Dissertations / Theses on the topic 'Filament manufacturing'

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.

An obstacle to the wide spread use of additive manufacturing (AM) is the difficulty in estimating the effects of process parameters on the mechanical properties of the manufactured part. The complex relationship between the geometry, parameters and mechanical properties makes it impractical to derive an analytical relationship and calls for the use of a numerical model. An approach to formulate a numerical model in developed in this thesis. The AM technique focused in this thesis is fused filament fabrication (FFF). A numerical model is developed by recreating FFF build process in a simulation environment. Machine instructions generated by a slicer to build a part is used to create a numerical model. The model acts as a basis to determine the effects of process parameters on the stiffness and the strength of a part. Determining the stiffness of the part is done by calculating the response of the model to a uniformly distributed load. The strength of the part depends on it's thermal history. The developed numerical model serves as a basis to implement models describing the relation between thermal history and strength. The developed model is suited to optimize FFF parameters as it encompass effects of all FFF parameters. A genetic algorithm is used to optimize the FFF parameters for minimum weight with a minimum stiffness constraint.
Ett hinder för att additiv tillverkning (AT), eller ”3D-printing”, ska få ett bredare genomslag är svårigheten att uppskatta effekterna av processparametrar på den tillverkade produktens mekaniska prestanda. Det komplexa förhållandet mellan geometri och processparametrar gör det opraktiskt och komplicerat att härleda analytiska uttryck för att förutsäga de mekaniska egenskaperna. Alternativet är att istället använda numeriska modeller. Huvudsyftet med denna avhandling har därför varit att utveckla en numerisk modell som kan användas för att förutsäga de mekaniska egenskaperna för detaljer tillverkade genom AT. AT-tekniken som avses är inriktad på Fused Filament Fabrication (FFF). En numerisk modell har utvecklats genom att återskapa FFF-byggprocessen i en simuleringsmiljö. Instruktioner (skriven i GCode) som används för att bygga en detalj genom FFF har här översatts till en numerisk FE-modell. Modellen används sen för att bestämma effekterna av processparametrar på styvheten och styrkan hos den tillverkade detaljen. I detta arbete har strukturstyvheten hos olika detaljer beräknats genom att utvärdera modellens svar för jämnt fördelade belastningsfall. Styrkan, vilket är starkt beroende på den tillverkade detaljens termiska historia, har inte utvärderats. Den utvecklade numeriska modellen kan dock fungera som underlag för implementering av modeller som beskriver relationen mellan termisk historia och styrka. Den utvecklade modellen är anpassad för optimering av FFF-parametrar då den omfattar effekterna av alla FFF-parametrar. En genetisk algoritm har använts i detta arbete för att optimera parametrarna med avseende på vikt för en given strukturstyvhet.

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

One of the major limitations in Fused Filament Fabrication (FFF), a form of additive manufacturing, is the lack of composites with superior mechanical properties. Traditionally, carbon and glass fibers are widely used to improve the physical properties of polymeric matrices. However, the blending methods lead to fiber breakage, preventing generation of long fiber reinforced filaments essential for printing load-bearing components. Our approach to improve tensile properties of the printed parts was to use in-situ composites to avoid fiber breakage during filament generation. In the filaments generated, we used thermotropic liquid crystalline polymers (TLCPs) to reinforce acrylonitrile butadiene styrene (ABS) and a high performance thermoplastic, polyphenylene sulfide (PPS). The TLCPs are composed of rod-like monomers which are highly aligned under extensional kinematics imparting excellent one-dimensional tensile properties. The tensile strength and modulus of the 40 wt.% TLCP/ABS filaments was improved by 7 and 20 times, respectively. On the other hand, the 67 wt.% TLCP/PPS filament tensile strength and modulus were improved by 2 and 12 times, respectively. The filaments were generated using dual extrusion technology to produce nearly continuously reinforced filaments and to avoid matrix degradation. Rheological tests were taken advantage of to determine the processing conditions. Dual extrusion technology allowed plasticating the matrix and the reinforcing polymer separately in different extruders. Then continuous streams of TLCP were injected below the TLCP melting temperature into the matrix polymer to avoid matrix degradation. The blend was then passed through a series of static mixers, subdividing the layers into finer streams, eventually leading to nearly continuous fibrils which were an order of magnitude lower in diameter than those of the carbon and glass fibers. The composite filaments were printed below the melting temperature of the TLCPs, and the conditions were determined to avoid the relaxation of the order in the TLCPs. On printing, a matrix-like printing performance was obtained, such that the printer was able to take sharp turns in comparison with the traditionally used fibers. Moreover, the filaments led to a significant improvement in the tensile properties on using in FFF and other conventional technologies such as injection and compression molding.
Doctor of Philosophy

La fabrication additive (FA) fait référence à une grande variété de procédés de fabrication pour le prototypage rapide et la production de produits finis et semi-finis. Contrairement aux procédés classiques ou soustractifs, en fabrication additive, le matériau est ajouté progressivement couche par couche pour former les pièces. La fabrication additive permet la fabrication de pièces complexes impossibles ou peu rentables à fabriquer avec les procédés traditionnels. Le procédé FFF (Fused Filament Fabrication) est basé sur la fusion d'un filament polymère ; le filament est ensuite déposé couche par couche pour fabriquer les pièces finales. Malgré l'intérêt croissant des industries et du grand public ces dernières années, ces procédés de fabrication ne sont toujours pas bien maîtrisés, en particulier pour les polymères qui ne sont pas de grande consommation. Dans cette thèse, nous allons nous intéresser à l’imprimabilité du PEEK (Polyétheréthercétone).Dans un premier temps, nous avons déterminé les propriétés du polymère influençant la qualité des pièces imprimées par FFF. Les propriétés rhéologiques, la tension superficielle, la conductivité thermique et la dilatation thermique ont été déterminées expérimentalement. Ensuite,le phénomène de coalescence des filaments polymères a été étudié par des mesures expérimentales, un modèle analytique et par simulation numérique. De plus, la stabilité du filament et ses propriétés d’écoulement lorsqu’il sort de l’extrudeuse dans le procédé FFF ont été déterminées expérimentalement puis par analytique et simulation numérique. Ensuite, nous nous sommes concentrés sur la détermination du gonflement des filaments de PEEK. Enfin, la cinétique de la cristallisation isotherme et non isotherme du PEEK a été étudiée expérimentalement. La cinétique de cristallisation a été appliquée au procédé FFF par simulation numérique afin de déterminer la température d’environnement optimale pour contrôler la cristallisation des pièces imprimées. La cristallisation du PEEK atteint sa valeur maximale (environ 22%) de cristallisation pendant le dépôt. En outre, la cristallisation libère de la chaleur dans le système
Additive manufacturing (AM) refers to a wide variety of manufacturing processes for rapid prototyping and production of final and semi-final products. In opposite to conventional orsubtractive processes, in additive manufacturing, the material is gradually added layer by layer to form the parts. AM enables the fabrication of complex parts which were impossible or not costeffective to manufacture with the traditional processes. Fused Filament Fabrication (FFF) is basedon the melting of a polymeric filament in an extruder; the filament is then deposited layer by layerto manufacture the final parts. Despite growing interest from industries and a large audience inrecent years, these manufacturing processes are still not well mastered, especially for not mass produced polymers. In this thesis, we will take an insight into the printability of PEEK(Polyetheretherketone). The aim is to find the printing conditions to obtain the best quality of theprinted parts by FFF process. In the first step, we have determined the polymer properties influencing the quality of the printed parts by FFF. The rheological properties, the surface tension,the thermal conductivity and thermal expansion have been determined experimentally. Then, thecoalescence phenomenon of the polymeric filaments has been studied by experimental, analyticaland numerical simulation. Furthermore, the stability of the filament and its flow properties when itexits from the extruder in the FFF process has been determined by experimental, analytical andnumerical simulation. Then, we have focused on the determination of the die swelling of PEEKextrudate. Lastly, the kinetics of isothermal and non-isothermal crystallization of PEEK has beenstudied by experimental study. The kinetics of crystallization has been applied to FFF process bynumerical simulation in order to determine the optimum environment temperature to control thecrystallization of printed parts. The crystallization of PEEK reaches its maximum value (about22%) of crystallization during the deposition

Consumer additive manufacturing (3D printing) has rapidly grown over the last decade. While the technology for the most common type, Fused Filament Fabrication (FFF), has systematically improved and sales have increased, fundamentally, the capabilities of the machines have remained the same. FFF printers are still limited to depositing layers onto a flat build plate. This makes it difficult to combine consumer AM with other objects. While consumer AM promises to allow us to customize our world, the reality has fallen short. The ability to directly modify existing objects presents numerous possibilities to the consumer: personalization, adding functionality, improving functionality, repair, and novel multi-material manufacturing processes. Indeed, similar goals for industrial manufacturing drove the research and development of technologies like direct write and directed energy deposition which can deposit layers onto uneven surfaces. Replicating these capabilities on consumer 3-axis FFF machines is difficult mainly due to issues with reliability, repeatability, and quality. This thesis proposes, demonstrates, and tests a method for scanning and printing dimensionally-accurate (unwarped) digital forms onto physical objects using a modified consumer-grade 3D printer. It then provides an analysis of the machine design considerations and critical process parameters.
Master of Science

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.

