As competition has intensified, many American manufacturers have sought alternatives to rejuvenate their production systems. Cellular manufacturing systems have received considerable interest from both academics and practitioners. This research examines three major issues in cellular manufacturing that have not been adequately addressed: applicability, structural design, and operational design. Applicability, in this study, is concerned with discerning the circumstances in which cellular manufacturing is the system of choice. The methodology employed is simulation and two experimental studies are conducted. The objective of Experiment I, a 2 x 3 x 3 factorial design, is to investigate the role of setup time and move time on system performance and to gain insight into why and how one layout could outperform another. The results of Experiment I suggest that move time is a significant factor for job shops and that workload variation needs to be reduced if the performance of cellular manufacturing is to be improved. Experiment II evaluates the impact of setup time reduction and operational standardization on the performance of cellular manufacturing. The results of Experiment II suggest that cellular manufacturing is preferred if the following conditions exist: (1) well balanced workload, (2) standardized products, (3) standardized operations, and (4) setup times independent from processing times. / Ph. D.

This thesis presents an approach for solving the problem of determining a near optimal number of machines in order to minimize total cost in a Cellular Manufacturing System. In addition, all aspects and design of a Cellular Manufacturing System are discussed along with other related topics such as Group Technology and Plant Layout as applied to Cellular Manufacturing. / Master of Science

Les techniques de groupement technologique sont aujourd’hui utilisées dans de nombreux ateliers de fabrication; elles consistent à décomposer les systèmes industriels en sous-systèmes ou cellules constitués de pièces et de machines. Trouver le groupement technologique le plus efficace est formulé en recherche opérationnelle comme un problème de formation de cellules. La résolution de ce problème permet de tirer plusieurs avantages tels que la réduction des stocks et la simplification de la programmation. Plusieurs critères peuvent être définis au niveau des contraintes du problème tel que le flot intercellulaire,l’équilibrage de charges intracellulaires, les coûts de sous-traitance, les coûts de duplication des machines, etc. Le problème de formation de cellules est un problème d'optimisation NP-difficile. Par conséquent les méthodes exactes ne peuvent être utilisées pour résoudre des problèmes de grande dimension dans un délai raisonnable. Par contre des méthodes heuristiques peuvent générer des solutions de qualité inférieure, mais dans un temps d’exécution raisonnable. Dans ce mémoire, nous considérons ce problème dans un contexte bi-objectif spécifié en termes d’un facteur d’autonomie et de l’équilibre de charge entre les cellules. Nous présentons trois types de méthodes métaheuristiques pour sa résolution et nous comparons numériquement ces métaheuristiques. De plus, pour des problèmes de petite dimension qui peuvent être résolus de façon exacte avec CPLEX, nous vérifions que ces métaheuristiques génèrent des solutions optimales. / Group technology techniques are now widely used in many manufacturing systems. Those techniques aim to decompose industrial systems into subsystems or cells of parts and machines. The problem of finding the most effectivegroup technology is formulated in operations research as the Cell Formation Problem. Several criteria can be used to specify the optimal solution such as flood intercellular, intracellular load balancing, etc. Solving this problem leads to several advantages such as reducing inventory and simplifying programming. The Cell Formation Problem is an NP-hard problem; therefore, exact methods cannot be used to solve large problems within a reasonabletime, whereas heuristics can generate solutions of lower quality, but in a reasonable execution time. We suggest in this work, three different metaheuristics to solve the cell formation problem having two objectives functions: cell autonomy and load balancing between the cells.We compare numerically these metaheuristics. Furthermore, for problems of smaller dimension that can be solved exactly with CPLEX, we verify that the metaheuristics can reach the optimal value.

