Dissertationen zum Thema „Fabrication additive métallique DED“
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Doutre, Pierre-Thomas. „Comment intégrer et faire émerger des structures architecturées dans l'optimisation de pièces pour la fabrication additive par faisceaux d’électrons“. Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAI039.
Der volle Inhalt der QuelleThanks to additive manufacturing, it is now possible to manufacture new geometric shapes. The prospects offered by the methods of conventional and additive manufacturing are very different. Highly constrained design proposals can become much freer with additive manufacturing. The freedom it offers brings forward a multitude of possibilities. In this manuscript, we focused on a particular type of structures (the octetruss) as well as the use of EBM (Electron Beam Melting) of ARCAM as a means of manufacturing. The work presented in this thesis was carried out in the laboratories G-SCOP and SIMAP as well as in partnership with the company POLY-SHAPE. This manuscript focuses on three main points.The first of which is the action of emergence of lattice structures during the design process. For this, two existing approaches are detailed. The first uses topological optimization and the second is based on the concept of equivalent material. Following these, there are two methodologies used to identify areas in which the integration of lattice structures is possible and appropriate. The first consists of creating the different zones by relying on a stress field resulting from a finite element calculation, the second establishes the different zones using a topological optimization result. This second methodology is applied to an industrial case study.Secondly, we study how to fill the different areas with appropriate lattice structures by focusing first on their generation. Particular emphasis is placed on the intersection of the various bars by the establishment of spheres. A methodology for generating rounded-shape is also proposed. A study is carried out on all the parameters and information in order to integrate a lattice structure to a given area. This study leads to a proposed methodology that is applied to an industrial case study.Finally, aspects related to manufacturing are taken into account. For this, we consider different limits of the EBM manufacturing and what they mean for lattice structures; such as maximum achievable dimensions or thermal problems. A study to predict powder removal in order to extract the fabricated structure is performed. Mechanical tests are carried out. Our results are compared to those obtained in other works. The impact of curve on the mechanical behavior of a product is discussed
Agouzoul, Asmaâ. „Nouvelles méthodes numériques pour la simulation de l’impression 3D métallique“. Thesis, Bordeaux, 2020. http://www.theses.fr/2020BORD0004.
Der volle Inhalt der QuelleSelective Laser Melting offers new perspectives in terms of part design and simplification of complex assemblies. However, severe thermo-mechanical conditions arise and are responsible for local plastic deformation, residual stresses and distortion of the manufactured component. Numerical simulation is an interesting tool for process understanding the physical phenomena and their impact on the quality of the part. In this thesis, we propose different approaches to perform simulations at a lower cost, by using model reduction algorithms. The results are compared with those obtained by the finite element method. A reverse analysis in order to identify the inherent strain responsible for the measured elastic springback makes possible to build offline numerical abacus. Therefore, we use a multi-parametric reduced order model using the so called Proper Generalised Decomposition (PGD) to construct this abacus. We also explore the benefits of an implementation of PGD on GPU
Carassus, Hugo. „Comportement dynamique des matériaux cellulaires issus de la fabrication additive pour l'allègement structural et la sécurité au crash et à l'impact“. Electronic Thesis or Diss., Valenciennes, Université Polytechnique Hauts-de-France, 2023. http://www.theses.fr/2023UPHF0003.
Der volle Inhalt der QuelleThe rise of additive manufacturing since the end of the 20th century has made it possible to consider the design of new architectural cellular materials combining lightness and high energy absorption capacity. Their use in the field of ground or air transport sectors is therefore of interest to contribute jointly to structural lightening and safety in the event of a crash and/or impact.The objectives of the research work are to investigate and model the mechanical behaviour, under uniaxial dynamic loadings, of this new category of cellular materials, the TPMS (Triply Period Minimal Surface) structures, for which the current state of the art is rather focused on quasi-static or cyclic loadings.The work presented in this thesis is organised in three parts. The first part aims to characterise the mechanical behaviour of the constitutive material, 316L steel chosen for its high ductility, produced by the SLM (Selective Laser Melting) process. The specificities induced by laser melting on a powder bed, such as anisotropy and strain rate sensitivity, are identified and modelised by material behaviour laws.The second part of this thesis focuses on the mechanical response of TPMS structures under quasi-static and dynamic solicitations. The mechanical responses of the structures show the characteristics of an ideal energy absorber with the absence of an initial peak, a long and slightly rising plateau phase, and a late densification. In addition, the deformation mechanisms are stable. Compared to other so-called conventional cellular materials, the energy absorption capacities of TPMS structures are superior with the advantage of being less sensitive to the direction of solicitation for uniaxial loading. In the dynamic regime, the observed increase in energy absorption capacities is linked to the sensitivity of the constitutive material.This experimental approach is coupled with a detailed numerical FE approach at the mesoscopic scale in order to better understand the local collapse mechanisms that measurement alone does not allow, especially under dynamic solicitations. The numerical model is capable of predicting the experimental mechanical response fairly accurately, based in particular on the material behaviour laws identified previously. Locally, the deformation is a combination of several mechanisms such as buckling, bending and shearing. Energy absorption diagrams and Gibson-Ashby laws are determined in order to relate the energy absorption capacities to the geometrical dimensions and thus to choose the most suitable configuration for the imposed specifications
Ratsimba, Alice. „Élaboration d’objets en cuivre par fabrication additive par extrusion de matière : Etude de la faisabilité : cas de pâtes chargées utilisant des hydrogels de polysaccarides comme systèmes liants“. Electronic Thesis or Diss., Bordeaux, 2024. http://www.theses.fr/2024BORD0054.
