Tesi sul tema "3D and 4D printing"

L’impression 3D et plus spécifiquement la technique de Fused Filament Fabrication (FFF) de matériaux composites à renforts continus est un domaine d’étude en plein essor visant à pallier les faibles performances mécaniques rencontrées par les composites élaborés en impression 3D et ainsi ouvrir les champs d’applications (aéronautique, course au large…). Autre tendance, l’impression 4D qui permet de développer des matériaux stimulables (capteurs et/ou actionneurs) et d’envisager des structures architecturées complexes se déformant sous l’action de divers stimuli (humidité, électricité, température, pression…). Le travail de thèse s’inscrit dans ce contexte pluriel et vise à développer de nouveaux matériaux multifonctionnels par impression 3D et 4D. Dans un premier temps, le travail de thèse a pour objectif scientifique de comprendre les relations entre le procédé, la microstructure induite, les performances mécaniques et hygro-mécaniques en vue d’applications structurelles (aéronautique, course au large …) sur des matériaux composites renforcés de fibres synthétiques (carbone et verre) et naturelles (lin). La deuxième partie des travaux de thèse vise à développer des matériaux composites hygromorphes renforcés de fibres continues (synthétiques et naturelles) par impression 4D avec une architecture en bilame bio-inspirée de la pomme de pin. Le caractère conducteur des fibres de carbone est utilisé pour développer de nouveaux actionneurs electro- thermo-hygromorphes présentant un actionnement contrôlé et accéléré par rapport aux hygromorphes classiques. Enfin, la liberté de design offerte par l’impression 3D a été utilisée pour contrôler localement la rigidité et l’actionnement d’actionneurs composites renforcés de fibres de lin continues
3D printing and especially Fused Filament Fabrication (FFF) technology for composite materials reinforced by continuous fibers is an emerging research field which aims to enhance the mechanical performance of 3D printing structures and to widen the field of application (aerospace, sailing…). Another trend, 3D printing allows to develop stimulable materials (sensor and/or actuators) and to consider parts with complex architecture that can be deployed under various stimulation (electricity temperature, pressure…). The present work is therefore part of this context and aims to develop new multi-functional materials elaborated by 4D printing. First, the scientific objective of this work is to better understand the relationship between the process, the induced microstructure, mechanical and the hygromechanical performances in order to target structural applications (aeronautic, sailing) for composite materials reinforced with synthetic fibers (carbon and glass) and natural fibers (flax). The second part of this work aimed to develop hygromorphic composites reinforced with continuous fibers (synthetic and natural) by 4D printing with a bioinspired bilayer architecture inspired by the pinecone scale. The conductive behavior of carbon fiber was used to create new electro-thermo-hygromorph actuators with controlled and accelerated actuation compared to conventional hygromorphs. Finally, the design freedom provided by 4D printing made it possible to control the local stiffness and actuation of composite actuators reinforced with continuous flax fiber

Au cours de cette thèse, des solutions innovantes ont été étudiées afin d'améliorer l'adhésion interfaciale entre du PLA et un TPC lors du procédé d'impression par dépôt de fil fondu. Deux solutions ont été proposées : (i) l'utilisation d'additifs promoteurs d'adhésion et (ii) la synthèse de copolymères incorporant des blocs PLA comme éléments constitutifs. Dans le premier cas, différents additifs issus de la biomasse ont été incorporés individuellement dans la formulation du PTC. Des conditions de fabrication des filaments ont été optimisées pour obtenir des filaments sans défaut et de diamètre constant. L'évaluation de l'adhésion a été faite en utilisant une version modifiée du test T Peel de pelage. L'amidon 2-hydroxyéthyle a présenté la plus forte amélioration de l'adhésion avec de faibles variabilités des résultats. Elle prouve que les additifs peuvent être utilisés comme promoteurs d'adhésion dans des systèmes où l'adhésion est faible, par exemple entre des polymères incompatibles comme un PLA et un TPC. De plus, cette formulation n'a pas modifié le comportement d'amortissement et de filtrage des vibrations du TPC. Par conséquent, il a été possible d'imprimer à l'aide d'un FFF multi-polymère un prototype d'équipement de protection combinant un PLA et le TPC formulé, comme une genouillère. En parallèle, la deuxième solution testée consiste à synthétiser par extrusion réactive de nouveaux copolymères multiblocs via des réactions de transestérification entre le PLA et le PBT. Différentes expériences ont été réalisées pour optimiser les conditions de la réaction de transestérification. Bien que les résultats obtenus par FTIR, RMN 1H, DSC et DMA confirme la formation du copolymère en petites quantités, le matériau présentait une faible imprimabilité et une délamination des couches. Par conséquent, l'évaluation de l'adhésion n'a pas été réalisée avec ce matériau
Solutions for improving multi-polymer FFF interlayer adhesion between PLA and a TPC were studied. Two solutions were proposed: (i) the use of adhesion promoter additives and (ii) the synthesis of copolymers incorporating PLA as building blocks. In the first one, different biosourced additives were individually incorporated into the formulation of the TPC. Filament fabrication conditions were optimized to achieve filaments with no defects and a constant diameter. Evaluation of adhesion was done using a modified version of the T-peel test. Only 2-hydroxyethyl starch presented the highest adhesion enhancement with low variabilities. Findings demonstrate the strategic potential of using modified biosourced additives to boost interfacial adhesion between two incompatible polymers. Furthermore, this formulation did not change the vibration-damping and filtering behavior of the TPC. Therefore, it was possible to print a prototype of protective equipment combining a PLA and the formulated TPC, such as a knee pad, using a multi-polymer FFF. The second solution refers to the synthesis through transesterification reactions of PLA and PBT new multiblock copolymers with a reactive extrusion process. Different experiments were done to optimize the transesterification's conditions. Although FTIR, 1H NMR, DSC and DMA results evidence the presence of the copolymer in small amounts, material had low printability presenting layer delamination. Therefore, the evaluation of adhesion was not achieved with this material

Inventée en 1983, comme procédé de prototypage rapide, la fabrication additive (FA) est aujourd’hui considérée comme un procédé de fabrication quasiment au même titre que les procédés conventionnels. On trouve par exemple des pièces obtenues par FA dans des structures d’aéronef. Cette évolution de la FA est due principalement à la liberté de forme permise par le procédé. Le développement de diverses techniques sur le principe de fabrication couche par couche et l’amélioration en quantité et en qualité de la palette de matériaux pouvant ainsi être mis en forme, ont été les moteurs de cette évolution. De nombreuses autres techniques et matériaux de FA continuent de voir le jour. Dans le sillage de la FA (communément appelée impression 3D) a émergé un autre mode de fabrication : l’impression 4D (I4D). L’I4D consiste à explorer l’interaction matériaux intelligents (MIs) – FA. Les MIs sont des matériaux dont l’état change en fonction d’un stimulus ; c’est le cas par exemple des matériaux thermochromiques dont la couleur change en réponse à la chaleur ou des hydrogels qui peuvent se contracter en fonction du pH d’un milieu aqueux ou de la lumière. Les objets ainsi obtenus ont – en plus d’une forme initiale (3D) – la capacité de changer d’état (en fonction des stimuli auxquels sont sensibles les MIs dont ils sont faits) d’où la 4e dimension (temps). L’I4D fait – à juste titre – l’objet d’intenses recherches concernant l’aspect fabrication (exploration de nouveaux procédés et matériaux, caractérisation, etc.). Cependant très peu de travaux sont entrepris pour accompagner les concepteurs (qui, a priori, ne sont ni experts FA ni des experts de MIs) à l’utiliser dans leurs concepts. Cette nouvelle interaction procédé-matériau requiert en effet des modèles, des méthodologies et outils de conception adaptés. Cette thèse sur la conception pour l’impression 4D a pour but de combler ce vide méthodologique. Une méthodologie de conception pour la FA a été proposée. Cette méthodologie intègre les libertés (forme, matériaux, etc.) et les contraintes (support, résolution, etc.) spécifiques à la FA et permet aussi bien la conception de pièces que celle d’assemblages. En particulier, la liberté de forme a été prise en compte en permettant la génération d’une géométrie minimaliste basée sur les flux fonctionnels (matière, énergie, signal) de la pièce. Par ailleurs, les contributions de cette thèse ont porté sur la conception avec les matériaux intelligents. Parce que les MIs jouent plus un rôle fonctionnel que structurel, les préoccupations portant sur ces matériaux doivent être menées en amont du processus de conception. En outre, contrairement aux matériaux conventionnels (pour lesquels quelques valeurs de paramètres peuvent suffire comme information au concepteur), les MIs requièrent d’être décrits plus en détails (stimulus, réponse, fonctions, etc.). Pour ces raisons un système d’informations orientées conception sur les MIs a été mis au point. Ce système permet, entre autre, d’informer les concepteurs sur les capacités des MIs et aussi de déterminer des MIs candidats pour un concept. Le système a été matérialisé par une application web. Enfin un cadre de modélisation permettant de modéliser et de simuler rapidement un objet fait de MIs a été proposé. Ce cadre est basé sur la modélisation par voxel (pixel volumique). En plus de la simulation des MIs, le cadre théorique proposé permet également le calcul d’une distribution fonctionnelle de MIs et matériau conventionnel ; distribution qui, compte tenu d’un stimulus, permet de déformer une forme initiale vers une forme finale désirée. Un outil – basé sur Grasshopper, un plug-in du logiciel de CAO Rhinoceros® – matérialisant ce cadre méthodologique a également été développé
Invented in 1983, as a rapid prototyping process, additive manufacturing (AM) is nowadays considered as a manufacturing process almost in the same way as conventional processes. For example, parts obtained by AM are found in aircraft structures. This AM evolution is mainly due to the shape complexity allowed by the process. The driving forces behind this evolution include: the development of various techniques on the layer-wise manufacturing principle and the improvement both in quantity and quality of the range of materials that can be processed. Many other AM techniques and materials continue to emerge. In the wake of the AM (usually referred to as 3D printing) another mode of manufacturing did emerge: 4D printing (4DP). 4DP consists of exploring the smart materials (SM) – AM interaction. SMs are materials whose state changes according to a stimulus; this is the case, for example, with thermochromic materials whose color changes in response to heat or hydrogels which can shrink as a function of an aqueous medium’s pH or of light. The objects thus obtained have – in addition to an initial form (3D) – the capacity to shift state (according to the stimuli to which the SMs of which they are made are sensitive) hence the 4th dimension (time). 4DP is – rightly – the subject of intense research concerning the manufacturing aspect (exploration of new processes and materials, characterization, etc.). However, very little work is done to support the designers (who, in principle, are neither AM experts nor experts of SMs) to use it in their concepts. This new process-material interaction requires adapted models, methodologies and design tools. This PhD on design for 4D printing aims at filling this methodological gap. A design methodology for AM (DFAM) has been proposed. This methodology integrates the freedoms (shape, materials, etc.) and the constraints (support, resolution, etc.) peculiar to the AM and allows both the design of parts and assemblies. Particularly, freedom of form has been taken into account by allowing the generation of a minimalist geometry based on the functional flows (material, energy, and signal) of the part. In addition, the contributions of this PhD focused on designing with smart materials (DwSM). Because SMs play a functional rather than a structural role, concerns about these materials need to be addressed in advance of the design process (typically in conceptual design phase). In addition, unlike conventional materials (for which a few parameter values may suffice as information to the designer), SMs need to be described in more detail (stimulus, response, functions, etc.). For these reasons a design-oriented information system on SMs has been developed. This system makes it possible, among other things, to inform designers about the capabilities of SMs and also to determine SMs candidates for a concept. The system has been materialized by a web application. Finally, a modeling framework allowing quickly modeling and simulating an object made of SMs has been proposed. This framework is based on voxel modeling (volumetric pixel). In addition to the simulation of SMs behaviors, the proposed theoretical framework also allows the computation of a functional distribution of SMs and conventional material; distribution which, given a stimulus, makes it possible to deform an initial form towards a desired final form. A tool – based on Grasshopper, a plug-in of the CAD software Rhinoceros® – materializing this methodological framework has also been developed

