Rozprawy doktorskie na temat „TAGUCHI DOE”

La industria de plásticos se encuentra en un crecimiento progresivo a comparación de otros sectores, ya que la gran mayoría de las empresas tienen procesos automatizados. Es por esto que las empresas del sector se vuelven más competitivas cada día. Esta investigación se realiza en una empresa peruana en la que se detecta como problema principal la alta tasa de productos defectuosos, que impacta a su vez negativamente en un 4.37% del costo fabricación. Por ello y en base a diversos estudios sobre la implementación de herramientas y metodologías de solución y mejora, se propone la implementación de un modelo basado en la filosofía Lean Manufacturing con el método Taguchi para la reducción de estos, obteniendo como resultado un decremento del 60.41% en la tasa de defectos. Si bien el objetivo del proyecto es posicionar la empresa dentro del porcentaje estándar, se logra estar por debajo de este.
The plastics industry is in progressive growth compared to other sectors since the vast majority of companies have automated processes. This is why the companies in the sector become more competitive every day. This investigation is carried out in a Peruvian company in which the high rate of defective products is detected as the main problem, which in turn negatively impacts 4.37% of the manufacturing cost. For this reason and based on various studies on the implementation of tools and methodologies for solution and improvement, the implementation of a model based on the Lean Manufacturing philosophy with the Taguchi method is proposed to reduce these, resulting in a decrease of 60.41 % in defect rate. Although the objective of the project is to position the company within the standard percentage, it is possible to be below this.
Trabajo de investigación

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia Mecânica
A complexidade do processo de encapsulamento de resinas epoxy em ignições, e o apertado controlo da qualidade, exige o desenvolvimento e o melhoramento contínuo dos processos de fabrico de forma a satisfazer as exigências dos clientes e a perpetuar a confiança que depositam na Delphi do Seixal. A insdústria automóvel, a par da indústria aeronáutica, adoptaram a filosofia 6 sigma para o controlo dos processos de fabrico de modo a maximizar a segurança dos consumidores e a qualidade do produto final ao mesmo tempo que se minimiza o número de produtos não conformes, por milhão de unidades produzidas, o que obriga a utilização de ferramentas de controlo estatístico e de melhoramento contínuo. O recurso a ferramentas estatísticas e metodologias desenvolvidas por especialistas na matéria, permite uma análise metódica, científica e eficiente, do processo, poupando tempo e dinheiro aos engenheiros que as aplicarem com sabedoria e humildade. O Controlo Estatístico do Processo, SPC, está presente na politica de qualidade da Delphi, no entanto, o método de experimentação contínua a ser feito numa base intuitiva, seguindo uma filosofia de “Tentativa-Erro”, cujo resultado nem sempre é rápido e satisfatório. Fatores-chave, como a estequiometria das reações químicas da resina com o endurecedor e o perfil de cura em função do tempo e temperatura, tornam o processo altamente sensível a variações provocadas por agentes externos, que podem comprometer a qualidade final do produto, o que motiva a introdução de ferramentas robustas em todas as etapas de desenvolvimento e controlo do processo. A carteira de clientes da Delphi Seixal, no campo das ignições, conta com marcas de renome, como é o exemplo da General-Motors, Mercedes-Benz, BMW, grupo PSA, entre outros. O aumento dos volumes de fabrico, torna por vezes necessária, a instalação de novas linhas de produção, que necessitam de ser certificadas para produzir de acordo com os padrões de qualidade da Delphi e critérios do cliente, exigindo a realização de um estudo rigoroso onde são definidos os parâmetros de processo e avaliada a sua capacidade. Este trabalho procura definir a melhor combinação de fatores controláveis que aumentam a robustez do processo, através do desenho de experiências de Genichi Taguchi, e verificar se os equipamentos se encontram aptos para produzir segundo os critérios de qualidade da Delphi (Cartas de controlo de Walter A. Shewhart).

The Veo+ projector is using a cooling system that consists of fan and blowers. This system is cooling the electronic components of the device and the lamp of the projector, however extracting a high noise. To lower this noise the rpm speeds (rotational speed) of the fan and blowers should be decreased. Thus, lowering the speed will result in higher temperature values in whole system (inside the device). While lowering the speed, the higher temperature values should be kept within the thermal design specifications of the electronic components. The purpose of this thesis work is to find an optimal solution with lower rpm speeds of the fan and blowers while keeping the temperatures of the various components of the device (touch temperature of the enclosure and electronic components) within the temperature design limits. Before testing the device to find the optimum state, the design limits of the device are determined. Then, by using the design of experiment methods like Taguchi, the optimum state for the device within the design specifications is obtained. Finally, additional tests are applied within the optimum state to demonstrate a fan algorithm as a final solution. While doing the experiments thermocouples are used for measuring the component temperatures.

This dissertation presents an empirical approach to identifying decisions for adapting cognitive radio parameters with no a priori knowledge of the environment. Cognitively inspired radios, attempt to combine observed metrics of system performance with artificial intelligence decision-making algorithms. Current architectures trend towards hybrid combinations of heuristics, such as genetic algorithms (GA) and experiential methods, such as case-based reasoning (CBR). A weakness in the GA is its reliance on limited mathematical models for estimating bit error rate, packet error rate, throughput, and signal-to-noise ratio. The CBR approach is similarly limited by its dependency on past experiences. Both methods have potential to suffer in environments not previously encountered. In contrast, the statistical methods identify performance estimation models based on exercising defined experimental designs. This represents an experiential decision-making process formed in the present rather than the past. There are three core contributions from this empirical framework: 1) it enables a new approach to decision making based on empirical estimation models of system performance, 2) it provides a systematic method for initializing cognitive engine configuration parameters, and 3) it facilitates deeper understanding of system behavior by quantifying parameter significance, and interaction effects. Ultimately, this understanding enables simplification of system models by identifying insignificant parameters. This dissertation defines an abstract framework that enables application of statistical approaches to cognitive radio systems regardless of its platform or application space. Specifically, it assesses factorial design of experiments and response surface methodology (RSM) to an over-the-air wireless radio link. Results are compared to a benchmark GA cognitive engine. The framework is then used for identifying software-defined radio initialization settings. Taguchi designs, a related statistical method, are implemented to identify initialization settings of a GA.
Ph. D.