Advanced composites are extremely strong, rigid, and light, even when compared with advanced metals. Advanced composites are replacing high-tech metals as the material of choice for aerospace engineering. However, the processes used to manufacture advanced composites generally lose some of the properties of the materials by their process limitations. One process that keeps the theoretically awesome qualities of the composite materials in tact is filament winding. Filament wound parts are used as rocket shells, bicycle frame tubes, drive shafts, pressure vessels, etc. Filament winding is an automated process and makes reliable parts to close tolerances. If a straight tube were to be made by all the existing composites manufacturing processes, filament wound tubes would be significantly better than any other. However, filament winding is generally limited to making straight tubes. A new process based on filament winding is proposed; one that can wind complex shapes of the same high quality as conventional filament winding. This process has achieved this by winding continuous, uncut, and aligned fibers. This process is called Lotus Filament Winding.

In this bachelor thesis, I examine how automation of fused filament fabrication (FFF) can be implemented, and what the limitations are for different kinds of automation solutions for FFF. Fused filament fabrication is a 3D-printing technology where a material is extruded through a nozzle, layer by layer, to create a print. The thesis also provides a calculation for the commercial feasibility of small batch rapid production with the implementation of an automation solution for FFF. The approach was a qualitative study containing five interviews, combined with empirical knowledge and data from the additive manufacturing company Svensson 3D. This was complemented with an analysis of which criteria to use when evaluating FFF automation solutions, and a framework for looking at FFF from an operator perspective. To calculate commercial feasibility of automation solutions for FFF, Internal Rate of Return and Payback Time were used. This resulted in six criteria to evaluate solutions for automation of FFF, three evaluations of problems within three solutions for automation of FFF, and a finding showing that small batch rapid production is commercially feasible with automated FFF. Lastly, the thesis contains a discussion regarding what the future is for FFF, and the limitations of the framework presented for evaluating automated FFF systems. Possible promising solutions for automated FFF are presented, together with ideas for how design for additive manufacturing can help shape the future of automated FFF.
I det här kandidatarbetet undersöker jag hur automatisering inom fused filament fabrication (FFF) kan implementeras, och vad begränsningarna är för olika sorters automatiseringslösningar för FFF. Det läggs även fram en uträkning för den kommersiella gångbarheten för small batch rapid production med implementeringen av ett automatiskt FFF-system. Tillvägagångsättet bestod av en kvalitativ studie baserad på fem intervjuer, kombinerad med empirisk kunskap och data från additiva tillverkningsföretaget Svensson 3D. Det här kompletterades med en analys av vilka parametrar som bör användas för att utvärdera lösningar för FFF-automatisering, och ett ramverk där automatiseringslösningarna betraktas ur ett operatörs-perspektiv. För att räkna ut den kommersiella gångbarheten för automatiseringslösningar av FFF användes internränta och återbetalningstid. Det här resulterade i sex parametrar för att utvärdera automatiseringslösningar för FFF, tre utvärderingar av vilka problem som finns i tre existerande automatiseringslösningar, och slutsatsen att small batch rapid production är kommersiellt gångbart för automatiserad FFF. Slutligen innehåller arbetet en diskussion gällande framtiden för FFF och begränsningarna hos det ramverk som presenterades för att utvärdera automatiserade FFF system. Möjliga lovande lösningar för automatiserad FFF presenteras och hur design för additiv tillverkning kan hjälpa till att forma framtiden för automatiserad FFF.

L’attività descritta nel presente elaborato è relativa alla prima fase di sviluppo di un innovativo sistema di caricamento automatico del filamento per una stampante 3D, prodotto da un’azienda che opera nel settore. In particolare, la progettazione meccanica qui illustrata è stata affrontata partendo dal progetto concettuale del nuovo dispositivo, per concludersi con il progetto costruttivo e il dimensionamento dei singoli componenti. In primo luogo, è stata effettuata un’analisi funzionale del problema, analizzando sistematicamente le specifiche tecniche richieste ed i vincoli di progetto dettati dall’azienda. Scomposto il problema in tal modo, sono state proposte ed analizzate soluzioni concettuali alternative, valutandone comparativamente punti di forza e criticità. Una volta individuata la soluzione ritenuta più vantaggiosa, si sono dimensionati opportunamente i componenti commerciali (e scelti a catalogo) e progettati quelli da realizzare ad hoc (con processo di produzione in additive manufacturing, secondo le richieste dell’azienda). L’elaborato è parte integrante di un progetto che prevede le successive fasi di prototipazione e programmazione del controller del sistema di caricamento automatico del filamento.

Fra le tecnologie additive, la Fused Filament Fabrication è fra le più diffuse per quanto riguarda l'utilizzo di materiali polimerici. Tuttavia, il semilavorato di partenza, ovvero un filamento, impone numerosi vincoli per quanto riguarda la scelta del materiale e costi di acquisto elevati. Un tentativo di superare questo limite è l'utilizzo della Fused Granulate Fabrication, ovvero una tecnologia di stampa che utilizza come materiale di partenza il materiale polimerico allo stato granulare, il che rende possibile l'utilizzo di molteplici materiali anche di riciclo, oltre ad abbassare notevolmente il costo d'acquisto. Per questi motivi WASP S.r.l ha implementato sulla sua macchina 3MT un estrusore FGF. Lo scopo di questo lavoro di tesi è quello di aumentare la produttività e l'efficienza del processo tramite la riprogettazione di un elemento centrale nell'estrusore: la vite plastificatrice. Per ottenere tale risultato si è inizialmente svolta un'analisi dello stato dell'arte di processi industriali analoghi, fra i quali è stato scelto il processo di estrusione di polimeri in impianti industriali come caso più analogo, dal quale sono stati presi i criteri di design poi utilizzati In seguito si è sviluppato un modello matematico che fosse in grado di prevedere la quantità di materiale estruso dalla vite a seconda della velocità di rotazione imposta. Allo stesso tempo si è progettata e fabbricata la nuova vite plastificatrice, che è stata poi montata sull'estrusore. Per verificare di aver ottenuto un miglioramento nella produttività e efficienza, si sono eseguite delle prove sperimentali utilizzando come confronto altre due viti plastificatrici di diverso design, precedentemente utilizzate sulla macchina 3MT. Per eseguire queste misure con sufficiente precisione si è programmato e costruito un sistema di misura automatico basato su una scheda di controllo Arduino. Per concludere il lavoro i dati raccolti sono stati analizzati e elaborati