Ces dernières années, la photopolymérisation a fait l'objet d'intenses efforts de recherche en raison de la croissance constante des applications industrielles. C’est un processus rapide pouvant être réalisée à température ambiante, sans solvant et permettant d'obtenir un contrôle spatial et temporel de la polymérisation. Ces dernières années, l'utilisation de conditions d'irradiation douce qui constitue une alternative aux procédés de photopolymérisation UV à l'origine de nombreux soucis de sécurité est activement recherchée. Par conséquent, le développement de nouveaux systèmes photoamorceurs absorbant fortement dans la région visible ou du proche infra-rouge sont activement recherchés par les communautés académiques et industrielles. Néanmoins, même si certains résultats sont prometteurs, les systèmes reportés sont souvent caractérisés par des réactivités modérées et rivalisent difficilement avec les systèmes UV actuels. Dans ce contexte, nous avons synthétisé une large librairie de molécules photosensibles capables d’absorber la lumière dans le domaine du visible ou du proche infrarouge et capables d’amorcer une réaction de polymérisation avec un système photoamorceur basée sur la catalyse photoredox. Dans ce manuscrit, nous présentons aussi bien la synthèse et les capacités de polymérisation de différentes familles de colorants. Leurs propriétés photochimiques ont également été étudiées par spectrométrie UV-visible, luminescence, photolyse, surveillance de la température et expériences de résonance paramagnétique électronique. Des applications telles que l'impression 3D et les expériences d'écriture laser sont également présentées
In recent years, photopolymerization has been the subject of intense research efforts due to the constant growth of industrial applications. It is a quick process that can be performed at room temperature, solvent-free conditions and enables to get a spatial and a temporal control of the polymerization process. In recent years, the use of irradiation conditions that constitutes an alternative to the UV photopolymerization processes at the origin of numerous safety concerns are actively researched. Therefore, the development of new photoinitiating systems which absorb strongly in the visible or near infrared region are actively researched by both the academic and industrial communities. Nevertheless, even if some results are promising, the reported systems are often characterized by moderate reactivities and hardly compete with current UV systems. In this context, we have synthesized a large library of photosensitive molecules capable of absorbing light in the visible or near infrared range and capable of initiating a polymerization reaction with a photoinitiating system based on photoredox catalysis. In this manuscript, we present both the synthesis and the polymerization abilities of different families of dyes. Their photochemical properties were also studied by UV-Visible spectrometry, luminescence, photolysis, temperature monitoring and electronic paramagnetic resonance experiments. Applications such as 3D printing and laser write experiments are also presented

Advances in the design of adaptive matter capable of programmable, environmentally-responsive changes in shape would enable myriad applications including smart textiles, scaffolds for tissue engineering, and smart machines. 4D printing is an emerging approach in which 3D objects are produced whose shape changes over time. Initial demonstrations have relied on commercial 3D printers and proprietary materials, which limits both the tunability and mechanisms that can be incorporated into the printed architectures. My Ph.D. thesis focuses on a new 4D printing method, which is inspired by the movements or natural plants. Specifically, we encode swelling and elastic anisotropy in printed hydrogel composites through the alignment of stiff cellulose fibrils on-the-fly during printing. Filler alignment parallel to the print path leads to enhanced stiffness in that direction; hence, upon immersion in water, the printed filaments expand preferentially in the direction orthogonal to the printing path. When structures are patterned with broken-symmetry, i.e., as bilayers, their anisotropic swelling leads to programmable out-of-plane deformation, determined by the orientation of printed filaments. We have demonstrated complex changes in curvature including bending, twisting, ruffling, conical defects, and more, all using a single hydrogel-based ink printed in a single step. We have demonstrated the ability to precisely control curvature by varying the actual and the effective thickness, the latter of which is governed by the interfilament spacing within the printed architectures. With collaborators, a model has been developed for solving both the forward and inverse design problems, based on an adaptation of the classic Timoshenko bending theory, allowing us to create nearly arbitrary structures. Our filled hydrogel ink is modular, allowing a broad range of hydrogel chemistries and anisotropic filler compositions to be explored. For example, both reversible and non-reversible hydrogels were explored; namely poly(N-isopropyl acrylamide) (PNIPAm) and poly(N,N-dimethylacrylamide) (PDMAm), respectively. Additionally, light-absorbing carbon microfibers were incorporated to demonstrate reversible, multi-stimuli responsive 4D printing. In this case, reversible shape changes were encoded via 4D printing and then triggered either by heating PNIPAm or illuminating the printed architectures with a near IR laser. In summary, this biomimetic 4D printing platform enables the design and fabrication of complex, reversible shape changing architectures printed with one composite hydrogel ink in a single step. These biocompatible shape-shifting architectures with interesting mechanical and photothermal properties may find applications in smart textiles, tissue microgrippers or scaffolds, or as actuators and sensors in soft machines.
Engineering and Applied Sciences - Engineering Sciences

Thesis: S.M., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, September 2013.
"September 2013." Cataloged from PDF version of thesis.
Includes bibliographical references (pages 69-76).
Inherent across all scales in Nature's material systems are multiple design dimensions, the existences of which are products of both evolution and environment. In human manufacturing where design must be preconceived and deliberate, static artifacts with no variation of function across directions, distances or time fail to capture many of these dimensions. Inspired by Nature's ability to generate complex structures and responses to external constraints through adaptation, "4D printing" addresses additive fabrication of artifacts with one or more additional design dimension, such as material variation over distance or direction and response or adaptation over time. This work presents and evaluates a series of enabling explorations into the material, time and information dimensions of additive manufacturing: a variable elasticity rapid prototyping platform and an approach towards Digital Anisotropy, a variable impedance prosthetic socket (VTS) as a case study of interfaces between nature and manufacture, CNSilk as an example of on-demand material generation in freeform tensile fabrication, and Material DNA as an exploration into embedded spatio-temporal content variation.
by Elizabeth Yinling Tsai.
S.M.

3D printing or Additive manufacturing is a process of making a three-dimensional solid object of virtually any shape from a digital model. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35039

Les structures déployables peuvent être déformées entre les différentes configurations par des mécanismes prédéterminés, ce qui montre le grand potentiel de nombreuses applications d'ingénierie. Cependant, leurs mécanismes complexes rendent également très difficile la conception de leur structure. Avec les développements croissants en impression 4D, ses caractéristiques d'auto-transformation sous des stimuli externes offrent de nouvelles possibilités pour le déploiement de structures actives, complexes et difficiles. En outre, l'ingénierie basée sur les origamis a fourni un soutien technique considérable pour la transformation des structures, en particulier en passant par les états 2D à 3D, ce qui a conduit à de nombreuses études de conception basées sur des structures déployables inspirées de l'origami. Toutefois, la relation complexe entre la géométrie de la structure déployable et les matériaux et paramètres techniques connexes de l'impression 4D n'a pas été étudiée en profondeur. Actuellement, le manque de méthodologie de conception basée sur les origamis pour l'impression 4D fait toujours défaut. Dans ce travail de recherche, nous nous concentrons sur l'exploration des connexions internes entre les multiples niveaux d'abstraction allant de la structure globale du produit et l'affectation spécifique des matériaux et la conception géométrique afin d'aligner la bonne stratégie de conception sur une technique d'impression 4D spécifique. En bref, ce travail se veut être une ligne directrice pour la conception de structures actives déployables. Pour démontrer cet objectif, nous avons d'abord introduit les informations de base de l'impression 4D, de la conception basée sur les origamis et des structures déployables. Ensuite, nous avons analysé et résumé l'état d'avancement de leurs recherches et les difficultés existantes. Ensuite, nous proposons un cadre de conception systématique pour la conception de structures actives par impression 4D. Chaque étape de l'ensemble du processus de conception est présentée en détail, en particulier la conception de modèles d'origami basée sur la stratégie "3D-2D-3D" et la planification et le contrôle de la séquence de pliage. Enfin, sur la base des connaissances existantes, nous appliquons ce processus de conception à la structure active déployable et fournissons quelques études de cas illustratives
Deployable structures can be deformed between the different configurations through predetermined mechanisms, showing the great potential in many engineering applications. However, their exquisite and intricate mechanisms also bring a great difficulty to the design of its structure. With the growing 4D printing efforts, its self-transforming characteristics under external stimuli provide new possibilities for deploying complex and challenging driving structures. Furthermore, origami-based engineering has provided tremendous technical support for structural conversion, especially from 2D to 3D states, leading to many design studies based on origami-inspired deployable structures. However, the complicated relationship between the deployable structure's geometry and the related materials and engineering parameters of 4D printing has not been thoroughly explored. Currently, the origami-based design methodology for 4D printing is still missing. In this research work, we focus on exploring the internal connections between the multiple abstraction levels over the overall product structure to the specific material allocation and geometric design to make the right design strategy aligned to a specific 4D printing technique. In short, this work intends to be a guideline for designing active deployable structures. To demonstrate this objective, we first introduced the basic information of 4D printing, origami-based design, and deployable structures. Then we analyzed and summarized their research status and existing difficulties. Secondly, we propose a systematic design framework for active structure design by 4D printing. Each step in the entire design process is then introduced in detail, especially the origami pattern design based on the "3D-2D-3D" strategy and the folding sequence planning and control. Finally, based on the existing knowledge, we apply this design process to the active deployable structure and provide some illustrative case studies

L’objectif de cette thèse est de proposer une méthodologie complète de reconstruction 3D d’objets sous-marins naturels, améliorée par une nouvelle méthode d’acquisition afin de permettre des mesures quantitatives. Il a d’abord fallu prendre en compte les différents problèmes liés au milieu sous-marin profond ; la contrainte principale est que le système utilisé pour faire l’acquisition des images doit être contrôlé à des profondeurs très importantes, jusqu’à 6000 mètres, à l’aide d’un véhicule positionné sur le fond. Ainsi, une méthode permettant l’acquisition automatique d’images a été développée, adaptée à tout type d’objet sous-marin de faible échelle (environ 1m3). L’acquisition d’image est réalisée avec un système de stéréovision contrÔlé par un bras manipulateur. La méthode que nous proposons permet de connaître les paramètres extrinsèques des caméras du système de vision, par le suivi d’une trajectoire définie par la géométrie de la tête stéréo. Ainsi, la trajectoire est générée par le déplacement d’une caméra sur la position de l’autre caméra par asservissement visuel. Avec cette méthode, nous pouvons enregistrer des images à intervalles réguliers directement liés à la géométrie de la tête stéréo. Ensuite, le modèle 3D de l’objet sous-marin est calculé à partir des images collectées et des paramètres des caméras. Le résultat final est une reconstruction 3D dense avec un plaquage de texture, qui permet de faire des mesures métriques. Mots-clés: métrologie 3D, vision par ordinateur, stéréovision, asservissement visuel, trajectoire d’acquisition, reconstruction 3D
The aim of this study is to propose a complete 3-dimension reconstruction method of natural submarine objects improved by a new acquisition method for quantitative measures, which can be used in operational conditions. First, it was necessary to take into account the various problems connected with the deep sea environment ; the main constraint is that the system used to collect images must be manipulated at very important depths, up to 6000 meters by an underwater vehicle positioned on the sea floor. Thus, a method allowing the automatic acquisition of images was developed, adapted to any type of small-scale submarine object (approximately 1m 3). The image acquisition is performed with a stereovision system operated by a manipulator arm. The method that we propose enables us to know extrinsic camera parameters by following a specific trajectory defined by the geometry of a stereo rig. Indeed, the trajectory is generated by the displacement of one camera onto the position of the other one by visual servoing. With this method, we can register images at regular intervals directly linked to the geometry of the stereo rig. Then, the 3D model of the underwater object is calculated from the collected images and camera parameters. The final result is a dense 3D reconstruction with texture mapping that enables metric measures. Keywords: 3D metrology, computer vision, stereovision system, visual servoing, camera trajectory, 3D reconstruction

What is a 3D printer? Is any fiction or real technology? 3D-printer - a device that uses the method of layering creating of a physical object in a digital 3D-model.In fact 3D printer is a device that can print any volumetric product. 3D-printing can be implemented in different ways and it uses materials.

