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A presente dissertação tem como objetivo otimizar o plano de produção de uma unidade fabril, procurando reduzir desperdícios, melhorar a utilização dos operadores e aumentar a eficiência global do sistema. O estudo surgiu da identificação de problemas no cenário atual, caracterizado por elevados períodos de ociosidade, dificuldades no cumprimento do plano produtivo e custos significativos associados a desperdícios. Para responder a estes desafios, foram propostas três medidas de melhoria: a redução dos tempos de preparação, a criação de uma estação de apoio e a redução da velocidade da linha, bem como combinações entre as várias alternativas. Inicialmente, procedeu-se a uma análise teórica das propostas, onde se verificou que, embora cada uma apresentasse ganhos em determinados aspetos, apenas as combinações de medidas revelaram impactos expressivos na redução de desperdícios. Em seguida, recorreu-se ao software Arena para desenvolver modelos de simulação de eventos discretos, que permitiram avaliar o desempenho dos diferentes cenários em função de quatro indicadores principais: número de produções concluídas, tempo médio de processamento, tempo médio de espera e taxa de utilização dos operadores. Os resultados demonstram que nenhum cenário apresentou desempenho inferior ao atual e que as soluções combinadas, em particular a linha mais lenta associada à redução dos tempos de preparação, oferecendo os melhores resultados globais. Finalmente, aplicou-se o Analytic Hierarchy Process (AHP) como ferramenta de apoio multicritério à decisão, de forma a integrar os diferentes critérios de avaliação e selecionar a alternativa mais adequada. Os resultados confirmaram a superioridade da proposta que combina a linha mais lenta com a redução dos tempos de preparação, destacando-a como a solução mais equilibrada entre produtividade, eficiência e utilização dos recursos. Este trabalho contribui tanto para a prática, ao fornecer à empresa soluções concretas de melhoria, como para investigação académica, ao demonstrar a relevância da integração da simulação com métodos de apoio à decisão multicritério na otimização de sistemas produtivos.
Abstract This dissertation aims to optimize the production plan of a manufacturing unit, seeking to reduce waste, improve operator utilization, and increase the overall efficiency of the system. The study arose from the identification of problems in the current scenario, characterized by high periods of idleness, difficulties in complying with the production plan, and significant costs associated with waste. To respond to these challenges, three improvement measures were proposed: reducing preparation times, creating a support station, and reducing line speed, as well as combinations of the various alternatives. Initially, a theoretical analysis of the proposals was carried out, which showed that, although each one presented gains in certain aspects, only the combinations of measures revealed significant impacts on waste reduction. Next, Arena software was used to develop discrete event simulation models, which made it possible to evaluate the performance of the different scenarios based on four main indicators: number of completed productions, average processing time, average waiting time, and operator utilization rate. The results show that no scenario performed worse than the current one and that the combined solutions, in particular the slower line associated with reduced preparation times, offered the best overall results. Finally, the Analytic Hierarchy Process (AHP) was applied as a multi-criteria decision support tool in order to integrate the different evaluation criteria and select the most appropriate alternative. The results confirmed the superiority of the proposal that combines the slower line with reduced preparation times, highlighting it as the most balanced solution in terms of productivity, efficiency, and resource utilization. This work contributes both to practice, by providing the company with concrete improvement solutions, and to academic research, by demonstrating the relevance of integrating simulation with multi-criteria decision support methods in the optimization of production systems.
Abstract This dissertation aims to optimize the production plan of a manufacturing unit, seeking to reduce waste, improve operator utilization, and increase the overall efficiency of the system. The study arose from the identification of problems in the current scenario, characterized by high periods of idleness, difficulties in complying with the production plan, and significant costs associated with waste. To respond to these challenges, three improvement measures were proposed: reducing preparation times, creating a support station, and reducing line speed, as well as combinations of the various alternatives. Initially, a theoretical analysis of the proposals was carried out, which showed that, although each one presented gains in certain aspects, only the combinations of measures revealed significant impacts on waste reduction. Next, Arena software was used to develop discrete event simulation models, which made it possible to evaluate the performance of the different scenarios based on four main indicators: number of completed productions, average processing time, average waiting time, and operator utilization rate. The results show that no scenario performed worse than the current one and that the combined solutions, in particular the slower line associated with reduced preparation times, offered the best overall results. Finally, the Analytic Hierarchy Process (AHP) was applied as a multi-criteria decision support tool in order to integrate the different evaluation criteria and select the most appropriate alternative. The results confirmed the superiority of the proposal that combines the slower line with reduced preparation times, highlighting it as the most balanced solution in terms of productivity, efficiency, and resource utilization. This work contributes both to practice, by providing the company with concrete improvement solutions, and to academic research, by demonstrating the relevance of integrating simulation with multi-criteria decision support methods in the optimization of production systems.
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Otimização da produção Simulação Arena AHP Planeamento industrial Production optimization Simulation Industrial planning