Dissertations / Theses on the topic 'Supervision de fabrication additive'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Supervision de fabrication additive.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
Mosser, Loïc. "Contribution à la conception et la fabrication de robots souples pneumatiques." Electronic Thesis or Diss., Strasbourg, 2024. http://www.theses.fr/2024STRAD009.
Full textThis thesis covers the design of pneumatic soft robots, which move thanks to deformation using pneumatic chambers. We contribute to the design of a robot from the formulation of the need to the manufacturing of the robot. We address the problems associated with the design and manufacture of these robots. For design, we propose a genetic algorithm accelerated by the use of an AI model enabling rapid estimation of the behavior of new geometries and the search for solutions. For manufacturing, we propose an instrumented silicone additive manufacturing platform enabling the acquisition of point clouds on each produced layer. Indicators are then proposed to monitor ongoing production and the integrity of soft robots, and these indicators are evaluated experimentally
Muller, Pierre. "Fabrication additive de pièces multimatériaux." Phd thesis, Ecole centrale de nantes - ECN, 2013. http://tel.archives-ouvertes.fr/tel-00918030.
Full textEtienne, Jimmy. "Tranchage courbe pour la fabrication additive." Electronic Thesis or Diss., Université de Lorraine, 2022. http://www.theses.fr/2022LORR0284.
Full textMost additive manufacturing processes fabricate objects by stacking planar layers of solidified material. As a result, produced parts exhibit a so-called staircase effect,which results from sampling slanted surfaces with horizontal planes. This negatively impacts the surface finish and accuracy of a part. While thinner slices reduce this effect, it remains visible in areas where the input shape surfaces almost align with the layers. This horizontal slicing scheme also impacts the resilience of the printed part as layers cannot be aligned to obtain the maximum strength. As with layers, the orientation of trajectories within a slice is often constrained and cannot be freely controlled. In this thesis, we exploit the ability of some additive manufacturing processes to deposit material slightly out of the plane to overcome these limitations. We mainly focus on extrusion-based technologies, particularly Fused Filament Fabrication technology, since most printers in this category can deposit along slightly curved paths underdeposition slope and thickness constraints. Our algorithms are split into two categories,the ones that produce freely oriented trajectories inside a layer and the ones that curve the layers themselves. My first contribution focuses on deposition trajectories inside a layer, allowing the users to control their orientation. This led to two novel infill patterns aiming at two different objectives. The first is a sparse infill that follows a direction field and density field, while the second is a dense, oriented staggered infill pattern with minimal porosity. My second contribution focuses on printing with curved layers, exploring two different approaches. The first one operates directly on the layers, making them either followthe natural slope of the input surface or, on the contrary, intersect the surfaces at a steeper angle, thereby improving the sampling quality. We demonstrate that this approach enforces all fabrication constraints, including the guarantee of generating collision-free toolpaths. The second method builds atop the staggered infill introduced before, generating trajectories with free orientation throughout the part's volume
Crouillere, Marie. "Nouveaux mélanges silicone pour la fabrication additive." Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEI015.
Full textAdditive manufacturing is a rapidly growing technical area within which a wide variety of methods have been developed. These new processes provide a higher degree of geometrical freedom when building specific objects for small series production or for custom-made use. The benefits against traditional processes are reductions of time, of cost and of material consumption, thanks notably to the suppression of specific equipment (e.g. moulds). Nowadays different types of materials are processed in additive manufacturing, like thermoplastic polymers (PLA, ABS, PA), metals or ceramics. However crosslinkable elastomeric materials like silicones have hardly been considered although they are widely used in several industries. This study focuses on 3D printing of new silicone formulations, in a view to creating new structures of light densities. Material extrusion (or fused deposition modelling, FDM) is used as an additive manufacturing process in which material is selectively dispensed through a nozzle. This method, commonly used with thermoplastic materials, requires a number of modifications and improvements with silicone formulations which containing silica nanofillers. In particular, the network, rheology and curing time have been studied to come up with a formulation that both fits perfectly with additive manufacturing and generates good mechanical properties of the finished product. Furthermore enhancement of homemade 3D printer characteristics seems to be obvious to fit also with this kind of new formulation and new design of pieces. Finally, new structured objects have been developed to reproduce the two most important parts of an orthopedic liner
Piaget, Alexandre. "Maîtrise de la qualité en fabrication additive." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAI004/document.
Full textBy using production solutions from Additive Manufacturing (AM) technologies, the industry is opening up new possibilities for manufacturing high added value parts. In order to be fully exploitable, these manufacturing processes must allow the production of parts whose quality is adapted to the needs of the industry. This work focuses on two aiming points of quality control in AM applied to Electron Beam Melting (EBM) technology.The first point deals with the impact of a part position in the manufacturing space of a machine on the geometric quality of this part. To characterize the manufacturing space of the Arcam A1 machine, several series of parts are manufactured at different locations of the space, then compared to their initial design. The differences measured between the parts and their desired geometry show that the periphery of the manufacturing space is a zone subject to important geometrical defects. These defects are characterized and solutions are proposed to limit the impact on the geometrical quality of parts.The second point deals with the porosity of manufactured parts. When the energy supply of the electron beam is not adequate to melt the powder properly, pores can form in the material of the manufactured parts. The geometry and material of the parts make it difficult to detect its pores. A detection method is provided to detect the presence of pores in parts via a standardized control on an item that copies the parts merging conditions. This method offers two control alternatives: an optical control (fast, affordable but not very accurate) and a tomographic control (more accurate than the previous one but slower and costlier). An innovative image processing algorithm is developed as part of this study to make the item tomography scans more reliable
Liboutet, Emile. "Fabrication additive de composants pour l'énergie nucléaire." Electronic Thesis or Diss., Bourgogne Franche-Comté, 2023. http://www.theses.fr/2023UBFCA001.
Full textFramatome is one of the world leaders in the nuclear industry. Its main business is the manufacture of nuclear reactors and nuclear fuels.All the reactors can be divided in two main categories: power reactors and research reactors. Nuclear research reactors are small nuclear reactors used by universities and research centers. Their purposes are training, research, development of power reactor components, production of neutrons for scientific experiments, irradiation of materials for industry and manufacture of radioisotopes for the medical field. Since nuclear research reactors are small, their fuels must be dense in uranium to sustain nuclear reactions and maximize their yield. The RERTR program (Reduced Enrichment for Research and Test Reactors), set up in 1978, pursues the objective of optimizing the fissile uranium density of research reactor fuels to offset the 93% reduction in enrichment to 20% in 235U. After having developed new alloys with higher density, other research is then put in place to allow the improvement of the cores by various means. One of the possible ways is to work on the geometry of the plate core.Current techniques for manufacturing research nuclear fuel plates are rolling and extrusion from cold-compacted metallic uranium powders. These two technologies have three main limitations. First, they require the plates to have planar or cylindrical core geometries whereas the geometry of nuclear reactions is rather spherical and dictated by neutron leakage and moderation in the reactor core. Then, these technologies are based on large deformations. The core of the uranium plate is indeed diluted in a ductile aluminum matrix to allow this deformation while remaining in the elastic domain. The percentage of aluminum added in the core is about 40% by mass. Finally, the large deformations applied during rolling or extrusion induce waves of deformation on the plate core and thus the formation of extra thicknesses on the plate core. They are compensated by the reduction in the thickness of the uranium plate core by almost 20%. All these technological constraints induce a loss of 235 uranium mass by a factor of two in the plate core. The change in technology could make it possible to overcome these limitations.The fuel plates of nuclear research reactors are objects with high added value, of small size (typically 1000 x 60 x 1.3 mm), produced in small series, not standardized, with many different designs and using metal powders. These features are perfect for additive manufacturing. In addition, the current improvements sought are geometric optimization with more complex geometries than those currently possible. These advantages are again typically those of additive manufacturing. So, we have a use case that seems well suited to additive manufacturing. However, there is a major difficulty. The uranium metal powder used is radioactive and flammable in air. It needs to be handled in a glove box, which complicates the implementation of additive manufacturing technologies.It is precisely to meet these requirements that a research project was born between the company Framatome and the University of Technology of Belfort-Montbéliard to study the additive manufacturing processes likely to manufacture nuclear fuel plates of research. Two additive manufacturing processes were selected and tested: Cold Spray and Laser Beam Melting
Bonnard, Renan. "Proposition de chaîne numérique pour la fabrication additive." Phd thesis, Ecole centrale de nantes - ECN, 2010. http://tel.archives-ouvertes.fr/tel-00585342.