This dissertation focuses on developing 3D printing as a fabrication method for microfluidic devices. Specifically, I concentrate on the 3D printing approach known as Digital Light Processing stereolithography (DLP-SLA) in which serially projected images are used to sequentially photopolymerize layers to build a microfluidic device. The motivation for this work is to explore a much faster alternative to cleanroom-based microfabrication that additionally offers the opportunity to densely integrate microfluidic elements in compact 3D layouts for dramatic device volume reduction. In the course of my research, an optical approach was used to guide custom resin formulation to help create the interconnected hollow regions that form a microfluidic device. This was based on a new a mathematical model to calculate the optical dose delivered throughout a 3D printed part, which also explains the effect of voids. The model was verified by a series of 3D printed chips fabricated with a commercial 3D printer and a custom resin. Channels as small as 108 µm x 60 µm were repeatably fabricated. Next, highly compact active fluidic components, including valves, pumps, and multiplexers, were fabricated with the same 3D printer and resin. The valves achieved a 10x size reduction compared with previous results, and were the smallest 3D printed valves at the time. Moreover, by adding thermal initiator to thermally cure devices after 3D printing, the durability of 3D printed valves was improved and up to 1 million actuations were demonstrated.To further decrease the 3D printed feature size, I built a custom 3D printer with a 385 nm LED light source and a 7.56 µm pixel pitch in the plane of the projected image. A custom resin was also developed to take advantage of the new 3D printer's features, which necessitated developing a UV absorber screening process which I applied to 20 candidate absorbers. In addition, a new mathematical model was developed to use only the absorber's molar absorptivity measurement to predict the resin optical penetration depth, which is important for determining the z-resolution that can be achieved with a given resin. The final resin formulation uses 2-nitrophenyl phenyl sulfide (NPS) as the UV absorber. With this resin, along with a new channel narrowing technique, I successfully created flow channel cross sections as small as 18 µm x 20 µm.With the custom 3D printer, smaller valves and pumps become possible, which led to the invention of a new method of creating large numbers of high density chip-to-chip microfluidic interconnects based on either simple integrated microgaskets (SIMs) or controlled-compression integrated microgaskets (CCIMs). Since these structures are directly 3D printed as part of a device, they require no additional materials or fabrication steps. As a demonstration of the efficacy of this approach, 121 chip-to-chip interconnects in an 11 x 11 array for both SIMs and CCIMs with an areal density of 53 interconnects per square mm were demonstrated, and tested up to 50 psi without leaking. Finally, these interconnects were used in the development of 3D printed chips with valves having 30x smaller volume than the valves we previously demonstrated. These valves served as a building block for demonstrating the miniaturization potential of an active fluid mixer using our 3D printing tools, materials, and methods. The mixer provided a set of selectable mixing ratios, and was designed in 2 configurations, a linear dilution mixer-pump (LDMP) and a parallelized dilution mixer-pump (PDMP), which occupy volumes of only 1.5 cubic mm and 2.6 cubic mm, respectively.

Introduktion: Tredimensionell printing (3DP) är en teknik som använder en digital fil för att producera ett 3D-objekt, exempelvis en läkemedelstablett, genom en så kallad additiv process, vilket innebär att byggmaterialet läggs på successivt lager för lager. Syfte: Denna studie har ett tvådelat syfte, dels att presentera två 3D-printingstekniker, laserbaserade system (SLA) och smält deponeringsmodellering (FDM) som idag används för läkemedelsframställning samt göra en metodjämförelse, dels att ge exempel på samt beskriva några olika tabletter som framställts med hjälp av dessa tekniker. Metod: Studien genomfördes i form av en systematisk litteraturstudie och använde i första hand databasen PubMed för att hitta relevanta vetenskapliga artiklar i ämnet. Resultat: Resultatet redovisas i två delar. Första delen jämför de två viktiga 3DP-tekniker laserbaserade system (SLA) och smält deponeringsmodellering (FDM). Andra delen beskriver olika typer av tabletter som kan framställas med 3D-printing. Slutsats: Utifrån resultatet framgår det att 3D-printing är en framväxande teknik som skapar nya, intressanta terapimöjligheter. Dessutom framgår det att FDM lämpar sig bättre än SLA som framställningsteknik inom läkemedelsvärlden där det ställs höga krav på kostnadseffektivitet men också på grund av dess förmåga att generera formuleringar med olika frisättningsprofiler och på så sätt producera individanpassade läkemedel.

In the last decades, additive manufacturing (AM), also called three-dimensional (3D) printing, has advanced micro/nano-fabrication technologies, especially in applications like lightweight engineering, optics, energy, and biomedicine. Among these 3D printing technologies, two-photon polymerization (TPP) offers the highest resolution (even at the nanometric scale), reproducibility and the possibility to create monolithically 3D complex structures with a variety of materials (e.g. organic and inorganic, passive and active). Such active materials change their shape upon an applied stimulus or degrade over time at certain conditions making them dynamic and reconfigurable (also called 4D printing). This is particularly interesting in the field of medical microrobotics as complex functions such as gentle interactions with biological samples, adaptability when moving in small capillaries, controlled cargo-release profiles, and protection of the encapsulated cargoes, are required. Here we review the physics, chemistry and engineering principles of TPP, with some innovations that include the use of micromolding and microfluidics, and explain how this fabrication schemes provide the microrobots with additional features and application opportunities. The possibility to create microrobots using smart materials, nano- and biomaterials, for in situ chemical reactions, biofunctionalization, or imaging is also put into perspective. We categorize the microrobots based on their motility mechanisms, function, and architecture, and finally discuss the future directions of this field of research.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2018.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 153-171).
Integrating diverse functions inside man-made parts with specific shapes, in a highly scalable manner, is the central challenge in manufacturing. Functional integration is typically achieved by assembling specialized parts, each independently made using carefully designed production techniques - for example, in assembly lines in the automotive industry. Externally assembling specialized parts is tedious at certain length scales (e.g. mesoscale manufacturing), imposes restrictions on achievable geometries, and limits functional integration. In contrast, nature excels at packing disparate materials and functions into unconstrained geometries across different length scales (e.g. distributed sensors in cuttlefish, or sensorimotor pathways and resonant muscles in insects). These far exceed our current fabrication capabilities, and replicating all the functions of natural systems has remained a distant dream. 3D-printing has resolved many challenges in fabricating complex geometries, but despite its promise, assembling diverse materials (including solids, liquids and thin-films) and functions inside a single, printed composite is a current challenge. This thesis presents a set of materials, processes and design strategies - a full experimental toolkit - to address the question: how can we distribute diverse materials and functions in free-form geometries? First, a fully-3D-printed autonomous composite that can sense an external stimulus, process it, and respond by varying its optical transparency is described. The composite consists of seamlessly integrated solids (UV-cured polymers), thin-films (conducting and semiconducting, solvent-evaporated films), and encapsulated liquids. Techniques to engineer material interfaces are also presented in this section. A stimulus-free strategy to 3D-print self-folding composites at room temperature is presented in the second part of this thesis. Specifically, the focus is on printing flat electrical composites that fold into pre-programmed shapes after printing using residual stress defined in specific regions. This provides advantages in the fabrication speed, and also expands the range of achievable geometries when using solvent-based inks. The third portion of this thesis focuses on 3D-printing soft actuators. After highlighting a few example applications of printed actuator arrays, this is used as a case study for topology optimization based design strategies. It is shown that the inclusion of a topology optimizer in the 3D-printing pipeline enables the automated design and fabrication of high-dimensional designs. The final section of this work focuses on creating tactile sensor arrays, with an emphasis on the acquisition of tactile datasets that can be used to understand the human grasp. The concluding section summarizes the role of the fabrication strategies presented here in creating composites of increasing levels of autonomy and self-sufficiency.
by Subramanian Sundaram.
Ph. D.

Thesis: M. Eng. in Logistics, Massachusetts Institute of Technology, Engineering Systems Division, 2014.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 53-54).
Increasing the pace of product innovation in the consumer packaged goods industry can be achieved by implementing new technologies and streamlining processes. Our research is conducted primarily through extensive interviews with 3D printing experts and stakeholders in product development of a leading cosmetics manufacturer. We identify a framework where additive manufacturing technology such as 3D printing can complement the steel mold tooling used in the development of consumer product packaging. Within hours, rapid tooling technology can provide molds that are ideal for low volume production required during the preliminary stages of product design and testing. Implementing our proposed solution may reduce 14% to 26% of a company's time to market by shortening the duration of some critical path activities. The company can therefore respond to customer demand faster, strengthening its competitive advantage in the industry.
by Hala Jalwan and Gregory Israel.
M. Eng. in Logistics

Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2016.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 71-72).
I augmented a 3D printer with software for a 3D scanning system in order to incorporate feedback into the printing process. After calibration of the scanning system and the printer, the 3D scanning system is capable of taking depth maps of the printing platform. The two main extensions of 3D printing enabled by the 3D scanning system are printing on auxiliary objects and corrective printing. Printing on auxiliary objects is accomplished by scanning an auxiliary object, then positioning the printer to print directly onto the object. Corrective printing is using the scanner during the printing process to correct any errors mid-print.
by Allen Park.
M. Eng.

3D printing is the production of an object based on various three-dimensional models located on a digital medium. The printing process is based on the principle of laying a large number of thin layers one after the other. 3D printing can be of different types, both laser or inkjet, and extrusion. Most common are inkjet printers. This method is non-contact and can use thermal, piezoelectric or electromagnetic technology to apply very small drops of living cells and various biomaterials to a special surface, conforming to all digital instructions for the production of soft tissues or individual human organs.

and the placement of the material. Hence, 3D printing can be an advantageous new method of constructing supercapacitors.In this thesis, the aim was to investigate how the different parameters of Electrohydrodynamic printing (EHD printing) will affect the spread of gold nanoparticles. The electrohydrodynamic printing method is a printing method that utilizes an electric field to cause droplet ejection from the nozzle. When the electric field exerts a force on the solution containing nanoparticles, it stretches the meniscus to a point where it becomes unstable and forms a droplet. EHD printing utilizes an electric field which gives the method a high spatial accuracy while being able to print droplets with within a separation distance of tens of nanometers.Different parameters were evaluated to achieve desired distribution of gold nanoparticles across a silicon wafer substrate. This thesis focuses on print speed, frequency, heat treatment and voltage, and how printing parameters affect the results. The results revealed a variation, while the printing patterns follow a trend. The best results achieved in this work came from a low nozzle-substrate voltage, high frequency, and high printing speed. The varying results could be brought on by variation in ink composition, the nozzle diameter, and the metal coating of the capillary, to name a few possible causes.Handledare:

L'impression 4D est considérée comme une technologie de fabrication prometteuse pour créer des dispositifs innovants capables d'évoluer dans leur environnement d'utilisation. En couplant les processus de fabrication additive (FA) avec des matériaux actifs/passifs, les objets peuvent changer de propriétés, de formes ou même de fonctionnalités sous l'effet d'une énergie de stimulation. Pour réaliser un changement de forme souhaité, les récents progrès en conception informatique autour des matériaux numériques nécessitent de s'attaquer à l'impression 4D multi-matériaux. Cependant, la déposition de matériaux actifs et passifs en une seule structure reste difficile en raison de la compatibilité limitée des imprimantes existantes avec les matériaux intelligents (MI) possédant les propriétés nécessaires. Pour surmonter cette limitation dans le contexte de la distribution de matériaux complexe, une approche originale consiste à aborder l'impression 4D multi-matériaux du point de vue de l'assemblage de blocs imbriqués. Ces types d'assemblages ont parcouru un long chemin d'évolution et ont suscité diverses applications. Ils ont été étudiés comme une solution aux défis d'assemblage des pièces grandes et complexes. Par conséquent, l'objectif principal de cette thèse est de proposer une approche de conception informatique qui transforme un objet 4D multi-matériaux avec une distribution de matériaux numériques calculée en blocs imbriqués appropriés. Ces derniers peuvent être imprimés séparément en utilisant la FA à matériau unique, puis assemblés pour atteindre le changement de forme ciblé. Cette thèse se déroulera en trois contributions majeures. Tout d'abord, une contribution couvrira la séquence des étapes utilisées pour développer l'algorithme de génération d'assemblage imbriqué. Ensuite, une autre contribution proposée approfondira l'approche de l'assemblage de blocs imbriqués en étudiant leur effet sur le comportement des structures imprimées en 4D multi-matériaux. L'étude en question comparera les structures imprimées en une seule opération à celles qui sont imbriquées. Des tests mécaniques/de stimulation et des simulations numériques seront effectués pour démontrer que les structures imbriquées présentent des performances mécaniques pertinentes tout en améliorant la réponse à l'activation par rapport aux structures multi-matériaux imprimées en une seule fois. Une contribution finale sera consacrée à la généralisation de l'applicabilité de l'approche d'assemblage de blocs imbriqués en améliorant l'uniformité des changements de forme/de propriété dans une structure 4D multi-matériaux assemblée. De plus, cette contribution vise également à résoudre les limitations qui peuvent survenir en raison des interfaces des blocs imbriqués, telles que le manque continuité du contact et de déformation. Ainsi, il s'agira de proposer un concept de blocs imbriqués personnalisés prenant en compte les SM et leurs transformations potentielles. Pour souligner leur pertinence et leur utilisation pratique, des cas d’études seront inclus en parallèle des contributions proposées
L'impression 4D est considérée comme une technologie de fabrication prometteuse pour créer des dispositifs innovants capables d'évoluer dans leur environnement d'utilisation. En couplant les processus de fabrication additive (FA) avec des matériaux actifs/passifs, les objets peuvent changer de propriétés, de formes ou même de fonctionnalités sous l'effet d'une énergie de stimulation. Pour réaliser un changement de forme souhaité, les récents progrès en conception informatique autour des matériaux numériques nécessitent de s'attaquer à l'impression 4D multi-matériaux. Cependant, la déposition de matériaux actifs et passifs en une seule structure reste difficile en raison de la compatibilité limitée des imprimantes existantes avec les matériaux intelligents possédant les propriétés nécessaires. Pour surmonter cette limitation dans le contexte de la distribution de matériaux complexe, une approche originale consiste à aborder l'impression 4D multi-matériaux du point de vue de l'assemblage de blocs imbriqués. Ces types d'assemblages ont parcouru un long chemin d'évolution et ont suscité diverses applications. Ils ont été étudiés comme une solution aux défis d'assemblage des pièces grandes et complexes. Par conséquent, l'objectif principal de cette thèse est de proposer une approche de conception informatique qui transforme un objet 4D multi-matériaux avec une distribution de matériaux numériques calculée en blocs imbriqués appropriés. Ces derniers peuvent être imprimés séparément en utilisant la FA à matériau unique, puis assemblés pour atteindre le changement de forme ciblé. Cette thèse se déroulera en trois contributions majeures. Tout d'abord, une contribution couvrira la séquence des étapes utilisées pour développer l'algorithme de génération d'assemblage imbriqué. Ensuite, une autre contribution proposée approfondira l'approche de l'assemblage de blocs imbriqués en étudiant leur effet sur le comportement des structures imprimées en 4D multi-matériaux. L'étude en question comparera les structures imprimées en une seule opération à celles qui sont imbriquées. Des tests mécaniques/de stimulation et des simulations numériques seront effectués pour démontrer que les structures imbriquées présentent des performances mécaniques pertinentes tout en améliorant la réponse à l'activation par rapport aux structures multi-matériaux imprimées en une seule fois. Une contribution finale sera consacrée à la généralisation de l'applicabilité de l'approche d'assemblage de blocs imbriqués en améliorant l'uniformité des changements de forme/de propriété dans une structure 4D multi-matériaux assemblée. De plus, cette contribution vise également à résoudre les limitations qui peuvent survenir en raison des interfaces des blocs imbriqués, telles que le manque continuité du contact et de déformation. Ainsi, il s'agira de proposer un concept de blocs imbriqués personnalisés prenant en compte les matériaux actifs et leurs transformations potentielles. Pour souligner leur pertinence et leur utilisation pratique, des cas d’études seront inclus en parallèle des contributions proposées

Additive Manufacturing (AM), popularly called “3D printing,” has benefited from many two-dimensional (2D) printing technology developments, but has yet to fully exploit the potential of digital printing techniques. The very essence of AM is accurately forming individual layers and laminating them together. One of the best commercially proven methods for forming complex powder layers is laser printing, which has yet to be used to directly print three-dimensional (3D) objects above the microscale, despite significant endeavour. The core discovery of this PhD is that the electrostatic charge on toner particles, which enables the digital material patterning capabilities of 2D laser printing/photocopying, is disabling for building defect-free 3D objects after the manner attempted to date. Toner charge is not mostly neutralized with fusing as previously assumed. This work characterizes and substantiates the accumulation of residual toner charge as a primary cause for defects arising in 3D printed bodies. Next, various means are assessed to manage and neutralize residual toner charge. Finally, the complementary implementation of charge neutralization with electrostatic transfer methods is explored.

This thesis is concerned with fused filament fabrication (FFF) of cellulose nanocrystal (CNC) and thermoplastic polyurethane (TPU) nanocomposites, focusing on preliminary optimization of a processing window for 3D printing of mechanically responsive composites and the influence of temperature on mechanical adaptivity, thermal stability, and rheology. CNC thermoplastic nanocomposites are a water responsive, mechanically adaptive material that has been gaining interest in additive manufacturing for 4D-printing applications. Using a desktop FlashForge Pro 3D printer, we first established a viable processing window for a nanocomposite comprising 10 wt% CNCs in a thermoplastic urethane (TPU) matrix, formed into a filament through the combination of masterbatch solvent casting and single screw extrusion. Printing temperatures of 240, 250, and 260°C and printing speeds of 600, 1100, and 1600 mm/min instituted a consistent 3D-printing process that produced characterizable CNC/TPU nanocomposite samples. To distinguish the effects of these parameters on the mechanical properties of the printed CNC/TPU samples, a design of experiments (DOE) with two factors and three levels was implemented for each combination of printing temperature and speed. Dynamic mechanical analysis (DMA) highlighted 43 and 66% increases in dry-state storage moduli values as printing speed increases for 250 and 260°C, respectively. 64 and 23% increases in dry-state storage moduli were also observed for 600 and 1100 mm/min, respectively, as temperature decreased from 260 to 250°C. For samples printed at 240°C and 1600 mm/min, it was determined that that parameter set may have fallen out of the processing window due to inconsistent deposition and lower dry-state storage moduli than what the slower speeds exhibited. As a result, the samples printed at 240°C did not follow the same trends as 250 and 260°C. Further analysis helped determine that the thermal energy experienced at the higher end printing temperatures coupled with the slower speeds decreased the dry-state storage moduli by nearly 50% and lead to darker colored samples, suggesting CNC degradation. Isothermal thermogravimetric analyses (TGA) demonstrated that the CNC/TPU filament would degrade at relative residence times in the nozzle for all the chosen printing temperatures. However, degradation did not eliminate the samples' ability to mechanically adapt to a moisture-rich environment. DMA results verified that mechanical adaptivity was persistent for all temperature and speed combinations as samples were immersed in water. However, for the higher temperatures and slower speeds, there was about a 15% decrease in adaptability. Optimal parameters of 250°C and 1600 mm/min provided the highest dry-state storage modulus of 49.7 +/- 0.5 MPa and the highest degree of mechanical adaptivity of 51.9%. To establish the CNC/TPU nanocomposite's use in 4D printing applications, shape memory analysis was conducted on a sample printed at the optimal parameters. Multiple wetting, straining, and drying steps were conducted to highlight 76% and 42% values for shape fixity and shape recovery, respectively. Furthermore, a foldable box was printed to serve as an example of a self-deployable structure application. The box displayed shape fixity and recovery values of 67% and 26%, respectively, further illustrating significant promise and progress for CNC/TPU nanocomposites in 4D-printed, shape adaptable structures. Further analysis of the effect of degradation during FFF of the CNC/TPU nanocomposite was conducted using rotational rheometry, Fourier-Transform Infrared Spectroscopy (FTIR), and polymer swelling experiments. A temperature ramp from 180 to 270°C showed a significant increase in complex viscosity (h*) at the chosen printing temperatures (240, 250, and 260°C). Moreover, h* of neat TPU suddenly increases at 230°C, indicating a potential chemical crosslinking reaction taking place. 20-minute time sweeps further verified that h* increases along with steady increases in storage (G') and loss (G'') moduli. From these results, it was hypothesized that crosslinking is occurring between CNCs and TPU. Preliminary characterization with FTIR was used to probe the molecular structure of thermally crosslinked samples. At 1060 and 1703 cm-1, there are significant differences in intensities (molecular vibrations) as the temperature increases from 180 to 260°C related to primary alcohol formation and hydrogen bonded carbonyl groups, respectively. The hypothesis is the disassociation of TPU carbamate bonds into soft segments with primary alcohols and hard segments with isocyanate groups. The subsequent increasing peaks at 1060 and 1703 cm-1 may indicate crosslinking of CNCs with these disassociated TPU segments. To quantify potential crosslinking, polymer swelling experiments were implemented. After being submerged in dimethylformamide (DMF) for 24 hours, CNC/TPU samples thermally aged for 15 minutes at 240, 250, and 260°C retained their filament shape and did not dissolve. The 240 and 250°C aged samples had relatively similar crosslink densities close to 900 mole/cm3. However, from 250 to 260°C, there was about a 36% increase in crosslink density. These results suggest that crosslinking is occurring at these printing temperatures because both CNCs and TPU are thermally degrading into reactive components that will lead to covalent crosslinks degradation. Additional characterization is needed to further verify the chemical structure of these CNC/TPU nanocomposites which would provide significant insight for CNC/TPU processing and 3D printing into tunable printed parts with varying degrees of crosslinking.
Master of Science
This thesis is concerned with the development of a processing window for mechanically adaptive cellulose nanocrystal (CNC) and thermoplastic polyurethane (TPU) nanocomposites with fused filament fabrication (FFF) and, evaluating the influence of elevated temperatures on the mechanical, thermal, and rheological properties of said nanocomposite. CNC thermoplastic nanocomposites are a water responsive, mechanically adaptive material that has been gaining interest in additive manufacturing for 4D-printing. Using a desktop 3D-printer, an initial processing window for a 10 wt% CNC in TPU was established with printing temperatures of 240, 250, and 260°C and printing speeds of 600, 1100, and 1600 mm/min. A design of experiments (DOE) was implemented to determine the effects of these parameters on the mechanical properties and mechanical adaptability of printed CNC/TPU parts. Dynamic mechanical analysis (DMA) suggests that combinations of higher temperatures and lower speeds result in reduced storage moduli values for printed CNC/TPU parts. However, mechanical adaptation, or the ability to soften upon water exposure, persists for all the printed samples. Additionally, there was significant discolorations of the printed samples at the higher temperature and slower speed combinations, suggesting thermal degradation is occurring during the printing process. The decrease in storage moduli and discoloration is attributed to thermal energy input, as thermogravimetric analysis indicated thermal degradation was indeed occurring during the printing process regardless of printing temperature. Using the parameters (250°C and 1600 mm/min) that displayed the superior mechanical properties, as well as mechanical adaptivity, shape memory analysis was conducted. The optimal printed part was able to hold 76% of the shape it was strained to, while recovering 42% of the original unstrained shape once immersed in water, indicating potential for shape memory and 4D-printing applications. Furthermore, a foldable box was printed with the optimal parameters and it displayed similar shape memory behavior, illustrating promise for CNC/TPU self-deployable shape adaptable structures. To further study the effect of degradation on the CNC/TPU system, melt flow properties, molecular structure, and polymer swelling were investigated. At the printing temperatures (240, 250, and 260°C), the complex viscosity of the CNC/TPU filament experienced an exponential increase, indicating potential network formation between the CNCs and TPU. Fourier-Transform Infrared Spectroscopy (FTIR) highlighted changes in the molecular structure for the CNC/TPU filament as temperature increased from 240 to 260°C, which suggests that chemical structure changes are occurring because of degradation. The hypothesis is TPU is disassociated into free soft and hard segments that the CNCs can covalently crosslink with, which can potentially be explained by the increases in the FTIR intensities relating to TPU and CNC's chemical structure. To further quantify potential crosslinking between CNCs and TPU, polymer swelling experiments were implemented. The results from these experiments suggest that increasing printing temperatures from 240 to 260°C will lead to higher degrees of crosslinking. Further investigation could yield the validity of this crosslinking and additional optimization of FFF printing with CNC/TPU nanocomposites.