La fabrication additive est un procédé d’élaboration permettant la mise en forme d’une pièce par ajout de matière, par empilement de couches successives. Bien que de plus en plus de polymères puissent être mis en œuvre par cette technologie, les polymères chargés en sont quasiment absents, alors qu’ils sont largement utilisés dans les autres types de procédés de mise en forme. Les objectifs scientifiques et technologiques du projet concernent (i) une meilleure compréhension des relations entre le comportement rhéologique de systèmes polymères et leur aptitude à la mise en forme par les technologies de fabrication additive FDM, (ii) le développement de formulations de base de polymères bio-sourcés adaptées à ces technologies et apportant une multifonctionnalité. Le premier objectif nécessitera tout d’abord d’identifier les conditions (température, gradients de vitesse, nature des contraintes, …) imposées par les procédés considérés puis de mettre en place et/ou d’adapter les moyens de caractérisation du comportement rhéologique des systèmes polymères dans ces conditions. Le comportement rhéologique en cisaillement mais aussi en élongation pourra être considéré. Il conviendra en particulier d’identifier les compromis nécessaires entre comportement adapté à l’écoulement en filière ou en buse et aptitude à la fusion et à la consolidation couche par couche. Enfin, l’effet des différentes voies de fonctionnalisation envisagées sur le comportement rhéologique et thermique et donc sur l’aptitude à la mise en forme devra être analysé. De façon à adapter les polymères bio-sourcés à un large panel d’applications, diverses voies de fonctionnalisation seront considérées, basées sur le compoundage avec des charges particulaires
Additive manufacturing process is a preparation for the forming of a workpiece by the addition of material, by stacking successive layers. Although more and more polymers can be implemented by this technology, the filled polymers are practically absent, so they are widely used in other types of shaping methods. The scientific and technological objectives of the project are (i) a better understanding of the relationship between the rheological behavior of polymer systems and their ability to shaping by additive manufacturing technologies FDM, (ii) the development of polymer-based formulations biosourced adapted to these technologies and providing multifunctionality. The first goal will require first of all to identify the conditions (temperature, velocity gradients, nature constraints ...) imposed by the processes considered then to implement and / or adapt the means of characterization of the rheological behavior of polymer systems under these conditions. The rheological behavior in shear but also in elongation may be considered. It should in particular identify the necessary compromise between behavior adapted to the flow at the die or nozzle and meltability and consolidation layer by layer. Finally, the effect of different ways of functionalization considered on the rheological and thermal behavior and thus on the ability to formatting will be analyzed. In order to adapt the bio-sourced polymers for a wide range of applications, various routes of functionalization will be considered based on compounding with particulate fillers

This research is based upon the additive manufacturing (AM) technology which aims to study the mechanical properties of innovative commercial wood-PLA composite material (Timberfill) and characterize its behavior. Specifically fatigue, tensile, and flexural tests are performed and the results are evaluated to conclude this issue. To manufacture the experimental samples one of the most common techniques named fused filament fabrication (FFF) is applied, consequently the influence of manufacturing parameters on the mechanical properties have been considered. For this reason some of the most influential printing parameters in different levels are selected and have been combined together to manufacture the samples in a wide range of building conditions. To avoid manufacturing a large number of specimens, a design of experiments (DoE) through Taguchi orthogonal arrays is designed and the influence of the factors have been analyzed performing an analysis of variance (ANOVA). As a conclusion the optimal combination of the parameters and levels have been obtained for each one of the applied mechanical tests and higher values of responses have been derived from these set of parameters. Since the above mentioned material is composite of wood fibers with PLA, all of the obtained results are compared to the pure PLA to find the effectiveness of this composition. In the other side tensile and flexural tests have been applied on solid Timberfill specimens manufactured through injection molding to investigate the differences between this technology and additive manufacturing. These investigations resulted that mechanical resistances of the printed samples were lower than injected ones which the solidity percentage could be main reason of this effect. Additionally the flexural strength of the material have been simulated and compare to the experimental results. The achieved deformation behavior curves validate the experimental test and that would be one of the main conclusions of this research.
Esta investigación se basa en la tecnología de fabricación aditiva (AM) y tiene como objetivo estudiar las propiedades mecánicas y caracterizar el comportamiento de un material comercial innovador, compuesto de PLA con fibras de madera (Timberfill). Específicamente, se realizan pruebas de fatiga, tracción y flexión y se evalúan los resultados para concluir sobre los mismos. Para fabricar las muestras experimentales se aplica una de las técnicas más comunes llamadas fabricación de filamentos fundidos (FFF), y se ha considerado la influencia de los parámetros de fabricación en las propiedades mecánicas de las mismas. Por esta razón, se han seleccionado algunos de los parámetros de impresión más influyentes en diferentes niveles y se han combinado para fabricar las muestras en una amplia gama de condiciones de construcción. Para evitar la fabricación de una gran cantidad de muestras, se ha utilizado un diseño de experimentos (DoE) a través de matrices ortogonales de Taguchi y se ha analizado la influencia de los factores realizando un análisis de varianza (ANOVA). Como conclusión, se ha obtenido la combinación óptima de los parámetros y niveles para cada una de las pruebas mecánicas realizadas y se han detectado los valores más altos de respuestas de éstos. Dado que el material mencionado anteriormente es un compuesto de PLA con fibras de madera, todos los resultados obtenidos se comparan con el PLA puro para encontrar la efectividad de esta composición. Por otro lado, se han realizado también pruebas de tracción y flexión a muestras sólidas de Timberfill fabricadas mediante moldeo por inyección para investigar las diferencias entre esta tecnología y la fabricación aditiva. Los resultados muestran que la resistencia mecánica de las muestras impresas es más bajas que las inyectadas, por lo que el porcentaje de solidez podría ser la razón principal de este efecto. Además, la resistencia a la flexión del material se ha simulado y comparado con los resultados experimentales. Las curvas de comportamiento de deformación logradas validan la prueba experimental lo cual es una de las principales conclusiones de esta investigación.
Aquesta investigació es basa en la tecnologia de fabricació additiva (AM) i té com a objectiu estudiar les propietats mecàniques i caracteritzar el comportament d'un material comercial innovador, format de PLA amb fibres de fusta (Timberfill). Específicament, es realitzen proves de fatiga, tracció i flexió i s'avaluen els resultats per concloure sobre els mateixos. Per fabricar les mostres experimentals s'aplica una de les tècniques més comunes anomenada fabricació de filaments fosos (FFF), i s'ha considerat la influència dels paràmetres de fabricació en les propietats mecàniques de les mateixes. Per aquesta raó, s'han seleccionat alguns dels paràmetres d'impressió més influents en diferents nivells i s'han combinat per fabricar les mostres en una àmplia gamma de condicions de construcció. Per evitar la fabricació d'una gran quantitat de mostres, s'ha utilitzat un disseny d'experiments (DoE) a través de matrius ortogonals de Taguchi i s'ha analitzat la influència dels factors realitzant una anàlisi de variància (ANOVA). Com a conclusió, s'ha obtingut la combinació òptima dels paràmetres i nivells per a cadascuna de les proves mecàniques realitzades i s'han detectat els valors més alts de respostes d'aquests. Atès que el material esmentat anteriorment és un compost de PLA amb fibres de fusta, tots els resultats obtinguts es comparen amb el PLA pur per trobar l'efectivitat d'aquesta composició. D'altra banda, s'han realitzat també proves de tracció i flexió a mostres sòlides de Timberfill fabricades mitjançant el procediment d’injecció per investigar les diferències entre aquesta tecnologia i la fabricació additiva. Els resultats mostren que la resistència mecànica de les mostres impreses és més baixes que les injectades, de manera que el percentatge de solidesa podria ser la raó principal d'aquest efecte. A més, la resistència a la flexió del material s'ha simulat i comparat amb els resultats experimentals. Les corbes de comportament de deformació assolides validen la prova experimental la qual cosa és una de les principals conclusions d'aquesta investigació.

In this thesis, the incorporation of drug loaded mesoporous magnesium carbonate as an excipient for the additive manufacturing of oral tablets by fused deposition modeling was investigated. Cinnarizine, a BCS class II drug, was loaded into the pores of the mesoporous material via a soaking method, corresponding to a drug loading of 8.68 wt%. DSC measurements on the loaded material suggested that the drug was partially crystallized after incorporation, meanwhile the XRD diffractogram implied that the drug was in a state lacking long range order. The drug loaded material was combined with two pharmaceutical polymers, Aquasolve LG and Klucel ELF, and extruded into filaments with a single screw extruder. Filaments of Klucel ELF and drug loaded Upsalite (30:70 wt% ratio) were successfully implemented for the printing oral tablets, in contrast to the Aquasolve LG based filaments which were difficult to print due to thickness variations and non-uniform material distributions. The drug content obtained by TGA suggested drug loadings of 7.71 wt% and 2.23 wt% in the drug loaded Upsalite and tablets respectively. Dissolution studies using an USP II apparatus showed a slower API-release from the tablets in comparison to the crystalline drug, most probably due to slow diffusion of drug species through the polymeric matrix. For future studies, pharmaceutical polymers with higher aqueous solubility should be investigated in order to thoroughly examine the potential of utilizing the immediate release property of Upsalite.

