151 |
An empirical investigation of manufacturing flexibility and organizational performance as moderated by strategic integration and organizational infrastructure.Rogers, Pamela Rose Patterson 08 1900 (has links)
The purpose of this study is empirically investigating four research questions related to manufacturing flexibility. 1) What are the components of manufacturing flexibility? 2) Is there a relationship between manufacturing flexibility and organizational performance? 3) Do integrated strategies strengthen the relationship between manufacturing flexibility and organizational performance? 4) Are there organizational characteristics that strengthen the relationship between manufacturing flexibility and organizational performance? This study used a cross-sectional survey design to collect data from manufacturing organizations in multiple industries. Organizational performance was quantified using common manufacturing measures. Strategic integration and organizational infrastructure were also measured. Data were collected using a self-administered questionnaire. Factor analysis, correlation analysis, and regression were used to analyze the data. The results indicate the variables and expected relationships exist as hypothesized. This study contributes to the manufacturing flexibility body of knowledge by identifying relationships between the manufacturing flexibility component, performance, strategic integration, and organizational infrastructure. The instrument development in this study is of particular value as there are few rigorously developed and validated instruments to measure the manufacturing flexibility components and performance. Understanding these relationships will help practitioners make better decisions in manufacturing organizations as well as enable application of the concepts in this study to other contexts such as service organizations.
|
152 |
MANUFACTURING OF POLYMER BASED HIGH RESOLUTION HOLLOW CHANNEL/FIBERS VIA CO-FLOW GENERATIONZijian He (14272541) 20 December 2022 (has links)
<p> </p>
<p>High-resolution enclosed channels/fibers are highly demanded by different disciplines such as microfluidic channels for chemical synthesis, bioreactors for drug metabolism, magnetic locomotor for drug delivery, and wearable devices for motion detection. However, the current fabrication techniques for enclosed channels/fibers are restricted to a few millimeters in size. Their manufacturing often involves time and energy-consuming multi-step processes with insufficient resolution. In this work, we demonstrate a novel co-flow-enabled fabrication method to resolve the technological restrictions in the fabrication of high-resolution enclosed channels/fibers with efficient production time, controllable morphologies, and high throughput manner.</p>
<p>An epoxy-based enclosed microfluidic channel was first built. A non-reactive paraffin oil and a liquid resin were pumped into a 3D-printed co-flow generator and worked as core and shell fluids, respectively. The epoxy resin was cured by external heat stimulus. As a result, the reaction region was limited between the generator wall surface and the boundary of core flow, eliminating the need for precise control over the curing system. The experiment was successfully conducted to cure build resin channel inside copper and resin tubes with good shell thickness.</p>
<p>Conductive hollow hydrogel microfibers were also fabricated by this method. Sodium Alginate and Calcium Chloride were chosen as the shell and core flows, respectively. The ionic crosslinking happens at the boundary of two flows and expands outwards across the radial direction. Thus, the diameter of the hollow channel can be easily adjusted by tuning the flow rate and the size of the core flow injection needle. PEDOT: PSS, a conductive polymer, was mixed with Sodium Alginate to impart fibers with excellent electrical conductivity. The synthesized hollow microfibers have shown their functionality in stretching movement detection by serving as a fundamental building element of motion sensors. </p>
|
153 |
Model Development for Autonomous Short-Term Adaptation of Cobots' Motion Speed to Human Work Behavior in Human-Robot Collaboration Assembly StationsJeremy Amadeus Deniz Askin (11625070) 26 July 2022 (has links)
<p> </p>