Der volle Inhalt der QuelleAmong the seven additive manufacturing methods applied to metals, Extrusion Additive Manufacturing (EAM) appears as a promising technique to produce copper objects. This indirect forming process involves conveying a material and pushing it through an orifice to form strands of material. Three-dimensional objects are built by stacking successive layers from a mixture of metal powder particles and a binding system.Typical formulations for this process include a thermoplastic binder, and the materials are usually packaged in filament form, which is complex to handle and convey. In addition, post-processing steps are usually lengthy and require specific equipment, which can lead to high costs and production lead times.In this perspective, the use of formulations using biobased binder systems appears to be a promising alternative, offering potential advantages in terms of production speed, energy efficiency and environmental impact. The considered materials are metal pastes based on polysaccharide hydrogels loaded with copper powder. The main objective of this work is to study the suitability of the behaviour of these formulations with the extrusion additive manufacturing process. Defining printability criteria helps to understand relationships between the properties of the formulations, the course of the shaping process, and the quality of the obtained objects
Coffigniez, Marion. „Additive manufacturing of 3D architectured metallic biomaterials by robocasting“. Thesis, Lyon, 2021. http://www.theses.fr/2021LYSEI007.
Der volle Inhalt der QuelleBeyond the personalisation aspect that it can bring to the medical field, additive manufacturing also gives access to the elaboration of cellular structures. These structures, with controlled porosity, make it possible both to modulate the mechanical properties of the object and to promote the cellular invasion necessary in tissue engineering. Among the metals commonly used in orthopaedic surgery, titanium alloys are those with the rigidity least distant from that of bone. This study therefore focuses on the development of structures made of Ti6-Al-4V, but also of magnesium since it has the advantage of being resorbable in the body. The scaffolds are obtained by robocasting, a process consisting of extruding, layer by layer, a pasty ink made up of powder and binder. The structures have then to be debinded and sintered at high temperature to achieve their final properties. For Ti-6Al-4V structures, a parametric study is carried out to evaluate the possibilities and limits of the process in terms of structures (and microstructures), chemical compositions and mechanical properties obtained. After optimisation, it is possible to obtain parts with two levels of interconnected porosities (intra-filament (interconnected) microporosity, beneficial for cell adhesion according to the literature, and drawn macropores), keeping a specific yield strength higher than that of bone (105 MPa.cm³/g) and a Young's modulus close to that of bone (28-30 GPa). An intra-filament porosity gradient can also be obtained by varying the powder size within a single part. Concerning magnesium, a binder compatible with the reactivity of the powder (ethanol base) has been identified and the first steps of the process (printing, debinding) are therefore quite feasible for this material. However, conventional sintering of (pure) magnesium is complicated by its reactivity. Alternative sintering methods are therefore being investigated (liquid phase sintering, Spark Plasma Sintering)
Chabot, Alexia. „Méthodologie de monitoring multiphysique des procédés DED : développement par une démarche expérimentale“. Thesis, Ecole centrale de Nantes, 2020. http://www.theses.fr/2020ECDN0022.
Der volle Inhalt der QuelleAdditive Manufacturing (AM) is a promising technology compared to subtractive processes, in terms of cost or freedom of manufacturing functional parts. Among the AM techniques, Laser Metal Deposition (LMD) and Wire-Arc Additive Manufacturing (WAAM), included in the Direct Energy Deposition (DED) processes, manufacture parts by directly melting the material in a layer-by-layer maner. Those processes are currently mainly operated in open-loop. Thus, an acceptable part regarding the specified specifications is often the result of a trial-and-error method. In order to improve DED processes performances and to get rid of this trial-and-error method, monitoring and numerical simulation are the most widely investigated solutions. These PhD works propose a generic multiphysic monitoring methodology, based on four independant control loops which can be operated simultaneously. Those control loops are dedicated to the part temperature, geometry, and structural health, and the Stick Out. In these PhD works, control loops have been mainly implemented on the WAAM process, and a specific attention has been devoted to their developments to ensure their applicability to the LMD process. Concurrent to these monitoring develoments, an evaluation of some existing numerical tools has been conducted, in order to integrate simulation together with monitoring in a manufacturing environement. This PhD project is part of the Joint Laboratory of Marine Techology formed by Naval Group and Centrale Nantes
Radel, Simon. „Implémentation d'un contrôle en ligne pour système de fabrication additive métallique de structures treillis par soudage à l'arc“. Thesis, Montpellier, 2018. http://www.theses.fr/2018MONTS078/document.
