109 research outputs found

    Design for microassembly: a methodology for product design and process selection

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    The thesis presents research carried out in the field of design for microassembly (DFµA), a field that has hereto been characterised by the absence of well defined methodologies intended to facilitate transfer of prototypes from the research lab to production on industrial scale. A DFμA methodology has been developed, serving the purpose of integrating product and micro assembly process development. It aims in particular at increasing the efficiency of the microproduct development process, decreasing the development time and the product and process cost, and enhancing the product quality. Chapter 1 presents the motivations, objectives, and structure of the thesis. The work carried out is inspired by the need to overcome barriers currently existing between the making of single research products and production on an industrial level. The main objective is to contribute to the creating of a novel DFμA that supports product design and process selection, thereby facilitating the efficient assembly of complex three-dimensional miniaturised devices. This is complemented by a range of secondary targets that deal with the development and verification of supporting methods and models related to DFμA. The summary of a comprehensive literature review is given in chapter 2. The survey provides results of studies closely related to the work reported in this thesis and relates that work to a larger ongoing dialogue about the topic of assembly and design in the microworld. Chapter 3 outlines the research approach adopted here for the developing of a DFμA methodology. It carefully analyses the way in which the knowledge gaps identified can be addressed and how the stated objectives can best be achieved. The key contributions made to the developing of a DFμA methodology are presented in chapters 4,5, and 6. The micro assembly process capability model is described first, in Chapter 4. It constitutes the first attempt made at introducing a general framework for capturing of microassembly characteristics. The model developed enables selection and characterisation of microassembly processes. A framework to characterise the model's application to microjoining, -feeding, and -handling is as well suggested. Chapter 5 concerns the actual DFμA methodology. The methodology's layout and structure are introduced in detail. Moreover, the main functions and key phases of the methodology are explained. Special attention is paid to the integration of the microassembly process capability model and to the development of further elements used within the methodology, such as support in product design. Provided in Chapter 6 is a comprehensive analysis of conventional DFA guidelines, intended to explain how the microspecific guidelines have been formulated. The chapter also describes how these are implemented within the overall DFμA methodology. The procedure of validating and illustrating the methodology, which includes applying it to practical test cases, takes place in Chapter 7. The thesis is concluded in Chapter 8, wherein evidence of the originality of the knowledge contribution achieved through the work presented is highlighted. Opportunities for further research work building on th

    Towards an integrated framework for the configuration of modular micro assembly systems

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    The future of manufacturing in high-cost economies is to maximise responsiveness to change whilst simultaneously minimising the financial implications. The concept of Reconfigurable Assembly Systems (RAS) has been proposed as a potential route to achieving this ideal. RASs offer the potential to rapidly change the configuration of a system in response to predicted or unforeseen events through standardised mechanical, electrical and software interfaces within a modular environment. This greatly reduces the design and integration effort for a single configuration, which, in combination with the concept of equipment leasing, enables the potential for reduction in system cost, reconfiguration cost, lead time and down time. This work was motivated by the slow implementation of the RAS concept in industry due, in part, to the limited research into the planning of multiple system reconfigurations. The challenge is to enable consideration of, and planning for, the production of numerous different products within a single modular, reconfigurable assembly environment. The developed methodology is to be structured and traceable, but also adaptable to specific and varying circumstances. This thesis presents an approach that aims towards providing a framework for the configuration of modular assembly systems. The approach consists of a capability model, a reconfiguration methodology and auxiliary functions. As a result, the approach facilitates the complete process of requirement elicitation, capability identification, definition and comparison, configuration analysis and optimisation and the generation of a system configuration lifecycle. The developed framework is demonstrated through a number of test case applications, which were used during the research, as well as the development of some specific technological applications needed to support the approach and application

    Towards an integrated framework for the configuration of modular micro assembly systems

    Get PDF
    The future of manufacturing in high-cost economies is to maximise responsiveness to change whilst simultaneously minimising the financial implications. The concept of Reconfigurable Assembly Systems (RAS) has been proposed as a potential route to achieving this ideal. RASs offer the potential to rapidly change the configuration of a system in response to predicted or unforeseen events through standardised mechanical, electrical and software interfaces within a modular environment. This greatly reduces the design and integration effort for a single configuration, which, in combination with the concept of equipment leasing, enables the potential for reduction in system cost, reconfiguration cost, lead time and down time. This work was motivated by the slow implementation of the RAS concept in industry due, in part, to the limited research into the planning of multiple system reconfigurations. The challenge is to enable consideration of, and planning for, the production of numerous different products within a single modular, reconfigurable assembly environment. The developed methodology is to be structured and traceable, but also adaptable to specific and varying circumstances. This thesis presents an approach that aims towards providing a framework for the configuration of modular assembly systems. The approach consists of a capability model, a reconfiguration methodology and auxiliary functions. As a result, the approach facilitates the complete process of requirement elicitation, capability identification, definition and comparison, configuration analysis and optimisation and the generation of a system configuration lifecycle. The developed framework is demonstrated through a number of test case applications, which were used during the research, as well as the development of some specific technological applications needed to support the approach and application