<p>У докторској дисертацији је представљен алгоритам за развој<br />конфигуратора сложених производа применом поступка груписања.<br />Детаљно је описано свих осам фаза алгоритма, а потом је извршена<br />емпиријска провера алгоритма на примеру расхладно-термичких<br />уређаја током које је развијен систем за конфигурисање сложених<br />производа. Утврђено је да се развијеним конфигуратором може<br />скратити време потребно да се конфигурише и испоручи производ<br />крајњем кориснику, а самим тим и укупно време потребно да се нови<br />или побољшани производ појави на тржишту. Резултати истраживања<br />су показали оправданост приступа развоју конфигуратора сложених<br />производа применом поступка груписања.</p> / <p>U doktorskoj disertaciji je predstavljen algoritam za razvoj<br />konfiguratora složenih proizvoda primenom postupka grupisanja.<br />Detaljno je opisano svih osam faza algoritma, a potom je izvršena<br />empirijska provera algoritma na primeru rashladno-termičkih<br />uređaja tokom koje je razvijen sistem za konfigurisanje složenih<br />proizvoda. Utvrđeno je da se razvijenim konfiguratorom može<br />skratiti vreme potrebno da se konfiguriše i isporuči proizvod<br />krajnjem korisniku, a samim tim i ukupno vreme potrebno da se novi<br />ili poboljšani proizvod pojavi na tržištu. Rezultati istraživanja<br />su pokazali opravdanost pristupa razvoju konfiguratora složenih<br />proizvoda primenom postupka grupisanja.</p>

Made available in DSpace on 2015-03-05T13:56:58Z (GMT). No. of bitstreams: 0 Previous issue date: 20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Este trabalho tem como objetivo a geração de um modelo de escalonamento aplicado ao Jobshop Scheduling Problem num Sistema de Manufatura Flexível que considera o tempo total de produção (makespan), o tempo total de atraso, o tempo total parado e o tempo total ocioso.O modelo proposto é composto por: (a) uma função objetivo que reflete, através de suas variáveis de decisão e seus pesos respectivos, as estratégias de otimização, e de (b) uma arquitetura que está dividida em cinco fases. O modelo utilizou o algoritmo Busca Tabu que,através de duas estratégias de geração de vizinhanças, busca a otimização da função objetivo. A arquitetura do modelo baseia-se na extração da demanda de produção, na Tecnologia de Grupo, nas Regras de Despacho, no Algoritmo Busca Tabu e na gravação do plano de produção, para tratar os Problemas de Seleção de Partes (Famílias de Partes) e do Escalonamento. Foram realizados, através de um estudo de caso, diversos experimentos que possibilitaram a comparação de estratégias de otimiza / This paper has the aim of generating a scheduling model applied to Job-shop Scheduling Problem in Flexible Manufacturing System, which considers the makespan, total tardiness time, total stop time, total idle time. The model proposed is composed for: (a) an objective function that reflects, through its variables of decision and its weights, the optimization strategies, and (b) arquitecture that is divided in five phases. The model used the Tabu Search algorithm which, through two strategies neighborhoods generation, searching the objective function optimization. The model architecture is based on extraction of production demand, in the Group Technology, in the Dispatching Rules, in the Tabu Search algorithm and save production plan, to deal the Part Selections (Part Families) and Scheduling Problems.Through a study of case, it has been realized several experiments which makes it possible the comparison of optimization strategies and real scheduling, and which proves conflicts in decision variables. For mo

Made available in DSpace on 2015-03-05T13:58:26Z (GMT). No. of bitstreams: 0 Previous issue date: 1 / Universidade do Vale do Rio dos Sinos / Neste trabalho é abordado o Problema de Escalonamento em um job shop, considerando restrições de datas de entrega, turnos de produção e tempo de setup entre operações. Considera-se um ambiente de Sistema de Manufatura flexível, que dado ao alto nível de automação, permite a previsibilidade dos processos de carregamento dos recursos à área de processamento. O problema foi modelado através de uma Função Objetivo fn composta de três variáveis de decisão. A importância da contribuição de cada variável para o valor de fn é gerida pela atribuição de valores aos pesos associados às variáveis. Na abordagem proposta, são utilizadas técnicas de Tecnologia de Grupo e Busca Tabu. O modelo implementado é uma modificação da técnica i TSAB, proposta por Nowicki e Smutnicki, a qual apresenta bons resultados no tratamento do Problema de Escalonamento em um job shop PEJS clássico. A consideração das restrições adicionais ao PEJS aumenta a complexidade do modelo implementado, porém, deixa o problema mais próximo da realidade. / In this work the Job Shop Scheduling Problem is studied, considering due dates, production turns and tooling constraints. This problem is applied in a Flexible Manufacturing System, which possesses high degree of automation, allowing previsibility in the processes of loading and unloading jobs on the machines. The problem is modeled through a objective function fn composed by three weighted decision variables. The importance of each variable in the fn final value is managed through assignment of values to the weights of these variables. In the proposed approach, it was used Group Technology and Tabu Search techniques. The implemented model is a modification of the i TSAB technique, proposed by Nowicki and Smutniki. The consideration of adicional constraints in the Job Shop Scheduling Problem increases the complexity of the implementation, otherwise, makes the problem closer to the industrial reality. The model was validated using benchmark instances, in which the data from the addional constraints were added.