Full textDiez, Jacob A. "Design for additive fabrication : building miniature robotic mechanisms." Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/17668.
Full textPitchumani, Mahesh. "ADDITIVE LITHOGRAPHY FABRICATION AND INTEGRATION OF MICRO OPTICS." Doctoral diss., University of Central Florida, 2006. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2458.
Full textPh.D.
Optics and Photonics
Optics
Raynaud, Jonathan. "Elaboration de pièces 3D multimatériaux par fabrication additive." Thesis, Limoges, 2019. http://www.theses.fr/2019LIMO0101.
Full textCurrently, HTCC and LTCC (High and Low Temperature Co-fired Ceramics) parts are produced by two processes: tape casting for the dielectric ceramic part and screen printing for the realization of metal tracks and vias. The main objective of this work is to propose a new process for obtaining monolithic multi-material parts using the coupling of two additive manufacturing technologies. In this respect, a hybrid additive manufacturing process capable of building a 3D ceramic / metal part could be of major interest in the manufacture of such electronic components. Stereolithography and robocasting seem to be complementary processes to achieve this goal. The advantage of using additive manufacturing instead of conventional methods is to be able to achieve forms that can not currently be obtained in microelectronics, which would allow a performance gain compared to current circuits. A strategy combining stereolithography and robocasting is proposed for the simple manufacture of HTCC and LTCC multi-material parts. The model parts are electronic circuits in the three dimensions of the space including a dielectric substrate as well as horizontal tracks and vias. To improve the performance of current circuits new geometries are being studied, such as armored or inclined vias. They will then be characterized in microwave to verify the application of selected materials in these frequency ranges
Duballet, Romain. "Systèmes constructifs en fabrication additive de matériaux cimentaires." Thesis, Paris Est, 2019. http://www.theses.fr/2019PESC1011.
Full textThis work addresses a particular topic of automation in construction called 3D concrete printing, or additive manufacturing of cementitious materials. It proposes new manufacturing techniques, other than casting or projection, making use of programmed robots to progressively bring the material where it needs to be, without traditional moulds. The associated promises are thus waste reduction, speed and versatility. More precisely we focus on extrusion techniques, they are inspired from a rapid prototyping approach called fused deposition modeling that consists in stacking laces of fresh mortar onto each other to form a three dimensional object.With such a technique, it is possible to "print" the walls of a house inside a gantry structure. This is the main idea proposed today, with promises of productivity, speed and labor cost reduction. This gained popularity in the past few years, businesses and academic projects were born all over the world, research being mostly focused on rheology and mortar formulation. The question of actual usage of such techniques is rarely placed at the center of discussion, whereas it is not clear yet how they will penetrate the market, and more importantly which among the many possible printing processes are more suited to be associated with complete building systems.The house printing idea is a direct and metaphoric transposition of the rapid prototyping method to a larger scale. With the current strategies, involving materials with high cement content, printing a single house in the form of straight or slightly curved walls can be seen as an environmental absurdity. To become a real solution to current housing issues, concrete printing has to bring significant innovation. It is not yet clear if productivity increase will be sufficient to do so. However, if new building products, of novel performances, could be made at a reasonable cost with such techniques, they could become a substantial addition to the building industry. The two courses of action are again material composition and geometry. Provided a very "poor" material is printable, massive straight wall houses can become competitive. Otherwise, material consumption can be decreased by printing walls with a complex and light internal structure. In chapter 4 we have proposed a potential solution to make lighter space structures for single house walls. Chapter 5 is dedicated to its prototyping.Apart from housing, the other main fields of application for building systems with robotic extrusion are infrastructures and public works. Some bridges have already been built. Specific underground structures have also been printed and installed in France, see figure below. For those sectors, complex geometrical context and specificity of prefabricated objects can account for 3D printing perhaps more easily than for housing. Surface finish and second work can indeed become less crucial, while productivity gains can be easily obtained.This work is divided in four chapters, and goes from theoretical to experimental. In chapter 2 we try to circumscribe our topic, namely robotic extrusion for automation in construction, through a state of the art report and some definition attempts. Many strategies are indeed possible to print cementitious materials, and can greatly differ in terms of physical phenomena at stake in the material or technology. This brings us to the subsequent question of actual building systems based on such printing processes. In chapter 3 we propose a classification method, to explore some possible approaches. The goal of this work is to shift the current discussion from the "house printing" approach to a generalized understanding of automated building systems with cementitious extrusion
Zhu, Zuowei. "Modèles géométriques avec defauts pour la fabrication additive." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLN021/document.
Full textThe intricate error sources within different stages of the Additive Manufacturing (AM) process have brought about major issues regarding the dimensional and geometrical accuracy of the manufactured product. Therefore, effective modeling of the geometric deviations is critical for AM. The Skin Model Shapes (SMS) paradigm offers a comprehensive framework aiming at addressing the deviation modeling problem at different stages of product lifecycle, and is thus a promising solution for deviation modeling in AM. In this thesis, considering the layer-wise characteristic of AM, a new SMS framework is proposed which characterizes the deviations in AM with in-plane and out-of-plane perspectives. The modeling of in-plane deviation aims at capturing the variability of the 2D shape of each layer. A shape transformation perspective is proposed which maps the variational effects of deviation sources into affine transformations of the nominal shape. With this assumption, a parametric deviation model is established based on the Polar Coordinate System which manages to capture deviation patterns regardless of the shape complexity. This model is further enhanced with a statistical learning capability to simultaneously learn from deviation data of multiple shapes and improve the performance on all shapes.Out-of-plane deviation is defined as the deformation of layer in the build direction. A layer-level investigation of out-of-plane deviation is conducted with a data-driven method. Based on the deviation data collected from a number of Finite Element simulations, two modal analysis methods, Discrete Cosine Transform (DCT) and Statistical Shape Analysis (SSA), are adopted to identify the most significant deviation modes in the layer-wise data. The effect of part and process parameters on the identified modes is further characterized with a Gaussian Process (GP) model. The discussed methods are finally used to obtain high-fidelity SMSs of AM products by deforming the nominal layer contours with predicted deviations and rebuilding the complete non-ideal surface model from the deformed contours. A toolbox is developed in the MATLAB environment to demonstrate the effectiveness of the proposed methods
Cherri, Alexis. "Poudres PEKK pour la fabrication additive par fusion laser." Thesis, Paris, HESAM, 2022. http://www.theses.fr/2022HESAE031.
Full textNowadays, the need to develop ever more innovative and efficient materials puts constant pressure on a large number of industrial sectors. Among them, aeronautics, aerospace, transport and energy production sectors seek to lighten the structure of their equipment in order to reduce energy consumption and minimize their environmental footprint. This reduction generally results in the conversion of metallic and dense materials towards plastic and lighter materials. The specificities of these industrial sectors, as well as the conditions of temperature, pressure, and accelerated aging to which some of their equipment are constrained, impose very precise specifications. The selective laser sintering process (also called SLS), recently implemented for the manufacture of thermoplastic parts, is of great interest for these different sectors of activity in which custom-made parts with complex geometry are often required. This process consists of the layer-by-layer manufacturing of parts by selective melting of powder by a laser beam. PEKK, a high performance semi-crystalline thermoplastic copolymer, validates many of the criteria for use in SLS manufacturing. However, the still limited knowledge that we have of this polymer, as well as its copolymer-like structure, still require substantial research work to this day. The aim of this work was to deepen our knowledge of the properties of crystallization and melting of a commercially available PEKK grade designed for use in SLS. These properties are of key importance for the successful implementation of the SLS process. A second objective was to develop a new grade of PEKK copolymers with a regular structure. In order to better understand the crystallization properties of our polymers, a model was used and a combination of SAXS / WAXS, DSC and rheological studies is carried out. The way of using in SLS the new grade of PEKK, hitherto very little explored, was also studied. We demonstrated that the copolymer with the regular chain structure exhibits a much simpler crystallization mechanism and a higher crystallization enthalpy which may be a advantage for use in SLS
Sakly, Adnene. "Fabrication additive de pièces à base d'alliages métalliques complexes." Thesis, Université de Lorraine, 2013. http://www.theses.fr/2013LORR0008/document.