    Standards in sustainable engineering and design

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    The financial and environmental costs associated with the manufacture and consumption of products may be reduced through design for efficient production, service life extension and post-consumer value recovery. In response to today’s need to design with consideration for the whole product life cycle, British Standards Institution (BSI) published BS 8887-1 (2006) Design for Manufacture, Assembly, Disassembly and End-of-life processing (MADE). Original research into the distribution and use of this first part of the MADE series is reported in this thesis. The organizations that accessed BS 8887-1 were categorised using their Standard Industrial Classification (SIC) code. The results are presented graphically in multilevel charts using the hierarchical structure of the SIC system. The study found that the majority of standards users that purchased or downloaded BS 8887-1 were companies in the manufacturing sector and particularly electronics producers. Educational institutions also showed high levels of interest in the standard. For the first time, the use of BS 8887-1 in practice has been investigated. The purpose was to discover if, why and how it is being used and to identify examples of its application in design practice. This was accomplished through semi-structured interviews with design practitioners from both industry and academia, thus helping to explain the results of the earlier SIC study. The information gathered through the interviews shows how BS 8887-1 has informed the design process and how it has been used in combination with various design and management techniques e.g. Advanced Product Quality Planning (APQP). These studies suggest that demand for the standard has been stimulated by the introduction of Extended Producer Responsibility (EPR) legislation, especially the Waste Electrical and Electronic Equipment (WEEE) directive. Importantly, the use of BS 8887-1 has been found to be helpful in winning new business and reducing the costs associated with manufacture, product maintenance and waste management. Based on the result of the qualitative research, a new model of the use of standards in the New Product Development (NPD) process is presented. The research was proposed by the Chairman of the BSI technical committee responsible for the BS 8887 series. The beneficiaries are BSI, industry and academia, since the investigation has shown BS 8887-1 to be of value, and has informed the continuing development of this series of standards. The thesis concludes by arguing for BS 8887 to become the basis of an International Organization for Standardization (ISO) standard in order to reach a wider audience. It also identifies a need for the standard’s design requirements to be supported with additional supplementary interpretation expanding on, and adding detail to, the information in the standard itself. Influenced by this research, at the time of writing a new BSI working group was being formed to consider developing BS 8887 as an ISO standard. BSI had also begun the process of commissioning a handbook to assist designers in the practical application of BS 8887 in industrial design.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    Prototyping for Research and Industry

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    In this thesis we want to present some of the activities carried out during the PhD studies held at the PhD School "L. da Vinci" in the period from January 2012 to December 2014. The activities were held in the fields of robotics and mechanical engineering, and the main theme was the prototyping of new concepts, as well as the activity of conceptual design in its different phases, from generation of the idea, to the realization and testing of prototypes. The conceptual design phase is of fundamental importance to structure the process of generation of new ideas. Sometimes it is a process that is carried out unconsciously by the inventor. Providing a tool that allows to guide him in the various stages of idea generation can lead to advantages that let the inventor to explore areas from which take inspiration, which otherwise would not have been taken into account. An aspect of fundamental importance in the development of new prototypes is a process that goes in the opposite direction of the idea generation phase. Initially the conceptual design tends to provide tools to generate as many ideas as possible, but at some point there is the need to select a limited number of cases to investigate. Through the selection phase, which can be structured at levels more or less structured, and more or less qualitative/quantitative, the inventor tends to identify, case by case, which are the ideas in which is worth investing time and resources, before moving to the following stages. Prototyping, as well as its previous phase, now commonly called pretotyping, are mandatory steps for those who want to develop any new idea. The success of the final product or service may depend from the analysis of the pretotype first, and of the prototype later, since it allows to detect limits and possible improvements of the concept before moving to the final implementation phase

    Development of microfluidic tools to reproduce and characterize the tumor microenvironment