Der volle Inhalt der QuelleWire Arc Additive Manufacturing (WAAM) has the possibility to build metallic structures in 3D space. WAAM system is based on welding process to deposit metallic material and on a robot that moves the welding torch to add material at a given position. For large skeleton structures, it was chosen to deposit material point by point. Welding process induces fluctuations.To be fully scalable, two main features must be taken into account. First, monitoring of the process is necessary. Local control on the geometry of the deposition must be used to reach the final shape. Secondly, some deposition strategies must be implemented to manage branch intersections. To reach these two objectives, anadaptive and modular slicer and a process manager have been developed in order to implement this control. It allows us, if an error occurs during the deposition, to change the position of the effector or the process parameters. To obtain the desired geometry, the CAM software have to be able to, (i) do a slicing during the additive process of the part with a variable deposit height in order to take into account variation of the deposition process and (ii) manage the deposition strategy at intersection to output the position of the torch
Chastand, Victor. „Etude du comportement mécanique et des mécanismes d'endommagement de pièces métalliques réalisées par fabrication additive“. Thesis, Ecole centrale de Lille, 2016. http://www.theses.fr/2016ECLI0012/document.
Der volle Inhalt der QuelleAdditive manufacturing offers new opportunities for industries to manufacture complex parts with no additional tooling and better optimization of the material used.This thesis is about the analysis of the mechanical properties and the damaging mechanisms of parts produced by additive manufacturing, using mechanical properties of casted and wrought parts as reference. This type of analysis is necessary in order to industrialize the process.The tensile and fatigue properties on Titanium Ti-6Al-4V and Aluminium AlSi7Mg0,6 were measured. The effects of the process, the manufacturing direction, the post-machining and the post-heat treatments were compared. Properties are at least at the level of casting.A correlation of these results with microstructures and fracture surfaces was made in order to extract the damaging mechanisms. A method to measure the criticity of the defects in a part was defined. Some of these hypotheses were verified using microtomographic in situ tensile tests
Corona, Galvan Luis. „Prototypage rapide de pièces en acier : étude du dépôt de matière et d'énergie lors de la fusion à l'arc d'un fil par le procédé MIG-CMT“. Thesis, Montpellier, 2018. http://www.theses.fr/2018MONTS062/document.
Der volle Inhalt der QuelleA test bench specially dedicated to additive manufacturing by a new technology based on the electric arc melting of a metallic wire has been developed. This technology uses an electric arc welding process called Cold Metal Transfer (CMT) as energy source to ensure the controlled melting of the wire and the deposition of liquid metal droplets to produce mechanical parts by superposing weld beads. The developed technology was used to make specimens from a low alloyed steel wire. The influence of the many parameters controlling the arc welding source on the mechanism of wire melting and transfer of molten metal droplets to form weld beads was studied. The melting-transfer cycles of liquid metal were analyzed in particular with special interest in the energies generated during each of the cycle phases. This knowledge has made possible to find different process settings for increasing the metal deposition rate compared to the pre-recorded standard settings in the microprocessor of the CMT welding generator. Walls consisting of the superposition of a large number of weld beads were then made, and the influence of the addition of many layers on the geometry of the deposits were discussed. Finally, a method of online control of the process, based on the principle of control charts, has been developed. A detailed study of the representative waveforms of current and voltage of the melting / transfer cycle with the CMT process has allowed to identify the most relevant characteristics for detecting, from a control chart, a deviation on the process that may lead to the appearance of geometrical defects
Odinot, Julie. „Développement de la fabrication additive directe par DED-CLAD : de la poudre à la mise en forme de pièces céramiques denses“. Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLN059.
Der volle Inhalt der QuelleThis work, in partnership between the ONERA Materials and Composite Structure Department (DMSC) and IREPA Laser within the CLADIATOR project, is based on the study of direct additive manufacturing of dense ceramic materials by direct melt deposition (also known as laser cladding) process. This process enables high dimensions or even multi-materials part manufacturing.It will deal with the adaptation of raw materials (ceramic powders) to the existing machine, especially in the case of powder flowability and optical absorption. Indeed, the powder flowability enables its transportation up to the laser nozzle, while the optical absorption of the laser signal is necessary to allow its melting.In parallel, the existing machine also needs to be adapted to ceramic materials : the main difficulty of this work will be the occurence of cracks during the manufacturing. This phenomena is due to the local heating by the laser and the materials brittleness. That’s why some secondary heating solutions, before or after the melt, will have to be defined to decrease the thermal gradient in the material while processing. Those solutions will be discussed between Onera and Irepa Laser, based on FEM simulations established with COMSOL Multiphysics software.Finally, the elaboration process influence on the manufactured ceramics parts will be investigated with microscopy, mechanical and thermal characterization
Azman, Abdul Hadi. „Méthode pour l'intégration des structures treillis dans la conception pour la fabrication additive“. Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAI004/document.
