published_or_final_version / Industrial Engineering / Master / Master of Science in Engineering

published_or_final_version / abstract / Industrial and Manufacturing Systems Engineering / Doctoral / Doctor of Philosophy

M.Ing. / Potential variation in tasks and relative location of manufacturing equipment (machine tools, robot, automated guided vehicles etc.) resulting from the need to restructure the production environment, require efficient and effective communication for optimal performance. The work presented makes use of information and data flow within a system to achieve an integrated and dynamic environment. Models are presented to describe the integration of processing and auxiliary equipment and to select auxiliary equipment for a specific environment. An analytical approach is included for the integration. Specific examples are included. The work presented attempts to contribute to the flexibility of modern manufacturing environments by integrating all facilities in the environment.

by Chan Lap-yan, Lawrence. / Bibliography: leaf 54 / Thesis (M.B.A.)--Chinese University of Hong Kong, 1986

Orientador: Fernando Bernardi de Souza / Banca: Silvio Roberto Ignacio Pires / Banca: Jose de Souza Rodrigues / Resumo: A análise do comportamento do fluxo das ordens de produção e dos recursos que compõem um sistema produtivo oferece um indicativo de onde se deve atuar para melhorar este sistema. A Teoria das Restrições (Theory of Constraints - TOC) indica três métodos de focalização de melhorias de recursos produtivos que impactam globalmente o sistema. Este trabalho busca avaliar o desempenho de cinco métodos de melhoria, incluindo os indicados pela TOC, em um ambiente de produção para estoque (make-to-stock - MTS) utilizando-se de simulação computacional. Para isto, estas abordagens são simuladas em seis configurações de linha de produção e o desempenho é medido em termos de Tempo de Ciclo (Cycle Time - CT) e Taxa de Preenchimento de Pedidos (Fill Rate - FR). Os resultados indicam que, em sistemas balanceados, a melhor abordagem de melhoria a ser utilizada é a que atua em todos os recursos simultaneamente. Em ambientes desbalanceados, por outro lado, é necessário utilizar um método que foca melhorias em um único recurso, como o método de nível de ocupação, estoque em processo ou Buffer Management. Neste caso, a focalização pelo nível de ocupação da máquina trouxe mais benefícios ao sistema. / Abstract: A behavioral analysis of the flow of production orders and resources that form a production system provides an indication of where to improve this system. The Theory of Constraints (TOC) suggests three approaches for identifying and improving resource constraints aiming to entirely affect the system: based on the largest queue of work-in-progress, the highest utilization level, and using the buffer management method. This study aims to assess the performance of these approaches comparing them with each other and with two others: dispersed improvements in all the resources and random improvements. Data was taken and analyzed from a simulated make-to-stock (MTS) environment, managed using the Simplified Drum Buffer Rope (S-DBR) method. For this, each improvement approach is simulated in six production line configurations and performance is measured in terms of Cycle Time (CT) and Fill Rate (FR). The results indicate that, in balanced systems, scattered improvements in all resources allowed better results than all three approaches recommended by TOC. In unbalanced environments, on the other hand, the focus on occupancy level exceeded all the other four approaches assessed. / Mestre

As atividades de planejamento de médio prazo (nível tático) são especialmente importantes em empresas de manufatura, visto que tratam do dimensionamento dos recursos produtivos (recursos humanos, materiais, equipamentos, instalações, etc) , que terá impacto na capacidade de atendimento da demanda e nos resultados operacionais da empresa. Este trabalho apresenta um modelo de Planejamento Agregado da Produção e Distribuição para aplicação em empresas do setor cimenteiro, com múltiplas famílias de produtos, múltiplas localidades (de produção e de demanda) e produção em dois estágios, tendo por objetivo a maximização do resultado operacional. O modelo desenvolvido é baseado em Programação Linear Inteira Mista e considera, além dos custos das operações de produção e de transporte, os gastos com impostos, que variam de acordo com a estratégia de abastecimento dos pontos de demanda, dada a existência de diferenças nas alíquotas do Imposto sobre Circulação de Mercadorias e Serviços entre operações inter e intra-estaduais. Os resultados obtidos demonstraram a importância da abordagem conjunta dos processos de produção e de distribuição, tornando clara a necessidade de integração dos mesmos no planejamento agregado num ambiente produtivo de múltiplas localidades e com mais de um processo de produção. / Middle-term production planning (tactical level) is an important activity in manufacturing companies, once it deals with production resources (work-force and production capacity) and stocks dimensioning, impacting on the company supply capacity and on its operating results. This dissertation presents an Aggregate Production and Distribution Planning model to be applied in multi-site, multi-product cement companies with the purpose of maximize operational results. The developed model is based upon Mixed Integer Linear Programming (MILP), and it considers, besides production and transportation operational costs, taxes expenses, which in the Brazilian context can change considerably depending on the supply strategy adopted, due to taxation differences between inter and intra-state sales operations. The results confirmed the importance of the combined approach of the production and distribution, demonstrating the relevance of integrating these two planning processes in a multi-site two-stage production environment.

Abstract not available

Thesis (Ph. D.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

The purpose of this research is to develop an approach to minimize makespan for assigning boards to production lines. Because of sequence-dependent setup issue, board assignment and component allocation have to be performed concurrently. An integrated methodology is proposed to obtain a solution of the two problems. The methodology consists of seven phases: PCB grouping, family decomposition, subfamily sequencing, Keep Tool Needed Soonest (KTNS), component setup determination, component allocation, and board assignment. PCB grouping based on component similarity between boards is used to reduce the problem size. Family decomposition is used when total number of feeder slots required by a family exceeds feeder capacity. Subfamily sequencing and Keep Tool Needed Soonest are applied to minimize the number of component setups. Classification of setup components into standard, semi-standard, and custom setup components is performed to reduce the complexity of the component allocation problem. A component allocation algorithm is developed to balance workload across machines. Assigning board families to production lines is performed using a modification of Longest Processing Time (LPT) rule. Assigning entire PCB families to production lines to minimize makespan is difficult to accomplish since the amount of production time for each family is very large compared to that of individual PCB lot. Splitting some subfamilies is allowed as long as this does not increase makespan. The PCB grouping, family decomposition, subfamily sequencing, Keep Tool Needed Soonest (KTNS), and component setup determination procedures are derived from published research results. The component allocation and board assignment are developed in this research, as well as an overall methodology to integrate the entire problem. Data provided by published literature are employed to evaluate performance of the component allocation algorithm and the integrated methodology. To examine the applicability of the methodology, an industrial data is used with the total imbalance due to setup time and placement time of individual PCB and global makespan as the performance measures. Experimentation is conducted with simulated data based on an industry data to investigate impact of threshold value, feeder capacity, and characteristics of data sets on system performance. / Graduation date: 2002

Thesis (M. Sc.)--University of Hong Kong, 1978.