Les techniques de groupement technologique sont aujourd’hui utilisées dans de nombreux ateliers de fabrication; elles consistent à décomposer les systèmes industriels en sous-systèmes ou cellules constitués de pièces et de machines. Trouver le groupement technologique le plus efficace est formulé en recherche opérationnelle comme un problème de formation de cellules. La résolution de ce problème permet de tirer plusieurs avantages tels que la réduction des stocks et la simplification de la programmation. Plusieurs critères peuvent être définis au niveau des contraintes du problème tel que le flot intercellulaire,l’équilibrage de charges intracellulaires, les coûts de sous-traitance, les coûts de duplication des machines, etc. Le problème de formation de cellules est un problème d'optimisation NP-difficile. Par conséquent les méthodes exactes ne peuvent être utilisées pour résoudre des problèmes de grande dimension dans un délai raisonnable. Par contre des méthodes heuristiques peuvent générer des solutions de qualité inférieure, mais dans un temps d’exécution raisonnable. Dans ce mémoire, nous considérons ce problème dans un contexte bi-objectif spécifié en termes d’un facteur d’autonomie et de l’équilibre de charge entre les cellules. Nous présentons trois types de méthodes métaheuristiques pour sa résolution et nous comparons numériquement ces métaheuristiques. De plus, pour des problèmes de petite dimension qui peuvent être résolus de façon exacte avec CPLEX, nous vérifions que ces métaheuristiques génèrent des solutions optimales. / Group technology techniques are now widely used in many manufacturing systems. Those techniques aim to decompose industrial systems into subsystems or cells of parts and machines. The problem of finding the most effectivegroup technology is formulated in operations research as the Cell Formation Problem. Several criteria can be used to specify the optimal solution such as flood intercellular, intracellular load balancing, etc. Solving this problem leads to several advantages such as reducing inventory and simplifying programming. The Cell Formation Problem is an NP-hard problem; therefore, exact methods cannot be used to solve large problems within a reasonabletime, whereas heuristics can generate solutions of lower quality, but in a reasonable execution time. We suggest in this work, three different metaheuristics to solve the cell formation problem having two objectives functions: cell autonomy and load balancing between the cells.We compare numerically these metaheuristics. Furthermore, for problems of smaller dimension that can be solved exactly with CPLEX, we verify that the metaheuristics can reach the optimal value.