Scopo dell'elaborato è stato la produzione di un materiale bio-composito formato da PLA ed un rinforzo di origine naturale derivante dal settore agricolo, nell'ottica di diminuire i costi dei manufatti costituiti da tale materiale, riducendo il contenuto di PLA, e rivalorizzare lo scarto di farine in applicazioni di stampa 3D. Inizialmente le farine sono state studiate mediante analisi spettroscopiche (FT-ATR), osservazioni al microscopio ottico e analisi TGA. Dopodiché sono stati prodotti filamenti per stampa 3D di materiale composito al 10% e caratterizzati termicamente (DSC, TGA, Cp) e meccanicamente (DMA). Successivamente alla stampa 3D di questi filamenti, sono stati analizzati comportamenti termici (CTE, DSC) e meccanici (prove di trazione, DMA) dei provini stampati. Si è infine valutata l'influenza del trattamento termico di ricottura sui provini stampati mediante analisi DSC e DMA.

3D printing applications have achieved increased success as an additive manufacturing (AM) process. Micro-structure of mechanical/biological materials present design challenges owing to the resolution of 3D printers and material properties/composition. Biological materials are complex in structure and composition. Efforts have been made by 3D printer manufacturers to provide materials with varying physical, mechanical and chemical properties, to handle simple to complex applications. As 3D printing is finding more medical applications, we expect future uses in areas such as hip replacement - where smoothness of the femoral head is important to reduce friction that can cause a lot of pain to a patient. The issue of print resolution plays a vital role due to staircase effect. In some practical applications where 3D printing is intended to produce replacement parts with joints with movable parts, low resolution printing results in fused joints when the joint clearance is intended to be very small. Various 3D printers are capable of print resolutions of up to 600dpi (dots per inch) as quoted in their datasheets. Although the above quoted level of detail can satisfy the micro-structure needs of a large set of biological/mechanical models under investigation, it is important to include the ability of a 3D slicing application to check that the printer can properly produce the feature with the smallest detail in a model. A way to perform this check would be the physical measurement of printed parts and comparison to expected results. Our work includes a method for using ray casting to detect features in the 3D CAD models whose sizes are below the minimum allowed by the printer resolution. The resolution validation method is tested using a few simple and complex 3D models. Our proposed method serves two purposes: (a) to assist CAD model designers in developing models whose printability is assured. This is achieved by warning or preventing the designer when they are about to perform shape operations that will lead to regions/features with sizes lower than that of the printer resolution; (b) to validate slicing outputs before generation of G-Codes to identify regions/features with sizes lower than the printer resolution.

La present tesi doctoral s’ha centrat en el repte d’aconseguir, mitjançant Fabricació Additiva (FA), models per a assaig quirúrgic, sota la premissa que els equips per fer-los haurien de ser accessibles a l’àmbit hospitalari. L’objectiu és facilitar l’extensió de l’ús dels prototips com a eina de preparació d’operacions quirúrgiques, transformant la pràctica mèdica actual de la mateixa manera que en el seu moment ho van fer tecnologies com les que van facilitar l’ús de radiografies. El motiu d’utilitzar FA, en lloc de tecnologies més tradicionals, és la seva capacitat de materialitzar de forma directa les dades digitals obtingudes de l’anatomia del pacient mitjançant sistemes d’escanejat tridimensional, fent possible l’obtenció de models personalitzats. Els resultats es centren en la generació de nou coneixement sobre com aconseguir equipaments d’impressió 3D multimaterials accessibles que permetin l’obtenció de models mimètics respecte als teixits vius. Per facilitar aquesta buscada extensió de la tecnologia, s’ha focalitzat en les tecnologies de codi obert com la Fabricació per Filament Fos (FFF) i similars basades en líquids catalitzables. La recerca s’alinea dins l’activitat de desenvolupament de la FA al CIM UPC, i en aquest àmbit concret amb la col·laboració amb l’Hospital Sant Joan de Déu de Barcelona (HSJD). El primer bloc de la tesi inclou la descripció de l’estat de l’art, detallant les tecnologies existents i la seva aplicació a l’entorn mèdic. S’han establert per primer cop unes bases de caracterització dels teixits vius -sobretot tous- per donar suport a la selecció de materials que els puguin mimetitzar en un procés de FA, a efectes de millorar l’experiència d’assaig dels cirurgians. El caràcter rígid dels materials majoritàriament usats en impressió 3D els fa poc útils per simular tumors i altres referències anatòmiques. De forma successiva, es tracten paràmetres com la densitat, la viscoelasticitat, la caracterització dels materials tous a la indústria, l’estudi del mòdul elàstic de teixits tous i vasos, la duresa d’aquests, i requeriments com l’esterilització dels models. El segon bloc comença explorant la impressió 3D mitjançant FFF. Es classifiquen les variants del procés des del punt de vista de la multimaterialitat, essencial per fer models d’assaig quirúrgic, diferenciant entre solucions multibroquet i de barreja al capçal. S’ha inclòs l’estudi de materials (filaments i líquids) que serien més útils per mimetitzar teixits tous. Es constata com en els líquids, en comparació amb els filaments, la complexitat del treball en processos de FA és més elevada, i es determinen formes d’imprimir materials molt tous. Per acabar, s’exposen sis casos reals de col·laboració amb l’HJSD, una selecció d’aquells en els que el doctorand ha intervingut en els darrers anys. L’origen es troba en la dificultat de l’abordatge d’operacions de resecció de tumors infantils com el neuroblastoma, i a la iniciativa del Dr. Lucas Krauel. Finalment, el Bloc 3 té per objecte explorar nombrosos conceptes (fins a 8), activitat completada al llarg dels darrers cinc anys amb el suport dels mitjans del CIM UPC i de l’activitat associada a treballs finals d’estudis d’estudiants de la UPC, arribant-se a materialitzar equipaments experimentals per validar-los. La recerca ampla i sistemàtica al respecte fa que s’estigui més a prop de disposar d’una solució d’impressió 3D multimaterial de sobretaula. Es determina que la millor via de progrés és la de disposar d’una pluralitat de capçals independents a fi de capacitar la impressora 3D per integrar diversos conceptes estudiats, materialitzant-se una possible solució. Cloent la tesi, es planteja com seria un equipament d’impressió 3D per a models d’assaig quirúrgic, a fi de servir de base per a futurs desenvolupaments.
La presente tesis doctoral se ha centrado en el reto de conseguir, mediante Fabricación Aditiva (FA), modelos para ensayo quirúrgico, bajo la premisa que los equipos para obtenerlos tendrían que ser accesibles al ámbito hospitalario. El objetivo es facilitar la extensión del uso de modelos como herramienta de preparación de operaciones quirúrgicas, transformando la práctica médica actual de la misma manera que, en su momento, lo hicieron tecnologías como las que facilitaron el uso de radiografías. El motivo de utilizar FA, en lugar de tecnologías más tradicionales, es su capacidad de materializar de forma directa los datos digitales obtenidos de la anatomía del paciente mediante sistemas de escaneado tridimensional, haciendo posible la obtención de modelos personalizados. Los resultados se centran en la generación de nuevo conocimiento para conseguir equipamientos de impresión 3D multimateriales accesibles que permitan la obtención de modelos miméticos respecto a los tejidos vivos. Para facilitar la buscada extensión de la tecnología, se ha focalizado en las tecnologías de código abierto como la Fabricación por Hilo Fundido (FFF) y similares basadas en líquidos catalizables. Esta investigación se alinea dentro de la actividad de desarrollo de la FA en el CIM UPC, y en este ámbito concreto con la colaboración con el Hospital Sant Joan de Déu de Barcelona (HSJD). El primer bloque de la tesis incluye la descripción del estado del arte, detallando las tecnologías existentes y su aplicación al entorno médico. Se han establecido por primera vez unas bases de caracterización de los tejidos vivos – principalmente blandos – para dar apoyo a la selección de materiales que los puedan mimetizar en un proceso de FA, a efectos de mejorar la experiencia de ensayo de los cirujanos. El carácter rígido de los materiales mayoritariamente usados en impresión 3D los hace poco útiles para simular tumores y otras referencias anatómicas. De forma sucesiva, se tratan parámetros como la densidad, la viscoelasticidad, la caracterización de materiales blandos en la industria, el estudio del módulo elástico de tejidos blandos y vasos, la dureza de los mismos, y requerimientos como la esterilización de los modelos. El segundo bloque empieza explorando la impresión 3D mediante FFF. Se clasifican las variantes del proceso desde el punto de vista de la multimaterialidad, esencial para hacer modelos de ensayo quirúrgico, diferenciando entre soluciones multiboquilla y de mezcla en el cabezal. Se ha incluido el estudio de materiales (filamentos y líquidos) que serían más útiles para mimetizar tejidos blandos. Se constata como en los líquidos, en comparación con los filamentos, la complejidad del trabajo en procesos de FA es más elevada, y se determinan formas de imprimir materiales muy blandos. Para acabar, se exponen seis casos reales de colaboración con el HJSD, una selección de aquellos en los que el doctorando ha intervenido en los últimos años. El origen se encuentra en la dificultad del abordaje de operaciones de resección de tumores infantiles como el neuroblastoma, y en la iniciativa del Dr. Lucas Krauel. Finalmente, el Bloque 3 desarrolla numerosos conceptos (hasta 8), actividad completada a lo largo de los últimos cinco años con el apoyo de los medios del CIM UPC y de la actividad asociada a trabajos finales de estudios de estudiantes de la UPC, llegándose a materializar equipamientos experimentales para validarlos. La investigación amplia y sistemática al respecto hace que se esté más cerca de disponer de una solución de impresión 3D multimaterial de sobremesa. Se determina que la mejor vía de progreso es la de disponer de una pluralidad de cabezales independientes, a fin de capacitar la impresora 3D para integrar diversos conceptos estudiados, materializándose una posible solución. Para cerrar la tesis, se plantea cómo sería un equipamiento de impresión 3D para modelos de ensayo quirúrgico, a fin de servir de base para futuros desarrollos.

