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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Systemic design methodology for changeable manufacturing systems / Méthodologie de conception systématique pour les systèmes de production changeables

Benkamoun, Nadège 02 September 2016 (has links)
Les systèmes de production sont devenus des systèmes de grande échelle dont la complexité est accentuée par des contextes marqués de plus en plus par le changement. La capacité des systèmes a répondre au changement – appelée également changea-bilité – est reconnue comme étant une propriété essentielle pour leur cycle de vie, aussi bien dans le domaine des systèmes de production que dans le domaine de la conception en ingénierie. Au regard de la complexité des systèmes de production changeables, la méthodologie proposée par cette thèse a pour objectif de supporter la change-abilité dans la conception en souscrivant au domaine de l’ingénierie des systèmes. La première contribution est un formalisme pour la modélisation des systèmes changeables étayé d’après les principes de la conception systémique. Les concepts de flexibilité et de reconfigurabilité ne sont ici pas limités à des composants organiques du système, mais englobent l’ensemble des artefacts d’ingénierie dans le domaine du problème (exigences) et le domaine de la solution (blocs structurels). La deuxième contribution est une méthodologie pour la conception et la gestion des systèmes changeables. Elle repose sur un modèle du cycle de vie des systèmes changeables où des phases de conception des capacités de change-abilité du système s’alternent avec des phases de reconception tirant bénéfice de ces capacités existantes. Ces processus complémentaires garantissent la cohérence entre les décisions de conception pour intégrer et réutiliser des capacités de change-abilité, augmentant alors leurs potentiels tout au long du cycle de vie des systèmes complexes. Les concepts et les méthodologies développés ont été validés par des projets de conception de systèmes de production chez un équipementier automobile. Enfin, des développements possibles d’outils d’aide à la conception supportant la méthodologie proposée sont discutés. / Manufacturing systems have become large scale systems with increasing complexity particularly magnified by highly changing contexts. The system’s ability to cope with change (i.e. changeability) is recognized as a critical lifecycle property in the manufacturing system and engineering design domains. Given the complexity of changeable manufacturing systems, the proposed methodology of this dissertation aims to support design of changeability in subscribing to the domain of system engineering. The first contribution is a formalism for modeling changeability in a systemic way. Flexibility and reconfigurability paradigms are not limited to physical components of the system, but to the overall system architecture that encompasses all engineering artifacts relating to the designed system in both the requirements and physical solution domains. The second contribution is the methodology for the design and the management of changeability. The methodology utilizes a lifecycle model for changeable systems, in which design for changeability phases alternate with re-design phases that embrace and benefit from the existing changeability capabilities. These complementary processes allow a better consistency between design decisions to embed and reuse changeability, increasing changeability potential during the lifecycle of complex systems. The developed concepts and methodologies are validated in manufacturing system design projects from an automotive supplier. Finally, perspectives on design tools assisting the proposed methodology are discussed.
2

Robotic in-line quality inspection for changeable zero defect manufacturing

Azamfirei, Victor January 2021 (has links)
The growing customer demands for product variety have put unprecedented pressure on the manufacturing companies. To maintain their competitiveness, manufacturing companies need to frequently and efficiently adapt their processes while providing high-quality products. Different advanced manufacturing technologies, such as industrial robotics, have seen a drastic usage increase. Nevertheless, traditional quality methods, such as quality inspection, suffer from significant limitations in highly customised small batch production. For quality inspection to remain fundamental for zero-defect manufacturing and Industry 4.0, an increase in flexibility, speed, availability and decision upon conformance reliability is needed. If robots could perform in-line quality inspection, defective components might be prevented from continuing to the next production stage. Recent developments in robot cognition and sensor systems have enabled the robot to carry out perception tasks they were previously unable to do. The purpose of this thesis is to explore the usage of robotic in-line quality inspection during changeable zero-defect manufacturing. To fulfil this aim, this thesis adopts a mixed-methods research approach to qualitative and quantitative studies, as well as theoretical and empirical ones. The foundation for this thesis is an extensive literature review and two case studies that have been performed in close collaboration with manufacturing companies to investigate how in-line quality inspection is perceived and utilised to enhance industrial robots. The empirical studies also aimed at identifying and describing what opportunities arise from having robotic in-line quality inspection systems. The result of this thesis is a synthesis of literature and empirical findings. From the literature review/study, the need for enhancing quality inspection was identified and a multi-layer quality inspection framework suitable for the digital transformation was proposed. The framework is built on the assumption that data (used and collected) needs to be validated, holistic, and online, i.e. when needed, for the system to effectively decide upon conformity to surpass the challenges of reliability, flexibility and autonomy. Empirical studies show that industrial robotic applications can be improved in precision and flexibility using the in-line quality inspection system as measurement-assisted. Nevertheless, this methodological changes and robot application face the hurdle of previous and current management decisions when passing from one industrial paradigm to another (e.g. mass production to flexible production). A discussion on equipment design and manufacturing process harmony and how in-line quality inspection and management can harmonise such a system was provided.
3

Investment Model to Evaluate Changeable Manufacturing Systems : An real options approach to measure the value of flexibility for investments in an industrial context / Investeringsmodel för utvärdering av föränderliga tillverkningssystem

Olsson, Fredrik, Werthén, Alexander January 2021 (has links)
Purpose: The purpose of the study is to develop an investment model which can be applied during the design of a manufacturing system, that considers DMS, FMS, and RMS. With the aim of the developed model is to give decision makers monetary basis for the added from changeability. To fulfill the purpose three research questions was created:   What methods in academia are currently used to evaluate changeable manufacturing system investments?  What methods in industry are currently used to evaluate manufacturing system investments? How can an investment model be adapted to incorporate both academia and industry preferences? Method: A single-case-study was conducted within a company that is transitioning into a more reconfigurable manufacturing system. This created an empirical framework for a practical model. In parallel with the case study a literature study was conducted to attain a theoretical framework for the study. The first research question was answered with the literature study. The second research question was answered through the case study, including document studies, interviews, and a focus group, complemented with a literature study. From the theoretical and empirical framework, research question three was answered by developing the investment model following the model creation method suggested by Mitroff et al. (1974).  Implication: The wide adoption of the reconfigurable manufacturing system has yet to be fulfilled in industry, partially hinder by finding economic motivation at the investment evaluation of such a system. The focal company and most other western companies use a net present value to evaluate investments. This approach has been proved inadequate to describe the benefits of a changeable system. Literature suggests that a real option approach could successfully describe the benefits of changeability. However, the approach has been perceived by industry to be too complex. Therefore, a model needed to have enough complexity to comprehend aspect of changeability, while still be simplistic enough gain acceptance from industry. The developed model supplements traditional NPV evaluation with a real options approach, adding scenarios to incorporate uncertainties. The study indicates that it is possible to present the monetary value of added flexibility from changeable manufacturing systems in a simplistic way.

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