Der volle Inhalt der QuelleIt is now possible to manufacture metallic lattice structures easily with additive manufacturing. Lattice structures can be used to produce high strength low mass parts. However, it does not exist a method to design lattice structures for additive manufacturing. This PhD focuses on lattice structure design methods and manipulation in CAD, CAE and CAM tools to facilitate the wide use of lattice structures in products. The thesis addressed the following research questions:• Why are lattice structures so little used in part designs?• What are the information necessary to help designers to design parts containing lattice structures?• How can lattice structures be created quickly and easily in CAD?The main contributions are:• An evaluation of current CAD tools in terms of human machine interface, CAD file formats, CAE and CAM to design lattice structures was conducted. The results show that current CAD tools and CAD file formats have insufficient performance in the context of design for additive manufacturing. Current CAD tools create and represent lattice structures using surfaces and volumes. This contributes to large file sizes, high RAM consumption, as well as time-consuming creations and operations.• A new lattice structure design strategy. This method serves as a guideline for designers to integrate lattice structures in additive manufactured parts using the concept of equivalent material. Designers will be able to choose lattice structure patterns and densities.• A methodology to create equivalent materials is presented. It is solid and does not contain any struts, thus has few surfaces only. With this equivalent material, it will be easier and quicker to conduct FEA due to the small number of surfaces involved. The characteristics of different lattice structure patterns and densities were determined, which are the relative Young’s modulus and relative strength in function of the relative density. This methodology can be applied to all lattice structures.• The main lattice structure geometrical characteristics were determined. A skeleton model was presented to define lattice structures with points, lines, sections and joints instead of surfaces and volumes. A method is presented to visualise in CAD and slice lattice structures in CAM from the skeleton model
Al-Meslemi, Yahya Ismail. „Modélisation prédictive pour la Fabrication Additive métallique : Caractéristiques clés et applications à la caractérisation de la porosité“. Thesis, université Paris-Saclay, 2021. http://www.theses.fr/2021UPAST007.
Der volle Inhalt der QuelleAbstract : Quality control remains the main barrier for broader adoption of Additive Manufacturing processes. Data analytics, physical process modelling, part measurement and metrological assessment, are more and more used to achieve better quality. However, there are still significant modeling, computational, and measurement challenges stemming from the broad range of the involved parameters affecting the quality of the final part.In this thesis, we focus on overcoming some of these quality-related limits. We propose a predictive modeling approach to perform porosity characterization and to determine the range of manufacturing working conditions based on a limited set of previously collected data.The proposed systematic modeling approach uses Gaussian Process (GP) to map the entire experimental space based on limited predetermined measured points. GP integrates a covariant function, which uses statistical bayesian inference coupled with Markov Chain to estimate model parameters, based on the collected data. These data are generated based on a proposed experimental design and CT scan image analysis protocol. Finally, and for an efficient implementation of approach, we benefit from establishing correlations between the manufacturing process conditions and the product’s features, based on Key Characteristics (KCs) while considering the whole value chain in AM. These KCs are evaluated based on their importance and ordered hierarchically from a statistical point of view
Marcos, Daniel. „Développement de MOULes INNOVants à haute conductivité thermique pour l’injection de matières plastiques fabriquées par Selective Laser Melting (SLM/LBM)“. Thesis, Paris Sciences et Lettres (ComUE), 2018. http://www.theses.fr/2018PSLEM080.
Der volle Inhalt der QuelleThe aim of this thesis is to propose materials adapted to the needs of a mold cavity for plastic injection, manufactured layer by layer by "Selective Laser Melting" (SLM). The production of high productivity tools requires the design of multi-cavity molds, with high heat dissipation and wear resistance to resist the injection of aggressive polymers with highglass transition and glass fiber reinforced. These molds must be able to with stand high rates and binding thermal cycles. The solution exposed in this thesis is to work on the fabrication by SLM of materials with high thermal conductivity and high hardness. At first, a commercial material partially meeting industrial demand has been proposed. It is a low alloy steel (42CrMo4). A characterization of the powder from a gas atomization was undertaken and its layering characteristics were evaluated. The experiences, of melting it with a laser, have identified a set of viable parameters, allowing the construction of parts with satisfactory metallurgical quality. The development of a suitable heat treatment completes the studyof this steel. The last part of this thesis consist in a proposition of a "design" of powder for the fabrication by SLM of MetalMatrix Composites, with WC base, fulfilling the industrial specifications. However, this study remains exploratory and focused on the identification of metallurgical mechanisms (reactions, changes in solid / liquid and liquid/ vapor states, etc.), thermo-capillarity phenomena and matter transport by gas convection
Schneider-Maunoury, Catherine. „Application de l’injection différentielle au procédé de fabrication additive DED-CLAD® pour la réalisation d’alliages de titane à gradients de compositions chimiques“. Thesis, Université de Lorraine, 2018. http://www.theses.fr/2018LORR0260/document.
