Holistische, fertigungsnahe, mehrskalige Messung blechmassivumgeformter Bauteile

New production technologies facilitate the production of increasingly complex workpieces with often reduced cycle times and minimized resource requirements. To ensure the economic benefits generated by process control measuring solutions are required to be as close to the process as possible. In this way relevant features can be measured randomly shortly after their production. At the same time a reduction of necessary workpiece handling time can be achieved. Current measuring technologies are challenged by the precise and holistic detection of relevant features varying in size and shape in a production-related environment. This work presents the basic scientific knowledge framework for a production-related design of a multi-scale multi-sensor measuring system to conduct a holistic measuring data acquisition using example workpieces of the new production technology “sheet-bulk metal forming”. Based on a detailed analysis of possible measuring object properties and tasks, resulting from the characteristics of the sheet-bulk metal forming, a prototypical measuring setup is realized. A calibration procedure, adapted on the setup, enables the combination of the several sensor datasets to a multi-scale multi-sensor dataset without the need of overlapping sensor measuring ranges. For this purpose, a calibration artefact was developed which can be adapted flexibly to different measuring tasks. By digitalizing the calibration artefact, a reference dataset is available for the alignment of the several sensor datasets. Thereby sensor-specific transformation matrices can be determined. These are required for the dataset alignment in a common coordinate system. With a detailed performance evaluation of the prototypical measuring system not only the correct functionality of the calibration procedure could be proven, but also the advantages and opportunities of multi-scale multi-sensor measurements over measurements with separate sensors were identified. Thereby radii, angels and step heights of the PTB micro contour normal were used as measuring objects. For multi-scale multi-sensor measurements of features, which reach out of the measuring range of one sensor, such as distance measurements, a dependence to the calibration accuracy was shown. In this case the limiting factor is the measuring system used for generating the digital reference dataset of the calibration artefact. In a concluding series of measurements using a two-spheres-artefact, similar to a dumbbell-artefact, the achievable measurement uncertainty, determined with the principle of substitution measurements was considered briefly.Neue Fertigungstechnologien ermöglichen die Herstellung zunehmend komplexerer Bauteile bei häufig reduzierter Taktzeit und minimiertem Ressourcenbedarf. Um die dadurch generierten wirtschaftlichen Vorteile voll auszuschöpfen, bedarf es möglichst prozessnaher Messsystemlösungen. Auf diese Weise können relevante Merkmale stichprobenartig bereits kurz nach deren Herstellung erfasst und gleichzeitig hierfür notwendige Werkstückhandhabungszeiten minimiert werden. Insbesondere die präzise, ganzheitliche Erfassung von Merkmalen variierender Größe und Form in einer fertigungsnahen Umgebung stellt die aktuelle Messtechnik vor Herausforderungen. Im Rahmen der vorliegenden Arbeit wurden daher die grundlagenwissenschaftlichen Erkenntnisse für die fertigungsnahe Auslegung eines Multisensor-Messsystems zur holistischen, mehrskaligen Messung am Beispiel komplexer Bauteile der neuen Fertigungstechnologie „Blechmassivumformung“ erarbeitet. Eine eingehende Untersuchung der messtechnisch relevanten Bauteileigenschaften und möglicher Umweltfaktoren bildete die Basis für eine detaillierte Anforderungsanalyse zur Konzeption und Realisierung eines Messsystemaufbaus. Durch die Entwicklung eines Multisensor-Kalibrierverfahrens konnte die Kombination von Sensordatensätzen, ohne auf eine Überlappung der Sensormessbereiche angewiesen zu sein, realisiert werden. Hierzu wurde ein Kalibrierkörper geschaffen, der flexibel an unterschiedliche Messaufgaben angepasst werden kann. Mit der Digitalisierung des Kalibrierkörpers steht ein Referenzdatensatz für die Ausrichtung der Datensätze der Einzelsensoren zur Verfügung. Hierdurch wird die Bestimmung von sensorspezifischen Transformationsmatrizen als notwendige Voraussetzung zur Ausrichtung der Datensätze in einem einheitlichen Koordinatensystem möglich. In einer Leistungsevaluation des prototypischen Messsystems erfolgte nicht nur der Funktionsnachweis für das Kalibrierverfahren, sondern vielmehr wurden in beispielhaften Messreihen die Vorteile mehrskaliger Multisensor-Messungen gegenüber Messung mit einzelnen Sensoren aufgezeigt. Als Merkmale kamen Radien, Winkel und Stufenhöhen des PTB-Mikrokonturnormals zum Einsatz. Für Merkmale, die bei mehrskaligen Messungen über den Messbereich eines Sensors hinausreichen, wie dies bei Abstandsmessungen der Fall ist, konnte eine Abhängigkeit zur Genauigkeit der Kalibrierung nachgewiesen werden. Dabei ist das Messsystem zur Erzeugung des Kalibrierkörper-Referenzdatensatzes der limitierende Faktor. Im Rahmen einer abschließenden Messreihe an einem, einer Kugelhantel angenäherten, Zweikugelkörper, fand eine kurze Betrachtung der erreichbaren Messunsicherheit nach dem Prinzip der Substitutionsmessung statt

