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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Optimization of Granulate 3D Printer : Focus on cooling

Ylander Mikkelsen, Kristoffer, Geraldsson, Oskar January 2019 (has links)
The authors, Oskar Geraldsson and Kristoffer Ylander Mikkelsen, together with Svenska Konstruktörsbyrån AB, have customized and optimized a granulate 3D printer. The main goal for the authors is to improve the cooling of the liquid ABS plastic leaving the nozzle to prevent displacement and dislocation during the printing process. Furthermore the printers current state is poor resulting in further work regarding the overall mechanics of the printer such as the power supply, electrical motors and linear guides. The authors have studied existing 3D printers and searched through scientific articlesto get inspiration and knowledge of the mechanical process of the printers aswell as the materials.
2

Google Bespoke!

Shinomiya, Mitsuyoshi January 2014 (has links)
In my master thesis, I decided to focus on process of design. Nowadays, there is huge difference between the process of software design and hardware design due to technological problem. Software design development has more flexibility than hardware design development. In addition, it can be adjustable for each user and can involve user in design process. In the future, some of technology such as 3D printer, modifiable material, and so on, will enable hardware designer to use software design process to design hardware. The process can make better relation between user and product. In this thesis, I used real user to simulate the future process. I did a lot of interview to the user and involve him to design process. I used current technology to interact with user as much as possible, for example, I used 3D scanner to scan his body data to make perfect size reference for his vehicle. In the end, I could design something unexpected in good way thanks to collaboration with the user. It was also unexpected for him, but he was satisfied with the result so much. I believe this process has a lot of potential to make better relation and story between user and product.
3

Dot Master : Braille printer

Ardestam, Fredrika, Soltaniah, Sara January 2018 (has links)
Braille is a writing system that uses tactile dots in apredetermined order which, in relation to each other, representdifferent letters in the alphabet. This writing systemmakes it possible for people with visual impairmentsto take part of the written media. But the availability ofhome based braille printers is limited and these printers areoften expensive. The purpose of this project is to investigateif it is possible to build a home based braille printerfor a low cost using microcontrollers, and thereby making itmore accessible to people with visual impairment. In orderto achieve this, a prototype was built using an microcontrollertogether with stepper motors and a solenoid. Thesecomponents were then controlled by code through user inputand translated to required movements. Each switchcase then calls a set of functions that activates the steppersand the solenoid in the order needed to get the desiredcharacter. In the time frame given, the project resulted ina prototype able to print out the input it was given. Asfor the cost of building your own Braille printer in comparisonto buying one on the market highly depends on whatprocessing machines are accessible. / Braille är ett skrivsystem som använder taktila prickari en förbestämd ordning i förhållande till varandra som representerarolika bokstäver i alfabetet. Detta skrivssystemgör det möjligt för personer med nedsatt syn att ta delav de skriftliga medierna. Men tillgången av hembaseradebraille-skrivare är begränsad och dessa skrivare är oftadyra. Syftet med detta projekt är att undersöka om detär möjligt att bygga en hembaserad braille-skrivare till enlåg kostnad med hjälp av mikrokontroller och därmed underlätta för personer med nedsatt syn. För att uppnå dettabyggdes en prototyp med en mikrokontroll tillsammansmed stegmotorer och en solenoid. För att styra dessa komponenterskrevs en kod som tar in information från vad somskrivits i Arduinos serial monitor och kopplar sedan dettatill specifika switch cases. Varje switch case anropar sedanen uppsättning funktioner som aktiverar stegmotorerna ochsolenoiden i den ordning som behövs för att få önskad bokstav.Med den givna tidsramen resulterade projektet i enprototyp som kunde skriva ut det input den var given. Vaddet gäller kostnaden för att bygga en Braille-skrivare påegen hand jämfört med att köpa en på marknaden berormycket på vilka bearbetningsmaskiner som är tillgängliga.
4