[ES] En la presente Tesis Doctoral se investigó la aplicación del proceso de ultrafiltración (UF) y el fenómeno de ensuciamiento de las membranas en la eliminación de sustancias disueltas y coloidales (DCS) de efluentes tratados de la industria papelera (PMTE) para su reutilización en los diferentes procesos de fabricación de papel y cartón reciclado. El objetivo general de esta investigación se dividió en tres partes principales: i) describe cómo encontrar las condiciones óptimas de operación de cuatro parámetros de proceso: presión transmembrana (TMP), velocidad de flujo cruzado (CFV), temperatura y corte de peso molecular (MWCO) para maximizar el flujo promedio de permeado (Jp) y rechazo de la demanda química de oxígeno (COD) y minimizar el descenso del flujo de permeado acumulado (SFD) utilizando el método de Taguchi (Design Robusto) y utility concept aplicado a un proceso de UF a flujo cruzado, para remover DCS de efluentes tratados de la industria papelera, ii) el descenso del flujo de permeado y los mecanismos de ensuciamiento de las membranas de UF ensuciadas con PMTE se examinaron mediante modelos matemáticos semi-empíricos. Los resultados para los diferentes ensayos de UF se expresaron en términos de variación del Jp en función del tiempo para verificar la precisión del ajuste (mayor valor de R2 y menor valor de desviación estándar) de los distintos modelos de Hermia adaptados a flujo tangencial y del modelo de formación de torta en filtración a presión constante ajustados a los datos experimentales, y iii) describe métodos de identificación, caracterización y posibles orígenes de las sustancias contaminantes (foulants) en las membranas de UF. Técnicas como el análisis físico-química, FESEM, SEM-EDS, ATR-FTIR y 3DEEM se llevaron a cabo para comprender qué fracción de los contaminantes son responsables por la formación de incrustaciones en las membranas. Los resultados obtenidos durante la etapa de optimización de parámetros del procesos demostraron que TMP y MWCO tienen la mayor contribución en el Jp y SFD. En el caso de la tasa de rechazo de COD, los resultados mostraron que MWCO tiene la mayor contribución seguida de CFV. Por consiguiente, las condiciones óptimas se encontraron para el segundo nivel de TMP (2.0 bar), el tercer nivel del CFV (1.041 m/s), el segundo nivel de la temperatura (15°C) y el tercer nivel de MWCO (100 kDa). Bajo estas condiciones óptimas de operación Jp, rechazo de COD y SFD alcanzaron respuestas de 81.15 L/m2.h, 43.90% y 6.01 (alrededor de 28.96 % para (FD), respectivamente, valores dentro del rango previsto del intervalo de confianza del 95%. Además, los modelos de Hermia adaptados a UF en flujo tangencial fueron capaces de predecir con gran precisión el descenso del Jp y los mecanismos de ensuciamiento en función del tiempo para todas las membranas seleccionadas (10, 30 y 100 kDa) y bajo diferentes condiciones ensayadas de UF. Por lo tanto, los modelos que presentan un mayor grado de ajuste son el bloqueo completo de poros (coeficiente de determinación R2 >0.97) y bloqueo intermedio (R2 >0.96), seguido por el modelo de formación de torta (R2 >0.94), lo que indica que estés son los principales mecanismos de ensuciamiento de las membranas. Análisis de 3DEEM revelaron que la mayoría de la materia orgánica fluorescentes en las membranas sucias eran proteínas coloidales (componentes similares a proteínas I + II) y proteínas macromoleculares (componentes similares a SMP). Además, polisacáridos (especie celulósica) y sustancias como ácidos grasos y resinosos fueron identificadas en las membranas contaminadas mediante análisis ATR-FTIR. Por fin, análisis SEM-EDS para las membranas ensuciadas con PMTE se detectó concentración de contaminantes inorgánicos (iones metálicos multivalentes) especialmente el Ca2+ que podría acelerar la formación torta en la superficie de la membrana.
[CA] En la present Tesi Doctoral es va investigar l'aplicació del procés d'ultrafiltració (UF) i el fenomen d'embrutiment de les membranes en l'eliminació de substàncies dissoltes i col·loïdals (DCS) d'efluents tractats de la indústria paperera (PMTE) per al seu reutilització en els diferents processos de fabricació de paper i cartó reciclatge. L'objectiu general d'aquesta investigació es va dividir en tres parts principals: i) descriu com trobar les condicions òptimes d'operació de quatre paràmetres de procés: pressió transmembrana (TMP), velocitat de flux creuat (CFV), temperatura i tall de pes molecular (MWCO) per a maximitzar el flux mitjà de permeat (Jp) i rebuig de la demanda química d'oxigen (COD) i minimitzar el descens del flux de permeado acumulat (SFD) utilitzant el mètode de Taguchi (Design Robust) i utility concept aplicat a un procés de UF a flux creuat en escala pilot, per a remoure DCS d'efluents tractats de la indústria paperera (PMTE), ii) el descens del flux de permeat i els mecanismes de embrutiment (fouling) de les membranes de UF embrutades amb PMTE es van examinar mitjançant models matemàtics semi-empírics. Els resultats per als diferents assajos de UF es van expressar en termes de variació del flux de permeat (Jp) en funció del temps per a verificar la precisió de l'ajust (major valor de R2 i menor valor de desviació estàndard) dels diferents models de Hermia adaptats a flux tangencial i del model de formació de coca en filtració a pressió constant ajustats a les dades experimentals, i iii) descriu mètodes d'identificació, caracterització i possibles orígens de les substàncies contaminants (foulants) en les membranes de UF. Tècniques com l'anàlisi física-química, FESEM, SEM-EDS, ATR-FTIR i 3DEEM es van dur a terme per a comprendre quina fracció dels contaminants són responsables per la formació d'incrustacions sobre la superfície i adsorció dins dels porus de les membranes. Els resultats obtinguts durant l'etapa d'optimització de paràmetres del processos van demostrar que TMP i MWCO tenen la major contribució en el Jp i SFD. En el cas de la taxa de rebuig de COD, els resultats van mostrar que MWCO té la major contribució seguida de CFV. Per consegüent, les condicions òptimes es van trobar per al segon nivell de TMP (2.0 bar), el tercer nivell del CFV (1.041 m/s), el segon nivell de la temperatura (15°C) i el tercer nivell de MWCO (100 kDa). Sota aquestes condicions òptimes d'operació Jp, rebuig de COD i SFD van aconseguir respostes de 81.15 L/m².h, 43.90% i 6.01 (al voltant de 28.96% per a (FD)), respectivament, valors dins del rang previst de l'interval de confiança del 95%. A més, els models de Hermia adaptats a UF en flux tangencial van ser capaços de predir amb gran precisió el descens del Jp i els mecanismes de embrutiment en funció del temps per a totes les membranes seleccionades (10, 30 i 100 kDa) i baix diferents condicions assajades de UF. Per tant, els models que presenten un major grau d'ajust són el bloqueig complet de porus (coeficient de determinació R2 >0.97) i bloqueig intermedi (R2 >0.96), seguit pel model de formació de coca (R2 >0.94), la qual cosa indica que estigues són els principals mecanismes de embrutiment de les membranes. Anàlisi de 3DEEM van revelar que la majoria de la matèria orgànica fluorescents en les membranes brutes eren proteïnes col·loidals (components similars a proteïnes I + II) i proteïnes macromoleculars (components similars a SMP). A més, polisacàrids (espècie cel·lulòsica) i substàncies com a àcids grassos i resinosos van ser identificades en les membranes contaminades mitjançant anàlisis ATR-FTIR, tals substàncies exerceixen un paper important en el embrutiment de les membranes. Per fi, anàlisi SEM-EDS per a les membranes embrutades amb PMTE es va detectar concentració de contaminants inorgànics (ions metàl·lics multivalents) especialment el Ca2+ que podria accelerar la formació coca en la àrea de la membrana.
[EN] In this PhD Thesis, the application of ultrafiltration process (UF) and membrane fouling phenomenon used to remove dissolved and colloidal substances (DCS) from paper mill treated effluent (PMTE) for reuse in different recycled paper and cardboard manufacturing processes was investigated. The overall goal of this research has been divided into three main parts: i) describes how to find optimal operating conditions of four controlling parameters, such as transmembrane pressure (TMP), cross-flow velocity (CFV), temperature and molecular weight cut-off (MWCO) for maximizing the average permeate flux (Jp) and chemical oxygen demand (COD) rejection, and minimizing the cumulative flux decline (SFD) using Taguchi method and utility concept for a cross-flow UF in pilot scale, used to remove DCS from a paper mill treated effluent (PMTE), ii) flux decline and fouling mechanisms of UF membranes fouled with PMTE were examined by theoretical modelling. The results from UF tests were expressed in terms of permeate flux (Jp) as a function of time to check modified Hermia's models adapted to crossflow filtration and cake formation in constant-pressure filtration, and iii) describes the Identification, characterization and possible origins of UF membrane foulants. Techniques such as chemical analysis, FESEM, SEM-EDS, ATR-FTIR and 3DEEM analysis were applied to understand which fraction of the foulants caused the fouling. This research found that the TMP and MWCO have the greatest contribution to the average permeate flux and SFD. In the case of the COD rejection rate, the results showed that MWCO has the highest contribution followed by CFV. The optimum conditions were found to be the second level of TMP (2.0 bar), the third level of the CFV (1.041 m/s), the second level of the temperature (15°C), and the third level of MWCO (100 kDa). Under these optimum conditions Jp, COD rejection and SFD resistance of 81.15 L/m2/h, 43.90% and 6.01 (around 28.96 % of (FD), respectively, were obtained and they were within of the predicted range at the 95% confidence interval. Furthermore, the results showed that the predictions of the modified Hermia's models adapted to cross-flow UF had good agreements with experimental data, under different conditions tested for PMTE. Therefore, it can be concluded that for all cases the best fit (higher accuracy) to the experimental data corresponds to the complete (coefficient of determination R2 >0.97) and intermediate (R2 >0.96) blocking, followed by the cake layer formation (R2 >0.94). Moreover, measurements of particle size distribution and zeta potential near the isoelectric point, showed a substantial reduction in colloidal compounds. The 3DEEM analysis revealed that the majority of the organic foulants with fluorescence characteristics on the fouled membranes were colloidal proteins (protein-like substances I+II) and macromolecular proteins (SMP-like substances). Further, polysaccharide (cellulosic specie), fatty and resin acid substances were identified on the fouled membrane by the ATR-FTIR analysis and they play an important role in membrane fouling. In addition, the membrane SEM-EDS analysis showed accumulate and adsorbed onto the membrane surfaces of inorganic foulants, such as multivalent metal ions and especially Ca2+ (acts as a binding agent) that could accelerate cake layer formation on the membrane.
Santos Sousa, MR. (2020). Optimization of Operation Parameters in Ultrafiltration by Experiment Design, Mathematical Modelling and Fouling Characterization of the Membranes Used to Remove Dissolved and Colloidal Substances from a Treated Paper Mill Effluent [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/155975
TESIS