Made available in DSpace on 2014-12-17T14:58:05Z (GMT). No. of bitstreams: 1 VivianeML_DISSERT.pdf: 4716607 bytes, checksum: b7769daeea7c8b8ab7ae776260a4a518 (MD5) Previous issue date: 2010-04-23 / On this research we investigated how new technologies can help the process of design and manufacturing of furniture in such small manufacturers in Rio Grande do Norte state. Google SketchUp, a 3D software tool, was developed in such a way that its internal structures are opened and can be accessed using SketchUp s API for Ruby and programs written in Ruby language (plugins). Using the concepts of the so-called Group Technology and the flexibility that enables adding new functionalities to this software, it was created a Methodology for Modeling of Furniture, a Coding System and a plugin for Google s tool in order to implement the Methodology developed. As resulted, the following facilities are available: the user may create and reuse the library s models over-and-over; reports of the materials manufacturing process costs are provided and, finally, detailed drawings, getting a better integration between the furniture design and manufacturing process / No desenvolvimento deste trabalho foi investigado como novas tecnologias podem auxiliar nos processos de modelagem e fabrica??o de m?veis modulados na ind?stria moveleira do estado do Rio Grande do Norte, constitu?da de pequenos fabricantes. O c?digo software CAD tridimensional Google SketchUp foi desenvolvido de tal forma que as estruturas internas do programa podem ser acessadas utilizando a API disponibilizada pelo fabricante e c?digos escritos na linguagem Ruby (plugins). Utilizando-se dos conceitos da Tecnologia de Grupos e desta flexibilidade, que permite acrescentar novas funcionalidades ao programa, foram desenvolvidos: uma Metodologia para Modelagem de M?veis Modulados, um Sistema de Codifica??o e um plugin para o Google SketchUp que possibilita a aplica??o da Metodologia desenvolvida. Como resultados t?m-se: facilidade na reutiliza??o dos modelos de uma biblioteca de m?veis modulados, obten??o imediata dos custos de fabrica??o dos modelos e gera??o de relat?rios detalhados com imagens e atributos dos modelos, tais como dimens?es e materiais utilizados, o que proporcionou melhor integra??o entre os processos de projeto e fabrica??o de m?veis modulados

Made available in DSpace on 2014-12-17T14:58:13Z (GMT). No. of bitstreams: 1 WalkysoSJ_DISSERT.pdf: 1722690 bytes, checksum: c91cde978dc7fb299b7363330ba2d411 (MD5) Previous issue date: 2012-03-23 / In this work was developed an information system to apply the concepts of CAD3D-BIM technology for the design activities of the furniture industry. The development of this system was based in an architecture comprised of two modules: a web interface to management the metadata of models from furniture's library and the combination of three-dimensional CAD software with a specific plugin to access the information from this model. To develop this system was also used a Data Base Management System (DBMS) designed to storage the information from models in a hierarchical way, based on concepts of Group Technology (GT). The centralization of information in a single database allows the automatic availability of any changes to all participants involved in a particular project when it&#8223;s happens. Each module from system has its own connection to this database. Finally was developed a prototype from a 3D virtual environment to help create Virtual Reality projects in the web. A study from available technologies to create 3D web applications for execution in websites was done to support this development. The interconnection between modules and the database developed allowed the assembly of a system architecture to support the construction and exhibition of projects of the furniture industry in accordance with the concepts proposed by BIM (Building Information Modeling), using as object of study the furniture industry of state of Rio Grande do Norte / No desenvolvimento deste trabalho foi desenvolvido um sistema que permite a aplica??o de conceitos da tecnologia CAD3D-BIM em projetos da ind?stria moveleira. Para desenvolver o sistema foi concebida uma arquitetura composta por dois m?dulos: uma interface web para gerenciamento dos metadados dos componentes existentes em uma biblioteca de m?veis e uma ferramenta CAD tridimensional que utiliza um plugin espec?fico para acessar as informa??es referentes a cada um destes componentes. Na constru??o do sistema tamb?m foi utilizado um SGBD (Sistema Gerenciador de Banco de Dados) projetado para armazenar as informa??es dos componentes de uma forma hier?rquica, baseada nos conceitos da Tecnologia de Grupo. A concentra??o de informa??es em um ?nico banco de dados permite que qualquer mudan?a realizada seja disponibilizada automaticamente para todos os participantes envolvidos no projeto. Os dois m?dulos que comp?em o sistema possui uma conex?o com esta base de dados. Finalmente, foi desenvolvido o prot?tipo de um ambiente virtual 3D com o objetivo de auxiliar a cria??o de projetos de Realidade Virtual na web. Para embasar o desenvolvimento, foi feito um estudo sobre as tecnologias dispon?veis para cria??o de aplica??es 3D web executadas diretamente em navegadores. Com a interliga??o de todos os componentes foi criada uma arquitetura de sistema para dar suporte ? constru??o e exibi??o de projetos da ind?stria moveleira, de acordo com os conceitos propostos pela tecnologia BIM (Building Information Modeling), tendo como objeto de estudo a ind?stria moveleira do estado do Rio Grande do Norte

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