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Orientador: Roseana da Exaltação Trevisan / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-12T19:13:48Z (GMT). No. of bitstreams: 1 Inglez_LuisFelipe_M.pdf: 2430907 bytes, checksum: 2ff762a89795106a40225f7d705b1d6f (MD5) Previous issue date: 2008 / Resumo: Apesar de todos os avanços tecnológicos, o desenvolvimento de projeto, na grande maioria das vezes, ainda é executado de forma interativa, empírica e intuitiva, baseado unicamente na experiência, inteligência ou criatividade dos engenheiros. O desenvolvimento de processo e máquinas para solda em plástico de tanques de combustível soprados não é exceção. Assim como na fase de desenvolvimento, a alteração ou correção de um projeto já existente também é realizada de forma empírica. Visando identificar as falhas de projeto de um processo de solda existente e orientar ações de correção e melhoria, o autor deste estudo utilizou uma metodologia de desenvolvimento sistêmico de projeto, no caso o Axiomatic Design, como uma ferramenta de análise. Para tanto, ele coordenou a construção da matriz de design do processo estudado para identificar os acoplamentos existentes. Num segundo momento, baseando-se nos documentos de controle de produção diário do período de 2005 a 2007, buscou-se estimar os valores anuais do conteúdo de informação deste sistema (Isys). A correção ou melhoria dos acoplamentos que obtivessem as menores eficiências no ano de 2005 foi priorizada. O cálculo dos valores de conteúdo de informação dos anos de 2006 e 2007 visou avaliar a eficácia do método proposto. Os resultados destes cálculos comprovaram que o projeto axiomático pode ser utilizado como ferramenta de análise. / Abstract: Despite all technological and scientific breakthroughs, design is being done empirically on a trial-and-error basis, depending on intuitive and innate reasoning rather than a rigorous scientific study. Design of welding machines for fuel plastic tanks is no exception. Refurbishment and corrective maintenance tasks are also made without any scientific basis. This work intended to demonstrate the use of axiomatic design as an analytic tool for an existent machine design in use on the shop floor. Based on the literature review about Axiomatic Design and Plastic Welding, the author determined the design matrix of an existent fuel tank welding machine, identifying the coupled elements. Moreover, based on production data from 2005 to 2007, the information content (Isys) of this machine was evaluated. The correction or improvement of design parameters with low information content values in 2005 was prioritized. In order to validate the efficacy of using axiomatic design as an analytic tool, the information content values of 2006 and 2007 were evaluated. The result proves that axiomatic design can be used as an analytical tool. / Mestrado / Materiais e Processos de Fabricação / Mestre em Engenharia Mecânica

This work establishes the relationships between several key Friction Stir Welding process parameters and the resulting microstructural and flexural properties of the welded joint. A series of four single parameter experiments were run. The parameters investigated were pin diameter, feedrate, shoe temperature, and pressure time. Butt welds were made in 6 mm thick stress-relieved extruded polypropylene sheet. Three-point bend tests were used to determine the ultimate flexural strength and coincident strain. The maximum bend angle before failure was used to label the welds as "good or bad." An optical microscope capable of cross polarization was used to examine and photograph the weld microstructure. Welds were evaluated according to 1) DVS bend angle, 2) flexural properties, and 3) weld microstructure. All welds made surpassed the DVS requirements for classification as a "good weld" established for hot-gas, extrusion, and laser welding processes. Most welds met the bend angle requirement for hot-plate welds. Welds created for this work maintained 80-92% of base material flexural strength. In the majority of the welds, the strength was between 85 and 90% of base material. The FSW joints showed a flexural strength of 10500 psi, compared to a base material strength of 12400 psi. Four microstructural zones were found to exist in the FSW joints. These were: 1)advancing interface, 2) retreating interface, 3) bottom disturbance, and 4) central zone. Several common microstructure types and defects were found to exist in the welds. These were: 1) spherulites, 2) voids, 3) root defects, 4) flow lines, and 5) onion skin. A distinct correlation was observed between weld microstructure and flexural properties. Those welds whose microstructure most nearly resembled the base material demonstrated the best flexural properties. This can be accomplished by operating with a low feedrate, a high shoe temperature, and a large pin.

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