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Outra
O interesse na diversificação da matriz energética por meio de fontes de energias renováveis tem promovido mudanças no âmbito nacional e internacional, em setores acadêmicos, industriais, sociais e governamentais com foco no desenvolvimento de processos biotecnológicos baseados nos três pilares da sustentabilidade: ambiental, social e econômico. Frente a esse contexto, as microalgas são consideradas uma fonte promissora alternativa para a produção de biocombustíveis por apresentarem alta taxa de crescimento e de concentração de lipídeos. O presente trabalho realizou um estudo do processo de cultivo da microalga marinha Chlorella minutíssima por meio da ferramenta DOE – Design of Experiments para maximização da sua concentração microalgal e do teor lipídico simultaneamente, além de sua caracterização termoquímica para aplicação no processo de gaseificação. O cultivo ocorreu em fotobiorreator tubular descontínuo do tipo coluna de bolhas seguindo o arranjo ortogonal L8 de Taguchi, e as variáveis de processo foram fluxo de CO2 na alimentação, concentração de nitrato, concentração de fosfato, suplementação, temperatura e salinidade. A investigação demonstrou que a concentração de nitrato e fosfato, o fluxo de gás carbônico, a suplementação do meio e a temperatura são fatores influentes na concentração microalgal e no teor lipídico, sendo a melhor configuração para maximização conjunta, utilizando-se a função desirability, com o nitrato operando em nível alto e os demais fatores em nível baixo. A análise elementar forneceu teores condizentes com alguns relatos da literatura, a termogravimetria auxiliou na identificação das faixas de temperatura com maior taxa de decomposição (300 °C a 400 °C), e o poder calorífico superior da biomassa encontrado se demonstrou atrativo para a produção de syngas quando comparado ao de materiais como casca de arroz e lascas de eucalipto já empregados na gaseificação em maior escala. Dessa forma, a metodologia empregada e os resultados apresentados neste trabalho podem auxiliar na busca da viabilização econômica do cultivo, em grande escala, da microalga marinha Chlorella minutíssima para produção de biocombustível pelo processo de gaseificação.
The interest in diversifying the energy matrix through renewable energy sources has promoted changes at the national and international levels in academic, industrial, social and governmental sectors, focused on the development of biotechnological processes based on the three pillars of sustainability: environmental, social and economic. In this context, microalgae are considered a strong promising alternative source for the production of biofuels due to their high rate of growth and lipid concentration. The present work carried out a study of the cultivation process of the marine microalgae Chlorella minutíssima using DOE – Design of Experiments to maximize the cell growth and the lipid content simultaneously, besides its thermochemical characterization for application in the gasification process. Cultivation occurred in a discontinuous-tubular photobioreactor, bubble-column type, following Taguchi L8 Orthogonal Array design, and the process variables were: CO2 feed flow rate, nitrate concentration, phosphate concentration, supplementation (metals and vitamins), temperature and salinity. Results showed that the nitrate and phosphate concentration, CO2 feed flow, supplements and temperature are influential factors in the cell growth and lipid content, and the best configuration presenting good results for simultaneous maximization, using desirability, was nitrate operating at high level and the other factors at low level. Ultimate analysis provided levels consistent with some reports in the literature. Thermogravimetric analysis identified the temperature ranges with the highest decomposition rate (300 °C to 400 °C). The higher heating value of the biomass found was attractive for the production of syngas when compared to raw materials such as rice husk and eucalyptus chips already used in the larger scale gasification. In face of, the methodology employed and the results presented in this work can be useful in seeking economic feasibility of the large-scale cultivation of Chlorella minutíssima for the production of biofuels by the gasification process.
PRH48 - ANP

