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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.
21

Novas metodologias para a fabricação de piezoeletretos termo-formados / New technologies for the manufacture of piezoelectrets thermo-formed

Yuri Andrey Olivato Assagra 28 August 2015 (has links)
Há vários métodos descritos na literatura sobre a forma como os piezoeletretos ou ferroeletretos podem ser fabricados, sendo que cada uma dessas técnicas apresenta suas vantagens e desvantagens. Por exemplo, espumas de polipropileno (PP) são fáceis de serem processadas em grande escala aliada a um baixo custo de produção, entretanto, seu efeito piezoelétrico é dependente da temperatura, assim como não há um controle dos vazios internos durante sua fabricação, ocasionando uma heterogeneidade da geometria desses vazios. Por outro lado, em outros métodos as dimensões das cavidades podem ser controlada e polímeros termicamente mais estáveis podem ser utilizados, no entanto, a um maior custo de produção. Em relação aos métodos que visam a produção dos piezoeletretos, neste trabalho é apresentada uma nova técnica baseada em termo selagem e template de água para criar piezoeletretos com canais tubulares abertos. Este tipo de estrutura vazada foi inicialmente produzida pela laminação de filmes de etileno propileno fluorado (FEP) com o template de politetrafluoretileno (PTFE) entre eles, sendo o template descartado após a laminação, gerando resíduos. Com a substituição do template de PTFE pela água na etapa de produção dos novos piezoeletretos, foi possível eliminar o descarte de resíduos sólidos ao mesmo tempo em que um tratamento químico foi efetuado na superfície do filme. Pelo método desenvolvido, a estabilidade térmica do piezoeletreto foi melhorada sem a necessidade de um tratamento prévio ou posterior dos filmes, diminuindo assim o custo de produção. Outro método inovador para produção dos piezoeletretos também foi exposto neste trabalho. Essa inovação consiste na fabricação de piezoeletretos com cavidades controladas por meio da impressão de filmes de ABS. Para a impressão dos filmes uma impressora 3D de baixo custo foi utilizada. / There are several methods described in the literature on how piezoelectrets or ferroelectrets can be manufactured, each of these techniques present their advantages and disadvantages. For example, foamed polypropylene (PP) are easy to be processed on a large scale combined with a low cost of production, however, its piezoelectric effect is temperature dependent, and there is no control of internal voids during its manufacture, causing a heterogeneity of the geometry of these empty. Furthermore, in other methods the cavities dimensions can be controlled and more thermally stable polymers can be used, however, with a higher production cost. Regarding the methods for producing piezoelectrets, in this work we present a new technique based on hot sealing and water template for creating multi-layered piezoelectrets with open-tubular channels. This type of voided structure have been initially produced by laminating fluoroethylene-propylene (FEP) films with a polytetrafluorethylene (PTFE) template in between although the template was discarded after lamination, creating residual waste. With the replacement of the PTFE template by water in the production step of the new piezoelectrets, it was possible to eliminate the disposal of solid waste at the same time a chemical treatment was performed on the film surface. By the developed method, the piezoelectrets thermal stability was improved without the need for a prior or subsequent treatment of the films, reducing the production cost. Another innovative method for production of piezoelectrets was also exposed in this work. This innovation consists in manufacturing piezoelectrets with cavities controlled by printing ABS films. In order to print the films, a 3D printer was used.
22

Desenvolvimento de um objeto simulador \"Canis Morphic\" utilizando impressora 3D para aplicação em dosimetria na área de radioterapia veterinária / Development of a phantom \"Canis Morphic\" using 3D printer for use in dosimetry in veterinary radiation therapy

