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CAD-Methodik zur Produktivitätssteigerung in der Prozesskette Konstruktion-Fertigung
No full textDanksagung
Für die wissenschaftliche und methodische Unterstützung während meiner gesamten Zeit als wissenschaftliche Mitarbeiter und Doktorand am Lehrstuhl für Rechnereinsatz in der Konstruktion gilt mein Dank meinem Doktorvater Prof. Dr.-Ing. Dipl.-Math. Peter Köhler sowie allen Lehrstuhlkollegen, vor allem jedoch Dr.‐Ing. Alexander Martha, Thivakar Manoharan M. Sc., Phil Hungenberg M. Sc. und René Andrae M. Sc.
Unstrittig ist, dass der Konstrukteur für die anforderungsgerechte Produktauslegung und Produkt-gestaltung verantwortlich ist und damit maßgeblich die Qualität und die Herstellkosten beeinflusst. Die Kompliziertheit und Komplexität der Konstruktionslösungen verhindert häufig eine angemessene Sichtweise auf die Herstellkosten bzw. auf Alternativen zur Herstellung eines Produktes. Die Kosten entstehen zumeist erst, wenn das Produkt durch die Fertigungsabteilung realisiert wird. Um dieser großen Kostenverantwortung der Konstruktion besser gerecht werden zu können, wird im Rahmen der Dissertation die technische Produktivität in der Prozesskette Konstruktion-Fertigung, welche sich über die Begriffe Effektivität und Effizienz ausdrücken lässt, betrachtet. Es werden Antworten auf die Fragen formuliert: Was kann getan werden, um die Produktivitätssteigerung in der heutigen Prozesskette Konstruktion-Fertigung zu erreichen?
Bei der Beantwortung dieser Frage werden CAD-Methoden vorgestellt, welche die Einbeziehung des Fertigungswissens in ein möglichst frühes Stadium des Entwicklungs- und Konstruktionsprozesses ermöglichen. Anhand von ausgewählten Problemfeldern für Bohr-, Dreh- und Fräsprozesse werden Lösungen zum zerspanungsorientierten Geometrieaufbau und der Fertigbarkeitsanalyse der 3D-CAD-Modelle aufgezeigt. Durch die Implementierung der Methoden und die Entwicklung einer spe-ziellen, zerspanungsorientierten Umgebung im 3D-CAD-System wird dem Konstrukteur die Möglichkeit gegeben, den Produktmodellierungsprozess an Konstruktionsrichtlinien und projektspezifischen fertigungstechnischen und wirtschaftlichen Randbedingungen zu orientieren. Durch den Einsatz spezieller Methoden der wissensbasierten Konstruktion (KBE) und angepasster Web-Techniken (Webservice) werden die in einem fertigungsorientierten Form-Feature gebündelten, geometrischen Informationen um weitere technologische Parameter, wie Werkzeuge, Werkzeugparameter, Verfahrwege und notwendige Fertigungsvorgänge (wie z. B. Schruppen und Schlichten) ergänzt. Für komplexere Geometrieausprägungen werden flächenbasierte Modellierungsmethoden zur Gestaltung räumlicher und fertigungskonformer Werkzeugbewegungshüllen bereitgestellt. Diese insgesamt höherwertigen, fertigungsorientierten Features stellen die Basis für die konstruktionsbegleitende Kostenabschätzung und die CAD-CAM-Kopplung dar. Dabei werden die fertigungsrelevanten Daten und Informationen in der CAM-Umgebung extrahiert, sodass für jeden Fertigungsschritt die dafür benötigten Fertigungsoperationen auf einfache Weise abgeleitet werden können. Somit ergibt sich letztlich eine durchgängige Prozesskette zwischen der Konstruktion und Fertigung, welche auch die Qualität von CAD-CAM-Kopplungen erhöhen kann.It is indisputable that a design engineer is responsible for the requirement-driven functional and geometrical design of new products and that through this responsibility, has a significant impact on the associated quality and manufacturing costs. The complexity of the design solutions often prohibits an adequate assessment of the production costs and can make it difficult to consider alternative manufacturing methods. The manufacturing costs normally emerge only once the product is phased into production. In order to allow the design engineer to better fulfill this responsibility for product costs, this dissertation considers the technical productivity (expressed with the terms effectivity and efficiency) of the process chain between the design engineering and production departments. There are answers to the questions formulated: What can be done to achieve an improvement in the current process-chain between the design engineering and production departments?
In answering this question, CAD methods will be introduced which allow the inclusion of production knowledge into the earliest possible stages of the design and development process. Considering selected problem fields in the drilling, turning and milling processes, solutions for creating geometry through machining methods and for analyzing the producibility of 3D CAD models will be presented. Through the implementation of the methods and the development of a special machining-focused environment in the 3D CAD system, the design engineer will be given the ability to align the product modeling process with design guidelines and project-specific manufacturing and economic constraints. By using special methods of knowledge-based design engineering (KBE) and adapted web technologies (Webservice), the geometric information which is bundled in a production-focused form feature will be supplemented with additional technological parameters, such as tools, tool parameters, tool paths and necessary manufacturing operations (e.g. roughing and finishing). For more complex geometrical features, surface-based modeling methods for the design of three-dimensional and production compliant tool-movement envelopes will be provided. These increased-value, production-oriented features are the basis for the cost-estimation in the design phase and for the coupling of the CAD and CAM environments. As a result, the manufacturing-relevant data and information will be extracted by the CAM environment so that the production operations for each step can be determined in a simple manner. This approach results in a complete chain between the design engineering and production departments and can improve the quality of the CAD-CAM information exchange
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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