Full textThis study aimed at developing new materials for additive manufacturing. We focused on producing parts containing complex metallic alloys (CMA) using a UV laser used for stereolithography. The selected intermetallic is a quasicrystalline alloy dominated by the icosahedral phase in the system AlCuFeB. The raw powders produced by gas atomization were characterized by X-ray diffraction and differential thermal analysis. The powders exhibit good optical absorption properties in the UV-visible range allowing direct laser sintering as evidenced by the formation of bridges between the grains at a temperature of about 820°C. In a second step, we have considered the manufacturing of parts made of a suspension of CMA powders in a binder. We have studied the wetting properties of the particles AlCuFeB and optimized a mixture consisting of an epoxy resin filled with 20 % vol. of CMA particles. The optical absorption of the suspension in the UV range was sufficient to produce composite parts by stereolithography. The particle size used was smaller than 25 micrometers. We have managed to make parts reaching 14 mm in height by adding layers with a thickness of 50 microns. Using test samples, we have characterized the hardness and the tribological properties of this new composite material. The hardness of the parts produced by stereolithography is larger than that of epoxy parts and reaches 88 Shore D. We have also shown a 30 % reduction of the friction coefficient as well as a 40 % reduction of wear losses compared to the epoxy matrix. These properties make attractive this new composite material for stereolithography applications
Antomarchi, Anne-Lise. "Conception et pilotage d'un atelier intégrant la fabrication additive." Thesis, Université Clermont Auvergne (2017-2020), 2019. http://www.theses.fr/2019CLFAC035/document.
Full textThe additive manufacturing is a field on the rise. However, companies wonder about the use of additive manufacturing for mass production. The problem raised in the context of this thesis is: How to make the process of sintering laser melting industrially viable? Our work focuses on the design and on the management of workshops integrating the additive manufacturing and of the complete process to obtain part according to three levels of decision: strategic, tactic and operational. About the strategic level, strong decisions of investment, machines selection and organization choice are taken with important economic issues. The aim is to define a multicriteria optimization method for the modular design of a production system integrating the additive manufacturing in the presence of uncertain data, optimal in the long term and the short term. From a tactical point of view, not all parts are necessarily relevant candidates for additive manufacturing. In this work, we developed a decision support tool that evaluates the relevance or not of additive manufacturing to obtain parts in a global cost approach. At the operational level, we offer a tool based on flow simulation that allows orders to be placed to production orders and their scheduling in order to guarantee the efficiency of the workshop. This research work is developed in collaboration with companies: AddUp, MBDA and Dassault, who contribute to our work and enable us to compare our tools with an industrial reality
Alvarado, Pérez Miriam. "Development of Flexible Gas Sensors Based on Additive Fabrication Processes." Doctoral thesis, Universitat Rovira i Virgili, 2020. http://hdl.handle.net/10803/669439.
Full textLos sensores de gas se utilizan para monitorear ambientes interiores y exteriores. Algunas aplicaciones comunes son para medir: el nivel de contaminantes en las calles, los gases liberados por los escapes industriales y de automóviles, los gases en la minería, el contenido de alcohol en la sangre a través del aliento exhalado, etc. A medida que crece el campo de aplicación de los sensores de gas, se hace necesario adaptar los sensores de gas a nuestros dispositivos y pertenencias diarias. Se requieren materiales mecánicamente flexibles y resistentes para fabricar los sensores de gas flexibles. Además de las pruebas de detección de gas, la resistencia a la flexión de los sensores debe probarse para llamar “flexible” a un sensor. El objetivo principal de esta tesis es fabricar sensores de gas flexibles a través de procesos aditivos utilizando óxidos metálicos como materiales sensibles. Los sensores de gas flexibles se fabricaron utilizando un sustrato polimérico flexible (Kapton). Los diferentes procesos empleados fueron compatibles con la temperatura de la temperatura de funcionamiento del sustrato. Entre las técnicas empleadas están la plantilla, la serigrafía, la inyección de tinta, AA-CVD. Además, se realizaron procesos superficiales para mejorar la adhesión de los óxidos metálicos al sustrato polimérico. La flexibilidad de los sensores se probó realizando una prueba de flexión cíclica.
Gas sensors are used to monitor indoor and outdoor environments. Some common applications are to measure: the level of pollutants in the streets, the gases liberated by industrial and car exhausts, gases in mining, blood alcohol content through the exhaled breath, etc. As the field of application for gas sensors is growing, it becomes necessary to adapt the gas sensors to our daily devices and belongings. This requires mechanically flexible and resistant materials to fabricate the flexible gas sensors. In addition to gas sensing tests, the resistance to bending of the sensors should be tested to call a sensor flexible. The main objective of this thesis is to fabricate flexible gas sensors through additive processes using metal oxides as sensitive materials. The flexible gas sensors were fabricated using a flexible polymeric substrate (Kapton). The different processes employed were compatible with the temperature of the operating temperature of the substrate. Among the techniques employed are stencil, screen-printing, inkjet-printing, AA-CVD. Also, surface processes were performed to improve the adhesion of the metal oxides to the polymeric substrate. The flexibility of the sensors was tested by performing a cyclical bending test.
Ganet-Mattei, Florent. "Fabrication additive de matériaux électroactifs pour applications à la mécatronique." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEI011/document.
Full textAdditive Manufacturing (FA) is a manufacturing process that began to develop in the 1980s and is now mature enough to be used in a cost-effective and functional way by manufacturers. Additive manufacturing is defined as the process of shaping a part by adding material, as opposed to traditional shaping by material removal (machining). This new technology is a real revolution and enables us to meet new unprecedented technological challenges. Whether on a material axis or more widely as part of the plant of the future, additive manufacturing is a real growth driver, but many research work is yet to be conducted to perfect this new technology. It is around this issue that the work of theses focused with a focus on the integration of electroactive materials for the realization of mechatronics function taking advantage of Additive Manufacturing processes. Research shows that additive manufacturing of electroactive materials will be increasingly used for the realization of hybrid mechatronic functions that will combine both the mechanical structure, silicon integrated circuits, conductive tracks and printed coupled materials, integrating as well as features, such as sensors, displays or power sources. The work shows the potential application around the health control of composite structures, but also the instrument shape control for surgery. To arrive at the development of these devices, the following points have been developed around electroactive materials and their integration and optimization rules
Metral, Boris. "Systèmes photoamorceurs et modèle pour la fabrication additive par photopolymérisation." Thesis, Mulhouse, 2020. https://www.learning-center.uha.fr/.
Full textVat photopolymerization technologies are emerging quickly in the field of additive manufacturing. To follow this fast expansion of the market, highly efficient and affordable photosensitive resins are necessary. In this work, we introduce a new three-component phototiniating system (3K PIS) based on the Safranine O (SFH+) dye which has been identified as a very efficient initiator in several 3K PIS for photopolymerization processes.The dye is combined with a Tetraphenylborate salt (TPB) as electron donor and a Triazine derivative (TA) as electron acceptor to form a photochemical regenerating cycle. The photocycling mechanism is explored via laser flash photolysis (LFP) and the photopolymerization is investigated through Real-Time-Fourier Transform Infrared spectroscopy (RT-FTIR). Infrared experiments with several irradiances allow disclosure of an empirical model predicting conversion as a function of time and light intensity.Following this, cure depth experiments are conducted in agreement with Jacobs’ equation and the resin 3D printing parameters, i.e. critical energy (Ec) and penetration depth (Dp), are established. These parameters are linked to RT-FTIR data, resulting in the determination of the critical time (tc) and the conversion at gel point.Finally, high resolution complex pieces are printed with the resin which composition was tailored in accordance with our studies, demonstrating the viability of this formulation in DLP 3D printing
Bernardo, Jesse Raymond. "Indirect Tissue Scaffold Fabrication via Additive Manufacturing and Biomimetic Mineralization." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/36312.