Glauco Rogério Veneziani 27 April 2017 (has links)
O aumento na longevidade humana fez surgir uma série de doenças com a idade; em contrapartida o avanço da medicina possibilitou o diagnóstico precoce e o tratamento de várias doenças antes incuráveis. Esse cenário atual estendese também aos animais domésticos (cães e gatos - PETs) que dobraram sua expectativa de vida nas últimas décadas, fato que os humanos demoraram séculos para alcançar. Do mesmo modo que os humanos, esse aumento na longevidade dos animais veio acompanhado de doenças relacionadas com a idade, entre elas o câncer. Uma das terapias utilizadas atualmente no tratamento do câncer é a radioterapia, técnica que utiliza a radiação ionizante para destruir as células tumorais (volume-alvo) com mínimo prejuízo aos tecidos circunvizinhos sadios (órgãos de risco). Essa técnica exige a realização periódica de testes de controle de qualidade, incluindo a dosimetria com a utilização de objetos simuladores equivalentes ao tecido, de modo a verificar a dose de radiação recebida pelo paciente em tratamento e compará-la posteriormente com a dose de radiação calculada pelo sistema de planejamento. A rápida expansão do mercado de impressoras 3D abriu caminho para uma revolução na área da saúde. Atualmente os objetos simuladores por impressão 3D estão sendo usados em planejamentos de Radioterapia para a localização espacial e mapeamento das curvas de isodose, realizando, assim, um planejamento mais personalizado para cada campo de radiação, além da confecção de implantes dentais, customização de próteses e confecção de bólus. Diante do exposto esse trabalho projetou e desenvolveu um objeto simulador chamado de \"Canis Morphic\" utilizando uma impressora 3D e materiais tecido-equivalentes para a realização dos testes de controle de qualidade e otimização das doses na área de Radioterapia em animais (cães). Os resultados obtidos demonstraram-se promissores na área de criação de simuladores por impressão 3D, com materiais de baixo custo, para aplicação no controle de qualidade em Radioterapia veterinária. / The increase in human longevity caused a number of diseases with age; in contrast the advancement of medicine made possible the early diagnosis and treatment of several previously incurable diseases. This scenario is also important for domestic animals (dogs and cats - PETs) that have doubled their life expectancy in recent decades, a fact that humans took centuries to reach. Like humans, this increase in animal longevity was accompanied by age-related diseases, including cancer. One of the therapies currently used in the treatment of cancer is radiation therapy, a technique that uses ionizing radiation to destroy tumor cells (target volume) with minimal impairment to healthy surrounding tissues (organs at risk). This technique requires periodic quality control testing, including dosimetry with the use of tissue-equivalent phantoms, in order to verify the dose of radiation received by the patient being treated and to compare it subsequently with the calculated radiation dose by the treatment planning system. The rapid expansion of the 3D printer opened the way for a health revolution. Currently the 3D impression of phantoms are being used in Radiation therapy\'s planning for the spatial location and mapping of the isodose curves, thus realizing a more personalized planning for each radiation field, besides the preparation of dental implants, customization of prostheses and build of bolus. This work aimed has designed and developed a simulator object called \"Canis Morphic\" using a 3D printer and tissue-equivalent materials to perform quality control and dose optimization tests in the area of Radiation therapy in animals (dogs). The results obtained demonstrated be promising in the area of development of phantoms by 3D printing, with materials of low cost, for application in quality control in Veterinary Radiation therapy.
23

Experimentální 3D tiskárna pro laserové sintrování plastů / Experimental 3D printer for the selective laser sintering of polymers

Kroutil, Tomáš January 2017 (has links)
The diploma thesis deals with design and realization of experimental 3D printer for selective laser sintering of plastic powders. The output of the work is a device that can create the main process conditions for laser sintering. A diode laser is used in the device, which allows aluminum composite powders to be processed. The printer allows you to heat up the applied layer of powder and set-up space. The research section focuses on similar equipment, process parameters, laser technology and control system. The design section contains solution variants and a description of the chosen solution.
24

Návrh a konstrukce CNC routeru pro DPS / CNC router for PCB

Gerják, Rastislav January 2017 (has links)
In mechanical industry, both additive and subtractive manufacturing methods are controlled by instructions in G-code, making it possible to utilize both technologies in one modular device. Main objective is to design, construct, and calibrate multipurpose machine based on RepRap 3D printer, which will be able to use attached spindle to precisely mill light materials. Particular emphasis is given to ability to carve a pattern and drill holes in plated substrate in order to create functional PCB by incision.
25

Design 3D tiskárny pro technologii Contour Crafting / Design of the 3D printer for technology Contour Crafting

Anderle, Peter January 2019 (has links)
The subject of this bachelor thesis is the design of the spatially adaptable 3D printer for Contour Crafting. Aiming to apply megascale aditive technology in a field of construction industry.
26

Jednostupňová převodovka vyrobená 3D tiskem / A single-speed gearbox made by 3D printing

Hykolli, Denis January 2021 (has links)
The aim of these theses was the creation of a single-stage gearbox by additive technology FDM / FFF. By chosen values was made dimension calculation for gears. The 3D model of the gearbox was designed in 3D software Autodesk Inventor. Single parts were produced on an FDM 3D printer by Prusa Research. Manufacturing programs for parts were prepared in PrusaSlicer. These programs were used for producing individuals parts on 3D Printer. Transparent material and printing parameters for the top of the gearbox were chosen by visual test and test of light intensity. The total cost of model production is calculated in the work. The result of these is a completely working model of a single-stage gearbox with a transparent top of the gearbox.
27

Konstrukce 3D tiskárny pro materiály s vyšší pevností / Design of 3D printer for high strength materials

