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Abstract(s)
A presente dissertação foi desenvolvida na empresa CIN Industrial Coatings, S.A., com o objetivo de eliminar a falta de reprodutibilidade entre a fase da aprovação de pré mistura (APM) e a produção, essencialmente observada nos produtos texturados e epóxipoliéster satinados. A paragem da linha de produção destes produtos críticos afeta negativamente a produtividade da empresa e, consequentemente, a Overall Equipment Effectiveness (OEE). Deste modo, surge na empresa o indicador Non Stop Yield (NSY), com o intuito de quantificar o número de vezes que a produção não para para controlo de qualidade. Assim, percebe-se que o NSY está diretamente relacionado com a OEE, pelo que se pretende reduzir o número de paragens da linha de produção. Inicialmente foi necessário ter em conta as variáveis do processo e amostragem dos produtos críticos em estudo, com o intuito de definir as condições ótimas que garantissem a repetibilidade e reprodutibilidade do brilho na APM e na produção. Para tal, traçou-se um desenho de experiências, verificando-se inicialmente que determinados fatores não influenciavam significativamente o valor do brilho, nomeadamente, a localização na qual é extraída a amostra, a influência das extrusões serem efetuadas de forma sequencial e a temperatura da pasta à saída da extrusora. De seguida, através do software Minitab efetuou-se o desenho de experiências, em que se definiram três fatores controláveis que evidenciavam influência na extrusora da APM, denominados por fator X, Y e Z. Estabeleceram-se três níveis para o fator X, de 70, 90 e 120 e dois níveis para o fator Y, de 150 e 250. Utilizou-se o método DMAIC para a resolução do problema em questão, pelo que na etapa Define está definido o problema; na etapa Measure, o método utilizado para a realização dos ensaios do desenho de experiência; na fase do Analyse está representado o diagrama de Ishikawa, bem como a análise da variância e na etapa Improve a análise da regressão obtida para cada produto. De notar que não se incluiu a última etapa deste método, a etapa Control, uma vez que as condições estudadas não permitiram uma reprodutibilidade ideal entre a APM e a produção. Concluiu-se, assim, que é necessária uma continuidade deste estudo, de modo a aumentar o NSY.
This dissertation was developed in cooperation with CIN Industrial Coatings, S.A. and the key issue addressed in this project was to eradicate the lack of reproducibility between the raw materials approval (RMA) phase and production, essentially observed in textured and epoxy-polyester satin products. When the production line is stopped due to these critical products, the company's production is negatively affected and consequently, the Overall Equipment Effectiveness (OEE). Therefore, the Non Stop Yield (NSY) indicator arises in the company, with the purpose of quantifying the number of times that production is not interrupted. Since the NSY is directly related to the OEE, the intention would be to reduce the number of production line stops. Initially it was necessary to take into account the process variables and sampling in the critical products, in order to define the optimal conditions that would guarantee the repeatability and reproducibility of the brightness in RMA and in production. Circumscribed in this context, an experimental investigation was outlined with the purpose of verifying that certain factors did not significantly influence the gloss value, namely, the location from where the sample is extracted, the influence of using a sequential extrusions procedure and the temperature of the paste at the extruder outlet. Subsequently, an experimental investigation of the processing parameters was conducted using Design of Experiments in Minitab Software, which were defined three controllable factors that influenced the RMA extruder, named factor X, Y and Z. Three levels were established for factor X, 70, 90 and 120, and two levels for factor Y, 150 and 250. The DMAIC method was used to solve the main problem in this project. This procedure comprises the step of Define, where the problem is defined; in the Measure stage, the method used to carry out the experiment design tests; in the Analyse stage the Ishikawa diagram is represented, as well as the variance analysis and in the Improve stage the regression analysis obtained for each product. It should be emphasized that the last stage of this method, the step Control, was not included, since the conditions studied did not allow for optimal reproducibility between the RMA and the production. Eventually, it was concluded that a continuity of this study is required to increase the NSY.
This dissertation was developed in cooperation with CIN Industrial Coatings, S.A. and the key issue addressed in this project was to eradicate the lack of reproducibility between the raw materials approval (RMA) phase and production, essentially observed in textured and epoxy-polyester satin products. When the production line is stopped due to these critical products, the company's production is negatively affected and consequently, the Overall Equipment Effectiveness (OEE). Therefore, the Non Stop Yield (NSY) indicator arises in the company, with the purpose of quantifying the number of times that production is not interrupted. Since the NSY is directly related to the OEE, the intention would be to reduce the number of production line stops. Initially it was necessary to take into account the process variables and sampling in the critical products, in order to define the optimal conditions that would guarantee the repeatability and reproducibility of the brightness in RMA and in production. Circumscribed in this context, an experimental investigation was outlined with the purpose of verifying that certain factors did not significantly influence the gloss value, namely, the location from where the sample is extracted, the influence of using a sequential extrusions procedure and the temperature of the paste at the extruder outlet. Subsequently, an experimental investigation of the processing parameters was conducted using Design of Experiments in Minitab Software, which were defined three controllable factors that influenced the RMA extruder, named factor X, Y and Z. Three levels were established for factor X, 70, 90 and 120, and two levels for factor Y, 150 and 250. The DMAIC method was used to solve the main problem in this project. This procedure comprises the step of Define, where the problem is defined; in the Measure stage, the method used to carry out the experiment design tests; in the Analyse stage the Ishikawa diagram is represented, as well as the variance analysis and in the Improve stage the regression analysis obtained for each product. It should be emphasized that the last stage of this method, the step Control, was not included, since the conditions studied did not allow for optimal reproducibility between the RMA and the production. Eventually, it was concluded that a continuity of this study is required to increase the NSY.
Description
Keywords
Tintas em pó Brilho Testes de hipóteses Análise de regressão Powder paints Gloss Hypothesis testing Regression analysis