Full textMaster of Science
Hayagrivan, Vishal. "Additive manufacturing : Optimization of process parameters for fused filament fabrication." Thesis, KTH, Lättkonstruktioner, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-238184.
Full textEtt hinder för att additiv tillverkning (AT), eller ”3D-printing”, ska få ett bredare genomslag är svårigheten att uppskatta effekterna av processparametrar på den tillverkade produktens mekaniska prestanda. Det komplexa förhållandet mellan geometri och processparametrar gör det opraktiskt och komplicerat att härleda analytiska uttryck för att förutsäga de mekaniska egenskaperna. Alternativet är att istället använda numeriska modeller. Huvudsyftet med denna avhandling har därför varit att utveckla en numerisk modell som kan användas för att förutsäga de mekaniska egenskaperna för detaljer tillverkade genom AT. AT-tekniken som avses är inriktad på Fused Filament Fabrication (FFF). En numerisk modell har utvecklats genom att återskapa FFF-byggprocessen i en simuleringsmiljö. Instruktioner (skriven i GCode) som används för att bygga en detalj genom FFF har här översatts till en numerisk FE-modell. Modellen används sen för att bestämma effekterna av processparametrar på styvheten och styrkan hos den tillverkade detaljen. I detta arbete har strukturstyvheten hos olika detaljer beräknats genom att utvärdera modellens svar för jämnt fördelade belastningsfall. Styrkan, vilket är starkt beroende på den tillverkade detaljens termiska historia, har inte utvärderats. Den utvecklade numeriska modellen kan dock fungera som underlag för implementering av modeller som beskriver relationen mellan termisk historia och styrka. Den utvecklade modellen är anpassad för optimering av FFF-parametrar då den omfattar effekterna av alla FFF-parametrar. En genetisk algoritm har använts i detta arbete för att optimera parametrarna med avseende på vikt för en given strukturstyvhet.
Vayre, Benjamin. "Conception pour la fabrication additive, application à la technologie EBM." Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENI096/document.
Full textNowadays, the use of Additive Manufacturing processes keeps growing in the industry. Among the numerous kinds of AM processes, metallic additive manufacturing processes, and metallic Additive Layer Manufacturing in particular, are the most interesting from a mechanical designer point of view. Several research studies have been conducted on the topic of Design For Additive Manufacturing, mostly discussing the choice of AM processes or presenting the redesign of parts. There is no specific design methodology for ALM processes that takes their specificities into account.During this PhD thesis, the changes that ALM processes bring to the design space were investigated. The designer has the opportunity to easily manufacture thin parts, complex parts, lattice structures or mechanisms that don't need any assembly. These processes also have specific manufacturing constraints compared to conventional processes. The heat dissipation is the most important factor since it can cause distortions and porosities. Powder removal, surface and geometrical quality also need to be considered during design. A specific design for additive manufacturing methodology is necessary to take these changes into account.This work focuses on the Electron Beam Manufacturing process. Experiments were conducted and analyzed to assess the manufacturability regarding the thermal phenomena (during melting), the powder removal and the quality of the parts produced by EBM. The impact of the part geometry on manufacturing duration and manufacturing cost was also established.In order to use allow designers to use these pieces of information, we suggested a designing methodology. From the requirements of the parts, one or several parts are generated by the designer or by using topological optimization tools. The orientation of the part inside the manufacturing space is set before designing a refined parametric geometry. This parametric geometry is optimized in order to meet the user requirements as well as the EBM requirements. The last step is the modification of the geometry to comply with the finishing operations (machining allowances for example) and the placement of supports, if needed. This methodology was illustrated with the redesign of two example parts and showed important mass savings from the parts (while meeting user and process requirements).The prospects discovered and highlighted during this work, some of which were preliminary investigated, are presented in a specific chapter
Heisel, Cyprien. "Conception et réalisation, par fabrication additive, de matériaux cellulaires architecturés." Thesis, Limoges, 2019. http://www.theses.fr/2019LIMO0046/document.
Full textThe "numerical materials" approach, developed at CEA Le Ripaut, consists to numerically optimize a structure, by using calculation codes that allow to realize numerical experiments, in order to answer, as precisely as possible, to a set of specifications. The manufacturing of these optimized structures, whose shapes can be complex, is sometimes not feasible with current manufacturing processes. However, the rapid progress of 3D printing now seems to be able to concretize this approach. The aim of this thesis is to study this manufacturing feasibility, through a concrete application: the optimization of the volumetric receivers of Concentrated Solar Power Plants (CSP). Currently, the design of these silicon carbide (SiC) receptors is restricted by the existing manufacturing techniques, and their morphologies are therefore mainly limited to foams or parallel channels. However, this type of structure does not allow to exploit all the 3D character proposed by the receivers, due in particular to a heterogeneous absorption of solar radiation in the volume. In this work, in order to find the distribution of the most homogeneous absorption possible in the whole volume, many structures with various shapes are generated virtually. A simulation of the solar irradiance received is carried out on all these structures, thanks to a calculation code developed especially for this application, thus allowing to choose three of them, respondents at best to the criteria of the specifications. These potentially optimized structures were then manufactured in SiC by 3D printing, by a binder jetting process. They were then tested on an experimental test bench of the PROMES laboratory, reproducing the conditions of a CSP. Results showed that these structures, where their shapes are totally different from foams or parallel channels, are able to produce a maximum air temperature of 860°C at the output of the receiver, and with efficiencies close to 0.65. Finally, a conducto-radiative coupled thermal computational code, improved during this work, made it possible to analyze these experimental results and will be used for the future work of optimization of the geometry of a receiver
Courtais, Alexis. "Conceptions optimales de réacteurs à lit fixe par fabrication additive." Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0003.
Full textThis thesis is a prospective work which aims to apply in Chemical Engineering shape optimization methods developed in other areas of engineering. The first part of this work is dedicated to the development of a shape optimization method to determine the optimal configuration of a two-dimensional packed reactor with a single phase liquid flow. The developed method is then applied to determine the shape of the reactor packing that minimizes the energy dissipation in the fluid due to viscous friction, the average outlet concentration of reactant, or both simultaneously using multi-objective optimization. The optimal configurations determined are satisfactory and allow a significant improvement of the conversion rate or the energy losses in the reactor. In a second part, an experimental campaign was carried out in order to validate the CFD simulation performed by OpenFOAM software, required by the developed shape optimization approach and modeling the fluid flow and reactions involved in the reactor. For this purpose, scale 1 prototypes of the initial and optimal reactors have been manufactured by 3D printing in order to experiment them. The experimental campaign is based on 3 measurement techniques, the PIV (Particle Image Velocimetry), the measurement of RTD (Residence Time Distribution) and the measurement of the conversion rate at the reactor outlet. Finally, it has been shown that the optimization of the reactor in its 2D form allows a significant improvement of its performance even if the determined configuration is probably sub-optimal. Indeed, after comparing the experimental measurements with 2D and 3D simulations, it has been found that the 3D simulation is more representative of reality than the 2D simulation. Thus, optimizing the reactor in its 3D form would be an interesting perspective for the future works, provided the problem of constraints related to the reactor additive manufacturing step is fixed
Vallereau, Robin. "Fabrication additive d'aimants liés anisotropes par dépôt de fil fondu." Electronic Thesis or Diss., Université Grenoble Alpes, 2024. http://www.theses.fr/2024GRALI012.
