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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

An investigation into part sequencing in a flexible assembly cell

Suliman, S. M. A. January 1987 (has links)
No description available.
2

Design assistance for complex engineering assemblies

Holbrook, A. E. K. January 1988 (has links)
No description available.
3

Metoda za projektovanje i optimizaciju sistema za montažu zasnovanih na lean konceptu / Method for optimisation and design of assembly systems based on leanconcept

Dragičević Dragan 11 April 2018 (has links)
<p>Istraživanja u okviru doktorske disertacije usmerena su ka razvoju<br />metode za projektovanje i optimizaciju sistema za montažu zasnovanih<br />na lean konceptu. Analizirani su postojeći instrumenti lean-a i posebno<br />je istražen njihov uticaj na razvoj sistema za montažu i analizu<br />ključnih parametara sistema. Na osnovu prethodnog istraživanja,<br />izvršena je selekcija instrumenata lean koncepta koji su<br />implementirani u metodu za projektovanje i optimizaciju sistema za<br />montažu. Verifikacija predložene metode realizovana je na studiji<br />slučaja optimizacije postojećeg sistema za montažu cirkulacionih<br />pumpi. Osim navedenog, izvršeno je i projektovanje potpuno novog<br />sistema za montažu cirkulacionih pumpi.</p> / <p>Research in this PhD thesis is focused on development of method for<br />optimization and design of assembly systems based on lean concept. Existing<br />instruments of lean are analysed especially their impact on development of<br />assembly system and key parameters analysis. Based on previous research a<br />selection of lean instruments was made and they were implemented in method<br />for optimization and design of assembly sustems. Verification of proposed<br />method was realized on case study where existing assembly system was<br />optimized. In adition to the above completely new assembly system was<br />designed using proposed method.</p>
4

A strategy for improving reliability in assembly processes

Dahlström, Tommy January 2021 (has links)
This report presents an explorative examination of the scientific literature regarding current methods utilized in mixed-model assembly lines and the challenges that are faced. Empirical data from a real mixed-model assembly line was collected and analyzed to explore the application of the identified methods and the problems that are faced in a realistic situation.  The report consists of a theoretic framework on the topics of assembly systems and topics relevant to managing the challenges. In addition a case study is conducted where an assembly system is observed and real production data is collected. Product assembly lines make up one of the final steps in the manufacturing process of a product. By implementing proven methods for process improvements highly effective assembly lines are realized. If an assembly line is experiencing reliability issues the probability of the company’s end-customers being directly affected is considerably increased.  Ensuring reliability in a mixed-model assembly line (MMAL) is an important task with an increasing level of difficulty given the current evolution of advanced technology. The resulting increase in product variety and complexity made possible increases the demands on the entire manufacturing process and the assembly line in particular. Added product variety and complexity poses an increased challenge from an automation perspective as well due to the limitations in flexibility inherited by industrial robots in comparison to a human operator. Many challenges in manufacturing and assembly processes stem from product development, increased variation between product models, and changes in production systems, due to the resulting increase in the complexity of the production processes (ElMaraghy ​​&amp; ElMaraghy, 2016). Historically, a vast number of manufacturing companies have seen significant improvements in their product quality and productivity, leading to improved financial results as well as customer satisfaction by implementing process development methods such as Lean production, Six Sigma, or Lean Six Sigma.  Therefore, the purpose of this report is to explore assembly system reliability and complexity management. The scope of this report is restricted to focus on reliability in assembly systems from a quality perspective. Suggestions for improvements are biased towards Lean Six Sigma methods and complexity management as described in current literature with the consequence of potentially valid methods and solutions being excluded. The theoretical framework of this report is based on selected books and scientific articles on the topics of complexity, assembly systems, process development, and human performance in the context of assembly systems.  The case study project is executed following the DMAIC-process as per the L6S methodology. Lean six sigma methodologies are applied in accordance with the selected literature with the objective of identifying a potential strategy for mitigating the quality deficiencies observed in the company´s assembly processes. The research presented in this report follows the abductive reasoning concept (Säfsten &amp; Gustavsson 2020). Abductive reasoning is initialized by a conclusion, which is followed up by constructing a theory based on literature, and finally analyzing empirical data to validate the constructed theory in the context given by the initial conclusion.  Additionally, a root cause analysis is conducted. The root cause analysis is initiated by constructing an Ishikawa diagram to categorize and identify possible causes of the identified errors. By systematically working through each of the categories the examined problem is look upon from different points of view, making for a comprehensive analysis. In this step the 5-why’s method is utilized to support the deductive reasoning process. The potential root causes are then utilized to construct a list of possible solutions and suggestions for improvement for the examined problem. The improvement suggestions are based on deductive reasoning as well as documented improvements from the literature.
5