This thesis illustrates analysis of the influence of the non-machining processes on product quality by experimental design and statistical analysis. For the analysis objective
dishwasher production in Arcelik Dishwasher plant is examined. Sheet metal forming processes of dishwasher production constitutes the greatest portion of production cost and using the Pareto analysis technique
four pieces among twenty six pieces are determined to be investigated. These four pieces are the U Sheet, L Sheet, Inner Door and Side Panel of the dishwasher. By the help of the flow diagrams production process of the determined pieces are defined. Brainstorming technique and cause&
effect diagrams are used to determine which non-machining process parameters can cause pieces to be scrapped. These parameters are used as control factors in experimental design. Taguchi&
#8217
s L16(215) orthogonal array, Taguchi&
#8217
s L16(215) orthogonal array using S/N transformation and 28-4 fractional factorial design are used on purpose. With repetitions and confirmation experiments the effective parameters are determined and optimum level of these parameters are defined for the improvements on scrap quantity and quality of production.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
One of the main considerations in selecting materials to manufacture aircraft structures is related to weight saving [1]. In this context, the promising aluminum-lithium alloys have been receiving special attention in aerospace applications due to its attractive combination of low density, high specific strength and corrosion resistance [2-5]. Due to difficulties joining these alloys by conventional welding processes associated to their high thermal conductivity and low melting temperature, solid-state joining technologies emerge as great possibilities to simultaneously solve problems of solidification defects and increasing weight. The feasibility of Friction Spot Welding (FSpW) in joining sheets of lightweight material (e.g. aluminum alloys) places this technology as a potential replacement to the spot-like joint processes, as resistance spot welding (RSW) and laser spot welding (LSW), for application in automotive and aerospace industries [6-8]. In this work, the influence of hook defect on the lap shear strength (LSS) of AA2198-T8 friction spot welds was studied. The effects of process parameters was evaluated in terms of LSS and related to the microstructural configurations. The values of hook length measurements and the LSS were used as response in optimization process developed using the statistical tool of DoE technique with Taguchi Method. Finally it was possible to compare the hook behavior with lap shear strength results. The higher influence on the weld performance was exerted by plunge depth whereas rotational speed was found to be a less significant parameter. Through the minimization of the hook defect, a beneficial response on the weld performance was observed, which was associated to the absence of a potential site for crack nucleation. In spite of inherent discontinuities, promising results were found for aluminum joints for aerospace applications.
Uma das principais considerações na seleção de materiais para a fabricação de estruturas de aeronaves está relacionada à redução de peso [1]. Neste contexto, ligas de alumínio-lítio têm se destacado em aplicações aeroespaciais devido à sua atraente combinação de propriedades como baixa densidade, alta resistência específica e resistência à corrosão [2-5]. Devido às dificuldades para união destas ligas por processos convencionais de soldagem associadas às altas condutividades térmicas e baixas temperaturas de fusão, tecnologias de soldagem no estado sólido emergem com grande potencial para simultaneamente reduzir os defeitos de solidificação e aumento de peso. A viabilidade da Soldagem por Fricção por Ponto (do inglês – Friction Spot Welding – FSpW) para unir chapas de materiais leves posiciona esta tecnologia como potencial substituta para os processos de união por ponto, como soldagem por resistência (RSW) e soldagem a laser (LSW), para aplicação nas indústrias automotiva e aeroespacial [6-8]. O presente trabalho visou estudar a influência do defeito de cunha na resistência ao cisalhamento (RC) das juntas da liga de alumínio 2198-T8 fabricadas por FSpW. O efeito dos parâmetros de processo foi avaliado em relação à RC e relacionado com as configurações microestruturais. Os valores de comprimento de cunha e RC foram utilizados como resposta no processo de otimização desenvolvido utilizando-se a ferramenta estatística de planejamento de experimentos com o Método de Taguchi. Por fim, foi possível comparar o comportamento da cunha com os resultados de RC. A maior influência sobre o desempenho de solda foi exercida pela profundidade de penetração enquanto a velocidade de rotação foi um parâmetro menos significativo. Com a minimização da cunha obteve-se uma resposta benéfica no desempenho de solda, o que foi associado à ausência de uma região potencial para a nucleação de trincas. Apesar de descontinuidades inerentes, resultados promissores foram encontrados para juntas de alumínio para aplicações aeroespaciais.

O processo de fundição sob pressão de alumínio tem se desenvolvido significativamente nas últimas décadas, ocupando um lugar de destaque na indústria por produzir componentes de engenharia inovadora. Dentre os problemas de qualidade deste processo, o mais recorrente é a porosidade causada por vários fatores, dentre eles os parâmetros do processo que são de difícil determinação, sendo comumente selecionados por meio da abordagem de tentativa e erro. A presente dissertação buscou responder a pergunta: Como determinar a melhor configuração de parâmetros do processo de fundição sob pressão de alumínio para minimizar a porosidade nas peças produzidas? Tendo como objetivo a melhoria da qualidade de uma peça de alumínio, fundida sob pressão, por meio da redução da porosidade. A principal contribuição desta dissertação concentra-se na aplicação do método de Taguchi utilizando dados categóricos ordinais (classes de porosidades) como característica de qualidade, por meio da análise da relação sinal-ruído ponderada. Os resultados dos experimentos foram analisados a partir do efeito médio dos fatores e da análise de variância (ANOVA). Como conclusão os parâmetros de temperatura do metal e velocidade de primeira e segunda fase de injeção foram os mais significativos na redução da porosidade da peça estudada. E ainda, o método de Taguchi alcançou o resultado esperado, trazendo significativa redução de porosidade na peça estudada por meio da otimização dos parâmetros do processo.
The aluminum die casting process has developed significantly in recent decades, occupying a prominent place for producing innovative engineering components. Among quality problems of this process is porosity due to several factors, including the process parameters that are difficult to determine, and are commonly selected by trial and error approach. This paper sought to answer the question: How to determine the best set of parameters of the aluminum die casting process to minimize porosity in the parts produced? Aiming improving die casting aluminum parts quality through reducing porosity. The main contribution of this paper focuses on the application of Taguchi method using ordinal categorical data (porosity classes) as a quality characteristic, by analyzing the weighted signal-to-noise ratio. The experimental results were analyzed from the average effect of factors and analysis of variance (ANOVA). In conclusion parameters metal temperature and speed of the first and second injection phase were the most significant in reducing the porosity of the part studied. Also, the Taguchi method achieved the expected result, bringing significant reduction of porosity in the part studied by optimizing the process parameters.

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnologico
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Revisão e análise dos modelos de planejamento econômico dos gráficos de controle por atributos e modelos correlatos existentes. Agrupamento dos modelos em conjuntos de enfoques semelhantes, com base, especialmente, na formulação da função custo/perda, seus pressupostos básicos e número de parâmetros de custo/risco envolvidos. Indicação do modelo que melhor se adapta às necessidades, características e capacidades de um sistema produtivo. Instruções adicionais, para a tomada de decisão, com base em análise de sensibilidade dos modelos. Estudo comparativo entre o modelo de Taguchi e outros que lhe são compatíveis.