Full textRare earth-based anisotropic permanent magnets have excellent magnetic properties and are therefore used in many electromechanical devices such as motors, actuators, generators, and even at small dimensions in micro-electromechanical systems. They can be found in sintered or bonded form. Although bonded magnets are less magnetised than sintered ones because they are diluted in a polymer matrix, they have the advantage of being able to be manufactured in very large series by injection moulding and can be complex in shape. However, the production of small series, or of magnets with a complex magnetic texture, is not currently feasible. The technique of additive manufacturing using molten wire deposition provides a solution to some of these problems: unlike moulding, 3D printing is suitable for small production runs, allows more complex shapes and consumes only the necessary volume of material. As for the texture, this thesis describes a print head based on a piston extruder and equipped with a magnetic aligner, which made it possible to obtain substantially anisotropic rare-earth-based bonded magnets. The composites were formulated in PA12 nylon with industrial-grade NdFeB powders, derived from the recycling of sintered magnets; we also used SmFeN already formulated in granulated form.The piston extruder is fed with pellets which, unlike wound filaments, can be highly charged with magnetic powder. The magnetic aligner is a ring of SmCo magnets assembled around the nozzle; it orients the magnetic particles during extrusion to induce axial anisotropy in the strand and improve its remanent magnetisation. It was designed following a study to determine the temperature and field to be applied to obtain optimum alignment under extrusion conditions. This device produces an axial induction of 545 mT in the zone of interest. Unlike conventional printheads, in our extruder the molten composite is extruded by a plunger, overcoming the frictional forces that confine the magnetic particles in the nozzle under the radial forces of the magnetic field gradient.The manufacture of dense, good quality bonded magnets requires optimisation of the printing parameters. However, there is always some porosity generated by the process itself, which helps to reduce remanent magnetisation. As for anisotropy, this is obtained by following a construction strategy for the bonded magnet that consists of depositing all the strands in the same direction and in the same sense. When printing anisotropic magnets, the friction of the nozzle on the freshly deposited layer mechanically misaligns the particles on the surface, again contributing to a degradation of the maximum properties. The composite filled with 63 %vol NdFeB (MF-P15) in PA12 nylon is particularly affected and has a degree of alignment of almost zero (µ0Mr = 0.3 T and Hc = 995 kA/m), while SmFeN/PA12 (60 %vol) has a degree of alignment of 0.3 (µ0Mr = 0.5 T, Hc = 875 kA/m). The SmFeN particles are very fine (d0.5 = 3 µm) compared with those of NdFeB (d0.5 ~75-100 µm) and spheroidal in shape: a printed layer 200 µm thick therefore contains many more SmFeN particles than NdFeB, and the particles on the surface, mechanically misaligned when the nozzle touches them, thus represent a smaller volume fraction.The long-term objective of the 6DMag project is to exploit this strategy of anisotropic deposition by alignment, to print bonded magnets composed of regions with different directions of magnetisation. The next challenge will be to magnetise the different regions of a multipolar magnet without impacting neighbouring regions
Laverne, Floriane. "Concevoir avec la Fabrication Additive : Une proposition d’intégration amont de connaissances relatives à une innovation technologique." Thesis, Paris, ENSAM, 2016. http://www.theses.fr/2016ENAM0042/document.
Full textThe onset of Additive Manufacturing (AM) upsets design practices and is receiving attention because its potential is promising for product innovation. However, while innovation issues are paramount during early design stages, few designers have sufficient knowledge about AM and use it poorly to develop creative solutions. Thus, our research objective is the increase of the innovation capacity of the design team through the integration of AM knowledge into early design. To do this, we propose to use “just needed” AM knowledge, i.e., AM knowledge whose contents, supports and instancing are tailored to the design team needs. Moreover, we propose that this integration takes place in a design model that allows the Design With Additive Manufacturing (DWAM) approach. Our contributions are both the proposal of a methodology based on Knowledge Management dedicated to the identification, the capitalization and the valorization of the “just needed” AM knowledge; and of a design model in 3 stages, in which the useful for DWAM approach AM knowledge is specified. Finally, this enriched model is valued in a digital tool in order to improve collaborative and concurrent design
Bruyas, Arnaud. "Apport de la fabrication additive multi-matériaux pour la conception robotique." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAD045/document.
Full textPercutaneous interventional radiology permits the diagnosis or the treatment of cancer tissues thanks to the use of needles and imaging devices. Being minimally invasive, such procedures are beneficial for the patient, but for the radiologist, they are highly complex. In order to assist the physician and remotely control the needle, we propose in this work the design and the manufacturing of multi-material compliant devices by taking advantage of multi-material additive manufacturing. To perform the design of such device, we propose several solutions in terms of kinematics, actuation and sensing. In particular, we developed a new compliant joint, the HSC joint, as well as a new pneumatic actuator for needle insertion. In the end, we demonstrate in the thesis the contributions of multi-material additive manufacturing for medical robotics, by combining all those solutions into a single device that remotely controls both the orientation and the insertion of the needle
Wang, Hongqing Vincent. "Computer-aided design methods for the additive fabrication of truss structure." Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/17249.
Full textBoyard, Nicolas. "Méthodologie de conception pour la réalisation de pièces en Fabrication Additive." Thesis, Paris, ENSAM, 2015. http://www.theses.fr/2015ENAM0015/document.
Full textThe aim of this thesis is to propose a design methodology to produce parts using additivemanufacturing (AM). Compared to standard manufacturing processes, as machining, forming, casting ormolding, AM processes have new features for manufacturing multi-material parts, nondetachableassemblies or complex shapes. The arrival of this new technology involves a paradigm shift that requiressupport to designers to develop quality products. Also the mechanical and finishing specifications of theparts obtained by AM depend on their orientation during the manufacturing. Furthermore, depending onthe process, the desired geometry and the orientation, it could be necessary to integrate a support in orderto ensure manufacturability of the part. We define a design methodology that respects the integrity of thedigital channel and whose purpose is to produce a sliced numerical model ready to be manufactured on anAM machine. For this, our methodology is based on data from functional specification and businessknowledge of the process indicated by the designer, to automatically propose a first solid geometry whichsatisfies all these requirements. After this first step, a step of topological optimization restricts the volumeof the part in order to reduce its weight, cost and manufacturing time. Finally, if necessary, optimizedsupport ensuring the manufacturability of the part is generated according to the same criteria. Thismethodology is accompanied by an industrial case study as well as of two experiments to observe thepossibility to finish parts made of ABS with acetone. The first experiment is an experimental design whichmeasures the obtained surface finish based on the temperature of the acetone, the operating time, theinclination of the surfaces of the piece and its thickness. The second experiment is a tensile stress testdesigned to observe a change in the mechanical resistance of the part. Regardless of the type of machineand the AM process, the methodology we propose is a first concrete step towards obtaining directlycompliant parts, whether for industrial or domestic use
Rias, Anne-Lise. "créativité par et pour la fabrication additive : proposition d'une méthodologie outillée." Thesis, Paris, ENSAM, 2017. http://www.theses.fr/2017ENAM0030.
Full textEmphasizing the integration of Additive Manufacturing (AM) into big industrial companies becomes crucial for subcontractors. Teaching additive processes and design rules is a techno-centric vision. It is not sufficient to project future applications of additive manufacturing in various industries such as aeronautics, energy, medical, etc. On one hand, the state of the art and field observations show that AM knowledge is steadily increasing. On the other hand, the state of the art about creativity shows that individuals creative capacity can be stimulated to guide them to the generation of creative ideas and concepts. This thesis then explores a possible linking between AM and creativity in order to propose a methodology and its application tools to stimulate creativity, in the specific context of additive manufacturing. This approach allowed us to bring out the major role of intermediate objects which articulate the interactions between several dimensions of the creative capacity: motivations, emotions, knowledge exploration, individual/collective work phases and spatial organization. It also highlighted the need for a new definition of intermediate objects’ roles regarding additive manufacturing. In this sense, we designed two operational devices, based on sensory manipulation of tangible objects, and tested them in real industrial contexts. Our experimental results show that the exploration of the knowledge embodied in these devices emphasizes the generation of creative ideas opening to potential applications of additive manufacturing. Finally, a model of Creativity Through Additive Manufacturing (CTAM) has been proposed. It enables us to contribute both to the methodological practices of design science and operational practices in two fields: the additive manufacturing industry and the field of innovation
Ponche, Rémi. "Conception pour la fabrication additive : application à la projection de poudres." Phd thesis, Ecole centrale de Nantes, 2013. http://www.theses.fr/2013ECDN0017.