Modelling and Control of Heat Distribution in a Powder Bed Fusion 3D Printer

Hanses, Jonathan, Eriksson, Morten January 2019 (has links)
This thesis report describes how to improve the control of the temperature in a Powder Bed Fusion 3D printer. This is accomplished by first creating a model ofthe thermal system. To create a good model, both black-box and grey-box models of the system are estimated and compared. Based on the best model, different control designs are examined and the results are compared to find the control design yielding the best results. The system being modelled is a multiple input multiple output system with acomplex internal structure. The modelling can be divided into several steps. Firstly, data has to be acquired from the system. Secondly, the data is analysed and processed. Thirdly, models are estimated based on the collected data. Different model structures such as state-space, ARX, ARMAX, Output Error, Box Jenkins and grey-box models are examined and compared to each other. Finally, the different derived models are validated and it turns out the ARMAX model yields the best prediction capabilities. However, when the controllers were tested on the actual system the controllers that are based on the grey-box model yield the best results. The different control designs examined in this work are diagonal PI controllers, decoupled PI controllers, feed forward controllers, IMC controllers and statefeedback controllers. The controllers are all based on the derived models. The controllers are implemented into a code structure capable of communicating with the printers. Here, tests of the performance for the different controllers on the actual system are executed. The results show that a non-linear system can be controlled using linear controllers. However, introducing some fuzzy control elements such as limiting the controllers to only be used within small temperature intervals and using a fixed input outside this interval yield better results. From these results, the best linear controller is a diagonal PI controller tuned from a grey-box model with as many states as there are controllable areas of the powder bed. The improvement is only marginal compared to the original PI controller, reinforcing the conclusion that some non-linear strategies are needed in the controller in order to achieve significant improvements.
5

Emprego de simulação computacional para avaliação de objetos simuladores impressos 3D para aplicação em dosimetria clínica / Use of computational simulation for evaluation of 3D printed phantoms for application in clinical dosimetry

Valeriano, Caio César Santos 29 May 2017 (has links)
O propósito de um objeto simulador é representar a alteração do campo de radiação provocada pela absorção e espalhamento em um dado tecido ou órgão de interesse. Suas características geométricas e de composição devem estar próximos o máximo possível aos valores associados ao seu análogo natural. Estruturas anatômicas podem ser transformadas em objetos virtuais 3D por técnicas de imageamento médico (p. ex. Tomografia Computadorizada) e impressas por prototipagem rápida utilizando materiais como, por exemplo, o ácido poliláctico. Sua produção para pacientes específicos requer o preenchimento de requisitos como a acurácia geométrica com a anatomia do individuo e a equivalência ao tecido, de modo que se possa realizar medidas utilizáveis, e ser insensível aos efeitos da radiação. O objetivo desse trabalho foi avaliar o comportamento de materiais impressos 3D quando expostos a feixes de fótons diversos, com ênfase para a qualidade de radiotherapia (6 MV), visando a sua aplicação na dosimetria clínica. Para isso foram usados 30 dosímetros termoluminescentes de LiF:Mg,Ti. Foi analisada também a equivalência entre o PMMA e o PLA impresso para a resposta termoluminescente de 30 dosímetros de CaSO4:Dy. As irradiações com feixes de fótons com qualidade de radioterapia foram simuladas com o uso do sistema de planejamento Eclipse™, com o Anisotropic Analytical Algorithm e o Acuros&reg XB Advanced Dose Calculation algorithm. Além do uso do Eclipse™ e dos testes dosimétricos, foram realizadas simulações computacionais utilizando o código MCNP5. As simulações com o código MCNP5 foram realizadas para calcular o coeficiente de atenuação de placas impressas expostas a diversas qualidades de raios X de radiodiagnóstico e para desenvolver um modelo computacional de placas impressas 3D. / The purpose of a phantom is to represent the change in the radiation field caused by absorption and scattering in a given tissue or organ of interest. Its geometrical characteristics and composition should be as close as possible to the values associated with its natural analogue. Anatomical structures can be transformed into 3D virtual objects by medical imaging techniques (e.g. Computed Tomography) and printed by rapid prototyping using materials, for example, polylactic acid. Its production for specific pacients requires fulfilling requirements such as geometric accuracy with the individual\'s anatomy and tissue equivalence, so that usable measurements can be made, and be insensitive to the radiation effects. The objective of this work was to evaluate the behavior of 3D printed materials when exposed to different photon beams, with emphasis on the quality of radiotherapy (6 MV), aiming its application in clinical dosimetry. For this, 30 thermoluminescent dosimeters of LiF:Mg,Ti were used. The equivalence between the PMMA and the printed PLA for the thermoluminescent response of 30 dosimeters of CaSO4: Dy was also analyzed. The irradiations with radiotherapy photon beams were simulated using the Eclipse™ treatment planning system,with the Anisotropic Analytical Algorithm and the Acuros&reg XB Advanced Dose Calculation algorithm. In addition to the use of Eclipse™ and dosimetric tests, computational simulations were realized using the MCNP5 code. Simulations with the MCNP5 code were performed to calculate the attenuation coefficient of printed plates exposed to different radiodiagnosis X-rays qualities and to develop a computational model of 3D printed plates.
6

Emprego de simulação computacional para avaliação de objetos simuladores impressos 3D para aplicação em dosimetria clínica / Use of computational simulation for evaluation of 3D printed phantoms for application in clinical dosimetry