MIG Welding had been widely used in the industry since decades for welding purposes due to its higher weld deposition rate, Ease of use, weld quality and Longer pass welding capability. These all features of this welding process makes the process most prefered welding process for the welding of propeller/Drive shaft. MIG has been proven as the easiest of all the welding processes that uses arc. In automobile sector, its had been widely used. The process uses continuously fed electrode to form the weld bead and joint formation. The process becomes more robust and efficient when it is automated and robots are inherited with the welding process. The usage and combination of robots with MIG Welding makes it robust but it needs to be optimized and process parameter like welding current, welding voltage, gas flow rate must be of such value that prevents any kind of weld defects to be formed over the weld bead. The most major issue that occurs while welding of propeller shafts is improper weld penetration and pin holes. The main aim of this research was to find the optimized value of all the weld parameters with the help of Taguchi design using minitab software and look for any other types of defects while welding and to rectify them and make the process as robust as possible. Addition of automation in any process makes it free from human errors that may occur.As robots can perform repeatative tasks more efficiently we just have to teach them what they have to do and they have to do that. MIG welding when combined with the robot can perform welding at same point without any deviation in position and weld parameters like arc length. To maintain arc length to be constant in MIG welding is almost impossible for any human being which directly effects the weld quality and penetration. An effort was undertaken to study the effects of using robotic arm for welding gun and effects of various process parameters over the weld bead. When non optimized parameters were used for the welding process there we have seen various defects in the final product.

碩士
國立高雄應用科技大學
電機工程系博碩士班
101
With the constant evolution of semiconductor technology, we used electronic products from the purely practical nature,continuously improve value of light weight, ultra thin, short, small, multi-function,huge memory capacity and high-performance.The electronic product's brain --- IC (Integrated Circuit )continued precision, it is the trend to produce and design the wafer into the nanoscale. The wafers constantly shrink in the nanoscale process can increase the particles produced of the unit area to reduce the production cost, relative..chip size lessens to the human eye is difficult to judge. When the chips produce getting smaller and smaller,manufacture can allow the amount of error must be getting smaller and smaller, equipment and instrument must increase control accuracy, how to reduce the amount of error is very important. This paper research die shift in the different image capturing and lighting variation by Taguchi Method, and find out the optimal parameters and methods to reduce die shift, and then reducing the causes of the low yield.

碩士
國立高雄應用科技大學
模具工程系碩士班
95
In cold forging, the forging die would be fractured easily and the life of the forging die would be reduced on high stress and high load in the forming process. In this paper, the stress of die applied on forming hexagonal head screw punch will be researched. The FEM package software DEFORM-3D is applied to analyze stress of die. By utilizing Taguchi Method, the each parameter which affects the stress in die can be analyzed to avoid die cracks and extend it’s life. The results of DEFORM-3D analysis demonstrate the maximum stress region of die is the easiest failure region in die. It also matches the failure location of practical case. In the other hand, the results of Taguchi method’s analysis demonstrate the outside diameter and the height of die are changed will affect the stress in the maximum stress region of die. To adjust the two parameters on design should avoid the die crack. Furthermore, as the round of die is larger and the angle between die and die-ring is changed, it would not only make stress uniform of the maximum stress region but also could improve die life. Advance, by using theory to design optimum outside diameter of die. The results of analysis show whatever the round of lower die, the angle between die and die-ring and height of die are changed. The parameters which affects the maximum stress region of die would be slow. Therefore, to design optimum outside diameter of die and cooperate with other parameters of die is very important. Summarizing all results of analysis, the conclusion will recommend the parameters of die and show that for a drawing in the end.

碩士
國立勤益科技大學
工業工程與管理系
101
The research will combine Taguchi and DMAIC approach, applies to Aluminum Casting so as to establish best parameters module, process improvement and reduce defects. First of all, Casting is the key target as set in order to increase profit and capability for competition as the company is looking for; secondly, we will apply Taguchi Method and combine 5 steps DMAIC of 6Sigma to improve casting process for product of Power Tools Industry than old fashion Try and Error so as to generate cost reduction, improve quality of product and capability for competition in the end. The result of experiment comes up Cpk value dramatically up to 1.89 was 0.11; porosity defect down to 4% was 34%; in terms of cost improvement, the cost saving from quality aspect, the cost saving was $231,000 before implementing the process ，and the cost saving was $1,155,000 after implementing the process. In other words, the best parameters identified through this study do improve the quality of aluminum die casting product.

碩士
國立屏東科技大學
機械工程系
92
This study is to develop optimal control conditions for thin-wall Magnesium die-casting to reduce the defects of products. This paper is first to find the optimal design for gate and runner of experiments model by simulation software, then to find the optimal injection parameters for process of 3C thin-wall magnesium alloy die casting parts by using Taguchi method. The well-known Taguchi method (TM) has good reappearance of experiments concerned only with the main effects of design parameters. The objectives of Taguchi method for parameter design are to find out the best combination of design parameters and reduce the variation for quality from minimum number of experiment. The injection conditions, such as, temperature, pressure, velocity and die release agent show significantly effects in reducing the shrinkage of magnesium die casting products, especially for AZ91D. From the experiment of note-book cover parts processing shows the results of this study is excellent.

碩士
高苑科技大學
機械與自動化工程研究所
100
Die is an important apparatus in manufacturing industry. Metal, glass or plastic materials can be formed to specific shapes by high temperature, high pressure, high-impact processes. Cold forging is widely used in industry. In this thesis, Taguchi method was used to conduct the optimal analysis for cold-forging process with less experiment numbers. The DEFORM 3D finite element software was applied to investigate the maximum equivalent stress of cold-forging die. The experimental controlling factors include stamping die speed, coefficient of friction, die-entrance angle and die material. According to the experimental results, the significant factor are stamping die speed and coefficient of friction. Therefore, die stress can be effectively reduced by a lower stamping die speed and coefficient of friction. Moreover, based on the calculations of signal to noise ratio, the optimal parameters combination in this study are as follows: stamping die speed, 1 mm/sec; coefficient of friction, 0.08; die-entrance angle, 0.9; and die material, Carbide (15% Cobalt).

碩士
國立雲林科技大學
工業工程與管理系
103
It is very important key element for wafer Die-Saw process and it also plays critical process in packaging technology. In Wafer Die-Saw process if there is a huge chipping issue, the strength of the wafer will be affected. Especially, the Front side chipping and Back side chipping the both issue were happened in Wafer Die-Saw, it could cause the wafer chipping area cracked if pressure from outside after Wafer Die-Saw process. It is very huge impact on wafer quality. The study was applied with Taguchi method design to find out the critical elements that could affect the process capability. In order to improve the capability of process, through the experiment analysis to gain the best parameters, improving the quality of front side chipping and back side chipping process. This study is taking one case of single wafer product for example, using the best parameter combination, it has boosted the Cpk from 1.43 to 1.99 for front side chipping and the back side chipping it has boosted the Cpk from 1.49 to 1.87. Through the SPC method, in 95% average, the front side chipping average is from 13.35µm down to 6.43 µm. It has worked for upgrading the capability of process and it also has minimized for the waste of cost.