Der volle Inhalt der QuelleSince 1984, the Functionally Graded Material (FGM) allow to create a thermal barrier and to reduce the strong discontinuities of properties between two materials of different composition. These multimaterials,whose consist of an intentional variation in the chemical composition and, consequently, modify the microstructural, chemical, mechanical and thermal properties, lead to a smooth distribution of the thermal stress. The in-situ development of these custom-made alloys is made possible by the use of additive manufacturing processes such as the DED-CLAD® powder deposition process. These processes have grown substantially since the 1980s and are optimal for the manufacture of FGM. During this industrial thesis, technical developments have been carried out to adapt the DED-CLAD® process and to allow the manufacturing of FGM. Thanks to two industrial collaborations, a full study was carried out on titanium-molybdenum and titanium-niobium alloys. These alloys make it possible, in the first case, to produce parts resistant to strong thermal stress (space sector), and in the second case to combine mechanical properties and biocompatibility (biomedical sector). The originality of this thesis rests on the study of a complete gradient, that is the addition in alloy element varied from 0% to 100%. In fact, studies reported in the literature do not mention titanium-refractory material for high levels of refractory element. Microstructural (XRD, crystallographic analysis by EBSD technique), chemical (EDS) and mechanical (microhardness, tensile test and instrumented indentation) analyses revealed an evolution of the properties along the chemical gradient. The mechanical characterization of the sample by instrumented indentation has also proved particularly relevant in the case of these multi-materials
Schneider-Maunoury, Catherine. „Application de l’injection différentielle au procédé de fabrication additive DED-CLAD® pour la réalisation d’alliages de titane à gradients de compositions chimiques“. Electronic Thesis or Diss., Université de Lorraine, 2018. http://www.theses.fr/2018LORR0260.
Der volle Inhalt der QuelleSince 1984, the Functionally Graded Material (FGM) allow to create a thermal barrier and to reduce the strong discontinuities of properties between two materials of different composition. These multimaterials,whose consist of an intentional variation in the chemical composition and, consequently, modify the microstructural, chemical, mechanical and thermal properties, lead to a smooth distribution of the thermal stress. The in-situ development of these custom-made alloys is made possible by the use of additive manufacturing processes such as the DED-CLAD® powder deposition process. These processes have grown substantially since the 1980s and are optimal for the manufacture of FGM. During this industrial thesis, technical developments have been carried out to adapt the DED-CLAD® process and to allow the manufacturing of FGM. Thanks to two industrial collaborations, a full study was carried out on titanium-molybdenum and titanium-niobium alloys. These alloys make it possible, in the first case, to produce parts resistant to strong thermal stress (space sector), and in the second case to combine mechanical properties and biocompatibility (biomedical sector). The originality of this thesis rests on the study of a complete gradient, that is the addition in alloy element varied from 0% to 100%. In fact, studies reported in the literature do not mention titanium-refractory material for high levels of refractory element. Microstructural (XRD, crystallographic analysis by EBSD technique), chemical (EDS) and mechanical (microhardness, tensile test and instrumented indentation) analyses revealed an evolution of the properties along the chemical gradient. The mechanical characterization of the sample by instrumented indentation has also proved particularly relevant in the case of these multi-materials
Millon, Célia. „Contribution à l’inspection d’échantillons de fabrication additive métallique par ondes de Rayleigh au moyen d’une méthode ultrasons-laser“. Thesis, Paris, CNAM, 2018. http://www.theses.fr/2018CNAM1195/document.
Der volle Inhalt der QuelleThis thesis contributes to the detection of flaws in laser metal deposition (LMD) additive manufacturing process samples towards an in situ control of the process. The in situ control foreseen concerns the last layers deposited by the process (316L and Inconel 718 steel) for which porosities and cracks may appear (~ 100 µm). The inspection is performed by laser-ultrasonics (LU), an all-optical and non-invasive technic. Experiments are conducted in thermoelastic mode. The LMD process gives rise to coarse grain microstructure and surface roughness, that make the control tricky. Indeed, those characteristics generate scattering elastic waves. Thus, this work contributes to the better comprehension of those phenomena and their effects of the detection on subsurface flaws which dimensions are close to the acoustic wavelength. Surface inspection has been optimized by designing an optical setup, improving the Rayleigh wave generation by using a thin laser line source (~200 µm). Hence, the spectral content has been increased until it reaches 10 MHz, that is to say a wavelength equals to 700 µm (λR). Then, the limits have been brought out through the inspection of LMD samples. Those samples include sided drilled holes and notches which dimensions are less than λR, on rough surface (multiple scattering of Rayleigh wave). Moreover, real subsurface flaws inspections have been studied. The flaws have been created by the instability of one of the process parameter: the hatch (distance between each layer), or by a bad powder quality. By intentionally deteriorating those parameters, the samples, then, have porosity rate (Φ) with ranging from 0.5% to 10%. Finally, two correlation methods have been studied to discriminate porosity rate: through the study of the normalized cross correlation function and by Principal Component Analysis (PCA). The first method, simple and fast to implement, does not allow distinguishing the porosity rates. Nevertheless, the PCA indicates that it is possible to discriminate all the flaws. Finally, preliminary tests have been carried out to show that LU measurements is feasible on rough surfaces, while keeping a good signal-to-noise ratio, without averaging, during an automated displacement
Andurand, Lewis. „Développement d'une méthode de génération de trajectoire versatile pour la réalisation de pièces par procédés DED multi-axes à partir de surfaces facettisées“. Electronic Thesis or Diss., Toulon, 2023. http://www.theses.fr/2023TOUL0001.
