Methods for computer aided inspection of geometric tolerances

This thesis investigates computational methods for assessing tolerance specifications of geometric features in a context of computer aided inspection. It is concerned with checking the sampled features for containment within tolerance zones specified at the design stage, not with explicit shape measurement. The significance of this difference is highlighted when two or more features are to be inspected in combination. The approach adopted is to express the tolerance information as a set of inequality constraints and then to seek efficient methods for determining the feasibility of the set, that is whether all the constraints can be simultaneously satisfied. Roundness inspection is used to introduce all the concepts of the new formulations. By linearisation of the constraints, a standard approximation in roundness measurement, a new algorithm is implemented which provides a “GO-NOGO” result of inspection by checking for feasibility in a highly efficient way. This algorithmic approach is then extended to other inspection situations where naturally linear constraints or valid linearisation occur. Since there are many inspection cases where linearisation is not appropriate, non-linear optimisation techniques are then investigated for their effectiveness in feasibility testing. The inspection of arrays of circular features is used here as a typical test case. Genetic search methods are explored as a possible alternative to formal non-linear programming and guidelines for their efficient use for this problem are proposed. These methods are then compared and contrasted with formal methods, particularly generalised reduced gradient (GRG) and sequential quadratic programming (SQP). The linear algorithm is shown to be the most efficient when it can be used, although all techniques were fast enough for on-line use with modest sized data sets. Currently all the non-linear methods are too expensive for routine use on large data sets. GRG is recommended as having the most favourable combination of good and bad features, but there is some evidence that genetic search might be relatively more efficient for more complex inspection problems

An Investigation of Improvement and Change Management Practices in a Brazilian Based Company

This paper reports the results of a case study research carried out in a Brazilian division of a multinational manufacturer of automobile components with the main objective of investigating improvement and change management practices. The theoretical framework for the research is based on the theories on improvement and change management programs, methods and capability development. After an overview of the theories, programs and approaches for improvement and change, the research method and questions of research are formalized so as to guide the case study. The case study itself is presented and discussed. Results of the study indicate that although several elements of improvement and change capabilities are present, functionally oriented organizational structure and a lack of formalized cross improvement and change business process undermine the potential for management performance improvements

Proposta de um modelo conceitual para o desdobramento de melhorias estratégicas A conceptual framework for deployment of strategy related improvements

Este artigo apresenta uma proposta de um modelo conceitual para o gerenciamento do processo de desdobramento de ações de melhoria por processos de negócio. A partir da expectativa dos clientes e de decisões estratégicas da empresa, o modelo propõe uma sistemática de desdobramento e priorização das ações de melhoria que mais possam contribuir para o alcance dos objetivos estratégicos. A proposta apresentada integra vários conceitos e práticas gerenciais como medição de desempenho e benchmarking, e sugere a utilização das matrizes do QFD como instrumento do processo de desdobramento e priorização das melhorias. A apresentação da proposta e o seu detalhamento são precedidos por uma discussão introdutória sobre estratégia de manufatura e gerenciamento da melhoria. Finalmente, algumas considerações são feitas sobre os potenciais benefícios e limitações da proposta.This paper presents a conceptual framework for managing the process of systematically deriving improvement actions from customer expectations and strategic decisions through business processes, and prioritizing improvement actions that will most contribute to strategic objectives. It proposes the use of management practices and concepts such as business process mapping, performance measurement and benchmarking. After some introductory theoretical background, the proposed framework and a set of steps to guide the implementation of such an approach are presented and detailed. Finally, some considerations are made based on the potential benefits and limitations of this proposal

MERGING TWO QFD MODELS INTO ONE: AN APPROACH OF APPLICATION

This paper presents an approach to the application of Quality Function Deployment that brings together the models developed by Don Clausing (Enhanced QFD) and Akao. In this way, the proposed approach benefits from focusing, at the same time, at: parameter extraction, systematizing the decision taking process within its matrices (Enhanced QFD); and the identification of relationships among different parameters of the product development process (QFD by Akao). The steps involved in the proposed approach are depicted and justified. Finally, a discussion is made on the effect of QFD on development cycle time and the benefits of the proposed approach

Modelo para identificação de ações de melhoria de desempenho aliadas à Estratégia