碩士
國立臺北科技大學
材料及資源工程系研究所
97
Die-casting magnesium alloys are often easily occurred defects as flow mark, insufficient filling, and warp etc. These defects are closely related with parameters of plunger velocity, injection temperature, and temperature of die etc. Due to liquid metal high-speed filling, it is not easy to predict the status of filling. So often easily design overflow and air vent at inappropriate location, making casting generated gas hole. Therefore, this study was the use of mold flow analysis software analysis tools as Procast to discuss filling the flow of liquid metal and the best location of the overflow and the air vent. On improvement manufacturing process, industry is often considered optimization to the many of quality. Therefore, this study is aimed at AZ91D magnesium alloy die-casting parameters, selected the three control factors (plunger velocity, injection temperature, die temperature), each factor are the three levels, quality goals are set to the smallest solidification, pressure difference, the average temperature. By Taguchi method by S / N ratio analysis, a single target can be the optimization. Using of gray relational analysis method, simultaneously weighs the preferred plan and ideal solution and negative ideal solution characteristic, undergoes the Grey relational analysis, can find a group of best die-casting parameter A2 B1 C1, and its total gray value of the highest degree, so its really for the best combination of factor levels. The results indicated that gray relational analysis method for multi-objective analysis of die-casting parameters can indeed find the best die-casting parameters, and effectively reduce the casting defects and improve product quality.

碩士
國立高雄第一科技大學
機械與自動化工程所
96
Drawing process needs maximum force during the stamping process for automobile body panel. Therefore the drawing die is designed the strongest structure in all of stamping dies. The die manufacture cost will increase when the structure of the drawing die is over-design. The objective of this thesis is on minimum the weight of the drawing die. Hybrid Taguchi-Genetic Algorithm and ANSYS Parametric Design Language is applied to get dimensions for the ribs of the drawing die at restrictions of yield stress for material, deformation and casting limits. In this thesis, the developed die as sample die, the constrain conditions including 500 ton of forming force, 0.1mm of deformation and 1.6 107N/m2 of yield stress. After the optimal process, the result shown the total weight of rib structure will reduce 8%. The rib thickness of upper die, blank holder and lower die can be reduce to 19mm, 17mm and 22mm, respectively.

碩士
元智大學
工業工程研究所
88
【Abstract】 Die Casting is a precise method of casting which puts the liquid into a deform metal mold mode with high pressure. This has the advantage of mass production with low cost. By now there are only a few products manufactured in this way of casting. Besides, the process was generally complicated, and some of these products were subject to surface defects. Recently, the progress and development of Taguchi method has become a tendency due to its recyclable features. This method has been playing important role in industrial community for manufacturers to promote their products with high quality. The purpose of this experimental research is to explore the most suitable parameter combination in Aluminum felly’s high-pressure process and to reach the high quality level with the lowest development cost. This research mainly provides a three-step processes of optimum improving strategy to optimize the setting of the parameter for Aluminum felly’s high-pressure process and to reduce the failure rate. The first step is to get the parameter level through the control flew. The second step uses the Taguchi method to get the experiment plan with a proper parameter setting using the L27 orthogonal table to control the quality elements SN ratio as the standard for evaluate the quality feature and also the results of the reaction analyzed picture will be used in robust manufacture process in order to improve the product variant the final step using reaction curve align parameter up to optimum set. Through this research of improvement the defect of real process is reduced from 1.03% to 0.33. The improvement range is 68%. Key Words: Aluminum felly Die Casting, Taguchi Quality Engineer Control Charts, Response Surface

碩士
國立高雄應用科技大學
模具工程系碩士班
101
The round clinch T welding nut is formed by six complex cold forming stages. The geometry of the forming die would affect the forming process of product. To obtain a good product, the optimization of geometry parameters of forming die is necessary. In this paper, an optimization is proposed for the forming die of round clinch T welding nut based on the finite element method and Taguchi method. The maximum forging force of fifth stage and the depth of wear by sixth stage punch are considered as the optimal objective. The optimal combination of parameters is obtained by S/N analysis and the analysis of variance (ANOVA). It is shown that, the geometry parameters of forging die by integration solution, the maximum forging force and the maximum effective stress of back ejector are obviously reduced about 10750N (13.60%) and 550MPa (26.44%) lower than the original parameters at fifth stage. Compare to the original parameters at sixth stage punch, the wear depth is effectively lower about 0.000002685mm (39.63%) and the die life evaluation is higher about 24291 (62.62%). Therefore, improvement of the die life and product quality can achieve better economic benefits.

碩士
國立高雄應用科技大學
製造與管理外國學生碩士專班
104
One of the most adopted methods for forming complex shaped parts with satisfactory geometrical accuracy is closed die hot forging process. The main reasons forgings are so important is the strength and reliability inherent in their manufacturing process. Hot forging technology has a special place in producing parts of superior mechanical properties with minimum waste of material. In manufacturing process, the optimization of product conditions is required to apply for decrease forming load and production time. Therefore, the effect of the most important process parameters has to be investigated. Finite element method was applied in this research to analysis closed die hot forging process. The most impact process parameters are flash thickness, billet temperature and friction coefficient parameters had been chose to do research with purpose to reduce forging load using Taguchi method. The most significant parameter affecting the responses is billet temperature using analysis of variance (ANOVA).

碩士
國立彰化師範大學
機電工程學系所
105
This research applies Taguchi method to design the optimization of turning process for electrical assisted bicycle motor case made by ADC6 die casting aluminum alloy material. To determine the optimized parameters for turning process of ADC6 die casting aluminum alloy, a two-step Taguchi method was adopted in this thesis. In the first step, a L9 (34) orthogonal array design was planned for selecting a bettering turning tool. In the second step, a L16(45) orthogonal array design was implemented to reach the aim of the finest surface roughness. The first Taguchi experimental results showed using diamond turning tool reached the best surface quality for ADC6 die casting aluminum alloy. The second Taguchi experiments illustrated the feeding rate was the most significant factor for ADC6 die casting aluminum alloy. A confirmation experiment was executed to demonstrate the characteristics of optimization parameters for ADC6 die casting aluminum alloy. The experimental result validates the optimization parameters for tuning ADC6 die casting aluminum alloy process is reliable and robust. The effectiveness of the Taguchi method shows practical industrial applications.

