The manufacturing systems operating within today's global enterprises are invariably dynamic and complicated. Lean manufacturing works well where demand is relatively stable and predictable where product diversity is low. However, we need a much higher agility where customer demand is volatile with high product variety. Frequent changes of product designs need quicker response times in ramp-up to volume. To stay competitive in this 21st century global industrialization, companies must posses a new operation design strategy for responsive manufacturing systems that react to unpredictable market changes as well as to launch new products in a cost-effective and efficient way. The objective of this research is to develop an alternative method to model, analyze, and design responsive manufacturing systems using classical control theory. This new approach permits industrial engineers to study and better predict the transient behavior of responsive manufacturing systems in terms of production lead time, WIP overshoot, system responsiveness, and lean finished inventory. We provide a one-to-one correspondence to translate manufacturing terminologies from the System Dynamics (SD) models into the block diagram representation and transfer functions. We can analytically determine the transient characteristics of responsive manufacturing systems. This analytical formulation is not offered in discrete event simulation or system dynamics approach. We further introduce the Root Locus design technique that investigates the sensitivity of the closed-loop poles location as they relate to the manufacturing world on a complex s-plane. This subsequent complex plane analysis offers new management strategies to better predict and control the dynamic responses of responsive manufacturing systems in terms of inventory build-up (i.e., leanness) and lead time. We define classical control theory terms and interpret their meanings according to the closed-loop poles locations to assist production management in utilizing the Root Locus design tool. Again, by applying this completely graphic view approach, we give a new design approach that determine the responsive manufacturing parametric set of values without iterative trial-and-error simulation replications as found in discrete event simulation or system dynamics approach. / Ph. D.

Made available in DSpace on 2016-06-02T19:52:13Z (GMT). No. of bitstreams: 1 DissEG.pdf: 974280 bytes, checksum: 8b68b7cd22a8e556ec3824797faa6614 (MD5) Previous issue date: 2005-12-21 / Nowadays enterprises are structuring themselves to become competitive in the world market. In the footwear business the search for competitiveness is even greater as this sector is highly dependent on labour and its products follow international fashion trends which make internal organisation and production and planning control (PPC) extremely difficult. A lot of research has been carried out to contribute to the improvement of this sector and this work is going to complement this body of research, helping the national footwear industry enterprises to become more competitive. The aim of this study is to adapt, implement and evaluate a model proposed in a doctorate thesis concerning a new approach of Responsive Manufacturing through action-research in a footwear factory. The object of study was a children s footwear factory in the city of Birigui in São Paulo state, whose workers had a strong influence on the research, thus characterising it as action-research. Considering these facts, it was possible to achieve the study s aim and to initiate the implementation of the Responsive Manufacturing paradigm in the footwear industry. Among the results obtained, we can highlight the following: reduction of production and labour costs; an increase in the amount of orders supplied within the deadlines; and the decrease of rework level. All these results also contribute to reducing the existing gap between theory and practice in Production Engineering studies and open up opportunities for new research in the footwear industry sector. / As empresas estão cada dia se estruturando para serem competitivas no mercado mundial. No ramo de calçados a busca por competitividade é ainda maior por ser um setor altamente dependente de mão-de-obra e seus produtos acompanharem a tendência da moda internacional, o que dificulta muito a organização interna, o planejamento e o controle da produção (PCP). Várias pesquisas vêm sendo feitas com objetivo de contribuírem para melhoria do setor e este trabalho vem complementar essas pesquisas e ajudar fabricantes de calçados nacionais a serem mais competitivos. O objetivo deste estudo é adaptar, implantar e avaliar o modelo, proposto em tese de doutorado, de nova abordagem para Manufatura Responsiva por meio de pesquisa-ação em fábrica de calçados. O objeto de estudo foi uma fábrica de calçados infantis localizada na cidade de Birigui Estado de São Paulo. Seus trabalhadores tiveram forte influência na pesquisa, caracterizando-a como pesquisaação. Diante disto foi possível atingir o objetivo do trabalho e dar início à implantação do paradigma Manufatura Responsiva na indústria de calçados. Dentre os resultados obtidos, destacam-se: reduções de custos produtivos e mão de obra, aumento nas quantidades de pedidos atendidos dentro dos prazos e diminuição dos índices de retrabalho. Todos resultados também contribuem para diminuir a lacuna existente entre a teoria e a prática da Engenharia de Produção e criam oportunidades de novas pesquisas para o segmento de calçados.

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