Este trabalho tem como objetivo principal a otimização dos protótipos fabricados pelo processo FDM (Fused Deposition Modeling) em procedimento baseado na análise do comportamento estrutural dos protótipos variando as estratégias de preenchimento das camadas. Para atingir tal objetivo, corpos de prova com diferentes orientações de preenchimento foram ensaiados experimentalmente e os resultados foram verificados em análise estrutural por elementos finitos. Foram verificados o caráter ortotrópico do material do protótipo e a validade do uso da Teoria Clássica dos Laminados na simulação de seu comportamento. Os conceitos e metodologia de análise foram validados em estudos de casos, mostrando a viabilidade de sua aplicação na obtenção de protótipos funcionais / The objective of this work is to develop an optimization procedure for FDM prototypes. This procedure is based on the structural analysis of the prototypes within different slice filling paths. In order to reach this objective, experimental tests with different filling trajectories are conducted and the results are used in structural analysis by finite element method. The orthotropic behavior of the prototype material and the use of the Classical Laminate Theory in the numerical simulation were validated. The results were applied in different case studies, showing the viability of its application in the design of functional prototypes.

To facilitate the transition of Stereolithography (SLA) into the manufacturing domain and to increase its appeal to the micro manufacturing industry, process repeatability and surface finish need to be improved. Researchers have mostly focused on improving SLA surface finish within the capabilities of commercially available SLA machines. The capabilities of these machines are limited and a machine-specific approach for improving surface finish is based purely on empirical data. In order to improve surface finish of the SLA process, a more systematic approach that will incorporate process parameters is needed. To achieve this, the contribution of different laser and process parameters, such as laser beam angle, irradiance distribution, and scan speed, to SLA resolution and indirectly to surface finish, need to be quantified and incorporated into an analytical model. In response, a dynamic analytical SLA cure model has been developed. This model has been applied to SLA geometries of interest. Using flat surfaces, the efficacy of the model has been computationally and experimentally demonstrated. The model has been applied to process planning as a computational inverse design method by using parameter estimation techniques, where surface finish improvement on slanted surfaces has been achieved. The efficacy of this model and its improvement over the traditional cure models has been demonstrated computationally and experimentally. Based on the experimental results, use of the analytical model in process planning achieves an order of magnitude improvement in surface roughness average of SLA parts. The intellectual contributions of this research are the development of an analytical SLA cure model and the application of this model to process planning along with inverse design techniques for parameter estimation and subsequent surface finish improvement.

Este trabalho tem como objetivo principal a otimização dos protótipos fabricados pelo processo FDM (Fused Deposition Modeling) em procedimento baseado na análise do comportamento estrutural dos protótipos variando as estratégias de preenchimento das camadas. Para atingir tal objetivo, corpos de prova com diferentes orientações de preenchimento foram ensaiados experimentalmente e os resultados foram verificados em análise estrutural por elementos finitos. Foram verificados o caráter ortotrópico do material do protótipo e a validade do uso da Teoria Clássica dos Laminados na simulação de seu comportamento. Os conceitos e metodologia de análise foram validados em estudos de casos, mostrando a viabilidade de sua aplicação na obtenção de protótipos funcionais / The objective of this work is to develop an optimization procedure for FDM prototypes. This procedure is based on the structural analysis of the prototypes within different slice filling paths. In order to reach this objective, experimental tests with different filling trajectories are conducted and the results are used in structural analysis by finite element method. The orthotropic behavior of the prototype material and the use of the Classical Laminate Theory in the numerical simulation were validated. The results were applied in different case studies, showing the viability of its application in the design of functional prototypes.

Les applications utilisant les procédés de fabrication directe par laser et projection de poudre sont en pleine expansion, en particulier, dans l'aéronautique. Néanmoins, cette technologie prometteuse fait état de quelques points durs et est confrontée aux problèmes d'instabilités du procédé. Lorsque ces phénomènes ne sont pas maîtrisés, cela conduit à des défauts (résistances mécaniques insuffisantes, porosités trop importantes, mauvais états de surface,….etc), qui, selon leur répartition et leur taille, risquent d'engendrer des non conformités, de détériorer les caractéristiques mécaniques des pièces et qui peuvent représenter un coût de post-traitement non négligeable. Par conséquent, il est primordial de maîtriser le procédé d'élaboration, afin de rendre le procédé de fabrication robuste et préserver l'intégrité structurelle de la pièce. Cela requiert la mise en place de système d'instrumentation du procède de projection laser, et par l'intermédiaire du contrôle procédé, d'avoir un système de commande temps réel permettant d'adapter les paramètres procédés en cours d'élaboration, afin de de maintenir une haute qualité de la pièce fabriquée. Dans cette perspective, nous avons développé une solution technologique (matérielle et algorithmique) à base de caméras (vision) permettant de suivre des paramètres clefs lors de la fabrication. L'application de ce système de vision a permis la mise en œuvre de méthodes innovantes, utilisant des outils de l'automatique moderne, pour surveiller l'état de pièces projetées, voire même corriger leurs défauts lors de la fabrication, en ayant un suivi et un contrôle du procédé en temps réel. De plus ce système de vision a permis à partir de mesures effectuées sur les entrées et les sorties du procédé, d'identifié un modèle dynamique qui ont conduit à la réalisation du système de contrôle procédé. / Applications using the direct metal deposition laser process have been expanded rapidly, particularly in aeronautics. However, this promising technology reported some difficult points and faced several problems, mainly the process instability. When these phenomena are not controlled, several defects was obtained (lack of mechanical strength, excessive porosity, poor surface, ... etc.). According to their distribution and size, non-conformity, deteriorate the mechanical characteristics of the parts was recorded and result in a significant cost of post-processing. Therefore, it is important to control the process, to make the process both robust and preserve the structural integrity of the piece. This requires the development of instrumentation through the control process, in order to have a real-time system able to adjust the process parameters to keep a high quality of the manufactured part. In this perspective, the studied thesis developed a technological solution (hardware and algorithms) based on cameras (vision) to monitor key parameters during manufacture. The application of this vision system has been allowed for the implementation of innovative methods by using modern automatic tools to monitor the status of the built part or even correct their defects during the manufacture parts, having a monitoring and process control in real time. Furthermore this vision system performed measurements for the inputs and outputs of the process, matched to a dynamic model that lead to the realization of the process control system.