Caio César Santos Valeriano 29 May 2017 (has links)
O propósito de um objeto simulador é representar a alteração do campo de radiação provocada pela absorção e espalhamento em um dado tecido ou órgão de interesse. Suas características geométricas e de composição devem estar próximos o máximo possível aos valores associados ao seu análogo natural. Estruturas anatômicas podem ser transformadas em objetos virtuais 3D por técnicas de imageamento médico (p. ex. Tomografia Computadorizada) e impressas por prototipagem rápida utilizando materiais como, por exemplo, o ácido poliláctico. Sua produção para pacientes específicos requer o preenchimento de requisitos como a acurácia geométrica com a anatomia do individuo e a equivalência ao tecido, de modo que se possa realizar medidas utilizáveis, e ser insensível aos efeitos da radiação. O objetivo desse trabalho foi avaliar o comportamento de materiais impressos 3D quando expostos a feixes de fótons diversos, com ênfase para a qualidade de radiotherapia (6 MV), visando a sua aplicação na dosimetria clínica. Para isso foram usados 30 dosímetros termoluminescentes de LiF:Mg,Ti. Foi analisada também a equivalência entre o PMMA e o PLA impresso para a resposta termoluminescente de 30 dosímetros de CaSO4:Dy. As irradiações com feixes de fótons com qualidade de radioterapia foram simuladas com o uso do sistema de planejamento Eclipse™, com o Anisotropic Analytical Algorithm e o Acuros&reg XB Advanced Dose Calculation algorithm. Além do uso do Eclipse™ e dos testes dosimétricos, foram realizadas simulações computacionais utilizando o código MCNP5. As simulações com o código MCNP5 foram realizadas para calcular o coeficiente de atenuação de placas impressas expostas a diversas qualidades de raios X de radiodiagnóstico e para desenvolver um modelo computacional de placas impressas 3D. / The purpose of a phantom is to represent the change in the radiation field caused by absorption and scattering in a given tissue or organ of interest. Its geometrical characteristics and composition should be as close as possible to the values associated with its natural analogue. Anatomical structures can be transformed into 3D virtual objects by medical imaging techniques (e.g. Computed Tomography) and printed by rapid prototyping using materials, for example, polylactic acid. Its production for specific pacients requires fulfilling requirements such as geometric accuracy with the individual\'s anatomy and tissue equivalence, so that usable measurements can be made, and be insensitive to the radiation effects. The objective of this work was to evaluate the behavior of 3D printed materials when exposed to different photon beams, with emphasis on the quality of radiotherapy (6 MV), aiming its application in clinical dosimetry. For this, 30 thermoluminescent dosimeters of LiF:Mg,Ti were used. The equivalence between the PMMA and the printed PLA for the thermoluminescent response of 30 dosimeters of CaSO4: Dy was also analyzed. The irradiations with radiotherapy photon beams were simulated using the Eclipse™ treatment planning system,with the Anisotropic Analytical Algorithm and the Acuros&reg XB Advanced Dose Calculation algorithm. In addition to the use of Eclipse™ and dosimetric tests, computational simulations were realized using the MCNP5 code. Simulations with the MCNP5 code were performed to calculate the attenuation coefficient of printed plates exposed to different radiodiagnosis X-rays qualities and to develop a computational model of 3D printed plates.
7

SHEAR BAND MANIPULATION IN POLYMERIC HONEYCOMB STRUCTURES USING RELIEF HOLES AND DIC ANALYSIS

Felicio Perruci, Gustavo Felicio 01 September 2021 (has links)
There is currently an interest in optimizing the structural design to improve materials' strength to weight ratio or improve stiffness for energy absorption. As such, cellular structures are continuously studied and improved. However, it is a well-known fact in the literature that one primary mechanism of failure of a honeycomb is the formation of shear bands. The impacts of these shear bands bring many questions and unknowns, especially when the cellular structures are created with the increasingly popular manufacturing technique of 3D printing. Therefore, understanding the deformations in 3D printed honeycomb structures is necessary to explain the behavior of materials generated through new additive manufacturing techniques and further the knowledge of the deformation localization and, consequently, formations of shear bands in the deformation process of cellular structures.In the first phase of this work, samples with a unit cell regular hexagonal honeycomb format were designed and manufactured using masked-stereolithography (M-SLA). After the curing process, the samples were prepared with a paint application in the format of speckle, and DIC was realized in a compression experiment to identify and analyze the presence of high strain regions indicating the presence of shear bands. A second phase was then conducted, aiming to consider the control and manipulation of the shear band through the utilization of relief holes. The results demonstrated that adding incisions in specific parts of the polymeric honeycomb makes it possible to change its strain spread through the shear band and change its toughness.
8

Návrh a realizace 3D tiskárny s vysokým rozlišením tisku / Design and realisation of 3D printer with high resolution of print

