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Advisor(s)
Abstract(s)
O presente estudo teve como âmbito a melhoria do indicador de desempenho, Overall Equipment Effectiveness, de uma máquina de corte de chapa. O processo de corte, é a etapa inicial na presente fábrica do setor metalomecânico, por isso, o seu desempenho e devida coordenação ao nível do planeamento (definição de prioridades), é fundamental, para que esta atividade não se torne um constrangimento na capacidade produtiva.
Portanto, para alvo de análise desta dissertação, foi selecionada a máquina de corte que apresentava a Disponibilidade mais baixa, de todas as existentes na secção de corte. Após a recolha dos dados, estes foram testados ao comparar diferentes fontes, que continham a mesma informação. Após ter uma amostragem suficiente, o Overall Equipment Effectiveness da máquina foi determinado e analisado em termos do seu comportamento, ao longo do tempo respetivo ao intervalo da amostragem. Foi aprendido que este indicador de desempenho, não era suficiente para caracterizar o output da máquina, mas sim a estabilidade do processo. Tendo em conta esse facto, foi também considerado para o trabalho o indicador Produtividade, cujo compara inputs e outputs.
A lei de Pareto foi aplicada de modo a existir uma definição das prioridades, a serem objeto das ações de melhoria. Também foram efetuadas análises de tendência, para averiguar se o comportamento das causas registado, ainda caracterizava o estado da máquina, quando este estudo foi realizado. Em concordância com os resultados da lei de Pareto e das análises de tendência, foram aplicadas aos setups da máquina, a metodologia 5S e a ferramenta Single-Minute Exchange of Die. Desenrolaram-se sugestões de melhoria ao nível das causas de paragem afetas às avarias e ao tempo de refeição e realizadas alterações à causa de paragem: embalagem, inspeção e identificação.
Foram comparados os estados do setup da máquina, antes e após a efetivação das ações de melhoria, tendo sido registada uma redução percentual média de 60%. Esta redução, em média, contribuiu para um aumento de 15% do indicador Overall Equipment Effectiveness.
The scope of this study was to improve the performance indicator, Overall Equipment Effectiveness, of a sheet metal cutting machine. The cutting process, is the initial stage in the present metalworking company, therefore, its performance and due coordination at the planning level (definition of priorities), is fundamental, so that this activity does not become a constraint on the production capacity. Hence, the cutting machine with the lowest Availability, of all the existing ones in the cutting section, was selected for the analysis of this dissertation. After collecting the data, the data was tested with the help of different sources, which contained the same information. After having a good sample size, the Overall Equipment Effectiveness of the machine was determined and analyzed in terms of its behavior, along the respective time of the sampling interval. It was learned that this performance indicator was not sufficient to characterize the output of the machine, but rather the stability of the process. Considering this fact, the Productivity indicator was also considered for the work, which compares inputs and outputs. Pareto's law was applied so that there was a definition of priorities, to be the object of improvement actions. Trend analyses were also carried out, to verify if the behavior of the causes of stoppage recorded, still characterized the state of the machine, when this study was carried out. In accordance with the results of the Pareto law and the trend analyses, the 5S methodology and the Single-Minute Exchange of Die tool were applied to the machine setups. Suggestions were made to improve the stop causes related to the machine breakdowns and mealtime. Changes were made to the stop causes group: packing, inspection, and identification. The conditions of the machine setup were compared, before and after the improvement actions were carried out, and an average percentage reduction of 60% was registered. On average, this reduction contributed to a 15% increase in the Overall Equipment Effectiveness indicator.
The scope of this study was to improve the performance indicator, Overall Equipment Effectiveness, of a sheet metal cutting machine. The cutting process, is the initial stage in the present metalworking company, therefore, its performance and due coordination at the planning level (definition of priorities), is fundamental, so that this activity does not become a constraint on the production capacity. Hence, the cutting machine with the lowest Availability, of all the existing ones in the cutting section, was selected for the analysis of this dissertation. After collecting the data, the data was tested with the help of different sources, which contained the same information. After having a good sample size, the Overall Equipment Effectiveness of the machine was determined and analyzed in terms of its behavior, along the respective time of the sampling interval. It was learned that this performance indicator was not sufficient to characterize the output of the machine, but rather the stability of the process. Considering this fact, the Productivity indicator was also considered for the work, which compares inputs and outputs. Pareto's law was applied so that there was a definition of priorities, to be the object of improvement actions. Trend analyses were also carried out, to verify if the behavior of the causes of stoppage recorded, still characterized the state of the machine, when this study was carried out. In accordance with the results of the Pareto law and the trend analyses, the 5S methodology and the Single-Minute Exchange of Die tool were applied to the machine setups. Suggestions were made to improve the stop causes related to the machine breakdowns and mealtime. Changes were made to the stop causes group: packing, inspection, and identification. The conditions of the machine setup were compared, before and after the improvement actions were carried out, and an average percentage reduction of 60% was registered. On average, this reduction contributed to a 15% increase in the Overall Equipment Effectiveness indicator.
Description
Trabalho final de mestrado para obtenção do grau de Mestre em Engenharia Mecânica
Keywords
Eficácia geral do equipamento Overall equipment effectiveness Manutenção produtiva total Total productive maintenance Kaizen 5S Análise de tendência Trend analysis Lei de Pareto Pareto law Troca de dados em um minuto Single-minute exchange of die Raciocínio baseado em casos Case based reasoning
Citation
CUNHA, Tiago Rafael Oliveira - Aplicação, análise e melhoria do indicador Overall Equipment Effectiveness numa Metalomecânica. Lisboa: Instituto Superior de Engenharia de Lisboa, 2021. Dissertação de mestrado.