碩士
明志科技大學
機械工程系機械與機電工程碩士班
107
With the development of industry, the requirements on product molds with complex shapes have been much improved in recent years, and using conformal cooling channels (CCCs) to improve cooling efficiency is a common technique. In order to quickly manufacture rapid tooling of CCCs, this study employed rapid tooling technology to develop wax filaments with a low melting point and adopted fused deposition modeling technology to produce wax CCCs that can easily be removed. It also discussed the suitable process parameters of wax patterns, and focused on the surface smoothing treatment of wax CCCs, so as to improve the surface quality of CCCs. Finally, it verified the feasibility of this method and used the wax CCCs to produce rapid tooling equipped with CCCs. The preliminary results showed that the suitable process parameters of wax patterns are at 62 ℃ nozzle temperature, 80 mm/s print speed, 40 ℃ bed temperature, 100% flow, and a maximum surface roughness Rmax value of 66.4 μm. The soak smoothing treatment parameters of wax patterns are at 65 ℃ soaking temperature, 10 seconds duration time, a Rmax value reduction from 66.4 μm to 24.0 μm, and an improvement rate of Rmax reaching 63.86%. This study used the Taguchi method to research the optimal process parameters of wax patterns, and determined the optimal process parameters of wax patterns to be at 64 ℃ nozzle temperature, 60 mm/s print speed, 40 ℃ bed temperature, and 100% flow.

Dissertação de Mestrado Integrado em Engenharia Mecânica apresentada à Faculdade de Ciências e Tecnologia
Neste século, as necessidades dos consumidores estão cada vez mais desafiantes. A industria 4.0 está a revolucionar ambos os sectores de entrega e produção, eliminando a separação entre o digital e o físico. Existindo a possibilidade de ter produtos personalizados, a geometria vai permitir a criação de produtos que até agora não poderiam ser executados. Neste contexto, o Fabrico Aditivo surge como o pilar de sustentação para o desenvolvimento desta nova tecnologia. Estas tecnologias permitem obter um produto final criado a partir de pós.O processo de impressão mais frequentemente utilizado é a Fusão Seletiva por Laser (SLM). No entanto, esta técnica não permite obter produtos de alta qualidade, uma vez que, a rugosidade resultante é excessivamente elevada quando produzindo peças em cobre. Assim, surge o FDMet, um processo adaptado da Modelagem por Deposição Fundida (FDM) - produção de de filamentos poliméricos por extrusão).Este estudo pretende aplicar o princípio constructal para o fabrico de insertos de cobre através de FDMet, começando com a mistura dos pós e finalizando com a sintetização do inserto final.Este estudo demonstra que é possível produzir peças com elevada complexidade geométrica através de FDMet.########################################################################################################################################################################################################################################################################################################################
In this century, consumer needs are becoming increasingly challenging. The 4th industry is revolutionising both production and delivering sectors, blurring the lines between physical and digital. With the possibility of costume made products, new ideas will flourish with geometries that could not be made until now.In this paradigm, Addictive Manufacturing appears as a fundamental pillar sustaining this technological trend. It is composed by different step-by-step technologies that utilises powders to produce the final components.Selective Laser Melting (SLM) is the most common printing process of them all. However, regarding the mould industry, this technology cannot be used to obtain high quality inserts since the superficial roughness when processing copper is undesirably high. For this reason, Fusion Deposition Modelling (FDM), a polymeric filament-extrusion based technique has been adapted to process copper filaments.This study aims to apply the constructal principle to copper inserts through a complete FDMet process. Starting by mixing copper powders and ending up sintering the final inserts.This study shows that complex geometries can be produced using copper powder through a conventional 3D Printer, with a greatly reduced production cost in comparison with the existing solution.########################################################################################################################################################################################################################################################################################################################

Additive Manufacturing (AM) is an area intrinsically linked to industry 4.0 because of its ability to meet some of the most significant challenges in the industry such as production of custom parts, complex geometries and direct processing (through cloud manufacturing). Due to its advantages, the market for functional parts based on inorganic materials via AM is in great development. The present study has focused on the Fused Deposition of Ceramics (FDC) process, which is suitable, in combination with post-processing steps such as debinding and sintering, for the consolidation of ceramic powder particles from filamentary materials. Although the volume content of ceramic powders is very limited, due to the absence of high pressures, the FDC has been of scientific and industrial interest due to its ability to eliminate some limitations imposed by other processes such as Selective Laser Melting (SLM), due to the sources of high energy consumption, and Powder Injection Molding (PIM), due geometric and mold cost limitations. The major challenges of this dissertation involved producing filaments for FDC, based on PIM or powder extrusion (PE) methodologies, joining the filaments of feedstock with optimized ratios of tungsten carbide powder (48.5%vol.) that should withstand the stresses involved in the FDC extrusion, and providing suitable extrusion fluidity. Afterwards, the challenges were overcome and the shaped parts through FDC were debinded and sintered. These processes led to the production of near net shape WC-10Co parts with characteristics and properties close to those resulting from conventional replicative processes of the powders.