Fused Filament Fabrication (FFF) is an extrusion-based additive manufacturing technique that can build 3D objects in successive layers, offering viable and affordable 3D printing solutions that produce minimum waste. There are two barriers that prevent the advanced application of FFF: The performance and geometric precisions of FFF printed products are prone to the anisotropy and residual stresses arising from the printing process, and objects with complex geometries must be printed with the aid of support structures. The thesis addresses these challenges by exploring the anisotropy and residual stress in FFF, whereby FFF printed objects can self-transform into desired shapes when triggered by heat – a process known as 4D printing. The research project utilises the residual stress and anisotropy as the morphing principle to initiate and control the shape transformation of the 4D printed structures. A broad range of FFF printing materials, including acrylonitrile butadiene styrene (ABS), Wood-Plastic Composite (WPC), and shape memory polymer (SMP), are explored. Initial research focuses on the experimental investigations on the anisotropic mechanical performance of 3D printed WPC and numerical modelling of the residual stress and geometric defects in 3D printed ABS. The results indicate that the raster angles and printing patterns are the key parameters influencing the anisotropic tensile and flexural properties of 3D printed WPC, and the residual stress and distortion of 3D printed ABS. Based on these findings, the FFF printed components can be programmed with desired anisotropic behaviours and built-in residual stresses through the design of printing patterns and control of the printing process. An FFF-based 4D printing framework for simulating and manufacturing heat-responsive self-morphing structures is developed. 4D printing prototypes of ABS, WPC, and SMP that can morph from flat printed shapes into various forms are presented.

Rapid prototyping is a relativity new technology and is based on layered manufacturing which has similarities to the method an ordinary desktop paper printer works. This research is to obtain a better understanding on how to use computer graphics software, in this particular case Autodesk Maya, to create a model. The goal is to understand how to create a suitable mesh of a 3D model for use with a 3D printer and produce a printed model that is equivalent to the CAD software 3D model. This specific topic has not been scientifically documented which has resulted in an actual 3D model.

Disruptive technologies influence the application and development of intellectual property. Additive manufacturing, colloquially known as 3D printing, is one such technology that has a profound impact on how goods are created, disseminated and consumed. This technology enables, in an unprecedented matter, the decentralised manufacturing of goods, supplemented by user-based creation and instantaneous dissemination of the underlying digital models. From the perspective of intellectual property law, the focus of this thesis is on analysing of how consumer 3D printing creates legal ambiguity and enforcement issues that affect a multitude of actors, in interrelated, conflicting and potentially overlapping capacities. It focusses on the intellectual property regimes that are at the forefront of 3D printing, including the laws of trade marks, copyright, patents and designs. Emphasis of this thesis is on the law of South Africa; however, in the absence of judicial guidance, an examination of the laws of the United Kingdom and the European Union provides additional insights and guidance. The development of arguments in this work is grounded in technological and social premises, determined by the characteristics of the consumer 3D printing ecosystem and the additive manufacturing process, including design creation, dissemination and production. The underlying research question of this thesis is how the intellectual property framework can be used and further optimised to promote consumer 3D printing. In this context, it investigates how the interests of the following key actors can be balanced: (i) rights holders that typically wish to control design dissemination; (ii) design sharing platforms that seek to facilitate design creation and dissemination; and (iii) consumers who require access to digital designs. This thesis submits that a balance can indeed be struck, subject to complementary actorand situation specific responses. In addition to these responses, this thesis proposes minor amendments to the current South African intellectual property framework, supplemented by the clarification concerning the application of intellectual property rights, and the implementation of non-restrictive digital rights management systems.

In this report, my work on 3D-printing will be presented. This project is what constitutes my examination project in the education of industrial design engineering.   3D-printers are tools that have undergone great development in recent years. Through this development, the machines have become increasingly accessible to private individuals thanks to reduced prices, easyer use and higher quality. Through an increased use of the tool on a more private level, new opportunities are created for how we manufacture products, as well as how our attitude to its components are viewed.   The purpose of the work was to investigate how 3D-printing can be used to create more efficient and sustainable products with a focus on users, manufacturers and the environment. The goal was to develop an approach to utilize the function of a 3D-printer in a way that contributes to higher sustainability and efficiency, where the end result should contribute to this without forcing the user to make any decisive sacrifices.   The work has been carried out with a three-part process, divided into the phases Inspiration, Ideation and implementation, which together constitute an iterative design process. Initially in the inspiration phase, inspiration was created for the work with the help of a literature study, theory collection and a context analysis. Then began the ideation phase, whose purpose was to start creating ideas and conceptualize the inspiration that has previously been collected in the inspiration phase. To implement these ideas and concepts, the implementation phase was carried out to achieve a more completed and implemented concept.   The work resulted in the concept TonePrint. TonePrint is a speaker and a pair of headphones that work together in a form of ecosystem to make the interaction smoother for the user when changing audio source. The product TonePrint is a product that the user 3D-prints by oneself. This contributes to a more efficient and sustainable product as well as production. The product is designed in a way that enables the user to configure the product based on their own needs, which contributes to increased personalization. It allows the user to reuse components from previous devices that would otherwise be discarded, or select components based on their own liking and taste.
I den här rapporten kommer mitt arbete rörande 3D-printeing presenteras. Det här projektet är det som utgör mitt examensarbete i utbildningen högskoleingenjör inom teknisk design.   3D-printers är verktyg som har genomgått stor utveckling de senaste åren. Genom den här utvecklingen har maskinerna blivit allt mer tillgängliga för privatpersoner tack vare lägre priser, smidigare användning och högre kvalitet. Genom en ökad användning av verktyget på mer privata plan skapas nya möjligheter för hur vi tillverkar produkter, samt hur vi ser på produkter och dess uppbyggande komponenter.   Syftet med arbetet var att undersöka hur 3D-printing kan användas för att skapa mer effektiva och hållbara produkter med fokus på användare, tillverkare och miljön. Målet var att ta fram ett tillvägagångssätt att nyttja de egenskaper en 3D-printer medför på ett sätt som bidrar till en högre hållbarhet och effektivitet, där det slutliga resultatet ska bidra till detta utan att tvinga användaren att göra några avgörande uppoffringar.    Arbetet har genomförts med en tre delad process, indelad i faserna Inspiration, Ideation och implementation som tillsammans utgör en iterativ designprocess. Initialt i inspirationsfasen skapades inspiration för arbetet med hjälp av en litteraturstudie, teoriinsamling samt en kontextanalys. Därefter påbörjades ideationsfasen, vars syfte var att börja skapa idéer och konceptualisera den inspirationen som tidigare blivit insamlad i inspirationsfasen. För att implementera dessa idéer och koncept utfördes implementationsfasen för att nå ett mer färdigställt och förverkligat koncept.   Arbetet resulterade i konceptet TonePrint. TonePrint är en högtalare och ett par hörlurar som samverkar i ett form av ekosystem för att göra interaktionen smidigare för användaren vid byte av ljudkälla. Produkten TonePrint är en produkt som användaren själv 3D-printar. Detta bidrar till en mer effektiv och hållbar produkt samt produktion. Produkten är utformad på ett sätt som möjliggör för användaren att konfigurera produkten utifrån eget behov vilket bidrar till en ökad personalisering. Det möjliggör för användaren att återanvända komponenter från tidigare enheter som annars skulle slängas, eller välja komponenter utifrån eget tycke och smak.

Additive manufacturing (AM) is currently on the verge of redefining the way we produce and manufacture things. AM encompasses many technologies and subsets, which are all joint by a common denominator; they build three dimensional (3D) objects by adding materials layer-upon-layer. This family of methods can do so, whether the material is plastic, concrete, metallic or living cells which can function as organs. AM manufacturing at the micro scale introduces new capabilities for the AM family that has been proven difficult to achieve with established AM methods at the macro scale. Electrohydrodynamic jet (E-jet or EHD jet) printing is a micro AM technique which has the ability to print at high resolution and speed by exploiting physical phenomena to generate droplets using the means of an electric field. However, when printing metallic materials, this method requires nanoparticles for deposition. To obtain a stable structure the material needs to be sintered, after which the deposited material is left with a porous structure. In contrary, electrochemical methods using the well-known deposition mechanism of electroplating, can deposit dense and pure structures with the downside of slow deposition. In this thesis, a new method is proposed to micro additive manufacturing by merging an already existing technology EHD with simple electrochemistry. By doing so, we demonstrate that it is possible to print metallic structures at the micro- and nanoscale with high speeds, without the need for presynthesized nanoparticles. To achieve this, a printing setup was designed and built. Using a sacrificial wire and the solvent acetonitrile, metallic building blocks such as lines, pillars and other geometric features could be printed in copper, silver, and gold with a minimum feature size of 200 nm. A voltage dependence was found for porosity, where the densest pillars were printed at 135-150 V and the most porous at 260 V. The maximum experimental deposition speed measured up to 4.1 µm · s−1 at 220 V. Faraday’s law of electrolysis could be used to predict the experimental deposition speed at a potential of 190 V with vexp = 1.8 µm · s−1 and vtheory = 0.8 µm · s−1. The microstructure of the pillars could be improved through lowering the applied voltage. In addition, given that Faraday’s law of electrolysis could predict experimental depositions speeds well, it gives further proof to reduction being the mechanism of deposition.

Additive manufacturing (AM) is a set of different techniques which use layer by layer deposition principle to join material together and manufacture three-dimensional objects from a CAD file. One of the most known and popular techniques within AM is Fused Deposition Modeling (FDM). Generally, the FDM process starts with a feedstock of filament which is pushed through an extruder head, which liquefies the filament and deposits it down on the print bed according to a specific pattern specified by the CAD file. This technique has found great success within the industry and has been adopted by many companies across many different applications such as automotive, aerospace and medical for rapid prototyping. The disadvantage with filaments is that the diameter tolerances are quite small which makes it expensive and difficult to manufacture. Another problem with 3D printing is the waste of money and time due to failed prints, both in the industry but also with private users. This is a result of not having a monitoring system that overwatches the printing process and stops the print when it detects defects, as the user usually does not stand by the printer and watch the whole process. The main aim of this study is to modify a desktop 3D printer to suit and install a pellet extruder and to investigate the feasibility of process monitoring for desktop printers. To evaluate the printability of the pellet extruder, tensile test artifacts are printed with PLA 4043D and TPE_S16300C in two different raster orientations and three different layer thicknesses, further, the influence of raster orientation and layer thickness on ultimate tensile strength is evaluated. Raster orientation refers to the different directions of the individual bead paths within a layer and layer thickness refers to the height of each layer that is deposited along the Z-axis. In this study, the pellet extruder was successfully installed on the Sovol SV01 printer. The open-source process monitoring system called the spaghetti detective was used during the experiments to monitor the 3D printing process. It uses a failure detection system (AI) to detect defects and automatically stop a print if defects are detected and alert the user via email or text. The tensile test artifacts were only printed with TPE_SE16300C and due to limitations in the pellet extruder, it is observed that tensile test samples were difficult to 3D print with PLA4043D. Regardless of the layer thickness, the 45°/-45° raster orientation produced a slightly higher ultimate tensile strength than the 0°/90° raster orientation. As for the influence of layer thickness on ultimate tensile strength, the increase of layer thickness in the 0°/90° raster orientation led to a decrease in ultimate tensile strength. In the 45°/-45° raster orientation no clear conclusion could be made as the differences were insignificant.

As a cutting edge manufacturing methodology, 3D printing or additive manufacturing (AM) brings much more attention to the fabrication of complex structure, especially in the manufacturing of metal parts.A number of various metal AM techniques have been studied and commercialized. However, most of them are expensive and less available, in comparison with Selective Laser Melting manufactured stainless steel 316L component.The purpose of this Master Thesis is to introduce an innovative AM technique which focuses on material extrusion-based 3D printing process for creating a Stainless Steel 316L part using a metal-polymer composite filament. The Stainless Steel test specimen was printed using an Fused Deposition Modelling based 3D printer loaded with a metal infused filament, followed by industrial standard debinding and sintering process. Investigation was performed on the specimen to understand the material properties and their behaviour during the postprocessing method. In addition effects of debinding, sintering and comparison of the test Specimen before and after debinding stages was also carried out. Metal polymer filaments for 3D printing could be an alternative way of making metal AM parts.
Som en avancerad tillverkningsmetodik ger 3D-printing eller additiv tillverkning (AM) mycket mer uppmärksamhet vid tillverkning av komplex struktur, särskilt vid tillverkning av metallkomponenter. Ett antal olika AM-tekniker vid tillverkningen av olika typer av metallkomponenter har studerats och kommersialiserats.De flesta av dessa AM-tekniker är dyra och mindre tillgängliga, i jämförelse med Selective Laser Melting vid tillverkningen av en komponent i rostfritt stål 316L. Syftet med detta examensarbete är att introducera en innovativ AM-teknik som fokuserar på materialsträngsprutningsbaserad 3D-printingprocess för att skapa ekomponent i rostfritt stål 316Lkomponent med ett metallpolymerkompositfilament. Ett prov bestående av rostfritt stål skrevs ut med en FDM-baserad 3D-skrivare laddad med filament av polymer och metal, följt av industriell avdrivnings-och sintringsprocess. Provet studerades för att förstå materialegenskaperna och dess beteende under efterbehandlingsmetoden. Dessutom genomfördes också resultat från avdrivning och sintring på provet och en jämförelse av provet före och efter avdrivnlngssteget. Metallpolymertrådar för 3D-printing kan vara ett alternativt sätt att tillverka AM-metallkomponenter.