<p>Manufacturing flexibility and human-centered designs are promising approaches to face the demand for individualized products. Human-robot assembly cells still lack flexibility and adaptability (VDI, 2017) using static control architectures (Bessler et al., 2020). Autonomous adaptation to human operators in short time horizons increases the willingness to work with cobots. Besides, monotonous static assembling in manufacturing operations does not accommodate the human way of working. Therefore, Human-Robot Collaboration (HRC) workstations require a work behavior adaptation accommodating varying work behavior regarding human mental and physical conditions (Weiss et al., 2021). The thesis presents the development of a cyber-physical HRC assembly station.</p>
<p>Moreover, the thesis includes an experimental study investigating the influence of a cobot’s speed on human work behavior. The Cyber-Physical System (CPS) integrates the experiment's findings with event-based software architecture and a semantic knowledge representation. Thereby, the work focuses on demonstrating the feasibility of the CPS and the semantic model, allowing the self-adaptation of the system. Finally, the conclusion identifies the need for further research in human work behavior detection and fuzzy decision models. Such detection and decision models could improve self-adaptation in human-centered assembly systems.</p>
|
154 |
A study of relationships between organizational characteristics and QR adoption in the U.S. apparel industryKo, Eunju 06 October 2009 (has links)
The purpose of this study was to identify the usage level of QR technologies and to examine the relationships between the organizational characteristics and the usage level of QR technologies and QR adoption in the U.S. apparel industry. Using the usage level of QR technologies and QR adoption as the dependent variables, the selected organizational characteristics, as independent variables, were: firm size (Le., numbers of employees, dollar amounts of sales volume), organizational strategy (i.e., prospector, analyzer, reactor, defender), product characteristics (i.e., product category, fashion change, seasonal change), and perception of QR benefits. The conceptual framework for this study was based on Rogers' adoption theory (1983). A factor approach was used to examine a cross-section of firms to determine significant characteristics influencing QR adoption.
A random sample of 306 apparel manufacturers without locational limitation were selected from a purchased list. The sample was stratified by firm size (i.e., number of employees) and product category (Le., men's, women's, children's/infant's wear). A mail questionnaire was pilot tested for content validity and instrument reliability, and the revised questionnaire was sent to plant managers. Adjusted response rate was 47.0% (n=103). Regression, discriminant analysis, and nonparametrics were used to test the statistical significance of hypothesized relationships.
The most frequently used technologies were small lot orders, short cycle cut planning, short cycle sewing, and production planning with customer. Firm size, organizational strategy, and fashion change were significantly related to the usage level of QR technologies. Firm size, organizational strategy, product category, and perception ofQR benefits were significantly related to QR adoption. Four QR elements (i.e., production planning, flexible manufacturing, inventory control, information sharing) were significantly related to QR adoption. / Master of Science
|
155 |
Development of an automated robot vision component handling systemJansen van Nieuwenhuizen, Rudolph Johannes January 2013 (has links)
Thesis (M. Tech. (Engineering: Electrical)) -- Central University of technology, Free State, 2013 / In the industry, automation is used to optimize production, improve product quality and increase profitability. By properly implementing automation systems, the risk of injury to workers can be minimized.
Robots are used in many low-level tasks to perform repetitive, undesirable or dangerous work. Robots can perform a task with higher precision and accuracy to lower errors and waste of material.
Machine Vision makes use of cameras, lighting and software to do visual inspections that a human would normally do. Machine Vision is useful in application where repeatability, high speed and accuracy are important.
This study concentrates on the development of a dedicated robot vision system to automatically place components exiting from a conveyor system onto Automatic Guided Vehicles (AGV).
A personal computer (PC) controls the automated system. Software modules were developed to do image processing for the Machine Vision system as well as software to control a Cartesian robot. These modules were integrated to work in a real-time system.
The vision system is used to determine the parts‟ position and orientation. The orientation data are used to rotate a gripper and the position data are used by the Cartesian robot to position the gripper over the part.