MUVOT - Establishing an International Vocational Training Program on the Topic of Measurement Uncertainty

Measurement results represent important information, which are necessary for evaluating and improving the quality of manufactured products and to control manufacturing processes. Furthermore, they build the basis for numerous decisions in the field of quality management, process and production automation or product development and design. Knowledge about the acquisition, evaluation and interpretation of measurement data as well as an understanding of the relevant influences on those measurement results are essential for employees working in the field of manufacturing metrology. Measurement results are always afflicted with deviations, due to a variety of causes. It follows that in order to assign a value to the reliability and quality of a measurement result its uncertainty must be determined and considered. However, employees in the field of quality management or metrology are often not familiar with methods for determination and interpretation of measurement uncertainty, because appropriate opportunities for training are missing in current vocational education. This need has led to the creation of the European project MUVoT, which will create a course for advanced vocational training in determining measurement uncertainty. The training course is based on a blended learning concept, combining self-dependent learning via a web-based platform and face-to-face workshops. This allows the adaption of individual knowledge and skills by self-controlled learning of abstract contents whilst the exercises enable the practical application of typical methods, which are generally considered as quite complex by many employees, and thus assure correct understanding. The featured Blended Learning concept facilitates the integration of the training into a workplace setting, thus the idea of Lifelong Learning is promoted in new fields of application. The curriculum and training concept for this newly developed training program have been designed such that the course can be applied internationally. To facilitate this, a harmonized scheme for course structure and contents has been defined albeit with inherent flexibility, allowing the adaptation to specific constraints

Measurement strategy for a production-related multi-scale inspection of formed work pieces

Part of: Seliger, Günther (Ed.): Innovative solutions : proceedings / 11th Global Conference on Sustainable Manufacturing, Berlin, Germany, 23rd - 25th September, 2013. - Berlin: Universitätsverlag der TU Berlin, 2013. - ISBN 978-3-7983-2609-5 (online). - http://nbn-resolving.de/urn:nbn:de:kobv:83-opus4-40276. - pp. 143–148.The technology of sheet-bulk metal forming provides numerous advantages in the field of manufacturing. Work pieces with filigree and complex structures can be formed by only a few forming steps. To ensure a sustainable and effective production, the forming process has to be controlled by a production-related measurement system. A measurement system, which meets the high requirements of a forming process like a short measuring time, a high measuring point density and the ability to measure different features at the same time, is a multi-scale fringe projection system with multiple sensors of different resolutions. However, an adapted definition of a measurement strategy is necessary in order to enable a rapid conformity decision of the manufactured work piece based on the evaluated measurement data and thus to be able to inspect as many work pieces as possible. It allows to correct the manufacturing during a primary forming process and to assure a sustainable forming process