Additive manufacturing technologies based on Material Extrusion (ME) have been growing, gaining popularity and maturity in the plastic processing sector. In this context, it is a major concern to establish a closed-loop plastic production system which allows to maximize the value and shell-life of the feedstocks used in these kind of manufacturing technologies, contributing to decrease their ecological footprint. Regarding ME or Fused Filament Fabrication (FFF), a possible closed-loop recycling scheme would consist of processes for material collection, preparation, and filament extrusion in order to produce 3D printing feedstocks that fits with the FFF requirements and allows to achieve new value-added parts. However, there are challenges to overcome related to the quality and performance of the recycled materials, since, after mechanical recycling, the molecular degradation of thermoplastics causes a shift on their properties, and, therefore, on their processability. In this work, it was hypothesized that the incorporation of chain extenders (CE) during the reprocessing cycle would allow to overcome these drawbacks. To attest this conjecture, the inuence of 1,3-Bis(4,5-dihydro-2-oxazolyl)benzene (PBO), a functional additive used as a CE for polylactic acid (PLA) and PLAbased blends, at a fixed concentration (1%, w/w) on mechanical, thermal, and rheological properties of recycled PLA-based filaments was studied, using virgin PLA-based material as control. PBO was able to partially recover the mechanical performance of recycled PLA-based systems, as reected by an increase in both tensile modulus and tensile strength of the filament specimens. However, these results did not corroborate with the evolution of the material's melt strength, monitored by the melt ow rate (MFR), since PBO increased the MFR of recycled PLA-based formulation. This behavior may be related to the low interaction established between PBO and PLA, as observed by Fourier transform infrared spectroscopy (FTIR). From the printability point of view, it was observed that the brittleness of each studied formulation remained as the major constraint for successfully establish a closed-loop recycling scheme for FFF.
As tecnologias de manufatura aditiva baseadas em extrusão de materiais termoplásticos como o Fabrico por Filamento Fundido (FFF) têm-se destacado, ganhando popularidade e maturidade no contexto da indústria de processamento de plásticos. Desta forma, o esbelecimento de modelos de produção de plásticos em ciclo fechado é uma área de extremo interesse, pois possibilita maximizar o valor dos materiais utilizados neste tipo de tecnologias de fabrico, contribuindo igualmente para a redução do seu impacto ambiental. No contexto do FFF, um possível sistema de reciclagem em ciclo fechado consiste nos processos de recolha, preparação dos materiais e extrusão de filamento com o objetivo de conformar o material de forma a que este possa cumprir os requisitos da tecnologia, possibilitando a produção de componentes de valor acrescentado. Contudo, existem um conjunto de desafios associados à qualidade e performance dos materiais reciclados, dado que, após a aplicação dos processos de reciclagem mecânica, a degradação ao nível molecular a que os materiais termoplásticos são sujeitos irá provocar uma alteração nas suas propriedades e, consequentemente, nas suas condições de processamento. Neste estudo, é colocada a hipótese de, através da utilização de extensores da cadeia (EC) polimérica durante o ciclo de reprocessamento, ultrapassar as limitações relacionadas com a excessiva degradação do material. Neste sentido, a influência do 1,3-Bis(4,5-dihydro-2-oxazolyl) benzene (PBO), um aditivo funcional utilizado como extensor da cadeia para o ácido poliláctico (PLA) e formulações baseadas em PLA, a uma dada concentração (1%, m/m), nas propriedades mecânicas, térmicas e reológicas do material foi estudada, utilizando PLA virgem como material de controlo. A incorporação do PBO permitiu a recuperação parcial das propriedades mecânicas dos sistemas baseados em PLA reciclado, refletido pelo aumento do modulo de elasticidade e da tensão de rotura nas amostras de filamento. No entanto, estes resultados não são comprovados pela evolução da fluidez do material, monotorizada através do índice de fluidez (MFR), dado que o PBO contribuiu para o aumento do MFR das formulações baseadas em PLA reciclado. Este comportamento pode estar relacionado com a interação limitada entre o PBO e o PLA, observada através da espetroscopia de infravermelho por transformada de Fourier (FTIR). Na perspetiva da capacidade de impressão, o comportamento frágil do material foi identificado como a maior limitação ao estabelecimento de um sistema de reciclagem em ciclo fechado para aplicações na tecnologia de FFF.
Mestrado em Engenharia Mecânica

abstract: Presented below is the design and fabrication of prosthetic components consisting of an attachment, tactile sensing, and actuator systems with Fused Filament Fabrication (FFF) technique. The attachment system is a thermoplastic osseointegrated upper limb prosthesis for average adult trans-humeral amputation with mechanical properties greater than upper limb skeletal bone. The prosthetic designed has: a one-step surgical process, large cavities for bone tissue ingrowth, uses a material that has an elastic modulus less than skeletal bone, and can be fabricated on one system. FFF osseointegration screw is an improvement upon the current two-part osseointegrated prosthetics that are composed of a fixture and abutment. The current prosthetic design requires two invasive surgeries for implantation and are made of titanium, which has an elastic modulus greater than bone. An elastic modulus greater than bone causes stress shielding and overtime can cause loosening of the prosthetic. The tactile sensor is a thermoplastic piezo-resistive sensor for daily activities for a prosthetic’s feedback system. The tactile sensor is manufactured from a low elastic modulus composite comprising of a compressible thermoplastic elastomer and conductive carbon. Carbon is in graphite form and added in high filler ratios. The printed sensors were compared to sensors that were fabricated in a gravity mold to highlight the difference in FFF sensors to molded sensors. The 3D printed tactile sensor has a thickness and feel similar to human skin, has a simple fabrication technique, can detect forces needed for daily activities, and can be manufactured in to user specific geometries. Lastly, a biomimicking skeletal muscle actuator for prosthetics was developed. The actuator developed is manufactured with Fuse Filament Fabrication using a shape memory polymer composite that has non-linear contractile and passive forces, contractile forces and strains comparable to mammalian skeletal muscle, reaction time under one second, low operating temperature, and has a low mass, volume, and material costs. The actuator improves upon current prosthetic actuators that provide rigid, linear force with high weight, cost, and noise.
Dissertation/Thesis
Doctoral Dissertation Biomedical Engineering 2017

