Application of lean scheduling and production control in non-repetitive manufacturing systems using intelligent agent decision support

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Lean Manufacturing (LM) is widely accepted as a world-class manufacturing paradigm, its currency and superiority are manifested in numerous recent success stories. Most lean tools including Just-in-Time (JIT) were designed for repetitive serial production systems. This resulted in a substantial stream of research which dismissed a priori the suitability of LM for non-repetitive non-serial job-shops. The extension of LM into non-repetitive production systems is opposed on the basis of the sheer complexity of applying JIT pull production control in non-repetitive systems fabricating a high variety of products. However, the application of LM in job-shops is not unexplored. Studies proposing the extension of leanness into non-repetitive production systems have promoted the modification of pull control mechanisms or reconfiguration of job-shops into cellular manufacturing systems. This thesis sought to address the shortcomings of the aforementioned approaches. The contribution of this thesis to knowledge in the field of production and operations management is threefold: Firstly, a Multi-Agent System (MAS) is designed to directly apply pull production control to a good approximation of a real-life job-shop. The scale and complexity of the developed MAS prove that the application of pull production control in non-repetitive manufacturing systems is challenging, perplex and laborious. Secondly, the thesis examines three pull production control mechanisms namely, Kanban, Base Stock and Constant Work-in-Process (CONWIP) which it enhances so as to prevent system deadlocks, an issue largely unaddressed in the relevant literature. Having successfully tested the transferability of pull production control to non-repetitive manufacturing, the third contribution of this thesis is that it uses experimental and empirical data to examine the impact of pull production control on job-shop performance. The thesis identifies issues resulting from the application of pull control in job-shops which have implications for industry practice and concludes by outlining further research that can be undertaken in this direction

Proposal of method for determination time buffer in a multi project environment with use of critical chain

Orientador: Olívio NovaskiTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia MecânicaResumo: O presente trabalho tem por objetivo apresentar uma proposta para a integração de ferramentas de gerenciamento de projeto e a determinação do pulmão de tempo em um ambiente de múltiplos projetos pelo uso de corrente crítica. Para o gerenciamento de projetos, utilizou-se um conjunto de ferramentas integradas e heurísticas de nivelamento de recursos. Para a determinação do pulmão de tempo foram escolhidas cinco variáveis de influência, tais como: flexibilidade na atividade; variação de consumo de recursos no tempo estimado; duração dos tempos estimados nas atividades, complexidade na rede e variável do atributo da incerteza e complexidade do projeto. Para tal, foi realizada uma comparação da proposta desenvolvida pelo o "Método Cortar e Colar" (C&PM) e o "Método da Raiz Quadrada do Erro" (RSEM), por intermédio dos indicadores: maior tempo de consumo do pulmão, tempo médio de consumo, número de vezes que o pulmão foi consumido. A presente proposta atende pela utilização de maior número de caraterísticas específicas da natureza de projeto no dimensionamento dos pulmões de tempo em relação aos dois métodos. Para essa comparação, foi realizada a aplicação da proposta de estudos de casos em três projetos. Após a análise dos Fatores Críticos de Sucesso (FCS), verificou que dos três projetos, dois alcançaram a faixa de projeto sucesso total, e o terceiro a faixa de projeto sucesso parcial. Acredita-se que a proposta desenvolvida pode ser utilizada para qualquer projeto e organização, e permite tomar decisões mais efetivas em ambientes de incerteza e complexidades em múltiplos projetos. E que seja uma opção de monitoramento para as empresas gerenciar seus projetos pelo uso da Corrente CríticaAbstract: The present work aims to present a proposal for the integration of project management tools and the determination of the time buffer in a multiple project environment by the use of critical chain. For project management, a set of integrated resource leveling tools and heuristics was used. For the determination of the time buffer, five variables of influence were chosen, such as: flexibility in the activity; variation of resource consumption over the estimated time; duration of estimated activities times, complexity in the network and attribute variable of uncertainty and complexity of the project. To do this, a comparison was made of the proposal developed by the "Cut and Paste Method" (C & PM) and the "Square Root Error Method" (RSEM), through the indicators: longer buffer consumption time, consumption, the number of times the buffer was consumed. The present proposal addresses the use of a greater number of specific characteristics of the nature of design in the design of the buffers of time in relation to the two methods. For this comparison, the proposal of case studies was applied in three projects. After analyzing the Critical Success Factors (FCS), it was verified that of the three projects, two reached the total success project track, and the third the partial success project track. It is believed that the proposal developed can be used for any project and organization, and allows to make more effective decisions in environments of uncertainty and complexities in mult projects. And it is a monitoring option for companies to manage their projects through the use of Critical ChainDoutoradoMateriais e Processos de FabricaçãoDoutor em Engenharia Mecânica33003017CAPE