Learning and reuse of engineering ramp-up strategies for modular assembly systems

Scrimieri, Daniele, Oates, R.F., Ratchev, S.M. 04 March 2020 (has links)
Yes / We present a decision-support framework for speeding up the ramp-up of modular assembly systems by learning from past experience. Bringing an assembly system to the expected level of productivity requires engineers performing mechanical adjustments and changes to the assembly process to improve the performance. This activity is time-consuming, knowledge-intensive and highly dependent on the skills of the engineers. Learning the ramp-up process has shown to be effective for making progress faster. Our approach consists of automatically capturing information about the changes made by an operator dealing with disturbances, relating them to the modular structure of the machine and evaluating the resulting system state by analysing sensor data. The feedback thus obtained on applied adaptations is used to derive recommendations in similar contexts. Recommendations are generated with a variant of the k-nearest neighbour algorithm through searching in a multidimensional space containing previous system states. Applications of the framework include knowledge transfer among operators and machines with overlapping structure and functionality. The application of our method in a case study is discussed. / Funded by the European Commission as part of the 7th Framework Program under the Grant agreement CP-FP 229208-2, FRAME project.
6

Characterisation of the Business Models for Innovative, Non-Mature Production Automation Technology

Maffei, Antonio January 2012 (has links)
Manufacturing companies are nowadays facing an unprecedented series of challenges to their survival: global competition and product mass-customization are the shaping forces of tomorrow’s business success. The consequent need for agile and sustainable production solutions is the utmost motivation behind the development of innovative approaches which often are not in line with the state of art. It is well documented that companies fail in recognizing how such disruptively innovative approaches can yield an interesting economic output. This, in turn, enhances the risk of leaving the aforementioned promising technologies conceptually and practically underdeveloped.  In the field of automatic production systems the Evolvable Production System paradigm proposes modular architectures with distributed, autonomous control rather than integral design and hierarchical, centralized control. EPS technology is thus disruptive: it refuses the present paradigm of Engineer to Order in industrial automation by proposing an advanced Configure to Order system development logic. This dissertation investigates the possibility of using the recent sophisticated developments of the concept of Business Model as a holistic analytical tool for the characterization and solution of the issue of bringing disruptive and non-fully mature innovation to proficient application in production environments. In order to purse this objective the main contributions in the relevant literature have been extracted and combined to an original definition of business model able to encompass the aspects deemed critical for the problem. Such a construct is composed of three elements: (1) Value Proposition that describe the features of a technology that generates value for a given customer, (2) the Value Configuration and the (3) Architecture of the Revenue which describe the mechanisms that allows to create and capture such value respectively.    The subsequent work has focused on the EPS paradigm as a specific case of the overall problem. The first step has been a full characterization of the related value proposition through an innovative approach based on a bottom-up decomposition in its elementary components, followed by their aggregation into meaningful value offerings: with reference to the EPS paradigm such an approach has disclosed an overall value proposition composed of six potentially independent value offerings. This collection of Value Offerings has then been used as a basis to generate the EPS business models. In particular for each single offering a possible set of necessary activities and resources has been devised and organized in a coherent value configuration. The resulting creation mechanisms have then been linked among each other following a logical supplier-customer scheme for capturing the value: this allowed establishing the architecture of revenue, last element of the overall production paradigm. Finally the results have been validated in a semi-industrial system developed for the (IDEAS, 2010-2013) project through the individuation of the areas of application of such business models. / <p>QC 20121120</p> / FP7-IDEAS- Instantly Deployable Evolvable Assembly System / FP6- EUPASS-Evolvable Ultra-Precision Assembly Systems / XPRES- Initiative for excellence in production research
7