Les tecnologies de fabricació additiva (FA) per deposició capa-a-capa de material expel·lit des d’un broquet aporten una versatilitat excepcional, però estan limitades en termes de velocitat d’impressió i resolució. L’emissió electrohidrodinàmica (EHD) de dolls permet generar dolls líquids submicromètrics que poden assolir velocitats per damunt de 1 m/s. Malgrat això, tals dolls no es poden dipositar amb precisió submicromètrica damunt substrats mòbils, fins i tot emprant platines motoritzades d’alta gama, les quals no superen els ~30 m/s^2. Aquí demostrem una nova forma d’imprimir en la que la trajectòria del doll EHD s’ajusta contínuament assolint acceleracions laterals de fins a 10^6 m/s^2 mitjançant el control de voltatges en elèctrodes situats al voltant del doll. Mitjançant tècniques de visualització a alta velocitat, hem fet una anàlisi paramètrica sobre com els paràmetres d’aquests senyals i les configuracions del muntatge influeixen en la deflexió del doll. Hem desenvolupat software propi per generar els senyals de deflexió del doll per a imprimir figures 2D, així com objectes 3D amb elements submicromètrics. Tals objectes 3D han estat impresos per superposició de nanofibres a freqüències capa-a-capa de fins 2000 Hz. Les altes velocitats del doll i freqüències capa-a-capa assolides es tradueixen en velocitats de impressió de fins 0.5 m/s en horitzontal i 0.4 mm/s en vertical, que corresponen a entre tres i quatre ordres de magnitud més de pressa del que són capaces les altres tècniques de FA comparables en resolució. També hem emprat la deflexió electrostàtica de dolls per a desenvolupar un mètode nou per a la determinació de la velocitat de dolls EHD. A diferència dels mètodes previs, que es basen en analitzar la fibra impresa emprant microscòpia d’alta resolució, el nostre mètode es basa en el reconeixement d’imatge de les impressions de patrons preestablerts, permetent el seguiment in situ de la velocitat del doll. Finalment, en un estudi sobre impressió de dolls EHD lents de polímers fosos damunt substrats mòbils, demostrem que l’ajust del recorregut de la impressió per a cada capa dipositada permet expandir enormement la varietat d’estructures imprimibles i així manipular les seves propietats mecàniques.
Las tecnologías de fabricación aditiva (FA) por deposición capa-a-capa de material expulsado desde una tobera aportan una versatilidad excepcional, pero están limitadas en términos de velocidad de impresión y resolución. La emisión electrohidrodinámica (EHD) de chorros permite generar chorros líquidos submicrométricos que pueden alcanzar velocidades per encima de 1 m/s. Sin embargo, tales chorros no se pueden depositar con precisión submicrométrica sobre sustratos móviles, incluso usando platinas motorizadas de alta gama, las cuales no superan los ~30 m/s^2. Aquí demostramos una nueva forma de imprimir en la que la trayectoria del chorro EHD se ajusta continuamente alcanzando aceleraciones laterales de hasta 10^6 m/s^2 mediante el control de voltajes en electrodos situados alrededor del chorro. Mediante técnicas de visualización a alta velocidad, hemos realizado un análisis paramétrico sobre cómo los parámetros de estas señales y las configuraciones del montaje influyen en la deflexión del chorro. Hemos desarrollado software propio para generar las señales de deflexión del chorro para imprimir figuras 2D, así como objectos 3D con elementos submicrométricos. Tales objetos 3D han sido imprimidos por superposición de nanofibras a frecuencias capa-a-capa de hasta 2000 Hz. Las altas velocidades del chorro y frecuencias capa-a-capa alcanzadas se traducen en velocidades de impresión de hasta 0.5 m/s en horizontal y 0.4 mm/s en vertical, que corresponden a entre tres y cuatro órdenes de magnitud más rápido de lo que son capaces las otras técnicas de FA comparables en resolución. También hemos usado la deflexión electrostática de chorros para desarrollar un método novedoso para la determinación de la velocidad de chorros EHD. A diferencia de los métodos previos, que se basan en analizar la fibra impresa usando microscopía de alta resolución, nuestro método se basa en el reconocimiento de imagen de las impresiones de patrones predefinidos, permitiendo el seguimiento in situ de la velocidad del chorro. Finalmente, en un estudio sobre impresión en sustratos móviles de chorros EHD lentos de polímeros fundidos, demostramos que el ajuste del recorrido de impresión para cada capa depositada permite expandir enormemente la variedad de estructuras imprimibles y así manipular sus propiedades mecánicas.
Additive manufacturing (AM) technologies based on layer-by-layer deposition of material ejected from a nozzle provide unmatched versatility but are limited in terms of printing speed and resolution. Electrohydrodynamic (EHD) jetting uniquely allows generating submicrometer jets that can reach speeds above 1 m/s, but such jets cannot be deposited on a moving substrate with submicron accuracy even when using state-of-the-art mechanical stages, which are limited to accelerations below ~30 m/s^2. Here, we demonstrate a new printing approach in which the EHD jet trajectory can be continuously adjusted with lateral accelerations up to 10^6 m/s^2 via controlling voltages applied to electrodes positioned around the jet. Using high-speed imaging we have conducted a parametric analysis of how the deflection signal parameters and setup configurations influence the jet deflection. Custom-made software has been developed to generate jet-deflecting signals which control the jet to print 2D patterns, as well as 3D objects with submicrometer features. Such 3D objects have been printed by stacking nanofibers at layer-by-layer frequencies as high as 2000 Hz. The high jet speeds and layer-by-layer frequencies achieved translate into printing speeds up to 0.5 m/s in-plane and 0.4 mm/s in the vertical direction, which is three to four orders of magnitude faster than for other AM techniques providing equivalent feature sizes. We have also used electrostatic jet deflection to develop a novel method for determining the speed of EHD jets. Unlike all previous approaches, which rely on ex-situ high-resolution microscopy analysis of the printed fiber, our method is based on image recognition of predefined printed patterns, allowing in-situ monitoring of the jet speed. Finally, in an additional study on stage-based printing of slow EHD jets of polymer melts, we show that updating the printing path for each deposited layer enables to significantly expand the range of printable structures and thus manipulate their mechanical properties.

This bachelor’s thesis has given us an opportunity to gain insight into how to create a service from scratch and to develop it into a fully functional service. The 3D printer service starts when a customer uploads a file containing the 3D design that they want to have made via a website. The file is stored and the printing request is placed into a queue. After that the client simply waits until the object is printed, with all of the various steps being handled automatically. The uploaded file containing the 3D design is automatically converted into Gcode by using the software Skeinforge. Gocde is the language that the printer interprets. The printer itself is controlled by the ReplicatorG program. The ReplicatorG program transfers the Gcode commands to the printer to print the desired object. This Gcode includes commands to warm up the automated build platform where the object will be created and to warm up the extruder head – through which plastic will be extruded to create the 3D object. If the customer wants to see the object while it is being printed – we have made this possible via a network attached camera. This camera is placed next to the printer. Once the object has been printed the automated build platform is allowed to cool and a motor driven belt advances to eject the object from the platform. In an ideal system the object would be put directly into a bag or other package – with a pre-printed label, thus it would be ready for shipping to the customer. This portion of the system has not yet been realized and is left as future work.
Detta kandidatexamensarbete har gett oss en möjlighet att få en inblick i hur det är att skapa en tjänst från grund och sedan bygga på den tills en fullt fungerande tjänst var skapad. 3D printertjänsten drar igång då en kund laddar upp den önskade filen via hemsidan, som sedan lagras och läggs i en eventuell kö. Från detta behöver inte kunden eller någon annan göra något mer utan allt sköts automatiskt. En konvertering av kundens STL fil till språket Gcode som skrivaren kan tolka sker med hjälp av programmet Skeinforge. Själva skrivaren styrs av programmet ReplicatorG där allt bestäms och slutligen ger order till skrivaren att börja skriva ut det som önskas. Om kunden vill så finns en möjlighet att med hjälp av en IP kamera även se sina produkter live då de tillverkas. Idén om att obtjekt direkt ska landa i en förpackning som är redo att skickas till kunden lämnas för framtida arbeten.

Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 62-64).
This thesis presents the development of MultiFab, a multi-material 3D printing architecture that is high-resolution, scalable, and low-cost. MultiFab enables the 3D printing of parts with materials that interact optically and mechanically. The hardware is low-cost since it is built almost exclusively from off-the-shelf components. The system uses commercial piezoelectric printheads that enable multi-material 3D printing with a resolution of at least 40 [mu]m. This thesis presents the design and fabrication of MiniFab, a 3D printer that implements the MultiFab architecture, and its key subsystems, including novel material feeding and UV LED curing systems. Additionally, results show that the printer is capable of producing multi-material parts for a wide variety of applications..
by Javier Eduardo Ramos-Maltés.
S.M.

Additive manufacturing has become a very popular and well mentioned technique in recent years. The technique, where 3 dimensional (3D) printing is included, creates opportunities to develop new designs and processing systems. As a research institute within the forest based processes and products, Innventia AB has an idea of combining 3D printing with cellulose. The addition of cellulose will increase the proportion of renewable raw material contributing to more sustainable products. However, when cellulose is added the composition of the filaments changes. The main aim for the project is to devise methodologies to improve properties of composite filaments used for 3D printing. Filament in 3D printing refers to a thread-like object made of different materials, such as PLA and ABS, that is used for printing processes. A literature study was combined with an extensive experimental study including extrusion, 3D printing and a new technique that was tested including 3D scanning for comparing the printed models with each other. The extruding material consisted of polypropylene and cellulose at different ratios, and filaments were produced for 3D printing. The important parameters for extruding the material in question was recorded. Because the commingled material (PPC) was in limited amount, UPM Formi granulates, consisting of the same substances, was used first in both the extrusion and printing process. Pure polypropylene filaments were also created in order to strengthen the fact that polypropylene is dimensional unstable and by the addition of cellulose, the dimensional instability will decrease. After producing filaments, simple 3D models were designed and printed using a 3D printing machine from Ultimaker. Before starting to print, the 3D model needed to be translated into layer-by-layer data with a software named Cura. Many parameters were vital during printing with pure polypropylene, UPM and PPC. These parameters were varied during the attempts and marked down for later studies. With the new technique, in which 3D scanning was included, the 3D printed models were compared with the original model in Cura in order to overlook the deformation and shape difference. The 3D scanner used was from Matter and Form. Photographs of the printed models, results from the 3D scanner, and screenshots on the model in Cura were meshed together, in different angles, using a free application named PicsArt. The result and conclusion obtained from all three parts of the experimental study was that polypropylene’s dimensional stability was improved after the addition of cellulose, and the 3D printed models’ deformation greatly decreased. However, the brittleness increased with the increased ratio of cellulose in the filaments and 3D models.
Additiv tillverkning har på den senare tiden blivit en mycket populär och omtalad teknik. Tekniken, där tredimensionell (3D) utskrivning ingår, ger möjligheter att skapa ny design och framställningstekniker. Som ett forskningsinstitut inom massa- och pappersindustrin har Innventia AB en ny idé om att kombinera 3D-utskrivning med cellulosa. Detta för att höja andelen förnybar råvara som leder till mer hållbara produkter. Dock kommer filamentens sammansättning vid tillsättning av cellulosa att ändras. Det främsta syftet med detta projekt är att hitta metoder för att förbättra egenskaperna hos de kompositfilament som används för 3D-utskrifter. Filament inom 3D-utskrivning är det trådlika objektet gjort av olika material, såsom PLA och ABS, som används vid utskrivningsprocessen. En enkel litteraturstudie kombinerades med en experimentell studie. Det experimentella arbetet var i fokus i detta projekt som omfattade extrudering, 3D-utskrivning samt en ny teknik som prövades, där 3D-scanning ingick, för att jämföra de utskrivna modellerna med varandra. Extruderingsmaterialet bestod av polypropen och cellulosa av olika halter, och av detta material tillverkades filament för 3D-utskrivning. De viktiga parametrarna för extrudering med det önskade materialet antecknades. Eftersom mängden cominglat material (PPC) var begränsat, användes först UPM Formi granuler, som består av samma substanser som i PPC, i både extruderingen och utskrivningen. Filament av ren polypropen tillverkades också för att stärka det faktum att polypropen är dimensionellt instabil. Genom att tillsätta cellulosa minskades dimensionsinstabiliteten. Efter att filamenten hade tillverkats, designades enkla 3D-modeller för utskrivning med en 3D-utskrivare från Ultimaker. Innan utskrivningen kunde börja behövde 3D-modellen bli översatt till lager-på-lager-data med hjälp av en programvara vid namn Cura. Många parametrar är viktiga vid utskrivning med ren polypropen, UPM samt PPC. Temperatur och hastighet varierades för de olika försöken och antecknades för senare studier.Med den nya tekniken, där 3D-scanning ingår, jämfördes de utskrivna 3D-modellerna med originalmodellen i Cura för att se över deformationen och formskillnaden. Den 3D-scanner som användes kom från Matter and Form. Fotografier på de utskrivna modellerna, resultaten från 3D-scannern och bilder på modellerna i Cura sammanfogades i olika vinklar med hjälp av ett gratisprogram som heter PicsArt. Det resultat som erhölls och den slutsats som kunde dras utifrån alla tre delarna av den experimentella studien var att polypropens dimensionsinstabilitet minskades efter tillsatsen av cellulosa, och att de 3D-utskrivna modellernas deformation minskade kraftigt. Skörheten ökade ju högre halt cellulosa som filamenten och de utskrivna modellerna innehöll.

