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.

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.

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.

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.

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.

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.

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.

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.

No description available.

Novel tissue mimicking materials have been developed for cancer treatment research. In the present research work, the tissue mimicking material is printed using 3D bioprinting technology. The nanoparticles are homogeneously mixed with tissue mimicking materials to enhance the heating capacity. The thermal conductivity of tissue mimicking materials is measured using a micropipette thermal sensor (MTS). Further, the optimal value is identified based on optimization technique and incorporated into a theoretical model to predict the surface temperature of microsphere. The heat conduction governing equation with Lambert law is numerically solved using COMSOL Multiphysics software. To validate the present simulation results, the experiments are conducted using a continuous laser system.