Aide à la Décision pour l’Optimisation du Niveau d’Automatisation lors de la Conception des Systèmes d’Assemblage Industriels. / Early Phase Assembly Systems Design, Automation Alternatives Description, and Optimization : A Support to Automation Decision

Salmi, Anas 05 December 2016 (has links)
Dans le cadre de ma thèse portant sur la détermination du niveau d’automatisation optimal pour la conception des lignes d’assemblage, une revue de littérature exhaustive a été élaborée en premier lieu sur le sujet. La revue a confirmé que peu de travaux traitent ce problème et montre un manque de méthodologies objectives et méthodiquement applicable afin de pouvoir fournir une aide à la décision d’automatisation. A la suite, les facteurs et critères intervenants dans la décision ont été identifiés. Une méthodologie guidant une décision multicritère dédiée aux systèmes d’assemblages a été établie. Cette méthode, permet la prise en compte de différents critères décisionnels, tels que : le temps et le coût d’assemblage, le critère qualité, l’aspect ergonomique, la stratégie et les préférences de l’industriel, la localisation et le contexte économique, la capacité d’investir ou l’aspect social de l’entreprise.La méthodologie de décision établie nécessite en particulier une méthode graphique standardisée de représentation du processus d’assemblage et de l’allocation des ressources. Les méthodes graphiques existantes concernant la représentation de processus d’assemblage ont été donc revues et analysées. Ceci a conduit à la définition d’une nouvelle méthode graphique dédiée établie par inspirations et combinaison de méthodes existantes afin de répondre aux exigences du sujet définies au préalable. Après définition de cette méthode baptisée ASML pour « Assembly Sequences Modeling Language », un vocabulaire standardisé de mouvements élémentaires d’assemblage a été réutilisé de la littérature.Un vocabulaire de plus haut niveau, celui des taches et techniques d’assemblage, en lien avec le premier, a ensuite été défini pour diverses raisons. Ceci permettra de bénéficier à la fois d’une facilité et d’une rapidité de modélisation avec l’utilisation du vocabulaire de taches défini, mais aussi des avantages du premier vocabulaire tel que la détermination des temps d’assemblage ou la détection des opérations répétitives comme signes propices pour une éventuelle automatisation à étudier. L’ensemble permet de définir, organiser, et représenter la séquence d’assemblage par analyse du design du produit. Une démarche d’allocation adéquate représente une conséquence directe qui a été définie en compagnie de certaines règles définie en cohérence avec les principes du « lean manufacturing ».Nous nous intéressons ensuite à l’intégration du critère coût vu l‘importance des investissements générés par des automatisations. Une revue exhaustive en estimation de coût a été ainsi établie. A la suite, un modèle intégré permettant l’estimation du coût d’assemblage par produit a été défini. Ce modèle, basé sur les estimations de temps du processus ainsi que sur des informations stratégiques de la production planifiée, a la vocation de prédire le coût d’assemblage par produit pour une alternative de système en question.A ce stade, tous les éléments sont réunis pour la modélisation et la prédiction de performance d’une alternative candidate de système d’assemblage. Or l’objectif est de déterminer la meilleure configuration possible, il est nécessaire d’appliquer l’approche sur plusieurs options possibles ou alternatives d’assemblage. Ce processus ne peut évidemment pas être réalisé d’une manière individuelle ou manuelle, et donc une implémentation d’un module de génération de scénarios possibles puis leurs évaluations est ainsi nécessaire. Cette implémentation a été réalisée par le développement d’une méthode de résolution exacte par formulation mathématique en un programme linéaire en nombre entiers. L’approche globale a été validée sur des exemples numériques, académiques de la littérature, mais