Der volle Inhalt der QuelleAdditive manufacturing is a category of processes that allows the production of mechanical parts by the adding of material. Directed Energy Deposition (DED) processes can be combined with multi-axis robots and are a promising option to obtain parts with complex structures. However, the path generation methods and the machine structures used remain an issue. With innovations in these areas, the industrial possibilities would increase tenfold.This thesis presents a numerical and systematic path generation method based on meshed surfaces and adapted to DED processes. The method was validated through simulations on minimal triply periodic surfaces and allows the creation of a first deposition path that meets the distance constraint between the part and the tool. This first path can be combined with region prioritization feedback to obtain a final path adapted to the physical warnings provided by the robot, the manufacturing material and the tool
Limousin, Maxime. „Développement d’inserts de moule pour l’injection plastique en acier inoxydable martensitique et en verre métallique massif produits par Laser Beam Melting (LBM)“. Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEE003.
Der volle Inhalt der QuelleThe aim of this thesis is to increase molds lifetime. Mains phenomena to limit are abrasion wear and corrosion. For this purpose, two material families have been preselected. They have been identified among stainless steels and bulk metallic glasses. This work details their selection, development in additive manufacturing and characterization for both materials. In the end, this thesis delivers a new steel grade adapted to the additive manufacturing and plastic injection molds, which affords good corrosion resistance, high hardness and a comparatively good thermal conduction. Concerning the bulk metallic glass, this work shows that the chosen composition allowed to preserve enough amorphous material to induce exceptional properties and give strong hopes to continue in this vein
Pouzet, Sébastien. „Fabrication additive de composites à matrice titane par fusion laser de poudre projetée“. Thesis, Paris, ENSAM, 2015. http://www.theses.fr/2015ENAM0051/document.
Der volle Inhalt der QuelleTitanium matrix composites are attractive materials for aeronautical applications, mainly because of their superior mechanical resistance at elevated temperature, combined with a low density. The critical machinability of such composites makes additive manufacturing processes particularly adapted for building complex 3D shapes. This study has been focused on the Direct Metal Deposition (DMD) of Metal matrix composites. In a first step, various powders and powder blends have been carried out in order to facilitate the DMD process and to obtain homogeneous microstructures. Following this, Ti-6Al-4V / B4C powder blends, allowing to obtain TiB + TiC particles distributed in the Ti matrix were more specifically considered. Metallurgical mechanisms involved in the formation of microstructures were identified prior to an investigation on mechanical properties at ambient and elevated temperature for various DMD process conditions and particle concentrations. Among the most interesting results of this study, the influence of a high carbon content solubilized in the Ti-matrix was considered as a dominant factor to explain the evolution of mechanical properties with increased amounts of reinforcements
Kang, Nan. „Élaboration "in-situ" par mélanges de poudres de composites à matrice métallique au cours du processus de fabrication additive“. Thesis, Belfort-Montbéliard, 2016. http://www.theses.fr/2016BELF0305/document.
Der volle Inhalt der QuelleAs a new manufacturing technology, Selective laser melting (SLM) has a large potential in the manufacturing of complex parts with ultrafine microstructure.Selective laser melting has many significant advantages over traditional manufacturing methods but still faces a low availability of powder materials. With SLM, the part is firstly designed via 3D computer-aided design (CAD)), then built layer-by-layer with a high energy computer-controlled laser beam The work done in this study was therefore aiming at developing a new way to obtain alloys and composites directly from elemental powder mixtures with a large composition flexibility.Experimentally the choice was made of the aluminum-silicon system with several silicon contents (12, 18, 50 wt. %).Adding a static magnetic field was also considered as an additional way to control the microstructure. When parts are manufactured by SLM, laser power and scanning speed are the main parameters determining the density, microstructure, phase composition and mechanical properties. A systematic analysis of the role of these parameter on the manufacturing of Al - Si alloys by SLM from mixtures of powders was therefore conducted. Al - Si alloys with a very fine microstructure were thus obtained for several composition ranges corresponding to practical applications (lightweight structures, high wear resistance alloys, electronic packaging material, ...). The properties of the materials obtained in this way, according to the performed characterizations, compares favorably with those obtained via the conventional production technologies
Masmoudi, Amal. „Modélisation et développement expérimental du procédé de fabrication additive par fusion laser sélective d'un lit de poudre métallique : influence de la pression de l'atmosphère“. Thesis, Belfort-Montbéliard, 2016. http://www.theses.fr/2016BELF0287/document.
Der volle Inhalt der QuelleThe selective laser melting process (SLM) of a metallic powder bed is an innovative process that allows the manufacturing of complex shape parts directly from a CAD file via a complete melting of powder layers deposited successively. During the SLM process, the high laser energy density creates many thermal cycles: melting - vaporization - solidification.The purpose of this work was: 1) to better characterize and understand experimentally the phenomena that occur during the laser beam - powder / molten metal pool interaction and 2) to develop a numerical model taking into account the phenomena of melting and vaporizing of the material and the presence of the surrounding gas in the build chamber.In a first time, considering simple geometries (tracks and surfaces) and 316L stainless steel as material, we studied the interaction between the laser beam, the powder bed and the liquid metal pool using several experimental techniques (spectrometry, calorimetry, ...) in order to understand the nature and the role of the metal vapor generated during the process. The results showed that the vapor has no effect on the transmission of the laser beam energy to the material during the SLM process. Meanwhile it leads to the deposition of condensed vapor and also drag some molten metal droplets.In a second time a numerical model was developed to determine the influence of the pressure of the surrounding environment on the melting process of a powder bed by a laser beam. Parameters characterizing the evolution of the physical properties of the material and of the gaseous medium according to the temperature and pressure were incorporated into the model database. Some material parameters were determined from the literature and others were obtained empirically using specific experimental measurements.Finally, this numerical model, complementing experimental results, was used to treat the main subject of the thesis which is the effect of the surrounding pressure on the SLM process. The model helped to clarify the physical phenomena provided by the change in the pressure level and its validity was checked through experimental measurements
Gomez, Ortega Arturo. „Prototypage rapide de pièces en alliage d’aluminium : étude du dépôt de matière et d’énergie lors de la fusion à l’arc d’un fil par le procédé MIG-CMT“. Thesis, Montpellier, 2018. http://www.theses.fr/2018MONTS067/document.