Full textManufacturers are constantly encountering tough international competition. In order to stay competitive they have to developed new products with time and cost constraints always more significant. In this context, as a ‘tool-less’ and digital approach to manufacture, additive manufacturing presents companies with a wide and expanding range of technical and economic benefits. However, the additive manufacturing processes, as the others, have also their own characteristics and limits. Finally, to take advantages of the technological breakthrough which is additive manufacturing, a new way of designing products is needed. This work deals with the development of a new methodology of design for additive manufacturing. Subdivided in four main steps, the proposed method allows from functional specifications and manufacturing process characteristics to define an optimised part geometry regarding both the functional objectives and the manufacturing constraints. In the first step, manufacturing orientations are chosen from the functional entities and allow to propose a design area. The general topology of the part is then optimised in this area regarding the functional specifications and the global manufacturing constraints. In the third step, the accurate part geometry is generated from a choice of manufacturing trajectories and thanks to the manufacturing process simulation. The fourth and last step is to determine and compare each other the different geometries corresponding to all the possible choices of manufacturing strategy. At the end, the best suitable is selected. The proposed method structure is generic and can be applied to all the additive manufacturing processes. However, the physical phenomena involved during the manufacturing processes are different for each one; the manufacturing constraints can be thus also different. This work deals more specifically with the laser claddingtechnology. Indeed, a physical model of this process has been proposed. It allows to estimate and optimise the manufacturing strategies regarding the functional needs and the manufacturing constraints. This model has been particularly used in the optimisation method of manufacturing paths which has also been developed in this work to manufacture thin wall metal parts
Cadiou, Stephen. "Modélisation magnéto-thermohydraulique de procédés de fabrication additive arc-fil (WAAM)." Thesis, Lorient, 2019. http://www.theses.fr/2019LORIS544.
Full textOne of the obstacles to the development of additive manufacturing processes is the quality of the built parts. Some defects, such as porosity, deformations or cracks, may appear. These defects depend strongly on the choice of operating parameters. Numerical modelling can therefore help to understand how these operating parameters control the final geometry, and the thermal cycles experienced by the material, which impact the microstructure, the deformations and residual stresses of the final part. In this thesis, several numerical models have been developped in order to better understand the final characteristics of the part. The first one concerns a 2D axial-symmetric model of arc to deal with a static TIG process. The Maxwell equations coupled with the mass, momentum, energy equations are solved in the plasma and the melt pool. Using this reference case, the arc model has been validated. This model has been made more complex by adding a level set method to track the gas-liquid interface present in pulsed MIG process in 2D axial-symmetric geometry. This model has been validated through experimental data and then extended to a 3D geometry to simulate the build-up of a wall using a CMT process. This multiphysics model was limited to the scale of the melt pool. A second 3D model was then proposed at the scale of the wall using a purely thermal model to simulate the multi-layer process with geometry prediction
Andreau, Olivier. "Nocivité en fatigue et contrôle de défauts produits par fabrication additive." Thesis, Paris, ENSAM, 2019. http://www.theses.fr/2019ENAM0037.
Full textThe Selective Laser Melting Process (SLM) consists in manufacturing metallic parts by melting successive powders layers. This new additive manufacturing method allows building new complex geometries that can help lighten structures, such as lattice parts. However, the mechanical properties of additive manufacturing parts are still an industrial concern, especially for high cycle fatigue behavior. Such parts can indeed comprise surface and internal pores that can be deleterious to mechanical properties. The goal of this thesis is to characterize the influence of porous defects on the high cycle fatigue fatigue performance of 316L SLM parts. Firstly, some key SLM parameters that can control the porosity and the microstructure of fabricated parts were quantified. A distinction between the pore types was proposed, and their characteristics were related to the volumetric energy density delivered by the laser. The microstructure was also investigated, with a focus on crystallographic orientation and grain size, depending on the melt pool overlap and morphology. Secondly, using X-ray tomography, a parametric research was conducted to generate and characterize optimized fatigue samples with a minimal amount of pores. Such samples were used as a reference for other fatigue samples containing various randomly distributed pore populations, with similar microstructures. The relative influence of different internal pore populations on the high cycle fatigue endurance was quantified, for similar surface pore population. Finally, deterministic pores with controlled morphology, position and various dimensions were generated after a detailed parametric optimization. A specific internal crack initiation threshold was evidenced for deterministic defects, which was supposed to be linked to the local gaseous environment during crack initiation and propagation
Querard, Vincent. "Réalisation de pièces aéronautiques de grandes dimensions par fabrication additive WAAM." Thesis, Ecole centrale de Nantes, 2019. http://www.theses.fr/2019ECDN0001/document.
Full textIn the field of additive manufacturing (AM), several processes are present and have different applications and levels of development: the main technologies are powder-bed based AM, powder projection and Wire Additive Manufacturing (WAM). We have studied, in this PhD work, the manufacturing of large scale components in aluminum alloy for aircraft industry with Wire Arc Additive Manufacturing (WAAM). This technology is based on a welding generator, a shielding gas protection and a feedstock (wire in this case). To solve this issue, several ways of research were investigated. The first one dealt with toolpath generation: several experiments have highlighted the importance of tool path generation and the tool orientation to manufacture complex parts and improve the part accuracy. The second one was about the validation of the material quality after deposit. Microstructural observations and mechanical tests have demonstrated the effect of process parameters on the deposit quality. Finally, in the context of a DGA/DGAC funded research project, whose partners were STELIA, CT INGENIERIE, CONSTELLIUM and l’Ecole Centrale de Nantes, the manufacturing of functional part in aluminum alloy has shown the interest of the process for aircraft industry. A structural component based on a double curvature geometry has been manufactured with WAAM. The methodologies developed in this PhD work have enabled us to solve the issues to manufacture that type of component
Ettaieb, Kamel. "Contribution à l'optimisation des stratégies de lagase en fabrication additive LPBF." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLN050.
Full textDuring manufacturing by Laser Powder Bed Fusion (LPBF), the achieved temperatures in local areas could generate significant thermal gradients. These gradients lead to the apparition of residual stresses which affect the mechanical characteristics of the part and may cause deformation, as well as micro and macro cracks. In this context, scanning paths play a fundamental role on temperature level and distribution during manufacturing. For that reason, it is necessary to validate the generation of trajectories considering the thermal behaviour induced by this process.The purpose of this PhD thesis is to use an analytical method in order to develop a model that allows a fast and efficient analysis of thermal behaviour, during part manufacturing. Indeed, with a given scanning path, material properties and process parameters, the developed tool performs a temperature simulation at each point of the part, over time and in a fast way, compared to other thermal simulation software. In order to reduce computation time and memory storage used for such a simulation, a set of optimization techniques has been proposed.The developed model has been validated in the case of the Ti6Al4V alloy through a comparison with a finite element thermal simulation obtained by industrial software. Then, the results of this model were compared to experimental results. Once validated, it has been implemented to analyze trajectories commonly used in the literature and industry.In order to reduce thermal gradients and improve part quality, the proposed solution consists in controlling the temperature and size of melt pool. For this purpose, the developed thermal model has been used to modulate the process parameters during manufacturing on the one hand and to develop an adaptive scanning strategy on the other hand
PREVIDI, ANITA. "ADDITIVE MICRO- AND NANOPATTERNING FOR THE FABRICATION OF BRAIN CELL NETWORKS." Doctoral thesis, Università degli Studi di Milano, 2022. http://hdl.handle.net/2434/895694.
Full textBraconnier, Daniel J. "Materials Informatics Approach to Material Extrusion Additive Manufacturing." Digital WPI, 2018. https://digitalcommons.wpi.edu/etd-theses/204.
