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Authors
Abstract(s)
A evolução da gestão por processos dispõe de metodologias com ferramentas muito
exigentes e precisas, entre as quais, uma das mais importantes é a metodologia seis sigma, que tem
como meta os zero defeitos. A abordagem de tratamento de processos utilizando esta metodologia
é de extrema importância e tem sido muito aplicada em processos industriais pelos benefícios
económicos que lhes estão associados. Pretende-se com o presente trabalho construir uma
referência documentada e desenvolvida no âmbito da Dissertação de Curso de MEMGI (Mestrado
em Engenharia Mecânica e Gestão Industrial) realizado no sector da indústria automóvel,
desenvolvendo um trabalho de campo na área do seis sigma, com o intuito de aumentar/melhorar
a eficiência da organização Huf Portuguesa, uma fábrica de componentes automóveis. O objetivo
deste trabalho centra-se na redução de “scrap” (rejeitados) gerado na produção de uma
determinada peça formada por injeção (compósito polimérico reforçado com fibras de vidro), e
tem como principal foco a redução de custos de seleção de peças e de recuperação de moldes,
assim como a otimização do processo de injeção. Este trabalho permitiu eliminar operações sem
valor acrescentado e continuar a garantir os requisitos de produto dentro das especificações dos
clientes internos e externos. De uma forma resumida, foi realizada uma recolha e avaliação
das taxas de rejeição e estratificação dos defeitos mais comuns. Foi dada ênfase aos defeitos
estéticos inerentes à textura e fragilidade da peça, dado que se trata de uma peça de utilização
exterior e porque o consumidor final revela uma atenção especial sobre este produto, dado que são
tampas de uma chave de um automóvel. Passo a passo, foi realizada uma abordagem aos
parâmetros de injeção, para que se mantivessem sempre dentro das tolerâncias ao longo de todo o
processo, embora se tenha considerado a aceitação de uma certa tolerância tanto para o material
injetado como no que se refere à capacidade de reação da máquina quando solicitada à mudança
de algum parâmetro. O trabalho realizado considerando as fases do ciclo DMAIC (Definir, Medir,
Analisar, Melhorar e Controlar) permitiu eliminar algumas causas dos problemas e implementar
algumas melhorias no processo. Importa realçar a melhoria feita no processo de seleção
entre gito e as peças, pela utilização de vários separadores em policarbonato, em que 80% dos
defeitos aconteciam na passadeira de transporte das peças até à embalagem. Finalmente, são
comparados os dois anos de produção, um antes das melhorias e outro após a implementação das
ações de melhoria promovidas através deste trabalho de tese. O resultado final revela uma redução
de custo muito significativa para a empresa.
ABSTRACT: The evolution of management processes has overcome with very demanding and precise tools and methodologies, among which, one of the most important is the six sigma methodology, where the goal is zero defects. The process approach using this methodology is extremely important and has been widely applied in the industrial processes due to its economic benefits. The aim of this work is to build a reference document developed within the scope of a Course Dissertation MEMGI (Masters in Mechanical Engineering and Industrial Management) carried out in an automotive industry sector, developing a work on a field of a six sigma area, with the aim to increase/improve the efficiency in the Huf Portuguesa group, an automobile factory of components. The objective of this work is focused on the reduction of scrap of a component manufactured by injection (reinforced glass fiber polymer composite), and has as main focus the reduction of costs from parts selection and mold recover, as well as the optimization of the injection process. This work allowed to eliminate operations without added value and to continue to assure the product requirements within the specifications of the internal and external customers. In summary, it was collected and evaluated the rejection rates and was carried out the stratification of most common defects. Emphasis was placed on the aesthetic defects inherent to the texture and fragility of the injected part, because it is an outdoor useful part and due to the fact that the final consumer pays special attention to this product, since is a key car cap. Step by step, it was carried out an approach to the injection parameters, so that it could always remain within tolerances throughout the process, accepting of a certain tolerance in the injected material part and with regard to the machine reaction capacity through any parameter change. This work, carried out considering the DMAIC cycle phases (Define, Measure, Analyze, Improve and Control) allowed to eliminate some of the root causes problems and to implement improvements in the process. It is important to highlight the enhancement made in the selection process between the injected parts and sprue, through the use of several polycarbonate separators, in which 80% of defects occurred in the conveyor belt for the parts to be transported to the packaging. Finally, it was compared two years of production, one before making the improvements by this work and the other after it. Finally, it was shown that this thesis has contributed to a very significant cost reduction in the company.
ABSTRACT: The evolution of management processes has overcome with very demanding and precise tools and methodologies, among which, one of the most important is the six sigma methodology, where the goal is zero defects. The process approach using this methodology is extremely important and has been widely applied in the industrial processes due to its economic benefits. The aim of this work is to build a reference document developed within the scope of a Course Dissertation MEMGI (Masters in Mechanical Engineering and Industrial Management) carried out in an automotive industry sector, developing a work on a field of a six sigma area, with the aim to increase/improve the efficiency in the Huf Portuguesa group, an automobile factory of components. The objective of this work is focused on the reduction of scrap of a component manufactured by injection (reinforced glass fiber polymer composite), and has as main focus the reduction of costs from parts selection and mold recover, as well as the optimization of the injection process. This work allowed to eliminate operations without added value and to continue to assure the product requirements within the specifications of the internal and external customers. In summary, it was collected and evaluated the rejection rates and was carried out the stratification of most common defects. Emphasis was placed on the aesthetic defects inherent to the texture and fragility of the injected part, because it is an outdoor useful part and due to the fact that the final consumer pays special attention to this product, since is a key car cap. Step by step, it was carried out an approach to the injection parameters, so that it could always remain within tolerances throughout the process, accepting of a certain tolerance in the injected material part and with regard to the machine reaction capacity through any parameter change. This work, carried out considering the DMAIC cycle phases (Define, Measure, Analyze, Improve and Control) allowed to eliminate some of the root causes problems and to implement improvements in the process. It is important to highlight the enhancement made in the selection process between the injected parts and sprue, through the use of several polycarbonate separators, in which 80% of defects occurred in the conveyor belt for the parts to be transported to the packaging. Finally, it was compared two years of production, one before making the improvements by this work and the other after it. Finally, it was shown that this thesis has contributed to a very significant cost reduction in the company.
Description
Keywords
Six Sigma Injeção Poupança Melhoria continua