Hardware for the control of the gripper, pneumatics and safety systems were developed. The automated system‟s hardware was integrated by the use of the different communication protocols, namely DeviceNet (Cartesian robot), RS-232 (gripper) and Firewire (camera).
|
156 |
Study of Fixturing Accessibilities in Computer-Aided Fixture DesignGhatpande, Puja Sudhakar 08 August 2008 (has links)
"Fixtures form an important factor in traditional and modern flexible manufacturing systems, since fixture design directly affects manufacturing quality and productivity. Hence, it is necessary to evaluate quality of fixture design. The fixturing accessibility refers to machining feature accessibility and loading /unloading accessibility. The development of Computer Aided Fixture Design (CAFD) has simplified this task. Fixture design activities include setup planning, fixture planning and fixture configuration design. Fixture design verification comes next. Fixturing accessibility using Computer Aided Fixture Design is part of the verification process and has not received much attention till date. Machining feature accessibility analysis involves the evaluation of possible interference between fixture components and the cutting tool, which moves with pre-programmed tool path, while the loading and unloading accessibility relates to the ease with which the operator attaches/detaches the workpiece from the surrounding manufacturing environment. This research has three main focuses. The first focus is to evaluate machining feature accessibility, by integrating fixture designs in SolidWorks and the NC programming in Esprit. The main goals are evaluation of fixture design for any kind of interference between tool/workpiece/fixtures and enable Esprit to indicate interference, if any. The next step is to modify the fixture design accordingly and thus, finally obtain an interference free fixture design by reiteration. The second and third focuses deal with analysis of loading and unloading accessibility. A simulation based approach is applied to evaluate loading/unloading paths for different workpiece-fixture setups and checking interference in a dynamic mode. Then the third focus is to develop analysis method and criteria of comparisons of fixturing accessibility in different fixture designs. Thus, this research establishes methods of analysis for accessibilities in fixture design. Also, the guidelines for good fixture design will prove to be of great use to both, the beginners as well as the experienced fixture designers in this field. "
|
157 |
Operational Performance Enhancement of Human Operated Flexible SystemsSorensen, Khalid Lief 08 July 2008 (has links)
Recent decades have been witness to explosive leaps in manufacturing productivity. Advances in communication technology, computing speed, control theory, and sensing technology have been significant contributors toward the increased productivity and efficiency that industry has exhibited. The continued growth of technological equipment and engineering knowledge challenges engineers to fully utilize these advancements in more sophisticated and useful automation systems.
One such application involves enhancing bridge and gantry crane operation. These systems are used throughout the globe, and are critical aspects of industrial productivity. Consequently, improving the operational effectiveness of cranes can be extremely valuable.
Effective control of cranes can be largely attributed to two distinct, but related aspects crane manipulation: 1) the expertise of operators, which are responsible for issuing commands to the structures, and 2) the dynamic properties of cranes, which influence how the structures respond to issued commands. Accordingly, the operational efficiency of cranes can be influenced by changing both the way that operators issue commands to cranes, and also how the crane responds to issued commands.
This thesis is concerned with dynamic control theory of flexible machines, and human/machine interaction, especially as these areas relate to industrial crane control. In the area of dynamic control, this thesis investigates control strategies that are specifically suited for use on systems that possess common actuator nonlinearities, like saturation, rate limiting, dead-zone, backlash, and finite-state actuation. In the area of human/machine interaction, this thesis investigates the effects of different crane interface devices on the operational efficiency of cranes.