Full textGa, Bastien. "Contribution à l’amélioration de la prise en compte des spécificités des procédés de fabrication additive en conception : application à la qualité de surface." Thesis, Reims, 2019. http://www.theses.fr/2019REIMS019.
Full textAM (Additive Manufacturing) is a manufacturing process that makes possible, by adding layer-by-layer material, to create three-dimensional parts. This technology has many interests as it allows complex shapes or structures integration, waste reduction, on-demand fabrication and reduced conception time. During this thesis, we tried to determine remarkable orientations of parts in order to manufacture them by AM process. Considering the large number of effects related to part orientation, we chose a multi-criteria approach taking into account the surface quality of the parts, the volume of support, the manufacturing time and cost. In order to have a good surface quality on functional faces of the part and to limit the post-treatment, a precise orientation has been defined. This methodology was developed in the structure of the Taal project, a research and development project precursor of Coretechnologie's 4D-Additive software. On this last, in addition to this methodology, many functions have been developed to prepare the manufacture of a part by an additive process. The orientation of a part in AM is a step that can’t be overlooked. It may make it possible to find a compromise between the specificities related to the AM processes or generate a high manufacturing cost and a poor surface quality of the part. Evolutions of the method are possible as a mechanical study of the part in the different orientations tested because many questions arise on the strength of the printed parts
Douellou, Corentin. "Fatigue des aciers élaborés par fabrication additive L-PBF : approche thermomécanique et comparaison de stratégies de fabrication." Thesis, Université Clermont Auvergne (2017-2020), 2020. http://www.theses.fr/2020CLFAC019.
Full textThe PhD thesis deals with the fatigue performance of steels manufactured by Powder Bed Fusion using a laser beam (L-PBF). The objective of the study is to develop a method for the rapid and reliable characterization of the produced material’s fatigue limit using infrared (IR) thermography. Preliminary conventional fatigue tests were performed, revealing two distinct populations among the printed specimens depending on their locations on the building plate. Next, fatigue tests instrumented by IR camera were processed using heat source reconstruction to measure the mechanical dissipation due to fatigue damage. A statistical model was then proposed to identify the fatigue limit of the material. Finally, a practical application was performed to compare different manufacturing strategies using the same powder of maraging steel, as well different steels (maraging, L40 and W360). The results open perspectives for the rapid optimization of the printing process with respect to the fatigue performance of the parts produced
Robert, Pascal. "Conception et fabrication de pièces métalliques intelligentes par procédé WAAM." Thesis, Université Grenoble Alpes, 2022. http://www.theses.fr/2022GRALI055.
Full textIndustry 4.0 highlights the need for massive data collection and therefore relies partly on the use of smart parts that are capable of providing data when they are used. In addition, metal additive manufacturing technologies seem to be a way to easily make smart parts and particularly the Wire & Arc Additive Manufacturing (WAAM) process that uses arc-welding technology. This raises the following issue, how to manufacture and design a smart metal part by WAAM? The research scope is limited to stress measurement in aluminum parts. In order to answer this problem, four scientific issues are identified and resolved in this manuscript:• The integration of a sensing technology within a part requires the part to be massive (composed of juxtaposed beads). Thus, making massive parts in aluminum is the first scientific challenge to resolve. Manufacturing parameters of the WAAM process are listed and explained in the state of the art. Wetting, regularity and mass energy of a bead are identified as indicators of the suitability of the selected parameters to be used to produce sound massive parts. Experimental campaigns are conducted to select parameters not identified by the state of the art to produce a wetted bead with low mass energy. Blocks are made and specimens are extracted then their mechanical characteristics are determined by tensile test in order to validate the selected parameters.• The second scientific challenge identified is to correctly choose the stress measurement technology to be inserted. Many devices that can be inserted during the WAAM process but also selection methods are reviewed in the bibliographic chapter. A synthesis in four families of strain measurement technologies relevant for the insertion during the WAAM process is therefore proposed. A selection guide based on evaluation criteria, on the knowledge of these technologies and on the specifications of parts to design as smart parts is proposed. Control by induction of an embedded magnetostrictive stress indicator is the most promising technology according to the proposed guide. This technology is used in the rest of the study.• The third challenge is to make the smart part manufacturable with the selected sensing technology. This technology requires the insertion of a thin steel indicator within the aluminum host part. In order to demonstrate its feasibility, various parameters (indicator’s coating, trajectory of the welding torch) are explored during experimental campaigns. Samples produced are analyzed by tomography. Thickness maps of the indicator are thus produced and allow to evaluate their deterioration. Scanning electron microscopy analysis of the intermetallic layer shows the fusion between the indicator and the host part and thus the feasibility of producing a smart part.• Finally, to realize a smart part with this technology, the last challenge is the choice of the indicator location in the part so that it reports the evolution of the stress in this one. Thus, recommendations for the selection of the mechanical characteristics of the indicator were formulated using the analysis of its magnetostrictive behavior and its mechanical coupling to its environment. Then, a method of placing the indicator for the measurement of the part maximum stress based on finite element simulations is presented for four distinct measurement scenarios.All the studies carried out allow to conclude on the interest of the use of the WAAM process for the production of smart parts
Joguet, David. "Maîtrise structurale de matériaux par fabrication additive en vue d'applications bio-médicales." Phd thesis, Université de Technologie de Belfort-Montbeliard, 2013. http://tel.archives-ouvertes.fr/tel-00879245.
Full textGrandvallet, Christelle. "Elicitation et structuration des connaissances dans le contexte de la Fabrication Additive." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAI071.
Full textAdditive Manufacturing (AM) has enabled the building of parts with new shapes and geometrical features. As this technology modifies the practices, new knowledge is required for designing and manufacturing properly. To help experts create and share this knowledge through formalization, this research work focuses on knowledge elicitation, analysis and structuring. After defining knowledge concepts we present the SoA in knowledge elicitation and classification. Three case studies present different approaches to capture AM knowledge. The first one points out the assets and limits of three individual elicitation techniques. The second one describes tools and techniques to elicit and structure knowledge about support structures for EBM parts. The last one proposes a method to model AM process rules in relation with EBM technology. As a conclusion, we provide some propositions and recommendations for a better elicitation and formalization of AM knowledge
Zaman, Uzair khaleeq uz. "Intégration Produit-Process appliquée à la sélection de procédés de Fabrication Additive." Thesis, Paris, ENSAM, 2019. http://www.theses.fr/2019ENAM0006/document.
Full textThe doctoral research focuses to build an integrated approach that can simultaneously handle the product and process parameters related to additive manufacturing (AM). Since, market dynamics of today are constantly evolving, drivers such as mass customization strategies, shorter product development cycles, a large pool of materials to choose from, abundant manufacturing processes, etc., have made it essential to choose the right compromise of materials, manufacturing processes and associated machines in early stages of design considering the Design for AM guidelines. As several criteria, material attributes and process functionality requirements are involved for decision making in the industries, the thesis introduces a generic decision methodology, based on multi-criteria decision-making tools, that can not only provide a set of compromised AM materials, processes and machines but will also act as a guideline for designers to achieve a strong foothold in the AM industry by providing practical solutions containing design oriented and feasible material-machine combinations from a database of 38 renowned AM vendors in the world today
Orquéra, Myriam. "Conception pour la fabrication additive : approche méthodologique pour les systèmes mécaniques multicorps." Electronic Thesis or Diss., Toulon, 2019. http://bu.univ-tln.fr/userfiles/file/intranet/travuniv/theses/sciences/2019/2019_Orquera_Myriam.pdf.
