For additive manufacturing, research has shown that the chemistry and microstructural properties of the feedstock powder can significantly affect the properties of the consolidated material. Thermal treatment and recycling parameters for powders used in both solid and liquid state processes can further affect the microstructure and properties of the consolidated parts. Understanding the powder microstructure and effects of powder pre-treatment can aid in optimizing the properties of the final consolidated part. This research proposes a method for the characterization and optimization of powder pre-processing thermal parameters using aluminum alloy powder as examples. Light microscopy, electron microscopy, and hardness were used to evaluate each condition.

<div>This work investigates several uses of additive manufacturing to meet modern security-related needs. All energetic materials when integrated in a practical system require an ignition device, e.g. a bridgewire or spark gap igniter, which is traditionally fabricated from metal components. A conductive polymer, polyaniline,</div><div>was chosen to create metal-free spark gap igniters in a process that lends itself well to large-scale manufacturing. The igniters proved consistent in terms of breakdown</div><div>voltage, as well as their effectiveness in igniting nanothermite, a representative energetic material. This work also establishes a simple and effective approach suitable for the precise material deposition of CL-20. This is relevant for the development of trace detection calibration standards. This work shows that CL-20 is compatible with inkjet</div><div>printing for this purpose. Furthermore, the need to secure sensitive information that is stored locally on electronic devices led to the study of the use of confined nanothermite to damage substrates used in electronics. The maximum thickness of PCB that permitted destruction with repeatable results was investigated o suggest a baseline for future system integration and production. In addition, the stress of the board was modeled using measured thrust data. In brief, this work has proven that the use of additive manufacturing with energetic materials is both a possible and effective means to secure devices, should a device containing sensitive material be unintentionally misplaced.</div>

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The study presents a normative framework for the Additive Manufacturing (AM) implementation process in the UK manufacturing sector. The motivations for the study include the lack of socio-technical studies on the AM implementation process and the need for existing and potential future project managers to have an implementation model to guide their efforts in implementing these relatively new and potentially disruptive technologies. The study has been conducted through case research with the primary data collected through the in-depth semi-structured interviews with AM project managers. Seven case studies were conducted representing AM implementation practice at different stages of the implementation cycle. The first stage involved a pilot study at a post-implementer to identify the main areas of interest for AM implementation research. The second involved a wider study of AM implementers at the post-implementation stage with cross case analysis of implementation practice. The final stage involved an investigation into pre-implementation of AM, applying the proposed framework in three companies yet to fully implement AM as a production method. Contribution towards the existing body of literature was in the form of a normative framework for AM implementation in a variety of industrial sectors. The framework describes the main activities in the implementation process and supports a taxonomy of implementers.

Additive Manufacturing (AM) is a class of echnologies whereby components are made in an additive, layer-by-layer fashion enabling production of complex parts in which complexity has little or no effect on cost. However typical components roduced using these techniques are basic structural items with no major strength requirement and low geometric tolerances made from a single material. his thesis develops a low-cost Fused Filament abrication (FFF) based AM technique to produce functional parts. This is achieved by through esearching and implementing new materials in ombination and using precise control of infill tool paths for existing materials. Robocasting has previously been shown to be extremely versatile, however is known to offer poorer build quality relative to its ess-versatile counterparts. Research was ndertaken to enable Robocasting to be combined with FFF to enable the print quality and practical benefits of FFF with the material flexibility of Robocasting. This resulted in the manufacture of several multiple-material omponents using the technique to demonstrate its potential. In order to minimise the number of materials required to obtain desired properties, the effect of process parameters such as layer height, infill angle, and infill porosity were investigated. In total over an order of agnitude variation in Young’s modulus and tensile strength were achieved, enabling these properties to be actively controlled within the manufactured components. Finally a novel non-eutectic low melting point alloy was developed to be compatible with the FFF process. Its greater viscosity compared to traditional eutectics resulted in improved print quality and the reliable deposition of electrically conductive track 0.57x0.25mm in cross-section. In addition the material is approximately three orders of magnitude more conductive that typical printable organic inks. A micro-controller was produced using the technique in conjunction with traditional electronics components. This represents the first time a functional electrical circuitry, with sufficient conductivity for the majority of applications and interfacing directly with standard electrical components, has been produced using a very low-cost AM technique such as FFF. The research undertaken builds components with substantially improved functionality relative to traditional AM products, enabling electromechanical components with varying mechanical and electrical properties. It is anticipated that this could substantially reduce the part-count for many engineering assemblies and open up Additive Manufacturing to many new applications.