The ABC transporter DerAB of <i>Lactobacillus casei</i> mediates resistance against insect-derived defensins

Bce-like systems mediate resistance against antimicrobial peptides in Firmicutes bacteria. Lactobacillus casei BL23 encodes an “orphan” ABC transporter that, based on homology to BceAB-like systems, was proposed to contribute to antimicrobial peptide resistance. A mutant lacking the permease subunit was tested for sensitivity against a collection of peptides derived from bacteria, fungi, insects, and humans. Our results show that the transporter specifically conferred resistance against insect-derived cysteine-stabilized αβ defensins, and it was therefore renamed DerAB for defensin resistance ABC transporter. Surprisingly, cells lacking DerAB showed a marked increase in resistance against the lantibiotic nisin. This could be explained by significantly increased expression of the antimicrobial peptide resistance determinants regulated by the Bce-like systems PsdRSAB (formerly module 09) and ApsRSAB (formerly module 12). Bacterial two-hybrid studies in Escherichia coli showed that DerB could interact with proteins of the sensory complex in the Psd resistance system. We therefore propose that interaction of DerAB with this complex in the cell creates signaling interference and reduces the cell’s potential to mount an effective nisin resistance response. In the absence of DerB, this negative interference is relieved, leading to the observed hyperactivation of the Psd module and thus increased resistance to nisin. Our results unravel the function of a previously uncharacterized Bce-like orphan resistance transporter with pleiotropic biological effects on the cell.This work was financially supported by DFG grant MA2837/3-2 (to T.M.) and by funds from the former Spanish Ministry of Science and Innovation and FEDER (grant AGL2010-15679) and the Generalitat Valenciana (grant ACOMP2012/137) (to M.Z.). A.R.-G. thanks the Federation of European Microbiological Societies for research grant FEMS-RG-2014-0067. Q.Z. is financially supported by a stipend from the China Scholarship Council (CSC).Peer reviewe

Holistic, production-related, multi-sclae measurement of sheet-bulk metal formed workpieces