aussi industriels. Les résultats s’avèrent ainsi prometteurs et représentent une approche innovante en matière de décision du niveau d’automatisation, un domaine qui manque de littérature et d’aide en décision. / This work is performed in the context of PhD dissertation of Anas Salmi in Grenoble INP – School of Industrial Engineering. The thesis is supervised by Dr. Eric Blanco (Grenoble INP – GSCOP laboratory) and co-supervised by Dr. Pierre David (Grenoble INP – GSCOP laboratory) and Pr. Joshua Summers (Clemson University – CEDAR laboratory).The work aims at defining a procedure and tool to help assembly manufacturers, particularly deciders, managers, and systems designers in the decision about automation for their assembly processes design. The purpose is to orient to the optimal Level of Automation (LoA) of the process since the early conceptual design phase.The purpose is to provide the most appropriate solution, most profitable, with consideration of the production requirements, product design features and characteristics, assembly sequence, and manufacturer’s exigencies and preferences and prior decision criteria from different point of views such as quality level, ergonomics, reliability, and manufacturer’s best practices and historical data. Different manufacturer’s constraints have also to be also taken into account in the decision such as social, financial and investment potentials, as well as the location and labor rate.A state of the art of the topic was realized and has shown that the literature about LoA deciding is not abundant. This need to support LoA deciding and delicacy of such process were also recognized by several assembly manufactures and researchers.A first main contribution consists in a multi-criteria LoA decision methodology proposal involving several identified decision criteria to be considered in the decision process.The approach generated a need to define an adequate modelling language. A new graphic Assembly Sequences Modeling Language (ASML) was then defined allowing conceptual assembly processes modelling since the early phase by assembly operations with different architectural possibilities. A standard model can be then defined introducing an intuitive and generic way to define systems with various automation levels alternatives.Rules and time standard databases were also developed allowing assembly systems ASML modelled time estimation based on standardized motions, corresponding time standards, and process’ architectures.To easier the alternatives generation and for better standardization, a high layer vocabulary of 20 standardized assembly tasks, associated to the modelling language, is defined. These developments allow a quick modelling and time estimation when automatically linked to the motions vocabulary.As the economic criterion represents the major occupation and criterion for every manufacturer in such heavy investment, an early phase cost model is developed after an exhaustive review in the field. The cost model, when combined to the previous developments, allows assembly systems alternatives cost prediction with consideration of selected automation options.To computerize the automation decision approach and the exhaustive generation of assembly systems alternatives for the sake of finding the optimal configuration, a mathematical integer formulation is developed and validated. The model is implemented in CPLEX OPL and allows the convergence to the optimal configuration with consideration of the different entered constraints and manufacturers preliminary preferences as input matrices.This work includes theoretical and industrial validations. It opens multiple perspectives and openings in the field of assembly systems design, particularly the rationalization of product and process integrated development by the assembly system automatic generation directly from the product design CAD tool. Other openings of work instructions generation and standardization may represent also promising openings.
8