This article presents a proposal of a conceptual model to identify initiatives ofperformance improvement, which are aligned to the organizational strategy. It makes arevision that approaches important themes as Strategy & Environment, Improvement &Change Management and Performance Assessment. It enhances it more and more presentneed for change and it revises the improvement approaches explaining both, continuousimprovement and reengineering, as important for the organization. In this proposal, it isseen steps for Manage the Improvement & Change that it could be understood as a cyclePDCA for the performance improvement. In the phase P, it analyzes the strategic planningthat will support the identification of change actions. The implementation of improvementactions and systems of performance measurement belongs to the phase D. In the phase C,it can be appraised the actions and in the case of success it is possible to consolidate theimprovements and change and the new system of performance measurement. It concludesemphasizing the importance and limitations of this work

Aplicação das técnicas de planejamento e análise de experimentos no processo de injeção plástica Application design of experiments in the injection molding process

Experimentos industriais são realizados pelas empresas com o intuito de melhorar o desempenho dos produtos e os processos de fabricação. Nesse sentido, este trabalho tem por objetivo estudar e aplicar as técnicas de planejamento e análise de experimentos na melhoria da qualidade industrial. Especificamente são aplicadas as técnicas de planejamento Fatorial Fracionado 2k-p, Metodologia de Superfície de Resposta e Análise de Variância, em um processo de moldagem por injeção plástica. Com essa pesquisa experimental foi possível identificar os níveis ótimos de regulagem e os parâmetros mais importantes da injeção plástica: temperatura da máquina e pressão de injeção. Para finalizar é avaliado o procedimento de implementação das técnicas de experimentação e as dificuldades práticas encontradas na empresa.<br>Industrial experiments are made by companies in order to improve the quality characteristics of products and production processes. In this sense, the objective of this paper is to study and apply the design of experiments in the industrial quality improvement. In addition, as a part of the objective, an application of the techniques of design Fractional Factorial 2k-p, Analysis of Variance and Response Surface Methodology is done. It is focused in an injection molding process applied by a company, that makes and trades plastic products for the civil construction. Using this experimental study, the most important parameters of plastic injection are identified: machine temperature and injection pressure. At the same time, the optimal levels of adjustment of these parameters are determined. From this study, it is evaluated both the implantation procedures of the designs of experiments as well as the difficulties faced. Also, this study tries to contribute to the university-company relationship

Proposta de um sistema de avaliação do desempenho para arranjos produtivos locais Purpose of a performance measurement system for an industrial cluster

Os Arranjos Produtivos Locais (APLs) são sistemas que podem ser utilizados para promover a cooperação empresarial, a inovação contínua e o desenvolvimento sustentável das Pequenas e Médias Empresas (PMEs). O processo de gestão de desempenho do APL é construído a partir do planejamento estratégico e com a implantação de ações coletivas de melhoria contínua. Também é necessário construir uma infraestrutura local e um ambiente que estimule a confiança e a cooperação dos membros do APL. A avaliação de desempenho é uma prática que fortalecerá a coordenação e execução das atividades de melhoria contínua do APL. Assim, o objetivo deste trabalho é propor um Sistema de Medição do Desempenho (SMD) que dê suporte ao processo de gestão de desempenho do APL. A proposta foi construída a partir das pesquisas de campo realizadas nos APLs de Ibitinga e Jaú. Os resultados demonstram que a medição de desempenho integrada a um processo sistemático de melhoria contínua promove a gestão colaborativa, aprimora o processo de tomada de decisão ou coordenação das ações planejadas pelas instituições, empresas e outros órgãos que fazem parte dos APLs. É um instrumento que pode ajudar a monitorar o desempenho das PMEs inseridas em uma rede de cooperação empresarial e direcionar as iniciativas coletivas ou ações de melhoria para as principais necessidades do APL.<br>Industrial clusters or cooperation network is an interesting alternative in promoting the sustainable development of Small and Medium Enterprises (SME's). The fundamental characteristics for managing the performance of clusters are the identification of the stakeholders, definitions of common strategies and objectives, development of collaborative improvement actions, design of a performance management system, organization of a support infrastructure, and promotion of social capital. The concepts of a performance management system can be of great value in managing collective efficiency and performance improvement of the companies of the cluster. The purpose of this article is to describe a model for the performance measurement and management of a cluster. In order to develop this study, a field research was carried out in two industrial clusters: Ibitinga, a textile industry cluster and Jau, a Lady's footwear cluster. The results show the applicability of performance measurement systems for the performance management of a cluster. It also helps to integrate the objectives of performance establishing actions, evaluating results promoting cooperation to improve the collective efficiency of a cluster