|
158 |
Método de resolução de deadlocks no controle de produção de sistemas de manufatura automatizados utilizando redes de Petri coloridasSouza, Wesley Willy Oliveira de 01 July 2011 (has links)
Made available in DSpace on 2016-06-02T19:06:03Z (GMT). No. of bitstreams: 1
4911.pdf: 4490259 bytes, checksum: 94cfbdb804ef2f55cb81e1163b1c6ad4 (MD5)
Previous issue date: 2011-07-01 / Universidade Federal de Sao Carlos / Resources sharing is one of the main characteristics of Automated Manufacturing Systems (SMA), this characteristic can be a synonym of advantages but on the other hand it may lead to the problem of deadlock. Several papers have suggested methods and techniques to reduce or eliminate the occurrence of deadlocks in SMA systems. The deadlock resolution strategies suggested in the literature can be classified into the following types: deadlock detection and recovery, deadlock prevention and deadlock avoidance. This work proposes a resolution method for the control of automated manufacturing systems using colored Petri nets, the main goal of the proposed method is to provide a deadlock-free production controller. To model, simulate and implement the technique in a production controller a dedicated software is used to model the Petri Nets. Initially, a model using Colored Petri Nets is proposed, then changes in the model are introduced in order to eliminate the deadlocks, resulting in a Colored Petri net control model of the SMA. Finally the model is implemented in the scenario of a Flexible Manufacturing System for testing and validation of the method. / O Compartilhamento de recursos é uma das principais características dos Sistemas de Manufatura Automatizados (SMA), esta característica pode ser um sinônimo de vantagens, mas por outro lado pode levar ao problema de deadlock. Diversos trabalhos têm sugerido métodos e técnicas para reduzir ou eliminar a ocorrência de deadlocks em SMA. As estratégias de resolução de deadlock sugerido na literatura podem ser classificados nos seguintes tipos: detecção e recuperação de deadlocks, prevenção de deadlocks e de deadlock. Este trabalho propõe um método de resolução para o controle de sistemas de manufatura automatizados utilizando redes de Petri coloridas, o principal objetivo do método proposto é obter um controlador da produção livre de deadlocks. Para modelar, simular e implementar a técnica em um controlador de produção um software dedicado é usado para modelar a rede de Petri. Inicialmente, um modelo usando Redes de Petri Coloridas é proposto, então mudanças são introduzidas, a fim de eliminar os deadlocks, resultando em um modelo de rede de Petri de um SMA livre de deadlock. Finalmente o modelo é implementado no cenário de um Sistema de Manufatura Flexível para testes e validação do método.
|
159 |
Proposta de um procedimento de programação on-line da produção de sistemas flexíveis de manufatura baseado em lógica fuzzy. / Proposal of a Production On-line Scheduling Procedure of Flexible Manufacturing Systems based on Fuzzy.Domingos, Jean Carlos 25 August 2004 (has links)
Made available in DSpace on 2016-06-02T19:06:23Z (GMT). No. of bitstreams: 1
DissJCD.pdf: 3954079 bytes, checksum: 63ef4f081a962ca21478327fb623632d (MD5)
Previous issue date: 2004-08-25 / Flexible manufacturing systems (FMS) have been designed to meet market
requirements that demand products that are quality and ready to deliver. In order to
meet the market requirements, the methodologies used in the FMS scheduling must
consider a highly dynamic environment, where it is often necessary to meet or to react
to uncertain demands and to get better use of its resources. An on-line scheduling
procedure based on fuzzy logic is proposed in this work, whose main characteristic is
shop floor tasks scheduling using fuzzy rules building with the support of an expert to
meet several measures of performance. A simulation study was carried out with the
objective to verify the applicability of the proposed approach, using a simulation tool
integrated with the on-line scheduling procedure based on fuzzy logic. / Os sistemas flexíveis de manufatura (FMS) têm sido projetados para atender as
necessidades do mercado, que demandam por produtos que apresentam qualidade e
prazos de entrega pequenos. Para atender as necessidades do mercado, as metodologias
usadas na programação de operações de FMS devem considerar um ambiente altamente
dinâmico, onde é frequentemente necessário atender ou reagir a demandas incertas e
fazer o melhor uso de seus recursos. Um procedimento de programação on-line baseado
em lógica fuzzy é proposto neste trabalho, cuja característica principal é programar as
tarefas do chão de fábrica utilizando regras fuzzy construídas com o apoio de um
especialista para atender a várias medidas de desempenho simultaneamente. Um estudo
por meio de simulação foi realizado com o objetivo de verificar a aplicabilidade da
abordagem proposta, utilizando uma ferramenta de simulação integrada ao
procedimento de programação on-line baseado em lógica fuzzy.