Montadesmontaremonta: significação dos sistemas de montagem / Disassembleness: the significance of assembling systems

Albano Soares Martins Junior 02 June 2008 (has links)
Nossa preocupação surgiu da necessidade de analisarmos a ordem, (dentro do domínio do icônico), que se estabelece nos sistemas de montagem de feiras e exposições, seus paradigmas e sintagmas, através do ponto de vista perceptivo, informacional, gerador de protótipos e experimentações. Por tratar-se de um ambiente inerentemente efêmero e transitório, as montagens realizadas em eventos tendem a proporcionar ambientes renovados. Em síntese, provocam menor impacto porque os prazos de sua existência são limitados. Removidos dos lugares que ocuparam devolvem-lhes suas condições originais. Logo, é esse o caminho para chegarmos aos usos justapostos e complexos, onde, sociedades cada vez mais industrializadas, exigem a necessidade da ocupação de espaços possibilitando diversas funções, com atividades sazonais e ou eventuais, organizam espaços cada vez mais informatizados, distintos de caráter essencialmente mecânicos e com a qualidade de fazer preservar espaços montados para atividades transitórias, os espaços como complexos portadores de informações e transformados intencionalmente em veículos informacionais. / In the iconic domain, this thesis focuses in analyzing the order that emerges in the erection systems of fairs and exhibits, their syntagmas and corresponding paradigms, under the perspective of perception, information and production, which generates experimentations, models and prototypes. Because the assemblies of several fairs and exhibits are inherently short-term and transitional spaces, they tend to constitute renewed environments. In short, these spaces cause less environmental impact because of their short existence. Once removed, the place they were set returns to its former condition. As demanded by increasingly industrialized societies, this leads to juxtaposed and complex uses, a more diversified occupation of spaces that permit various functions, with eventual and/or regular activities. In this sense, more and more computerized spaces emerge, different from the essentially mechanic ones, and able to carry short-term transitional activities; spaces as complex carriers of information and intentionally transformed into informational vehicles.
9

Montadesmontaremonta: significação dos sistemas de montagem / Disassembleness: the significance of assembling systems

Martins Junior, Albano Soares 02 June 2008 (has links)
Nossa preocupação surgiu da necessidade de analisarmos a ordem, (dentro do domínio do icônico), que se estabelece nos sistemas de montagem de feiras e exposições, seus paradigmas e sintagmas, através do ponto de vista perceptivo, informacional, gerador de protótipos e experimentações. Por tratar-se de um ambiente inerentemente efêmero e transitório, as montagens realizadas em eventos tendem a proporcionar ambientes renovados. Em síntese, provocam menor impacto porque os prazos de sua existência são limitados. Removidos dos lugares que ocuparam devolvem-lhes suas condições originais. Logo, é esse o caminho para chegarmos aos usos justapostos e complexos, onde, sociedades cada vez mais industrializadas, exigem a necessidade da ocupação de espaços possibilitando diversas funções, com atividades sazonais e ou eventuais, organizam espaços cada vez mais informatizados, distintos de caráter essencialmente mecânicos e com a qualidade de fazer preservar espaços montados para atividades transitórias, os espaços como complexos portadores de informações e transformados intencionalmente em veículos informacionais. / In the iconic domain, this thesis focuses in analyzing the order that emerges in the erection systems of fairs and exhibits, their syntagmas and corresponding paradigms, under the perspective of perception, information and production, which generates experimentations, models and prototypes. Because the assemblies of several fairs and exhibits are inherently short-term and transitional spaces, they tend to constitute renewed environments. In short, these spaces cause less environmental impact because of their short existence. Once removed, the place they were set returns to its former condition. As demanded by increasingly industrialized societies, this leads to juxtaposed and complex uses, a more diversified occupation of spaces that permit various functions, with eventual and/or regular activities. In this sense, more and more computerized spaces emerge, different from the essentially mechanic ones, and able to carry short-term transitional activities; spaces as complex carriers of information and intentionally transformed into informational vehicles.
10

Delivery Performance Prediction Tool for Complex Assembly Systems

Beladi, Faried D 01 January 2014 (has links)
Complex assembly systems are made up of hundreds, and in some cases, thousands of parts, that all need to be managed in a proper manner so part arrivals will coincide to meet a build plan, and ensure production requirements are satisfied. A major challenge faced by manufacturers for these complex systems is that many parts have long and complex supply chains, which result in long and highly variable supply lead times. The high cost and low volume makes holding large stocks of these components unviable. Thus, the need arises for the development of a simulation tool that can predict the time all of the required parts are ready for assembly, and allow for comparison of various ordering and inventory strategies. Two strategies were tested, the current practice of ordering to an agreed upon quoted lead time, and a strategy which accounts for lead time variability through advanced ordering. The results of these two strategies displayed the benefits of synchronizing the system through advance ordering, as a potential 60% reduction in inventory was observed. Future development in the tool would incorporate more granular steps of the build sequence, as well as the inclusion of quality non-conformance (QN) issues.

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