Der volle Inhalt der QuelleA new additive manufacturing process for metallic parts, based on the arc welding process known as CMT (Cold Metal Transfer), is studied with the objective of building parts with the aluminium alloy Al5Si. A workbench for additive manufacturing based on the 3D printers open-source principle, on which the CMT generator was integrated, was specially developed. The CMT process allows to control the aluminium wire melting and its deposition under the form of droplets on the building surface, forming, after solidification, beads that can be superposed for the parts construction. The process parameters influence on the material transfer and heat transfer during the metal melting and deposition on the build surface, as well as on the geometric characteristics of the deposed beads, in the case of mono-layer deposits, and in the case of multi-layer walls, is studied. Many geometric defects were observed, and their apparition conditions analysed, thanks in particular to the use of a high-speed camera. The understanding of the relations between the process parameters, the melting and heat transfer mechanisms, and the beads geometry, allowed the defects correction by identifying and modifying the process parameters responsible of their apparition. Finally, an on-line control method for the process, based on the analysis of the voltage and current signals produced by the welding generator during the deposition phenomena, making possible the early detection of defects, and then the modification of the process parameters before they are amplified, has been proposed
Wang, Zeya. „Robotisation de la fabrication additive par procédé arc-fil : Identification et amélioration de la commande“. Electronic Thesis or Diss., Université de Lorraine, 2022. http://www.theses.fr/2022LORR0068.
Der volle Inhalt der QuelleAdditive manufacturing of metallic parts has gained significant popularity in recent years as an important technological solution for the production of complex parts. Among the different processes of metal additive manufacturing, the wire-arc additive manufacturing (WAAM) using CMT (Cold metal transfer) welding is taken for our study because of its high deposition rate, low cost of equipment and little loss of material (low spatter) during manufacturing. In the literature review, it can be noted that one of the most important problems that prevent the industrial application of the WAAM is the poor geometric accuracy of the manufactured parts due to the instability of the process and the lack of reliable control system to deal with irregularities during deposition. The focus of this work is to improve the stability and geometric performance of the process. In this work, an experimental system is implemented to robotize the process and to monitor the geometry of the deposited parts. The process is modeled by artificial neural networks and a control system is developed to regulate the geometry of the deposit and to reduce manufacturing errors. Furthermore, an improvement strategy is applied in order to reduce the geometric instabilities at the ends of the bead; an in-situ monitoring method is also developed to detect the internal defects of deposited parts
Blanc, Toinou. „Fabrication additive par dépôt laser direct de TA6V : étude expérimentale dans des régimes de forte productivité, modèles de comportement et recyclage de la poudre“. Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLEM047.
Der volle Inhalt der QuelleAdditive manufacturing, also known as 3D printing, aggregates several processes that allows to build parts by stacking layers of a given material, directly from CAD models, without specific tools. Over the past decade, additive processes have gained in notoriety much more rapidly than their industrial applications gained in profitability.Indeed, these technologies must still mature, especially for metallic applications. This is the challenge of the project FUI-9 FALAFEL, in which this thesis takes place, carried out in partnership with several industrial and academic actors. It aims to accompany the development of the direct laser deposition process (DLD), also known as laser metal deposition (LMD).This consists in projecting and melting metal powder on a substrate in a defined pattern, layer by layer. It allows to obtain large size and low complexity parts with high roughness and a proper productivity, despite being still insufficient for industrialization.The specificity of the present work is to study the DLD process in operating modes that allow to reach high build rates (> 100 cc/h), in application to the titanium alloy TA6V.This work is driven by two research focus. In the first place, we try to improve the understanding and control of the process by establishing the relationships between operating parameters, geometric criteria, melt pool stability, process efficiency and generated microstructure.In a second stage, we focus on the possibility to reuse powders that remain unmelted after deposition. Up to 3 levels of powder recycling are studied, without dilution with new powder. We then carried out tests to check that the mechanical properties were in accordance with the aeronautical requirements
Chen, Shuai. „Investigation of FEM numerical simulation for the process of metal additive manufacturing in macro scale“. Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEI048/document.
