of thermoplastic polymer and metal powder is a good solution as many granular feedstocks already exist for Metal Injection Molding applications. To perform the shaping process, the Fused Granular Fabrication 3D printing technology is set up by diverting the use of a feedstock in the form of pellets that are directly inserted into the print head. This solution, which is less costly, is implemented here by modifying a mid-range printer, the Tool Changer from E3D, and by making the hardware and software adaptations to mount a compact granulates extruder on it, which is also available on the market. The polymer portion present in the green part can then be removed in order to perform the heat treatments that will densify the powder by sintering and give a fully metallic dense object.

Fabrication of soft magnetic ceramic materials relies on time consuming conventional methods, such as molding and sintering, which restricts the possibilities of shapes the components can be given. Additive manufacturing of such materials can help reduce production lead time and unlock topological design limitations. In this work, the implementation of an indirect additive manufacturing methods for soft magnetic Mn-Zn ferrite, intended for high frequency applications, is presented. A blend of light sensitive polymer binder and fine powder is used for the shaping stage using Digital Light Processing (DLP) followed by a heat treatment that allows to remove the polymer part and to obtain a final dense part. Simple shapes were produced in order to characterize their magnetic performances and to validate this method for further fabrication of more complex magnetic core.

The performance and energy efficiency of electro-mechanical converters are strongly bound to the properties of their magnetic cores. The latter are mostly made from stacked laminations of soft magnetic materials such as Fe3%Si which limits the core geometry design. However, when complex geometries are required, usually forging processes may be employed but with very low silicon steels (<0.5%) to be able to forge the steel. In that case, the low silicon content yields to higher electrical conductivity and then to higher eddy current losses. In this work, an additive manufacturing technique allowing to build complex geometries is studied with Fe3%Si magnetic materials. The fabrication process allows to obtain green parts which are then densified through a final sintering step. The electromagnetic characterization of samples is performed. Finally, the results and possible improvement will be discussed in comparison with conventional Fe3%Si electrical steels and a forged magnetic steel that is commonly found in electromechanical applications.

In this work, we propose an FDM additive manufacturing process that uses a feedstock in the form of small pellets composed of a similar mix of 316L Stainless Steel powder bound by a thermoplastic polymer. The printing stage is performed using an affordable Archimedes screw system that is mounted on a classical 3-axis cinematic frame. The feedstock, provided by PolyMIM, is diverted from its original use, which is Metal Injection Moulding (MIM), and is intended to be debinded and sintered. This allows to consider a wide range of materials already available. The impact of the deposition strategy on the tensile properties will be investigated in relation with the microstructure.

This paper presents a topology optimization process for tuning the leakage inductance of a High Frequency (HF) transformer. The 2D Magnetic Equivalent Circuit (MEC) is used to model the studied transformer. Then, through an optimization problem, primary winding positions ensuring maximal and minimal leakage inductances will be gotten.

L’utilisation des technologies de fabrication additive s’est fortement démocratisée depuis la fin des années 80 et l’apparition des premières imprimantes 3D. Grâce aux nombreux développements dont elles ont fait l’objet, ces solutions constituent désormais une réponse pertinente aux problématiques des divers secteurs de la recherche scientifique et de l’industrie. En particulier, le génie électrique peut grandement tirer profit des nouvelles opportunités offertes par l’impression 3D. Ces travaux de thèse portent sur la mise en place et l’étude d’un procédé de fabrication additive pour le génie électrique, en particulier pour l’impression de matériaux magnétiques doux utilisés lors de la réalisation de dispositifs électriques de conversion d’énergie. Un procédé indirect inspiré des technologies de moulage métal par injection est développé et deux matériaux classiques du domaine sont considérés en particulier : le fer silicium 3% et le ferrite manganèse zinc. La validation du procédé ainsi que l’étude de son impact sur les performances sont d’abord présentées. Par la suite, le développement d’un feedstock polymère chargé en poudre de ferrite est exploré pour les méthodes d’impression FFF et DLP. Enfin, la mise en place d’un processus d’optimisation topologique basé sur un modèle de réluctances maillées est réalisée. Celui-ci est appliqué au cas d’un composant magnétique passif et suivi de l’impression et de la caractérisation des géométries optimales