Today, the world that we live in is moving fast towards the Digital, which is causing profound technological mutations. Additive Manufacturing (AM), commonly called “3D printing”, is one of the symbols of these digital and technological effervescence. Initially, AM technologies were only seen as rapid prototyping tools. Nowadays, this stigma has changed and the market began to look at AM technologies as an effective and competitive alternative to the manufacture of products besides the conventional techniques. Cork is the world’s ambassador Portuguese material! A 100% natural material and it presents a unique combination of properties, given its composition and alveolar structure. Low density, hydrophobic character, elasticity and impact resistance are some its properties. This feature makes cork a material high potential in several applications. Wine stoppers is the major application of cork. From this production is generated a large amount of cork residues with different granulometries, where residues with calibres superior than 0.5-1.0 mm are already used in the development of cork-based composites for flooring and insulation applications. The valorisation of these cork residues through the development of new sustainable composite materials was one of the main motivations that triggered the present work. This thesis reports the development of cork-polymer composites (CPC) and cork-based formulations adapted to conventional and AM technologies. It will involve a conventional technology, the injection moulding (IM) technique, and two AM technologies, namely Fused Filament Fabrication (FFF) and 3D Printing (3DP). The preservation of cork alveolar structure after processing by these technologies was always sought. The present thesis is composed by a set of published papers in scientific journals and in conferences. Papers are integrated into two chapters (Chapter II and Chapter III). At the beginning of each chapter, it is presented an introduction to the topic. Chapter II concerns the development of CPC solutions adapted for IM, while Chapter III focus on the development of CPC and cork-based formulations solutions adapted to FFF and 3DP, respectively. Chapter II presents the study of the rheological and the non-isothermal crystallization behaviours of CPC. These studies have shown that the addition of cork did not compromise the flowability of CPC and its processability by IM. In addition, cork powder surface acted as a nucleating agent during non-isothermal crystallization. The presence of a coupling agent based on maleic anhydride (MA) contributed to the development of CPC with enhanced flowability, crystallinity degree and interfacial adhesion between the polymeric matrix and cork particles. A case study related to the effect of the high pressures applied during a standard IM process on the integrity of cork alveoli was performed. The application of low pressures, the removal of holding and back pressures and the use of shut-off nozzles were analysed as an adapted IM solution. Cork alveoli were able to recover from the deformation caused by the IM process, especially when cork granules were near to matrix defects (voids). A promising result which indicates that after an IM process the cork particles can recover its initial shape and size. On the other hand, Chapter III reports (i) the development of a cork-like filament with an incorporation of cork powder equal to 15 % (w/w), which represents 55 % in volume and (ii) the development of cork-based formulations adapted to 3DP. Focusing on the FFF technology, a case study was conducted to evaluate the usefulness and printability of the developed CPC filament. The printed parts exhibited unique characteristics, such as a non-plastic and warm touch, a natural colour and the release of a pleasant odour during the printing process. A case study, based on the 3DP technology, was conducted to evaluate the printability of the developed cork-based formulations. Previously, the applicability of the Washburn Capillary Rise (WCR) method was studied to determine the wettability of cork powders by a commercial binder (≥ 95% (w/w) of water). Cork powders are slightly wetted by the commercial binder (contact angles of (𝜃) ≈ 86 – 87º). 3DP cork parts with complex geometry were successfully printed. Parts exhibited lightweight and, warmness and softness to the touch. From the available knowledge, it is believed that this was the first time that cork powders were processed by 3DP. In addition, the autoclave technique was also studied and validated as a post-processing phase in the 3DP process. The main conclusions and perspectives of future work are presented in Chapter IV. The present thesis constitutes an original approach for the valorisation of cork powder residues. The combination of a natural and traditional product, such as cork, with high-tech technologies, can lead to the development of cork products never processed before, or to new applications of cork products never thought before.
Hoje, vivemos num mundo que caminha rapidamente para o Digital, o que provoca profundas mutações tecnológicas. A Manufatura Aditiva (MA), comumente denominada de Impressão 3D (3DP) é um dos símbolos desta efervescência digital e tecnológica. Inicialmente, as tecnologias de MA eram vistas como ferramentas de prototipagem rápida. Atualmente, esse estigma foi alterado e o mercado começou a olhar para as tecnologias de MA como uma alterativa eficaz e competitiva no fabrico de produtos para além das tecnologias de fabrico convencionais. A cortiça é o embaixador português no mundo dos materiais! É um material 100% natural e apresenta uma combinação única de propriedades, dada a sua composição e estrutura celular. Baixa densidade, carácter hidrofóbico, elasticidade e resistência ao impacto são exemplo de algumas das suas propriedades. Esta combinação única torna a cortiça num material com um elevado potencial em diversas aplicações. A produção de rolhas é a principal aplicação da cortiça. Desta produção são gerados resíduos com diferentes granulometrias, onde os resíduos com calibres superiores a 0.5-1.0 mm são já aplicados no fabrico de compósitos, nomeadamente para aplicações de revestimento e isolamento. A valorização destes resíduos de cortiça através do desenvolvimento de novos materiais compósitos sustentáveis foi uma das principais motivações que desencadeou o presente trabalho. A presente tese reporta o desenvolvimento de compósitos poliméricos de cortiça (CPC) e de formulações à base de cortiça adaptadas a tecnologias convencionais e de MA. O estudo envolve uma tecnologia convencional, a moldação por injeção (MI), e duas tecnologias de MA, nomeadamente as tecnologias de Fabricação por Filamento Fundido (FFF) e de 3DP. Após o processamento por estas tecnologias, procurar-se-á manter intacta a estrutura alveolar da cortiça. A tese é composta por um conjunto de artigos publicados em revistas científicas e em conferências. Os artigos encontram-se integrados em dois capítulos (Capítulo II e III). No início de cada capítulo é apresentada uma introdução ao tópico em questão. O Capítulo II apresenta um estudo reológico e um estudo de cristalização não isotérmica de CPC. Estes estudos demonstraram que a adição de cortiça não comprometeu a fluidez do CPC e o seu processamento por MI. Além disso, a superfície das partículas do pó de cortiça atuaram como agentes nucleantes durante a cristalização não-isotérmica. A presença de um agente compatibilizante à base de anidrido maleico (AM) contribuiu para o desenvolvimento de CPC com maior fluidez, grau de cristalinidade e adesão interfacial entre a matriz polimérica e a cortiça. Um estudo de caso foi conduzido para avaliar o efeito das pressões elevadas aplicadas, durante o processo de MI, na integridade da estrutura alveolar da cortiça. O efeito da injeção a baixas pressões, a remoção da pressão de compactação e de contrapressão e o uso de bicos obturadores foram analisados como uma solução adaptada ao processo de MI. Nesta solução adaptada de MI, os alvéolos da cortiça foram capazes de recuperar da deformação, em especial quando estavam próximos de defeitos da matriz (vazios). Um resultado promissor, pois indica que as partículas de cortiça podem recuperar a sua estrutura e tamanho após um processo de MI. Por outro lado, o Capítulo III relata o (i) desenvolvimento de um filamento de cortiça com uma incorporação de pó de cortiça igual a 15 % (p/p), o que representa 55% em volume e (ii) o desenvolvimento de formulações à base de cortiça adaptadas ao processo de 3DP. Focando na tecnologia de FFF, foi realizado um caso de estudo para avaliar a usabilidade e a capacidade de impressão do filamento de CPC desenvolvido. As peças impressas por FFF exibiriam características únicas, nomeadamente um toque não plástico e quente, uma cor natural e a libertação de odor agradável durante a impressão. Foi efetuado, por 3DP, um estudo de caso para avaliar a capacidade de impressão das formulações desenvolvidas. Previamente, a aplicabilidade do método de Washburn foi estudada para avaliar a molhabilidade de pós de cortiça por um ligante comercial (água ≥ 95% (p/p). Os pós de cortiça são ligeiramente molhados pelo ligante comercial (ângulo de contacto (𝜃) de ≈ 86 – 87º). Foram impressas peças com geometrias complexas por 3DP. As peças exibiram leveza e um toque quente e macio. Do conhecimento disponível julga-se ter sido esta a primeira vez que se processaram pós de cortiça por 3DP. Além disso, foi também estudada e validada a técnica de autoclave como fase de pós processamento no processo de 3DP. As principais conclusões e as perspetivas de trabalhos futuros estão descritas no Capítulo IV. A presente tese constitui uma abordagem original na valorização de resíduos de pó de cortiça. A combinação de um material natural e tradicional, como a cortiça, com tecnologias de ponta, irá contribuir para o desenvolvimento de produtos de cortiça nunca antes processados ou, até mesmo, para novas aplicações de produtos de cortiça nunca antes pensadas.
Programa Doutoral em Ciência e Engenharia de Materiais

Dissertação de Mestrado em Engenharia de Materiais apresentada à Faculdade de Ciências e Tecnologia
As técnicas de fabrico aditivo (FA) permitem a criação de peças/componentes com geometrias complexas de uma forma mais fácil, com simplicidade e, às vezes, com maior velocidade de produção quando comparada a outros processos convencionais. Uma das técnicas incluídas no FA é a fabricação de filamentos fundidos (FFF), que consiste na extrusão de um material polimérico em várias camadas, recriando as peças 3D anteriormente desenhadas em CAD.Os dispositivos, peças ou objetos obtidos por esta técnica podem ser utilizados nas mais variadas aplicações em diversos setores industriais como aeroespacial, mecânico, elétrico, automóvel e médico.Os materiais mais comuns para esta técnica são polímeros termoplásticos e compósitos de matriz polimérica. O reforço pode ser de polímero, metal ou materiais cerâmicos permitindo assim a criação, inovação e melhoria das propriedades dos produtos. Um dos usos da incorporação de nanopartículas metálicas em filamentos poliméricos é fornecer atividade antibacteriana ao compósito.Nesse contexto, o objetivo principal desta dissertação é avaliar a capacidade antimicrobiana de espécimes impressos, pela técnica de FFF, a partir de filamentos nanocompósitos contendo cobre. Para tanto, foram escolhidos dois filamentos: (i) um com matriz polimérica de poli (ácido lático), (PLA), termoplástico biodegradável, e outro (ii) com matriz de poliuretana (TPU), termoplástico de alta resistência mecânica e resistência química, mas com ductilidade semelhante à dos elastómeros. Como controlo foram utilizados os mesmos polímeros, porém sem adição de metal. Todos os filamentos e espécimes impressos foram submetidos à caracterização química, morfológica, térmica e microbiana. Os parâmetros de impressão foram otimizados em relação à temperatura de impressão, temperatura da plataforma e velocidade de impressão. Além disso, diferentes geometrias e percentagens de preenchimento foram avaliadas a fim de entender se poderiam ou não influenciar a atividade antimicrobiana.A principal conclusão deste trabalho é que, embora os filamentos comerciais apresentem alguma atividade antimicrobiana contra Escherichia coli, Pseudomonas aeruginosa e Staphylococcus aureus, os espécimes impressos não apresentaram atividade antimicrobiana. Este facto deve-se principalmente ao cobre estar presente na superfície dos filamentos comerciais, mas, após a impressão, o elemento metálico está ausente da superfície. Consequentemente, as bactérias não são inibidas no seu crescimento e proliferação, pois o PLA e o TPU não apresentam nenhum risco químico para os microrganismos.
Additive manufacturing techniques (FA) allow the creation of complex geometries parts/components in an easier, with simplicity and, sometimes, at a higher production speed when compared to other conventional processes. One of the techniques included in the FA is the fused filament fabrication (FFF), which consists of the extrusion of a polymeric material in several layers, recreating the 3D parts that were previously drawn in CAD.The devices, parts or objects obtained by this technique can be used in the most varied applications and its presence is verified in several industrial sectors such as aerospace, mechanics, electrical, automobile and medical.The most common materials for this technique are thermoplastic polymers and polymeric matrix composites. The reinforcement can be of polymer, metal or ceramic materials thus allowing the creation, innovation and improvement of the properties of designed products. One of the uses of incorporating metal nanoparticles into polymeric filaments is to provide antibacterial activity to the composite.In this context, the main objective of this dissertation is to evaluate the antimicrobial capacity of printed specimens, using the FFF technique, from nanocomposite filaments containing copper. For this purpose, two filaments were chosen: (i) one with a polymer matrix of poly(lactic acid), (PLA), biodegradable thermoplastic, and another (ii) with a polyurethane matrix (TPU), thermoplastic with high mechanical strength and chemical resistance, but with a ductility similar to elastomers. As a control, the same polymers were used, but without the addition of metal. All the filaments and printed specimens where subjected to chemical, morphological, thermal and microbial characterization. The printed parameters were optimized regarding the printing temperature and platform temperature, and the printing speed. Also, different geometries and infill percentages of the specimens where chosen in order to understand whether or not they could influence the antimicrobial activity.The main conclusion of this work is that, although the commercial filaments present some antimicrobial activity against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus, the printed specimens did not present any antimicrobial activity. This is mainly due to the fact that the copper is present in the surface of the commercial filaments but, after printing, the metallic element is absent from the surface. Consequently, the bacteria are not inhibited to grow and proliferate, as PLA and TPU do not present any chemical hazard for the microorganisms.