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    A pesar de que la incidencia del cáncer está en aumento, sobre todo en los países desarrollados, el desarrollo de nuevos fármacos contra esta enfermedad es cada vez menos efectivo. Para revertir esta tendencia, aparece la necesidad de desarrollar mejores herramientas para reproducir y caracterizar el microentorno tumoral. Una de ellas son modelos in vitro más precisos.En este contexto, la microfluídica se presenta como una potente alternativa para el desarrollo de estos nuevos modelos in vitro más precisos, que puedan emplearse para un desarrollo y selección de fármacos más racional y efectivo. No obstante, se trata de un conjunto de técnicas poco extendido en los laboratorios de biología molecular. Así, en la presente tesis se desarrollan dos modelos microfluídicos del microentorno tumoral para tumores sólidos, junto a las herramientas necesarias para su caracterización, todo ello de fácil uso para tratar de generalizar la aplicación de los mismos.En el capítulo 1 se realiza una revisión del estado de la cuestión en lo referente a modelos de cáncer in vitro y su caracterización. En el capítulo 2 se desarrolla un modelo microfluídico de co-cultivo que permite estudiar las interacciones endotelio-tumor, así como la capacidad de penetración y erradicación de células tumorales de nuevos fármacos. En el capítulo 3 se presenta una herramienta para caracterizar los niveles de oxígeno molecular en cualquier punto de un cultivo in vitro 3D. En el capítulo 4 se presenta un modelo de tumor centrado en la generación y caracterización de gradientes biológicos, así como su adaptación a las técnicas tradicionales de biología molecular para el análisis del perfil genético del microentorno tumoral a lo largo del tiempo. Para generar los sistemas microfluídicos descritos anteriormente, se emplearon dispositivos fabricados mediante distintas técnicas y materiales. En los dispositivos se sembraron distintas poblaciones celulares, intentando así reproducir la estructura y organización de los tejidos biológicos. Mediante diferentes técnicas de microscopía (óptica, fluorescencia, confocal, imagen en tiempo real) y sondas fluorescentes se monitorizó la evolución y comportamiento celular. La caracterización del hidrogel sensible al oxígeno se realizó a través de las técnicas ya citadas, así como espectrofotometría, microscopía de fuerza atómica y electrónica de barrido en condiciones ambientales. Finalmente, la extracción de las células de los hidrogeles se realizó por medio de degradaciones enzimáticas, y la cuantificación de la expresión génica mediante extracción de RNA, retrotranscripción y reacción en cadena de la polimerasa cuantitativa.La conclusión general de la tesis, es que la utilización de modelos biomiméticos cambia dramáticamente el resultado de los ensayos realizados in vitro, por lo que su uso es necesario para obtener resultados relevantes y trasladables a la clínica. Asimismo, el desarrollo de sistemas biomiméticos in vitro del microentorno tumoral de uso generalizado es posible mediante el desarrollo de dispositivos de fácil uso, así como del establecimiento de métodos robustos de caracterización de los mismos, tanto in situ como “aguas abajo” del establecimiento de los modelos. Bibliografía: 1. Balkwill FR, Capasso M, Hagemann T (2012) The tumor microenvironment at a glance. J Cell Sci 125: 5591-5596.2. Junttila MR, de Sauvage FJ (2013) Influence of tumour micro-environment heterogeneity on therapeutic response. Nature 501: 346-354.3. Scannell JW, Blanckley A, Boldon H, Warrington B (2012) Diagnosing the decline in pharmaceutical R&D efficiency. Nat Rev Drug Discov 11: 191-200.4. Adriani G, Pavesi A, Tan AT, Bertoletti A, Thiery JP, et al. (2016) Microfluidic models for adoptive cell-mediated cancer immunotherapies. Drug Discov Today 21: 1472-1478.5. Ayuso JM, Virumbrales-Munoz M, Lacueva A, Lanuza PM, Checa-Chavarria E, et al. (2016) Development and characterization of a microfluidic model of the tumour microenvironment. Sci Rep 6: 36086.6. Ayuso JM, Monge R, Martínez-González A, Virumbrales-Muñoz M, Llamazares GA, et al. (2017) Glioblastoma on a microfluidic chip: Generating pseudopalisades and enhancing aggressiveness through blood vessel obstruction events. Neuro-Oncology: now230.<br /

    Advances in Bioengineering

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    The technological approach and the high level of innovation make bioengineering extremely dynamic and this forces researchers to continuous updating. It involves the publication of the results of the latest scientific research. This book covers a wide range of aspects and issues related to advances in bioengineering research with a particular focus on innovative technologies and applications. The book consists of 13 scientific contributions divided in four sections: Materials Science; Biosensors. Electronics and Telemetry; Light Therapy; Computing and Analysis Techniques
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