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Abstract(s)
A indústria automóvel encontra-se em constante mudança, tanto por alterações na economia e consequente disponibilidade de compra por parte do utilizador, como pelo constante desenvolvimento tecnológico, como é o caso dos veículos de utilização mais amiga do ambiente e dos automóveis de condução autónoma. Invariável, por outro lado, tem sido o crescimento da indústria a nível global, a exigência dos mais elevados índices de qualidade e produtividade, que aliados à cada vez maior automatização do processo, apontam o caminho para a implementação da indústria 4.0. A taxa de sucata que a indústria produz induz uma pegada ecológica enorme, que tem sido estudada cada vez mais, de forma a obter-se uma produção mais verde. Também a produção desse material não conforme, é precedida pela ineficiência do processo e custos de tratamento, que na indústria automóvel se pagam com perda de competitividade. É nesta linha de pensamento que o presente estudo encaixa, tendo como propósito o aumento do Know How sobre a imperfeição “degrau” que ocorre durante a emenda no processo de corte metálico, e a proposta de soluções com potencial de a eliminar. O estudo foi realizado na Continental Mabor – Indústria de Pneus S.A., em parceria com o Instituto Superior de Engenharia do Porto. Começou-se por compreender o processo, as máquinas e a área fabril, de forma a orientar as escolhas ao ambiente e circunstâncias de laboração. A investigação sobre a origem da imperfeição revelou existir um elevado número de causas potenciais que, após classificação, se resumiram em três, nomeadamente tensão, adesividade e operador, sendo mais influentes as primeiras duas. Foi então feito um estudo a estas duas caraterísticas do material. Os dados revelaram haver pouca consistência na adesividade do material, explicada pela grande variação das caraterísticas do produto natural utilizado, a borracha natural. No que se refere à tensão do material, encontrou-se também inconsistência das suas caraterísticas, desta vez devido à falta de controlo do processo de calandra, originada pela grande liberdade de operação dada ao operador. Posto isto, dado no momento em que foi feito o estudo não ser possível controlar os valores de adesividade, sugeriu-se a implementação de um sistema que tem como objetivo tornar a máquina menos sensível a variações desta caraterística. Relativamente à tensão, como tentativa de melhorar o comportamento do creel superior, que foi o que revelou piores resultados, projetou-se a alteração a fazer à posição de desenrolamento do fio, para obter o mesmo princípio de funcionamento do creel inferior. No processo de calandra, sugeriu-se também traçar um caminho de restrição da intervenção do operador, começando pela implementação de um sistema de controlo automático da pressão do creel. Entre as propostas feitas, implementou-se apenas a alteração do creel superior que, segundo os testes feitos, apresenta bons indicadores.
The automobile industry is in constant transformation due to changes in the economy, the consequent purchasing power of the users and also because the constant technological development, such as environmentally friendly vehicles and autonomous cars. Invariably, on the other hand, it has been the growth of the industry at a global level, the requirement of quality and productivity indexes, which together with the increasingly process automation, pointing the way to the implementation of the industry 4.0. The scrap rate that the industry produces induces a huge ecological footprint, which has been studied more and more, in order to obtain a greener production. Also, the production of this nonconforming material is preceded by inefficiency of the process and treatment costs which, in the automobile industry, are paid with loss of competitiveness. It is in this line of thought that the present study fits, aiming to increase the Know How about the imperfection "step" that occurs during the amendment in the process of metal cutting, and the proposal of solutions with the potential to eliminate it. The research was made at Continental Mabor - Indústria de Tires S.A., in partnership with the Instituto Superior de Engenharia do Porto. It began by understanding the process, the machines and the manufacturing area, in order to guide the choices to the environment and working conditions. The investigation on the origin of the imperfection revealed a high number of potential causes which, after classification, were summarized in three ways, namely tension, adhesiveness and operator, and the most influential being the first two. The study was supported on these two material characteristics. The data obtained revealed a little consistency in the adhesiveness of the material, explained by the great variation of the characteristics of the natural product used, the natural rubber. As it regards the material tension, its characteristics were also inconsistent, at this time because of the lack of control of the calendering process due to the wide autonomy of the operation given to the operator. Hereupon, at the moment when the research was made, it was not possible to control the values of adhesiveness, so it was suggested the implementation of a system that aims to make the machine less sensitive to variations of this characteristic. Concerning the tension, in an attempt to improve the demeanor of the upper creel which was the one that revealed the worst results, it was designed a change to be made to the unwinding position of the yarn to achieve the same operating principle of the lower creel was designed. In the calendering process, it was also suggested to draw a path of restriction of operator intervention, starting with the implementation of an automatic creel pressure control system. Among the proposals made, only the alteration of the upper creel was implemented which, according to the tests done, shows good indicators.
The automobile industry is in constant transformation due to changes in the economy, the consequent purchasing power of the users and also because the constant technological development, such as environmentally friendly vehicles and autonomous cars. Invariably, on the other hand, it has been the growth of the industry at a global level, the requirement of quality and productivity indexes, which together with the increasingly process automation, pointing the way to the implementation of the industry 4.0. The scrap rate that the industry produces induces a huge ecological footprint, which has been studied more and more, in order to obtain a greener production. Also, the production of this nonconforming material is preceded by inefficiency of the process and treatment costs which, in the automobile industry, are paid with loss of competitiveness. It is in this line of thought that the present study fits, aiming to increase the Know How about the imperfection "step" that occurs during the amendment in the process of metal cutting, and the proposal of solutions with the potential to eliminate it. The research was made at Continental Mabor - Indústria de Tires S.A., in partnership with the Instituto Superior de Engenharia do Porto. It began by understanding the process, the machines and the manufacturing area, in order to guide the choices to the environment and working conditions. The investigation on the origin of the imperfection revealed a high number of potential causes which, after classification, were summarized in three ways, namely tension, adhesiveness and operator, and the most influential being the first two. The study was supported on these two material characteristics. The data obtained revealed a little consistency in the adhesiveness of the material, explained by the great variation of the characteristics of the natural product used, the natural rubber. As it regards the material tension, its characteristics were also inconsistent, at this time because of the lack of control of the calendering process due to the wide autonomy of the operation given to the operator. Hereupon, at the moment when the research was made, it was not possible to control the values of adhesiveness, so it was suggested the implementation of a system that aims to make the machine less sensitive to variations of this characteristic. Concerning the tension, in an attempt to improve the demeanor of the upper creel which was the one that revealed the worst results, it was designed a change to be made to the unwinding position of the yarn to achieve the same operating principle of the lower creel was designed. In the calendering process, it was also suggested to draw a path of restriction of operator intervention, starting with the implementation of an automatic creel pressure control system. Among the proposals made, only the alteration of the upper creel was implemented which, according to the tests done, shows good indicators.
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Keywords
Breaker Processos de fabrico Corte metálico Melhoria contínua Qualidade Manufacturing Processes Cutting Continuous Improvement Quality