碩士
逢甲大學
纖維與複合材料學系
104
There have been relatively few industrial projects focusing on the application and development of geotechnical engineering. Artificial fiber are developed, which allow diverse artificial fiber-based fabrics for wide application in the geo-engineering field, as geotextiles have functions of reinforcement, isolation, filter, drainage, and protection. In response, this study uses polyester (PET) fiber, polypropylene fiber (PP) and Kevlar fiber at different ratios to make basis fabrics, and examines the optimal parameters for the production of these basis fabrics. The fabrics are laminated with PET continuous (cont.) filament or glass-fiber woven fabrics, after which the whole is processed with needle punching and hot pressing. High-modulus composite fabrics are yielded and tested for mechanical properties and permeability. According to mechanical test results, the optimal parameters of high-modulus composite fabrics are Kevlar content (40 wt%), needle punch depth (19 mm) , and needle punch speed (250 needles/min). The needle punch depth pertains to the mechanical properties of the composite fabrics after cont. filament is added. In addition, the speed of the filament motor also affects the CV% of mechanical properties. Using cont. filament can mechanically improve the high-modulus composite geotextiles to a greater extent, in comparison to using glass-fiber woven fabric. Regardless of the reinforcement being cont. filament or glass-fiber woven fabric, the thermally treated composite geotextiles exhibit an increasing trend in mechanical properties. However, a small amount of samples exhibit permeability that is lower than the standard geotextile requirements (0.1 cm/s). The proposed high-modulus composite geotextiles can be produced with the corresponding required functions, such as reinforcement, drainage, and filtration, based on the applications in protecting hillsides, retaining roadbeds, and dredging reservoirs.

It is estimated that, in industrialized societies, over 9 to 10 Kg of tires per habitant are annually discarded and pilled in huge deposits with serious environmental problems associated. It is of maximum importance recycling used tires and developing new applications and new products of recycled tires. In this work, recycled tire granulates, produced by RECIPNEU, are incorporated in polylactic acid (PLA) to prepare polymeric composite formulations to be extruded into a filament for sustainable additive manufacturing of an acoustic panel. The preparation of the formulations involved a first theoretical/modelling study based on the mechanical properties and density to “guide” the establishment of the amount of recycled tire granulates to be included. Then, some formulations containing rubber percentages from 10 to 60 wt.% were prepared using a Brabender mixer. Then, upon extrusion of the filaments with the different formulations, it was verified that the composite mixture containing 20 wt.% of rubber was the one presenting a higher degree of homogeneity despite its brittleness. A plasticizer, namely glycerol, was added to improve the filament flexibility and allow its rolling. A printable filament was obtained, and small prototypes of acoustic type panels were printed. Acoustic properties were determined in the laboratory of Professor Doctor Luís Godinho, director of the Department of Civil Engineering of the University of Coimbra, using the Wave Impedance Tube method, and were compared with similar shaped printed pure PLA. Resuming, recycling tires waste were successfully incorporated in PLA and the polymeric composites could be extruded in filament form that can be used as a sustainable material for additive manufacturing. The acoustic performance of the printed panels, tested by Wave Impedance Tube method, revealed an inferior performance when compared with standard mineral wool sample, being necessary to perform more studies in this field
Estima-se que, em sociedades industrializadas, cerca de 9 a 10 Kg de pneus por habitante são, anualmente, descartados e despejados em enormes depósitos que acarretam sérios problemas ambientais. É de extrema importância reciclar pneus usados e desenvolver novas aplicações e novos produtos tendo por base os pneus reciclados. É precisamente este o enquadramento em que se realiza este trabalho de mestrado. Neste trabalho, granulados de pneus reciclados, produzidos pela RECIPNEU, são incorporados em ácido poliláctico (PLA) de forma a preparar formulações de compósitos poliméricos para serem extrudidos em forma de filamento e serem, posteriormente, testados como material sustentável para manufatura aditiva de um painel acústico. A preparação das formulações envolveu um estudo teórico prévio, baseado nas propriedades mecânicas e densidade, para definir a quantidade de granulados de pneus reciclados a ser incorporada. De seguida, formulações contendo 10 a 60 %, em peso, de granulados de borracha foram preparadas usando uma misturadora Brabender. Após extrusão dos filamentos com as diferentes formulações, verificou-se que o compósito contendo 20 %, em peso, de granulado de borracha foi o que apresentou a melhor homogeneidade, apesar da sua fragilidade. Adicionou-se um plasticizante, glicerol, de modo a melhorar a flexibilidade do filamento e permitir o seu enrolamento. As condições de extrusão foram otimizadas de modo a obter um filamento capaz de ser impresso, sendo este testado através da impressão de um pequeno protótipo de um painel acústico. As propriedades acústicas foram determinadas pelo Dr. Luís Godinho, Diretor do Departamento de Engenharia Civil da Universidade de Coimbra, através do método do tubo de impedância, e comparadas com uma amostra de PLA puro, de forma idêntica. Resumindo, os granulados de pneus reciclados foram incorporados com sucesso em PLA, sendo possível extrudir os compósitos poliméricos em forma de filamento que pode ser usado como material sustentável para a manufatura aditiva. É possível imprimir painéis customizados, contudo estes não apresentam boas propriedades acústicas, não sendo, na sua forma atual, uma boa solução para soluções acústicas. A percentagem de borracha necessita de ser otimizada, de modo a melhorar a performance acústica
Mestrado em Engenharia de Materiais

碩士
輔仁大學
織品服裝學系碩士班
103
This thesis is planned to spinning two kind of Covered Yarn, one is double core yarn (Spandex 40D+T400) what has been called Duo Core Yarn(D.C.Y.), another is single core yarn (Spandex 40D) what has been called Single Covered Yarn(S.C.Y.). First we put up above two kinds of yarn with the ring spinning cotton roving and will go through the draft rate 2.5 rollers in spandex and T400 fed directly form the core wire and cotton as the outer coating. The D.C.Y. and S.C.Y. have been finished then sent to weaving house to weave the greige. After then send them to dyeing mill to make the Prepare For Dyeing (P.F.D.) fabric. Finally, the P.F.D. fabric will be cut and sew then arranged into garment dyeing factory for fabric dyeing vat. The final test would be compared with the changes in physical properties of various stages of its component conditions and to investigate both them dyeing uniformity for grin. Based on the above experimental findings that the elongation and elastic recovery rate of　Duo Core Yarn is better than the Single Covered Yarn. Nevertheless S.C.Y., cotton content value is higher then D.C.Y. the lower ratio of its core is wire, and will be fewer grins. Through this experiment for spun woven fabrics, which to be used the radio of Duo Core Yarn to produce their high flexibility, high recovery fabric but it’s too high will be grin problem in finished fabric which will be concerned by us.