In this project, an additive manufacturing technique called Direct Ink Writing has been used to 3D print structures from polymer solutions containing cellulose acetate. Cellulose acetate is a synthetic compound derived from plants. The intended application involves protein separation filters for medical purposes. The printing has been performed in a lab environment with focus on high resolution, with less than 10 micrometers in fibre size. Glass capillaries with an inner diameter of 3-10 micrometers were used as nozzles. Three-dimensional structures with a height of 100 micrometers and a fibre thickness of 2 micrometers were made. The results indicates that cellulose acetate is a promising polymer for Direct Ink Writing in high resolution. Improvements are needed in the ink design and/or the technical construction of the printer to avoid clogging of the nozzle.

This project was initiated by Dr. Sasan Dadbaksh upon listening to the requirements I presented for my master thesis. My requirements were to do a master thesis project in the field of additive manufacturing specifically fused deposition modeling that should not only involve the research work but should also present an opportunity to develop hardware and should involve experimental testing. Then Sasan came up with the idea of developing a system capable to perform 3D printing with the extruder fixed in one position and the motion required for 3D printing will be provided by the robotic arm. The title of developing green build strategies for robot assisted plastic 3D printing came into being. The main concept behind the title of developing robot assisted plastic 3D printing platform is to develop such a system that can offer additive manufacturing services, specifically of fused deposition modeling 3D printing, as an inbound process during the manufacturing of any part through subtractive processes with the help of a robotic arm along with the repair of any kind of parts with the assistance of fused deposition modeling 3D printing. The main objectives of the master thesis include building a stationary filament extrusion module to interact with a robot hand and establishing a strategy for a robot hand to move the part to appropriate locations to complete building a part on a preform without support structures. The targets that were achieved with the completion of this thesis project includes the development of the complete hardware that consists of a mechanical structure with the option of mounting the components required to run the extrusion setup, learning the basic working of the software that are able to simulate the 3D printing process with the robotic arm (Robot Studio and Robo DK), creation of the simulation of the whole process, achieving communication between the robotic arm and the microcontroller of the extruder and finally the printing of a simple part for the demonstration. The components needed to be installed on the structure includes the motor, extruder, hot end, nozzle, filament. The structure also accumulated the required electronics that includes power supply, microcontroller, and an LCD to monitor the extrusion parameters. The developed machine runs on the state-of-the-art components that belong to the few of the best manufacturers of the technology.

3D-skrivare har många användningsområden och de har blivit vanliga i många industrier.Idag talas det om att denna teknik kan vara en möjlig väg till mer hållbart byggande.Tekniken anses lovande inom byggproduktion bland annat för att det visat sig att den kanreducera materialspillet och ge kortare byggtider. Till viss del används tekniken redan förbyggnadstillverkning, men då främst med betong.Målet med arbetet är att beskriva nuvarande kunskap rörande 3D-printing medträbaserad massa, samt att undersöka möjligheten till att använda en träbaserad massabestående av sågspån, vatten och lignin vid 3D-printing.För att kunna nå målet användes en kombination av litteratursökning och laborativaexperiment. Litteratursökningen användes både för att undersöka tidigare genomförda studiergällande träbaserade material i samband med 3D-printing, samt som inspiration för deingredienser och proportioner som används i de laborativa experimenten.Enbart studier om träbaserad 3D-printing studerades. De testobjekt som togs fram i delaborativa experimenten utvärderades i hållfasthet, dimensionsstabilitet och vidhäftning.Resultaten av det laborativa arbetet tyder på att det framtagna materialet går att extrudera,men att det har låg draghållfasthet. Lagren bands samman bra för samtliga tester, medantryckhållfastheten gav varierande resultat. Högst tryckhållfasthet gavs av den blandning somhade högst andel lignin, samt torkades under längst tid.Slutsatsen är att materialet kan vara till nytta, men att rätt användningsområde börbestämmas, då materialet inte tål alltför stora laster.
3D printers have many uses and they have become common in many industries. Today, thistechnology is seen as a possible route to more sustainable construction. The technology isconsidered promising in construction engineering, among other things because it has beenshown that it can reduce material waste and provide shorter production times. To someextent, the technology is already being used for building construction, but then mainly withconcrete.The aim of this study is to describe current knowledge regarding 3D printing with woodbasedpulp and to investigate the possibility of using a wood-based pulp consisting ofsawdust, water and lignin for 3D printing.In order to reach the goal, a combination of literature search and laboratory experiments wasused. The literature search was used both to investigate previously conducted studiesregarding wood-pulp based materials in 3D printing and as inspiration for the ingredients andproportions used in the laboratory experiments.Only studies on wood-based 3D printing were studied. The test objects produced in thelaboratory experiments were evaluated in strength, dimensional stability and adhesion. Theresults of the laboratory work indicate that the produced material can be extruded, but that ithas low tensile strength. The layers bonded well for all tests, while the compressive strengthresults varied. The highest compressive strength was given by the mixture with the highestproportion of lignin and the longest drying time.The conclusion is that the material might be useful, but that the correct area of use should bedetermined, as the material cannot withstand excessive loads.Keywords:

Fabricating and 3D printing gamepads is challenging not only in terms of appearance of them but also in terms of their physical validity and user experience that they might provide. This thesis addresses the issue of providing users the ability to hold in their hand a fabricated gamepad, which is an object similar to that the virtual character keeps in his/her hand inside the virtual world. Thus, this thesis presents a basic approach for converting 3D objects found in a variety of online datasets to functional gamepads by retargeting the structure of the gamepad’s buttons to the 3D model. The fabricated gamepads can then be used by gamers to enjoy their favorite game. The authors assumed that gamepads that have a relationship with the game enhance the game experience of users. This assumption is mainly based on a variety of previous work that investigates the use of “natural” interfaces. Therefore, in addition to the proposed approach, a two-part user study was also conducted to firstly understand whether the fabricated gamepads can be considered as valid physical objects and also to understand the way that participants experienced a game. First, the results indicated that the fabricated gamepads can be considered as valid physical objects and secondly, that they enhance the gaming experience of the users.

In this PhD project, novel polymer nanocomposites are developed with the aim to increase the performances of 3D-printed parts obtained by fused deposition modeling (FDM). The attention is focused on carbon-based nanomaterials incorporated into an acrylonitrile–butadiene–styrene (ABS) polymer by a solvent-free process. ABS-based nanocomposites were prepared by incorporating different kinds and amounts of graphene nanoplatelets (GNP), carbon nanotubes (CNT) and hybrid (GNP/CNT) systems. In order to understand the effect of the manufacturing process on the material’s properties, the samples were produced into two different processing routes: (i) melt compounding and compression molding, and (ii) melt compounding, following by filament extrusion, and fused deposition modelling (FDM). Several characterization techniques were employed in order to evaluate the flowablity, morphology, mechanical and functional properties of the materials. In the first part of work, ABS-graphene nanocomposites are described. Two ABS matrices having different viscosity were compared with the addition of various types of commercial graphene nanoplatelets (xGnP® M5, C300, C500, and C750 by XG Sciences) in the range 2-8 wt%. The better processability and higher stiffening effect on compression molded plates were achieved by utilizing the low viscosity ABS. The effects of GNPs on the thermal, electromagnetic shielding (EMI SE), electrical and mechanical behaviour of an ABS matrix were investigated. Melt flow index (MFI) values almost linearly decreased with all the type of GNP, especially with the highest surface area nanofiller (GNP-C750). Due to large size of graphene, nanocomposites filled with GNP-M5 showed the better properties of in electromagnetic interference shielding efficiency (EMI SE) and stiffness. Consequently, GNP-M5 were selected and incorporated at 4 wt% in ABS filaments used to feed a FDM machine to obtain specimens with various build orientations. The elastic modulus and dynamic storage moduli of 3D printed parts along three different build orientations were increased by the presence of GNP-M5 in the ABS matrix. At the same time, a decrease in both strength and strain at break was observed when GNP-M5 is added to ABS. Moreover, higher thermal stability was induced on 3D printed parts by GNP, as indicated by a reduction in both coefficient of linear thermal expansion and creep compliance. A comparison between 3D printed and compression molded parts highlighted the importance of the orientation effects induced by the FDM process. In the second part of work, the results of the investigation on ABS-carbon nanotubes nanocomposites are reported. ABS-CNT nanocomposites plate production by compression molding and their characterization was a preliminary step. Nanocomposite ABS/CNT filaments at 1-8 wt % were obtained by using direct melt compounding and extrusion. The optimal CNT content in the filaments for FDM was found to be 6 wt %; for this composite, a detailed investigation of the thermal, mechanical and electrical properties was performed. The presence of CNT in ABS filaments and 3D-printed parts resulted in a significant enhancement of the tensile modulus and strength, accompanied by a reduction of the elongation at break. As documented by dynamic mechanical thermal analysis, the stiffening effect of CNT in ABS is particularly pronounced at high temperatures. Besides, the presence of CNT in 3D-printed parts accounts for better creep and thermal dimensional stabilities of 3D-printed parts, accompanied by a reduction of the coefficient of thermal expansion. 3D-printed nanocomposite samples with 6 wt% of CNT exhibited a good electrical conductivity, even if lower than pristine composite filaments. In addition, the strain sensing capabilities of the conducting 3D-printed samples with 6 wt% of CNT with two different infill patterns (HC, and H45) were studied. Upon the strain applied, the resistance change and damage in the conductive FDM parts were detectable. Fatigue and creep loading on FDM products were also carried out. In last part of work, ABS-GNP-CNT hybrid nanocomposites are described. ABS nanocomposites plates with addition GNP-M5 and CNT at 2-8 wt% were compared. A significant higher reduction in MFI value by the addition of CNT compared to GNP was observed. The ABS/GNP nanocomposites showed the slightly higher stiffness and the creep stability compared to the ABS/CNT nanocomposites, but showed the lower tensile strength. Also, the ABS/CNT samples showed significant higher electrical properties in comparison to ABS/GNP. The total nanofiller content of CNT/GNP hybrid plates was fixed at 6 wt%. The hybrid nanocomposites showed a linear increase in modulus and strength as a function to CNT/M5 ratio. Moreover, conductive hybrid nanocomposite plates were obtained by the addition of CNT. The composition of 50:50 of CNT/GNP at 6 wt% was selected for FDM process due to the good compromise between processability and properties (e.g. mechanical and electrical). In agreement with electrical resistivity, EMI SE of 6 wt% ABS/CNT and 50:50 hybrid ABS nanocomposites resulted to be -46 dB and -31.7 dB for plate samples. EMI SE of FDM parts is about for -14 dB HC and H45 build orientation and –25 dB for PC build orientation printing from ABS/CNT nanocomposites, while parts had EMI SE about -12 dB for HC and H45 and -16 dB for PC from hybrid nanocomposites.