Peml, Luboš January 2014 (has links)
This thesis deals with the design and realisation of the stereolithographic 3D printer using DLP projector. The work describes the selection of suitable components for the printer´s mechanical construction and manufacturing of this construction, the solution of printer´s electronics and creation of the printer´s host software and firmware. Recommendations based on executed experiments for the parameters´ values settings have been given here.
9

Characterization of 3D printed metal oxide composite polymers

Joshi, Sharmad Vinod 27 July 2020 (has links)
No description available.
10

Life Cycle Assessment of a 3D printer : A comparative and attributional life cycle assessment of 3D printer / Livscykelbedömning av 3D-skrivare

Senthil, Rishi Akash Chinnakonda January 2022 (has links)
Three-dimensional (3D) bio printing offers a wide range of applications, including the placement, design, and patterning of biological components such as living cells, nucleic acids, tissues, and many more. Bioprinting has seen great growth and breakthroughs in recent years, particularly in 3D printing. The company (which do not want to be named) produce a user- friendly and adaptable bioprinter that provides the best bioprinting experience.  This thesis examines the environmental consequences of a 3D printer, through Life Cycle Assessment (LCA) over its lifetime which is anticipated to be 1 year for the study. To examine the impacts of the 3D printer over its lifetime, a comparative life cycle assessment (Comparative LCA) and attributional life cycle assessment (ALCA) was undertaken between the supply chains known as linear supply chain (LSC) and circular supply chain (CSC). Global warming (GW), terrestrial acidification (TA), freshwater eutrophication (FET), terrestrial ecotoxicity (TEC), freshwater ecotoxicity (FEC), marine ecotoxicity (MEC), land use (LU), and water consumption (WC) are the impact categories chosen for the study from ReCiPe 2016 (H) Midpoint.  According to the LCA results, the impacts generated by CSC are smaller than those contributed by LSC, and the impact categories that are most and least affected are recognized. Furthermore, from the 3D printer, potential hotspots with higher contributions were discovered. Airway transfer of 3D printer’s components from their manufacturing site to the company had a significant impact on the impact categories chosen. Printed Circuit Boards (PCB) used in 3D printers are another influential component that has a significant impact on the impact categories. When specifically looking, the manufacture of Integrated Circuits (IC) has a greater impact, which reflects on PCB production.  To identify the opportunities and improve 3D printer’s environmental performance, a sensitivity analysis is carried out, which yields results on how to improve its environmental performance. As a result, it is suggested that airway transportation be modified with seaway transportation, that virgin aluminium and copper materials be replaced with its scrap material / Tredimensionell (3D) bioprinting erbjuder en mängd olika applikationer, inklusive placering, design och mönster av biologiska komponenter, såsom levande celler, nukleinsyror, vävnader och mer. De senaste åren har bioprinting fått många genombrott och vuxit mycket, framför allt inom 3D-printing. Företaget (som inte vill bli namngivet) producerar en användarvänlig och anpassningsbar bioprinter som ger den bästa bioprinterupplevelsen.  Detta examensarbete undersöker den miljöpåverkan som en 3D-skrivare har, genom livscykelanalys (LCA) under sin livslängd, som beräknas vara 1 år för denna studie. För att undersöka 3D-skrivarens påverkan under dess livstid har en jämförande livscykelanalys (Comparative LCA) och attributionell livscykelanalys genomförts mellan försörjningskedjorna, som kallas linjär försörjningskedja (LSC) och cirkulär försörjningskedja (CSC). Global uppvärmning (GW), terrestrisk försurning (TA), sötvattenseutrofiering (FET), terrestrisk ekotoxicitet (TEC), sötvattenekotoxicitet (FEC), marin ekotoxicitet (MEC), markanvändning (LU) och vattenförbrukning (WC) är kategorier valda för studier från ReCiPe 2016 (H) Mid Point. Enligt LCA-resultat är miljöpåverkan från CSC mindre än den som LSC bidrar med. Dessutom, med 3D-skrivare, har potentiella hotspots med högre bidrag upptäckts.  . Luftburen överföring av 3D-skrivarkomponenter från deras tillverkningsplats till företaget hade en inverkan på de berörda kategorierna. Printed Circuit Boards (PCB) som används i 3D-skrivare är en annan påverkande komponent. Mer specifikt har tillverkning av integrerade kretsar (IC) en stor inverkan.  För att, identifiera utsläpp och möjligheter och förbättra 3D-skrivarens miljöprestanda, genomförs en känslighetsanalys som ger resultat om hur man kan förbättra dess miljöprestanda. Som ett resultat föreslås att flygtransporter ersätts med sjötransporter, att jungfruligt aluminium och kopparmaterial ersätts med dess ersätts material.

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