碩士
國立高雄應用科技大學
模具工程系碩士班
102
Increase the added value of products is focused on the transformation of Taiwan's fastener industry, the production of high strength fasteners will help to enhance the added value of products, in order to develop products with high strength fasteners, the production design is appropriately shaped necessary. This study assessed based on high strength hex flange bolts FMEA forming problems , the risk priority number (RPN) came to the severity of the problem, and then using commercial graphics software Pro / Engineer parametric way to construct billet die etc. geometry, import finite element analysis software DEFORM 3D to analyze forming and die stress, and establish a high strength flanged socket head bolt forming limit and mold design standards. In this study, forming and die for high strength flanged socket head bolt designed to make improvements , for example , to determine the quality of the head forging billet diameter ratio of the volume of billet、forging flow line installation stress ring, etc. In order to provide subsequent developers do use and reference.In this paper, the Taguchi method to reduce the third pass, the goal of forging force.The optimal combination of parameters is obtained by S/N analysis and the analysis of variance , the study of flanged socket head bolt forming the design is complete , and effectively reduce the strength of forging the third 29%.

碩士
逢甲大學
材料與製造工程所
96
Electronic products are more widespread for human needs along with time progress. In order to reduce manufacturing cost and improve the competitiveness, press working is a key method to process electronic parts because of the production speed and stability. However the durability of the punch is an important factor on the efficiency and effect of press working. Most researches on punch wearing are studied by metallograph, and then analyzed by least square method to discover the abrasion reason. This article adopts the finite element analysis software ANSYS to analyze and improve the punch structure. After computer simulation, the results will be verified by experiment and coordinated by Taguchi Method to find out the strongest factor in the punch and die design. The analysis method in this article would be useful in press processing and save a lot of tedious die testing work. This article also gives a brief discussion in continuous press die design since there are few related researches in this area. The discussion includes computation of shear force, safety factor, and appropriate selection of the press. Moreover, the terminologies of press die components are explained to more understanding the die design and press work.

碩士
國立台灣工業技術學院
機械工程技術研究所
85
Taguchi experimental design method and ANalysis Of VAriance technique (ANOVA) are used in this study to optimize the die- casting process parameters of the C443M aluminum alloy. The analyzed parameters are silicon percentage, magnesium percentage, molten temperature, injection speed, high speed position, intensification pressure time, cooling method, solution treatment, aging time, and aging temperature, All of them affect the porosity content of the cast. In addition, the effects of heat treatments on the mExperimental results show that the optimum combination of process parameters for the die- casting C443M aluminum alloy is 6%Si, 0.3%Mg, 720℃molten temperature, 0.23m/sec low injection speed, 1.65m/sec high inject speed, 8cm high speed position, 0.037sec intensification pressure time, and cooling the casting in the water. Moreover, the results of ANOVA method show that the contribution of errors for density, strength and % elongation were 6.353%, 8.977%, and 3.256% respectively, All of them are below 15% indAfter T5 and T6 heat treatments the silicon phase in C443M die-castings is changing from neadlelike plates to rounded rods, improving both tensile strength and % elongation. The improvement on tensile strength is not very significant, while the % elongation can be increased from 10.5% in the as-casting condition to 24.7% after solid solutioning at 510℃ for 6 hours followed by aging at 150 ℃ for 6 hours.

碩士
國立高雄應用科技大學
機械與精密工程研究所
97
Abstract The purpose of this study is to investigate the forming hot extrusion of Al6061 and Al6063 aluminum alloy of rectangular tubes by finite element analysis. Taguchi’s experimental approach and analysis of variance technique were applied to conduct the optimal die design. By the use of Taguchi Orthogonal table, several important process parameters for finite element analysis were planed, such as the height of mandrel with inclination characteristic in welding chamber, bearing height in mandrel and draft angles of divided bridge. After FEM simulation, ANOVA analysis for flow speed difference between two divided material after welding chamber was conducted. Therefore, an optimal die design for hollow extruded aluminum parts can be obtained. The study found that by the integration of finite element analysis and Taguchi quality engineering, the best process design can be obtained. By comparing the best design to original design, the flow speed difference was reduced. Therefore, a best hollow extruded aluminum part can be obtained.

碩士
大葉大學
工業工程與科技管理學系碩士在職專班
93
Because of the fact that the processing cost of mold is increasing and the life cycle of the new product development is ever shortening, the application of the accurate ceramic mold casting to the development of the relevant metal mold seems to attract more and more attention. The accurate ceramic mold casting can not only shorten the mold forming cycle time but also cut down production cost to a great extent, which will extensibly uplift the market competitive. The thesis is mainly devoted to the finding of the factors and their combination affecting the mold forming via the Taguchi method and the operation criterion for high quality. And then, basing on the findings, we hope to upgrade the mold strength so as to get them spread within the scope of 25+0.2 kn/m2 and 25-0.2 kn/m2, and to avoid the corruption of mold through the insufficiency of the mold strength, which will lead to rework, cost up and losing of productivity. According to our experiment, we have found if we do make some adjustments to the relevant control factors, we may obtain the optimization result. They are A1-Pouring Temperature (1690~1720 0C), B3-Zircon Flour (50%), C3- Zircon Sand (35 %), D3- Mulgrain Sand (15%), E1-Ethyl Silicate (20.5kg), F3-Burning Temperature (11500C), G3- Mold Sand (28.3 kg), H2-Sodium Silicate (4.1 kg).

碩士
國立高雄應用科技大學
模具工程系
99
The purpose of this study mainly utilized the forging analysis software DEFORM-3D and the Taguchi experimental design method to simulate the three-dimensional manufacture processes for retaining groove of screw tail point die. The Taguchi experimental design method is applied to focus on the main factor of the simulation analysis, it can respond the difference levels of each factor, then a set of optimum design parameters can be learned for the retaining groove of each factor to increase the extent of the influence of the cavity filling. Analysis of a series of retaining groove forging results shows the filling ratio, the maximum principal stress and the equivalent stress are obviously affected by the retaining groove parameters. Effect of these parameters from high to low are: the retaining groove to the edge line from the cavity, the retaining groove depth, and the retaining groove width. In the mean time, the retaining groove has the best filling ratio when overlapping is staggered. The analysis results also show that after a new design of retaining groove, the product volume is increased, the equivalent stress is reduced, and the length of excess material is significantly reduced. Taguchi analysis result shows that the excess material length can be reduced 41.47%, product volume can be effectively increased, molding stress can be reduced 18.34%, and the equivalent stress can also be reduced 4.83%. The result of study can provide retaining groove designer a reference and reduce the bad products.