No description available.

No description available.

La Fabrication Additive (FA) vient aujourd’hui bouleverser des habitudes de conception bien ancrées, et suscite dans le même temps un intérêt grandissant pour les perspectives qu’elle offre pour l’innovation produit. Pourtant, alors que les enjeux liés à l’innovation sont prépondérants en conception amont, peu de concepteurs connaissent et utilisent le potentiel des connaissances FA pour développer puis sélectionner des solutions créatives. Dans ce contexte, notre recherche a pour objectif d’augmenter la capacité d’innovation des concepteurs en intégrant des connaissances FA lors de la conception amont. Pour cela nous proposons d’intégrer des connaissances FA explicites dites « au juste besoin », c’est-à-dire dont le contenu, l'instanciation et le support sont adaptés aux besoins des équipes de conception. De plus, nous proposons que cette intégration s’effectue dans un modèle de conception permettant l’approche Design With Additive Manufacturing (DWAM). Nos apports sont la proposition : d’une démarche, basée sur le Knowledge Management, permettant de repérer, capitaliser puis valoriser les connaissances FA au juste besoin ; mais également d’un modèle de conception amont en 3 étapes dans lequel les connaissances FA utiles à l’approche DWAM sont spécifiées. Enfin, ce modèle enrichi est valorisé dans un outil numérique support afin de faciliter le travail collaboratif et concourant. / The 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.

Two direct consolidation methods usually used for advanced ceramics have been combined in this project in order to develop a novel fabrication route for traditional ceramics. Specifically the method used is based on the Additive Manufacturing extrusion process using direct writing of high solid loading ceramic pastes and then freeze-casting to solidify the deposited material. This novel fabrication method, for which a patent has been granted, has been christened “Direct Writing Freeze-Casting” (DWFC). Although the DWFC process is the subject of investigation by other researchers for a range of different applications, including the production of medical implants with alumina, the research presented in this thesis focuses on its use in the manufacture of white wares, giftware, and applied arts and crafts in general. This new system will provide designers, potters, artists, craft makers and manufacturers with a flexible and automated way of manufacturing porcelain objects. One of the major challenges to be overcome to exploit the DWFC process is the development of suitable slurry material formulations. Initial trials demonstrated that it is not possible to use conventional clay based porcelain materials with a platelet shaped microstructure which inhibits freeze casting. In this thesis the development and characterisation of non plastic porcelain slurry, based on substitution of kaolin (clay) with a calcined clay material (molochite), which can be processed using this new method is presented. The new non plastic porcelain formulation, which has a high solid load of 75.47% wt., has been subjected to detailed analysis to assess its suitability at each stage of the process; extrusion, freeze-casting (solidification) and firing.

Process-structure-property relationships in material extrusion additive manufacturing (MEAM) are complex, non-linear, and poorly understood. Without proper characterization of the effects of each processing parameter, products produced through fused filament fabrication (FFF) and other MEAM processes may not successfully reach the material properties required of the usage environment. The two aims of this thesis were to first use an informatics approach to design a workflow that would ensure the collection of high pedigree data from each stage of the printing process; second, to apply the workflow, in conjunction with a design of experiments (DOE), to investigate FFF processing parameters. Environmental, material, and print conditions that may impact performance were monitored to ensure that relevant data was collected in a consistent manner. Acrylonitrile butadiene styrene (ABS) filament was used to print ASTM D638 Type V tensile bars. MakerBot Replicator 2X, Ultimaker 3, and Zortrax M200 were used to fabricate the tensile bars. Data was analyzed using multivariate statistical techniques, including principal component analysis (PCA). The magnitude of effect of layer thickness, extrusion temperature, print speed, and print bed temperature on the tensile properties of the final print were determined. Other characterization techniques used in this thesis included: differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and scanning electron microscopy (SEM). The results demonstrated that printer selection is incredibly important and changes the effects of print parameters; moreover, further investigation is needed to determine the sources of these differences.