Žlebek, Michal January 2015 (has links)
Thesis deals with FDM 3D printing method and testing capabilities of optimum printing conditions for different materials. The aim of this work is to design and manufacture of experimental device that enables printing to investigate these conditions. A device designed in this work was named UK3DP and allows dual color object printing with maximum dimensions of the square base of 150 mm and a height of 150 mm. Before printing, the user can set almost all parameters affecting the printing process, including air temperature in heated chamber that is part of it. To verify the functionality several materials are tested, including ABS, PC and PEI. It also describes basic verification of the influence of selected parameters on the print result. Performs tensile tests confirming the influence of ambient temperature during printing on the quality of fiber connections, examines the final quality of the surface for each layer height and compares the resulting deformation of printed objects with other printers. The result of this work is a 3D printer capable of testing printing conditions for both existing and new types of materials with a range of user adjustable parameters.
28

Stavba a aplikace 3D FDM tiskárny typu deltabot / Production and aplication of 3D FDM deltabot printer

Knapil, Josef January 2015 (has links)
The thesis describes design and aplication of 3D FDM printer type of delta. The first part describes methods of rapid prototyping. The second part describes 3D printers type of delta. The third part deals with construction and calibration of delta printer. In the fourth part are made suitable modifications to the design of the printer, to improve the quality of printing, which is then applied on a sample product. The final section is devoted to technical and economic evaluation.
29

3D tiskárna / 3D Printer

Ctibor, Jiří January 2016 (has links)
Master thesis deals with topic about 3D printers, concretely making hardware of control and power electronic for FDM 3D printer. The work could offer an overview about basic 3D printing technologies after reading. More information could be read about FDM technology, which is used in our printer, also with description of all important components. The furthest is discussed about electronic drives. If reader is interested in this topic, part of this thesis is schematic design of control electronics, which can be used to build own boards. Design of printed circuit boards is not present in attachment and can be obtained by contacting the author. For own control is used one of the open source control software. Mechanical problems and also mechanical design is done in parallel thesis by other student of Faculty of mechanical engineering.
30

Vidareutveckling och kvalitetstestning av 3D-skrivare i storformat / Further development and quality testing of large format 3D-printer

Johansson, Isak January 2023 (has links)
År 2017 genomfördes ett projekt att vidareutveckla en äldre 3D-skrivare för att skapa en större och mer robust skrivare. Denna 3D-skrivare blev tyvärr aldrig blev färdigställd och med ett ökat behov av tillverkning av komplexa prototyper fanns behovet att färdigställa 3D-skrivaren. Detta arbete startades genom att undersöka 3D-skrivarens komponenter och komplettera med det som saknades. Styrkortet Duet 2 jämfördes mot andra styrkort för att undersöka ifall det var tillräckligt till 3D-skrivaren. En pekskärm och expansionskort kompletterades då till styrkortet. Inbyggd programvara till styrkortet saknades så detta uppdaterades och ställdes in korrekt. Olika typer av inbyggd programvara jämfördes även. En inkapsling för byggytan konstruerades av plexiglas för att skydda mot drag från fönster och ventilation. Styrkort monterades även i en separat inkapsling med tillhörande fläktar för att säkerställa funktion. En PEI byggyta och silikonvärmeplatta monterades på byggplattan och kopplades in med ett halvledarrelä till styrkortet. Med alla komponenter monterades provkördes slutligen 3D-skrivaren och kvalitetstestades grundligt med en #3Dbenchy i 250% skala. Resultatet av projektet blev vidareutvecklad och färdigställd 3D-skrivare i storformat kapabel att tillverka avancerade 3D-utskrifter med godkänd kvalitet. / In 2017, a project was carried out to further develop an older 3D printer to create a larger and more robust printer. This 3D-printer was unfortunately never completed and with an increased need to manufacture complex prototypes there was a need to complete the 3D-printer. This work was started by examining the 3D-printer's components and supplementing with what was missing. The Duet 2 control board was compared against other control boards to investigate if it was sufficient for the 3D-printer. A touch screen and expansion card were then added to the control board. Firmware for the control board was missing so this was updated and set up correctly. Different types of firmware were also compared. An enclosure for the print bed was constructed from Plexiglas to protect against drafts from windows and ventilation. Control boards were also mounted in a separate compartment with associated fans to ensure correct function. A PEI build surface and silicon heater pad were mounted on the build plate and connected with a solid-state relay to the control board. With all the components mounted the 3D printer was test run and quality tested thoroughly with a #3Dbenchy at 250% scale. The result of the project was a further developed and completed 3D printer in large-format capable of producing advanced 3D-prints with adequate quality.

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