Biodegradable and bio-based polymers have raised great attention since sustainable development policies tend to become more and more important with the growing concern for the environment and the decreasing reserve of fossil fuel [1]. The increasing demand for environmentally friendly materials attracted the attention on biopolymers reinforced with cellulose, that is a virtually inexhaustible source of raw material [2] and on new manufacturing ways such as additive manufacturing (AM) [3]. The most diffused AM technology for polymers is Fused Deposition Modelling (FDM), a technique where a filament of thermoplastic polymer is extruded through a nozzle and deposited layer by layer to form the final object with the support of computer aided design. The aim of this work is the development of different kind of thermoplastic biodegradable composites based on commercially available polymers reinforced with cellulose and to study their applicability in fused deposition modeling (FDM). The final goal is the production of plastic filaments suitable to feed a commercially available FDM 3D-printing machine. Starting from microcrystalline cellulose (MCC), two different types of nanocellulose: crystalline nanocellulose (CNC) and nanofibrillated cellulose (NFC) were produced and studied to be applied as natural reinforcing fillers for selected types of biopolymers. Cellulose nanocrystals in water solution were prepared from micro-cellulose through a sulfuric acid hydrolysis while the fibrillated nanocellulose was obtained with high energy ultrasonication. The commercial grade polymer matrices selected in this research were: i. polyvinyl alcohol (PVA), a water-soluble biodegradable material; ii. poly(lactic acid) (PLA), a biodegradable polymer that comes from the fermentation of agricultural waste; iii. poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) that belongs to the family of polyhydroxyalkanoates (PHA) and it is entirely synthesized by microorganism as an intracellular storage product under particular growth conditions. Composite materials containing various amounts of cellulose fillers produced by solution or melt mixing were grinded and extruded through a single screw extruder to obtain filaments. With the aid of a desktop 3D printer, dumbbell specimens were fabricated, and their mechanical properties determined. Several characterization techniques were used in order to assess the effect of micro- and nanocellulose on the physical and thermo-mechanical behavior of these thermoplastic composites. According to SEM analysis, CNC particles appear homogeneously dispersed in PVA without noticeable aggregates. Thermal degradation of PVA was shifted towards higher temperatures with the increase of filler content, enhancing the thermal stability of the composites as compared with neat PVA. An enhancement in the storage modulus with the amount of CNC was observed in both filament and 3D printed specimens. In particular, an increase of about three times in the storage modulus at room temperature was reached in 3D samples with a CNC concentration of 10wt%. An improvement of the dimensional stability was observed with a reduction of the creep compliance with the filler content. Quasi-static tensile tests evidenced an increase of the stiffness and the strength of PVA due to the CNC introduction. A comparison between the reinforcing effect of nanocellulose and microcellulose in 3D printed samples highlighted the higher efficiency of CNC over MCC in reducing the rubber-like behavior of polyvinyl alcohol. Maleic anhydride (MAH) was employed to improve the interaction between hydrophilic microcrystalline cellulose and the PLA matrix. Infrared spectroscopy confirmed the grafting of maleic anhydride on the PLA backbone during melt mixing and SEM analysis revealed that microcellulose was well dispersed in PLA and maleic anhydride was able to enhance the interface between the two components. Thermal degradation of PLA was not affected by the presence of MAH. On the other hand, glass transition temperature, crystallization temperature and melting temperature were lowered by the increasing amount of MAH. Glass transition temperature at 10wt% of MAH decreased from 70°C to 48°C. Tensile tests highlighted that microcellulose in low concentration was able to improve the stiffness and the stress at break of 3D printed specimens. The maximum in term of stiffness and strength is reached for composite at 1wt% of MCC and at 5 wt% with the presence of MAH. NFC was dispersed in PLA by solution mixing and nanocomposites were printed and characterized. The creep compliance curves of the 3D printed samples were well fitted by a power law model and resulted that NFC was able to reduce the time-dependent linear response under constant load conditions, improving the geometrical stability. Static tensile test on plates obtained by solution casting displayed an increase in stiffness of the filament samples with increasing amount of nanocellulose. The same effect was not observed on 3D printed samples where a poor adhesion between subsequent layers was evidenced from SEM analysis upon the introduction of NCF. Lauryl functionalized nanocellulose was incorporated in PLA with solution mixing technique but the limited quantity of materials did not permit to go further with the production of filaments. Scanning electron microscopy indicated that up to a filler content of 6.5 wt. %, LNC was well dispersed. Nanocomposites with 3 and 5 wt. % of LNC showed the highest strain at break and a large amount of plastic deformation due to a strong interfacial adhesion between the PLA and filler particles while for higher LNC fractions the presence of aggregates weakened the nanocomposite. A decrease in stiffness was measured upon the introduction of LNC related to the low stiffness of the short aliphatic chains attached to the surface of the cellulose and so the formation of a soft phase between filler and the matrix as highlighted also by gas permeability tests. Finally, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) was successfully extruded and 3D printed. PHBH and NCF were mixed in solution and extruded in form of filaments used to feed a 3D printing machine. The reinforcing effect of the nanocellulose in terms of stress at break and of elongation at break showed a maximum at a content of 0.5 wt%. An increase in stiffness for filament with increasing amount of nanocellulose was measured but also in this case it was not observed in 3D printed samples. Anyway, the presence of NCF did not affect the thermal behavior of the materials.

Biodegradable and bio-based polymers have raised great attention since sustainable development policies tend to become more and more important with the growing concern for the environment and the decreasing reserve of fossil fuel [1]. The increasing demand for environmentally friendly materials attracted the attention on biopolymers reinforced with cellulose, that is a virtually inexhaustible source of raw material [2] and on new manufacturing ways such as additive manufacturing (AM) [3]. The most diffused AM technology for polymers is Fused Deposition Modelling (FDM), a technique where a filament of thermoplastic polymer is extruded through a nozzle and deposited layer by layer to form the final object with the support of computer aided design. The aim of this work is the development of different kind of thermoplastic biodegradable composites based on commercially available polymers reinforced with cellulose and to study their applicability in fused deposition modeling (FDM). The final goal is the production of plastic filaments suitable to feed a commercially available FDM 3D-printing machine. Starting from microcrystalline cellulose (MCC), two different types of nanocellulose: crystalline nanocellulose (CNC) and nanofibrillated cellulose (NFC) were produced and studied to be applied as natural reinforcing fillers for selected types of biopolymers. Cellulose nanocrystals in water solution were prepared from micro-cellulose through a sulfuric acid hydrolysis while the fibrillated nanocellulose was obtained with high energy ultrasonication. The commercial grade polymer matrices selected in this research were: i. polyvinyl alcohol (PVA), a water-soluble biodegradable material; ii. poly(lactic acid) (PLA), a biodegradable polymer that comes from the fermentation of agricultural waste; iii. poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) that belongs to the family of polyhydroxyalkanoates (PHA) and it is entirely synthesized by microorganism as an intracellular storage product under particular growth conditions. Composite materials containing various amounts of cellulose fillers produced by solution or melt mixing were grinded and extruded through a single screw extruder to obtain filaments. With the aid of a desktop 3D printer, dumbbell specimens were fabricated, and their mechanical properties determined. Several characterization techniques were used in order to assess the effect of micro- and nanocellulose on the physical and thermo-mechanical behavior of these thermoplastic composites. According to SEM analysis, CNC particles appear homogeneously dispersed in PVA without noticeable aggregates. Thermal degradation of PVA was shifted towards higher temperatures with the increase of filler content, enhancing the thermal stability of the composites as compared with neat PVA. An enhancement in the storage modulus with the amount of CNC was observed in both filament and 3D printed specimens. In particular, an increase of about three times in the storage modulus at room temperature was reached in 3D samples with a CNC concentration of 10wt%. An improvement of the dimensional stability was observed with a reduction of the creep compliance with the filler content. Quasi-static tensile tests evidenced an increase of the stiffness and the strength of PVA due to the CNC introduction. A comparison between the reinforcing effect of nanocellulose and microcellulose in 3D printed samples highlighted the higher efficiency of CNC over MCC in reducing the rubber-like behavior of polyvinyl alcohol. Maleic anhydride (MAH) was employed to improve the interaction between hydrophilic microcrystalline cellulose and the PLA matrix. Infrared spectroscopy confirmed the grafting of maleic anhydride on the PLA backbone during melt mixing and SEM analysis revealed that microcellulose was well dispersed in PLA and maleic anhydride was able to enhance the interface between the two components. Thermal degradation of PLA was not affected by the presence of MAH. On the other hand, glass transition temperature, crystallization temperature and melting temperature were lowered by the increasing amount of MAH. Glass transition temperature at 10wt% of MAH decreased from 70°C to 48°C. Tensile tests highlighted that microcellulose in low concentration was able to improve the stiffness and the stress at break of 3D printed specimens. The maximum in term of stiffness and strength is reached for composite at 1wt% of MCC and at 5 wt% with the presence of MAH. NFC was dispersed in PLA by solution mixing and nanocomposites were printed and characterized. The creep compliance curves of the 3D printed samples were well fitted by a power law model and resulted that NFC was able to reduce the time-dependent linear response under constant load conditions, improving the geometrical stability. Static tensile test on plates obtained by solution casting displayed an increase in stiffness of the filament samples with increasing amount of nanocellulose. The same effect was not observed on 3D printed samples where a poor adhesion between subsequent layers was evidenced from SEM analysis upon the introduction of NCF. Lauryl functionalized nanocellulose was incorporated in PLA with solution mixing technique but the limited quantity of materials did not permit to go further with the production of filaments. Scanning electron microscopy indicated that up to a filler content of 6.5 wt. %, LNC was well dispersed. Nanocomposites with 3 and 5 wt. % of LNC showed the highest strain at break and a large amount of plastic deformation due to a strong interfacial adhesion between the PLA and filler particles while for higher LNC fractions the presence of aggregates weakened the nanocomposite. A decrease in stiffness was measured upon the introduction of LNC related to the low stiffness of the short aliphatic chains attached to the surface of the cellulose and so the formation of a soft phase between filler and the matrix as highlighted also by gas permeability tests. Finally, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) was successfully extruded and 3D printed. PHBH and NCF were mixed in solution and extruded in form of filaments used to feed a 3D printing machine. The reinforcing effect of the nanocellulose in terms of stress at break and of elongation at break showed a maximum at a content of 0.5 wt%. An increase in stiffness for filament with increasing amount of nanocellulose was measured but also in this case it was not observed in 3D printed samples. Anyway, the presence of NCF did not affect the thermal behavior of the materials.

CAD / CAM techniques applied to solving dental problems demonstrate that there are many solutions available on the market to help the dentist individually perform the rehabilitation of a dental element to meet the specific needs of each patient. These manufacturing technologies close a digital workflow, potentially managed entirely by the dentist, which involves taking the impression of the oral cavity and the dental elements present through an intraoral scanner with the generation of a file on which to create the CAD project and to start extrapolating the file of the final work to be produced by subtractive or additive CAM. The 3D printing techniques allow to work easily with polymeric and ceramic materials, in order to create dental crowns that can satisfy practically all the needs encountered in the dental field. Leaving aside the techniques applied to polymers, this PhD project focuses on the applications of ceramic materials. This PhD thesis focuses on the design, study and implementation of 3D printing of ceramic supports specifically dedicated to the stabilization of dental implants. Through the development of a prototype of a 3D printer, it was possible to obtain the printing of ceramic products useful for the intended purpose.

With burgeoning world demand and a limited rate of discovery of new reserves, there is increasing impetus upon the industry to optimize recovery from already existing fields. 4D, or time-lapse, seismic imaging is an emerging technology that holds great promise to better monitor and optimise reservoir production. The basic idea behind 4D seismic is that when multiple 3D surveys are acquired at separate calendar times over a producing field, the reservoir geology will not change from survey to survey but the state of the reservoir fluids will change. Thus, taking the difference between two 3D surveys should remove the static geologic contribution to the data and isolate the timevarying fluid flow component. However, a major challenge in 4D seismic is that acquisition and processing differences between 3D surveys often overshadow the changes caused by fluid flow. This problem is compounded when 4D effects are sought to be derived from vintage 3D data sets that were not originally acquired with 4D in mind. The goal of this study is to remove the acquisition and imaging artefacts from a 4D seismic difference cube using Curvelet processing techniques.