Der volle Inhalt der QuelleAdditive manufacturing (AM) has become a new option for the fabrication of metallic parts in industry. However, there are still some limitations for this application, especially the unfavourable final shape and undesired macroscopic properties of metallic parts built in AM systems. The distortion or crack due to the residual stress of these parts leads usually to severe problems for some kinds of metal AM technology. In an AM system, the final quality of a metallic part depends on many process parameters, which are normally optimized by a series of experiments on AM machines. In order to reduce the considerable time consumption and financial expense of AM experiments, the numerical simulation dedicated to AM process is a prospective alternative for metallic part fabricated by additive manufacturing. Because of the multi-scale character in AM process and the complex geometrical structures of parts, most of the academic researches in AM simulation concentrated on the microscopic melting pool. Consequently, the macroscopic simulation for the AM process of a metallic part becomes a current focus in this domain. In this thesis, we first study the pre-processing of AM simulation on Finite Element Method (FEM). The process of additive manufacturing is a multi-physics problem of coupled fields (thermal, mechanical, and metallurgical fields). The macroscopic simulation is conducted in two different levels with some special pre-processing work. For the layer level, the reconstruction of 3D model is conducted from the scan path file of AM machine, based on the inverse manipulation of offsetting-clipping algorithm. For the part level, the 3D model from CAD is reconstructed into a voxel-based mesh, which is convenient for a part with complex geometry. The residual stress of a part is analysed under different preheat temperatures and different process parameters. These simulations imply the potential technique of reducing residual stress by the optimisation of process parameters, instead of the traditional way by increasing preheat temperature. Based on the FEM simulation platform above, two simulations at line level are also studied in this thesis, aiming at the relation between the AM process and part's final quality. These examples demonstrate the feasibility of using macroscopic simulations to improve the quality control during the AM process. In the first task, dataset of heating parameters and residual stress are generated by AM simulation. The correlation between them is studied by using some regression algorithm, such as artificial neural network. In the second task, a PID controller for power-temperature feedback loop is integrated into AM process simulation and the PID auto-tuning is numerically investigated instead of using AM machine. Both of the two tasks show the important role of AM macroscopic process simulation, which may replace or combine with the numerous trial and error of experiments in metal additive manufacturing
Boissier, Mathilde. „Coupling structural optimization and trajectory optimization methods in additive manufacturing“. Thesis, Institut polytechnique de Paris, 2020. http://www.theses.fr/2020IPPAX084.
Der volle Inhalt der QuelleThis work investigates path planning optimization for powder bed fusion additive manufacturing processes, and relates them to the design of the built part. The state of the art mainly studies trajectories based on existing patterns and, besides their mechanical evaluation, their relevance has not been related to the object’s shape. We propose in this work a systematic approach to optimize the path without any a priori restriction. The typical optimization problem is to melt the desired structure, without over-heating (to avoid thermally induced residual stresses) and possibly with a minimal path length. The state equation is the heat equation with a source term depending on the scanning path. Two physical 2-d models are proposed, involving temperature constraint: a transient and a steady state one (in which time dependence is removed). Based on shape optimization for the steady state model and control for the transient model, path optimization algorithms are developed. Numerical results are then performed allowing a critical assessment of the choices we made. To increase the path design freedom, we modify the steady state algorithm to introduce path splits. Two methods are compared. In the first one, the source power is added to the optimization variables and an algorithm mixing relaxation-penalization techniques and the control of the total variation is set. In a second method, notion of topological derivative are applied to the path to cleverly remove and add pieces. eventually, in the steady state, we conduct a concurrent optimization of the part’s shape and of the scanning path. This multiphysics optimization problem raises perspectives gathering direct applications and future generalizations
David, François. „Etude de composants micro-coaxiaux à fort facteur de qualité pour applications en bande Q/V“. Thesis, Limoges, 2017. http://www.theses.fr/2017LIMO0095/document.
Der volle Inhalt der QuelleThis work concerns the study and the fabrication of passive RF components with a high quality factor on Q/V bands. The components were fabricated with an air-filled 3D architecture. Air-filled rectangular micro-coaxial lines and air filled cavity filters were demonstrated. Also, micro-additive fabrication processes were demonstrated for the realization of the 3D air-filled components
Marion, Guillaume. „Modélisation de procédés de fabrication additive de pièces aéronautiques et spatiales en Ti-6AI-4V par dépôt et fusion sélective d'un lit de poudre par laser : Approche thermique, métallurgique et mécanique“. Thesis, Paris Sciences et Lettres (ComUE), 2016. http://www.theses.fr/2016PSLEM055.
Der volle Inhalt der QuelleAdditive manufacturing processes allow to build finished industrial parts with very complex geometry, while reducing development time and costs compared to conventional manufacturing processes. The main principle of all these processes is to build components directly from a CAD file defining its geometry without requiring any mold nor specific tools.This study is part of the FALAFEL research project focused on additive manufacturing processes by laser and electron beams. It is composed of academic research laboratories and industrial partners from Aeronautics and Laser Processes industries. The main goal of this project is to implement, improve and validate additive manufacturing processes regarding the production of metallic components for Aeronautics. Studies are conducted under industrial conditions.The aim of our thesis is to provide a numerical model to obtain, within a reasonable time, information about the mechanical and metallurgical properties of industrial components made out of titanium Ti-6Al-4V. It is aimed at two additive manufacturing processes: the Direct Metal Deposition (DMD) and the Selective laser melting (SLM)