|
160 |
Aplicação de metodologias de administração da produção em um fabricante de cabos eletricos / An application of management methodologies to a continous production manufacturing systemPinto, Claudio Ricardo Monteiro 18 September 2006 (has links)
Orientador: Antonio Batocchio / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-08T16:29:28Z (GMT). No. of bitstreams: 1
Pinto_ClaudioRicardoMonteiro_M.pdf: 1016323 bytes, checksum: 092608f0049fe6576d6787fc00dd93ca (MD5)
Previous issue date: 2006 / Resumo: Atualmente o aumento da competitividade industrial e da concorrência, está gerando uma busca constante de produtos inovadores e de baixo custo. Alguns seguimentos industriais também tem sentido o poder das 'commodities', onde grande parte dos custos envolvidos nos processos, principalmente matérias-primas, não são de controle da empresa dificultando e reduzindo a sua margem de atuação frente a concorrência. Existem diversas técnicas administrativas que demonstram excelentes resultados com as suas implementações, como a Teoria das Restrições (TOC), Manufatura Enxuta, Manufatura Agil, etc e estes sistemas podem ser tratados de forma integrada e comparativa (Godinho Fº e Fernandes, 2005). O objetivo deste trabalho é avaliar a aplicação destas ferramentas em uma empresa com regime de produção semi-contínuo de condutores elétricos, analisando os resultados das implementações realizadas através de métricas aplicadas ao setor. A Empresa estudada é uma empresa multinacional do ramo Eletroeletrônico, mais especificamente Condutores Elétricos, que atua principalmente no segmento de Energia e a linha de produtos selecionada para este estudo foi a de cabos flexíveis. Realizou-se o levantamento do fluxo de valor da empresa adotando a metodologia da Manufatura Enxuta e avaliou-se o impacto de cada fase do processo em relação ao processo como um todo, através deste levantamento determinou-se o ponto de restrição do sistema, e a partir daí foram definidas algumas ações de controle, como kanban, supermercado de peças e planos de manutenção preventiva nos equipamentos. Como resultado atingiu-se um incremento de 100% de capacidade de fabricação de cabos flexíveis com um aumento de produtividade na ordem de 90%, uma redução do nível de inventário de 33% e uma melhoria de qualidade com a redução de 20% no nível de ppm?s gerados por falhas. Outro fator importante foi a redução no tempo de dimensionamento e implementação dos novos processos com o auxílio da Simulação por computador. Foi possível observar que é viável o uso conjunto da TOC e da Manufatura Enxuta comprovando a aplicabilidade destas teorias em um processo de fabricação de condutores elétricos / Abstract: The increasing degree of industrial competitivity and competition has been generating recently a constant search for innovative and low-cost products. Some industrial segments have also been affected by the power of 'commodities', in relation to which a significant part of process-related costs, chiefly raw-materials, are not controlled by the enterprise, something that makes difficult and reduces its margins for maneuver before competition. There are several managing techniques that present optimum implementation results, as is the case of the Theory of Constraints - TOC), Lean Manufacturing and Agile Manufacture, systems that can be approached in a integrated and comparative way (Godinho Fº e Fernandes, 2005). This work aims to evaluate the application of these tools in a company producing electric conductors in a semi-continuous production regime by means of the evaluation the results of implementations introduced by metrics applied to the sector. The Enterprise studied is an Electronics multinational that produces electrical conductors, chiefly for the Power segment, and we selected for this study the production of flexible cables. The value flow of the company was evaluated adopting the "Lean Manufacture" philosophy and we examined the impact of each phase of the process in relation to the process as a whole. This survey allowed determining the system?s point of restriction, and the identification of the system?s restrictions allowed to define some controlling actions, like kanban, parts supermarket and preventive equipment-maintenance plans. As a result, an increment of 100% in manufacture capacity of flexible cables was reached, with an increase in productivity of 90%, a reduction in the level of inventory of 33% and a quality improvement with the reduction of 20% in the level of failure-induced PPMs. Another important factor was the reduction in the time of dimensioning and implementation of the new processes with the help of computer-based simulation. The work showed the joint use of TOC and Lean Manufacturing to be possible, proving these theories to be applicable to a manufacturing process of electric cables production / Mestrado / Materiais e Processos de Fabricação / Mestre em Engenharia Mecânica
|
Page generated in 0.1221 seconds