Full textTopological optimization (TO) is a mathematical tool used to obtain an optimal distribution of material density. From a given volume, subjected to loads, the TO leads to a concept of part fulfilling an objective and respecting constraints. The optimized part shapes are often too complex to be manufacturable thanks conventional processes. Additive manufacturing (AM) allows the material to be deposited where it is needed. Consequently, the choice of AM to manufacture topological optimized parts is often wise. In scientific literature, published design methods often remain applied to a single mechanical part, with few articles dealing with the design optimization of a product. The purpose of this PhD is to suggest a design method of an additively manufactured multibody mechanical system. It is composed of parts linked together and have relative motions. For this purpose, and in order to take advantage of all the possibilities of the AM, this manuscript suggests in a first step a classification of the optimizations achievable during the design of a product. Three optimizations are identified: architectural optimization, functional optimization and topological optimization. Both the application timeline and a demonstration of the contributions of each optimization are established. In a second step, a topology optimization methodology of multibody systems (denoted TOMS for Topological Optimization of a Mechanical System) is developed to take into account the interaction of the mass and inertia decrease on each part of the system. An organization chart is introduced. It presents a method of loop optimization in order to take into account new boundary conditions. Then, different paths for managing the impact of inertia are shown. Finally, a path ranking taking into account the objectives of the designer is proposed and some optimization principles are suggested. At last, these three optimizations are one step in the process of designing a product. In order to achieve this step with all the skills and knowledge in AM, a global design methodology is proposed. This methodology helps designers to design a single part as well as a multi-body mechanical system, from the specifications to final product
Danty, Paul. "Mise en forme par fabrication additive de céramique phosphocalcique mimant l'os humain." Electronic Thesis or Diss., Limoges, 2023. http://www.theses.fr/2023LIMO0052.
Full textHydroxyapatite (HA) is a widely used material for developing bone substitutes. In cases of significant bone defects where natural healing is not feasible, HA presents an excellent option for bone augmentation due to its chemical similarity to natural bone. Furthermore, its osteoconductive properties facilitate effective cell colonization, promoting new bone formation. The porous and interconnected structure of these engineered substitutes enhances this process. Designing these structured substitutes is a challenge aimed at improving mechanical strength and bone integration. Leveraging 3D printing technologies, especially Stereolithography (SLA), addresses the need for creating complex bone architectures. The primary objective of this study is to create a bioceramic substitute that mimics human trabecular bone using additive manufacturing. Human tibia samples, obtained during surgical procedures, were collected and subjected to microtomography to generate a high-resolution 3D database of trabecular bone. Using this data, a 3D ceramic substitute was fabricated through additive manufacturing (SLA) and then sintered to achieve controlled multi-scale porosity. A comparative analysis between the printed piece and the original STL file was performed to ensure accurate reproduction of the porous network. The results will inform adjustments to printing parameters for improved mimicry. Finally, human bone cells were seeded onto the engineered structures to investigate cell adhesion, attachment, and proliferation on their surfaces. The comprehensive results demonstrate the efficiency of SLA in producing phosphocalcic ceramic architectures that closely resemble natural trabecular bone, with promising biological performance
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.
Full textTitanium 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
Palmer, Andrew. "The Design and Development of an Additive Fabrication Process and Material Selection Tool." Master's thesis, University of Central Florida, 2009. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3635.
Full textM.S.
Department of Industrial Engineering and Management Systems
Engineering and Computer Science
Industrial Engineering MS
Booysen, G., M. Truscott, D. Mosimanyane, and Beer D. De. "Combining additive fabrication and conventional machining technologies to develop a hybrid tooling approach." Interim : Interdisciplinary Journal, Vol 8, Issue 2: Central University of Technology Free State Bloemfontein, 2009. http://hdl.handle.net/11462/367.
Full textSouth Africa is constantly loosing contracts for the manufacturing of innovative projects to the East, due to its non-competitive mould-making industry. The paper will report on progress made in a specific focus area in mould-making, namely Hybrid Moulds for injection moulding. Hybrid Moulds refers to a hybrid between Additive Fabrication and conventional methods through the use of amongst others, Direct Metal Laser Sintering techniques, combined with conventional CNC machining (High Speed) techniques. Although the emphasis is on an economically viable process for limited production runs, once the moulds have been developed, it normally is pushed to its limits to realize production quantities. One of the competitive edges is the cutting of lead-times, which obviously impacts on production costs. Another aspect is the ability to manufacture short runs of injection moulded parts in the required engineering material Realising that Laser Sintering of metals is an expensive manufacturing process, a concurrent manufacturing process was developed. Intricate mould details, which normally are time-consuming to manufacture through EDM processes, were grown as inserts, while the less-complex parts of the mould is machined in Aluminium through 3 and 5 Axis High Speed CNC Machining. Using a 3-axis CNC wire cutter, pockets will be created where the more complex Laser Sintered Metal inserts will be fitted. One of the competitive edges is the cutting of lead-times, which obviously impacts on production costs. Another aspect is the ability to manufacture short runs of injection moulded parts in the required engineering material.
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.
Full textIt 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
Lambert, Océane. "Solutions architecturées par fabrication additive pour refroidissement de parois de chambres de combustion." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAI048/document.
Full textCombustion chamber walls are perforated with holes so that a cooling air flow can be injected through them. The wall is cooled by convection and an insulating film is created on the hot surface (film cooling). This PhD thesis aims to use the possibilities of additive manufacturing to provide new architectured solutions that could enhance the internal heat exchanges, and lead to a higher cooling effectiveness.The first approach is to develop new designs of multiperforated walls by Electron Beam Melting (EBM) and Selective Laser Melting (SLM) used at the resolution limits of the processes. They are characterized by microscopy, X-ray tomography and permeability tests. Some aerothermal simulations help understanding the effects of these new designs on the flow and on heat exchanges. These results lead to a geometry adaptation.The second approach is to simultaneously manufacture an architectured part with dense and porous zones by EBM. Thanks to image analysis combined with large field EBSD, it is possible to investigate the mechanisms leading to the porous zones and to link them to permeability and porosity. The film cooling effect could be favoured by the orientation of pores towards the cooling flow. Therefore, a new powder-based manufacturing process named Magnetic Freezing, where metallic powders organize into an oriented structure thanks to a magnetic field, is developed.The various solutions studied during this thesis are tested on an aerothermal bench. They all show a more efficient and homogeneous cooling than the industrial reference. Some first tests on one of the selected solutions are performed on a combustion bench. This lighter and more permeable structure proves to be a solution as efficient as the industrial reference at a given flow rate. It should therefore be a more efficient solution for a given overpressure
Constantin, Loic. "Fabrication additive assisté laser de matériaux composites 3D et revêtement diamant par CVD." Thesis, Bordeaux, 2020. http://www.theses.fr/2020BORD0066.
Full textThe constant increase of the working frequency of semiconductor-based devices with their miniaturization led to severe overheating, which affect their lifetime and reliability. Hence, thermal management has become a significant concern for the microelectronic area and needs to be addressed. Diamond (D) is known to be an excellent material for thermal dissipation as it possesses one of the highest thermal conductivity (TC) of any natural material and has a high electrical resistivity. D can cool electronic chips in two ways. When used in the form of a film, D acts as a heat spreader. When utilized in powder-form, Ds can be introduced into metals to enhance their TC and bring dimensional stability at elevated temperatures. The resulting metal/D composite materials are thus, excellent component to form heat sinks. Naturally, the thermal performances of heat sinks are closely related to their surface area. Although the attractiveness of D-based materials in term of thermal performance, they often exhibit simple geometry mostly due to the complexity of machining D-based materials into intricated designs. Laser 3D printing is an emerging method of manufacturing sophisticated designs and has shown promising results for various metal and alloys. In this study, the laser 3D printing of copper/D composite materials is proposed to fabricate highly complex Cu/D structures which could remodel their applications. Before additively manufactured Cu/D composite materials, several challenges need to be addressed. First, the additive manufacturing of pure Cu is optimized and characterized. Then, due to a lack of a chemical affinity between Cu and D, the Cu-D interfacial zone is introduced in the composite material. Later, a molten salt coating process is studied to produced graded and multilayer coating of oxide/carbide and carbide/carbide, respectively, on carbon materials. Next, the additive manufacturing of highly sophisticated Cu/D composite structures is presented. Finally, the deposition of D films is performed by laser-assisted combustion flame. The effects of introducing ultraviolet lasers into the combustion flame are characterized in terms of chemical reaction and D film quality and growth rate