碩士
國立成功大學
工程科學系碩博士班
96
In addition to the qualities of light-weight, mini-size, low costs, and excellent electrical and thermal performances, electronic products are further required to have qualities such as multiple functions and high capacity to meet the demand of the market in recent years. With this view, the 3D packaging technology facilitated to above purposes has been gradually noticed. By incorporating with the 3D packaging technology, this study focuses on quad flat lead-free package which is widely used in portable electronic products to further analyze the stacked die QFN package. This study adopts ANSYS9.0 software for analysis. Based on the JEDEC code, the stacked die QFN is loaded by a temperature cycle of -40℃~125℃. The solder paste is assumed to be Anand’s model. The Coffin-Manson fatigue life formula is applied to predict the fatigue life of the solder paste in the stacked die QFN package. The single-factor experiment is conducted to predict the impact on the fatigue life of the stacked die QFN in which factors such as the amplitude of temperature cycling range, the average temperature of temperature cycling range, die size, thickness of die, thickness of PCB, CTE of PCB, CTE of mold compound, CTE of adhesive, the shape of solder paste, CTE of die pad and Young’s modulus of die pad are analyzed. Accordingly, the Taguchi Method is applied to obtain the optimal parameter combination to improve the reliability of the stacked die QFN package. The single-factor analysis shows that the solder fatigue life increases along with the reduction of the amplitude of temperature cycling range, die size, thickness of PCB, CTE of die pad, CTE of PCB as well as the increase of CTE of mold compound, Thus other factors have no significant effects on the solder paste fatigue reliability. Finally, the optimal design derived from the Taguchi Method results in the fatigue life of 8124 cycles which shows a 4.21 times increase compared to 1926 cycles of the original design. Therefore the reliability of the stacked die QFN module package has been efficiently improved.

碩士
國立成功大學
機械工程學系碩博士班
96
In this investigation, performing a series of experimental tests (such as friction coefficient testing, tensile testing and plastic deformation performance) on copper alloy C2680, 0.8 mm thickness is to attain required material properties and key those data in the finite element analysis software. Forming flow characteristic of stretch forming is different from that of general deep drawing, using massive flanging material frequently. Due to drawing the flange occurs rarely in the situation of wide flange. In this investigation, author simplifies the progressive drawing to the optimum solution of the individual drawing step by using Taguchi methods and set it to be the blank for next step of Taguchi analysis. In each stage, the design parameters include the radii of die and punch, the clearance between the punch and the die, the diameter of punch. And using these parameters perform the smaller-the-better characteristic of Taguchi analysis for the variation of the sheet metal thickness. The result perform : the contribution rate of the first stage is 33.9% of the radii of die, 26.9% of the radii of punch, 23.4% of the clearance between the punch and the die, 15.8% of the diameter of punch. The contribution rate of the second stage is 68.8% of the radii of punch, 16.2% of the radii of die. The contribution rate of the third stage is 81.0% of the radii of punch. Key words : Taguchi Methods, Drawing, Progressive Die, Copper Alloy

碩士
國立勤益科技大學
機械工程系
95
The properties of Ceramic tools have high hardness and brittleness, but the poor of toughness. It easily caused Ceramic tools broken while cutting the hardness materials. There is closely connection between the fractures of tool and cutting parameters. Therefore, it is demand to find out the best way between fracture of tool and cutting parameters and to setting out the best conditions of Ceramic tools is necessary. The purpose of this study is using Taguchi method to research the best cutting conditions of Ceramic tools. Using ceramic tool on SKD11 die steel (HRc60) for hard cutting experiment at this study. Adopt standards from cutting tool supplier. The main control factors including: cutting speed, feed rate and depth of depth. We found the best cutting conditions of ceramic tool can be provided to related industries who would like chose ceramic tool to cutting hardness materials. The results of this studying can be offered for reference. The experiment in this article can be divided into two parts. First part of details: according to flank wear and surface roughness to acted as response values for quality parameters. It aims to find out the best combination for cutting parameters with both minimum flank wear and optimal surface roughness. The second part of details: according to tool life to acted as response values for quality parameters. It aims to find out the best combination of condition for cutting parameters with tool life. According to the results of Taguchi method after analyzed, we found the cutting speed is the main factor to effected flank wear and tool life. Besides, the workpiece of surface roughness would be influenced by feed rate.

碩士
國立高雄應用科技大學
模具工程系碩士班
93
This research aims at the optimization design of the stamping die supporting structures. The parameters of die stress distribution, locations and patterns of supporting ribs were analyzed using the design of experiment (DOE) method. The optimization design criteria were established using the DOE results. A topological design scheme was proposed to generate the die supporting ribs. The Genetic Algorithms Method (GAM) was adopted to optimize the die supporting structures in order to reduce the die weight and save the power consumption of stamping. In this thesis, the stamping process is simulated with FEM software to evaluate the die face design and obtain the boundary force condition of die. An oop (object oriented program) system was established to get the pressure distribution of blank. A simplified beam model is proposed to recreate the force boundary condition of die base on the pressure distribution of blank. The automatic topological design of supporting ribs was developed using the simplified beam model. The GAM was adopted to minimize material utilization, die stress and stress variation. The results of the proposed system were compared with the topological optimum results of ANSYS and demonstrated a good agreement in the layout pattern of ribs. The industrial case of a stamping die of fender was examined. The design results of this thesis were better than the traditional uniform design both in the maximum die stress and material utilization.

碩士
國立交通大學
機械工程研究所
85
The dynamic characteristics of magnetic bearings are often suffered from many problems, such as nonlinearities, parameter variations and external disturbances. To solve these problems, we applied Taguchi method associated with the decentralized control to design a decentralized PID controller with robustness. The results show that the performance of the decentralized PID controller system is better than that of the decentralized PD control system in the ability of suppressing the external force except that chattering effect exists in the responses. 　　In the study, the Taguchi method is employed to determine beast parameters in control rules for a decentralized PID control method. Two major characteristics of the Taguchi method are, firstly, the use of total possible combinations to estimate the main factor effect and some, not all, of the interaction. Secondly, signal-to-noise (S／N) ratios are used to evaluate the system performance of a system in the presence of noise factor, so that the performance can be made insensitive to noise factor. For control systems with uncertainty, the Taguchi method is found to be effective to improve system performance. 　　Finally, we developed a current driver circuit for a high speed spindle with five degrees of freedom supported by magnetic bearings. The prototype is tested under various operating conditions. We found that the control performance fulfills our design specifications, which directly verify our design methodology.

碩士
國立交通大學
工學院碩士在職專班精密與自動化工程學程
92
Die casting products of magnesium alloys very often show non-filling, hot cracking, apparent flow mark and deformation etc. These defects are closely related with process conditions of filling time, fusion temperature, cooling temperature of die and maintaining pressure etc. Generally, in the development of magnesium die casting products, trial and error method was used to find the suitable combination of process conditions. It is time consuming and not necessarily assure the best results. Recently TAGUCHI experiment design methods are adopted for improving product quality. In this study, we combine TAGUCHI experiment design method with Flow-3D flow analysis package for simulation of making large plane thin wall workpiece of magnesium alloys. L9 orthogonal table was used, and filling time, fusion temperature, cooling temperature of die, maintaining pressure, viscosity was chose as control parameters. Three levels of each parameter were selected for the experiment. Minimum solid fraction and most homogeneous temperature and pressure distribution in the die cavity, were set as the best casting conditions. From variance analysis, we found out the combination of optimum process condition are, fusion pressure-17Mpa, fusion speed-100m/s, fusion temperature-625℃, cooling temperature of die-250℃. An independent analytical process parameters combination was selected based on the result found for die-casting simulation, and the result shows the improvement of the product.