Neue Fertigungstechnologien ermöglichen die Herstellung zunehmend komplexerer Bauteile bei häufig reduzierter Taktzeit und minimiertem Ressourcenbedarf. Um die dadurch generierten wirtschaftlichen Vorteile voll auszuschöpfen, bedarf es möglichst prozessnaher Messsystemlösungen. Auf diese Weise können relevante Merkmale stichprobenartig bereits kurz nach deren Herstellung erfasst und gleichzeitig hierfür notwendige Werkstückhandhabungszeiten minimiert werden. Insbesondere die präzise, ganzheitliche Erfassung von Merkmalen variierender Größe und Form in einer fertigungsnahen Umgebung stellt die aktuelle Messtechnik vor Herausforderungen. Im Rahmen der vorliegenden Arbeit wurden daher die grundlagenwissenschaftlichen Erkenntnisse für die fertigungsnahe Auslegung eines Multisensor-Messsystems zur holistischen, mehrskaligen Messung am Beispiel komplexer Bauteile der neuen Fertigungstechnologie „Blechmassivumformung“ erarbeitet. Eine eingehende Untersuchung der messtechnisch relevanten Bauteileigenschaften und möglicher Umweltfaktoren bildete die Basis für eine detaillierte Anforderungsanalyse zur Konzeption und Realisierung eines Messsystemaufbaus. Durch die Entwicklung eines Multisensor-Kalibrierverfahrens konnte die Kombination von Sensordatensätzen, ohne auf eine Überlappung der Sensormessbereiche angewiesen zu sein, realisiert werden. Hierzu wurde ein Kalibrierkörper geschaffen, der flexibel an unterschiedliche Messaufgaben angepasst werden kann. Mit der Digitalisierung des Kalibrierkörpers steht ein Referenzdatensatz für die Ausrichtung der Datensätze der Einzelsensoren zur Verfügung. Hierdurch wird die Bestimmung von sensorspezifischen Transformationsmatrizen als notwendige Voraussetzung zur Ausrichtung der Datensätze in einem einheitlichen Koordinatensystem möglich. In einer Leistungsevaluation des prototypischen Messsystems erfolgte nicht nur der Funktionsnachweis für das Kalibrierverfahren, sondern vielmehr wurden in beispielhaften Messreihen die Vorteile mehrskaliger Multisensor-Messungen gegenüber Messung mit einzelnen Sensoren aufgezeigt. Als Merkmale kamen Radien, Winkel und Stufenhöhen des PTB-Mikrokonturnormals zum Einsatz. Für Merkmale, die bei mehrskaligen Messungen über den Messbereich eines Sensors hinausreichen, wie dies bei Abstandsmessungen der Fall ist, konnte eine Abhängigkeit zur Genauigkeit der Kalibrierung nachgewiesen werden. Dabei ist das Messsystem zur Erzeugung des Kalibrierkörper-Referenzdatensatzes der limitierende Faktor. Im Rahmen einer abschließenden Messreihe an einem, einer Kugelhantel angenäherten, Zweikugelkörper, fand eine kurze Betrachtung der erreichbaren Messunsicherheit nach dem Prinzip der Substitutionsmessung statt.New production technologies facilitate the production of increasingly complex workpieces with often reduced cycle times and minimized resource requirements. To ensure the economic benefits generated by process control measuring solutions are required to be as close to the process as possible. In this way relevant features can be measured randomly shortly after their production. At the same time a reduction of necessary workpiece handling time can be achieved. Current measuring technologies are challenged by the precise and holistic detection of relevant features varying in size and shape in a production-related environment. This work presents the basic scientific knowledge framework for a production-related design of a multi-scale multi-sensor measuring system to conduct a holistic measuring data acquisition using example workpieces of the new production technology “sheet-bulk metal forming”. Based on a detailed analysis of possible measuring object properties and tasks, resulting from the characteristics of the sheet-bulk metal forming, a prototypical measuring setup is realized. A calibration procedure, adapted on the setup, enables the combination of the several sensor datasets to a multi-scale multi-sensor dataset without the need of overlapping sensor measuring ranges. For this purpose, a calibration artefact was developed which can be adapted flexibly to different measuring tasks. By digitalizing the calibration artefact, a reference dataset is available for the alignment of the several sensor datasets. Thereby sensor-specific transformation matrices can be determined. These are required for the dataset alignment in a common coordinate system. With a detailed performance evaluation of the prototypical measuring system not only the correct functionality of the calibration procedure could be proven, but also the advantages and opportunities of multi-scale multi-sensor measurements over measurements with separate sensors were identified. Thereby radii, angels and step heights of the PTB micro contour normal were used as measuring objects. For multi-scale multi-sensor measurements of features, which reach out of the measuring range of one sensor, such as distance measurements, a dependence to the calibration accuracy was shown. In this case the limiting factor is the measuring system used for generating the digital reference dataset of the calibration artefact. In a concluding series of measurements using a two-spheres-artefact, similar to a dumbbell-artefact, the achievable measurement uncertainty, determined with the principle of substitution measurements was considered briefly

The Nestlé crash

On November 17, 1988, the board of directors of Nestlé AG decided to allow foreign investors to hold Nestlé registered stock, reversing a longstanding practice. This decision had a tremendous impact on the prices of the firm's three classes of common stock, as well as on the prices of several other corporations traded on the Zürich stock exchange. These price changes can be explained by the hypothesis that demand curves slope down

Measures of improvement MUVoT, a Blended Learning course on the topic of measurement uncertainty for advanced vocational training

In verifying the tolerance specification and identifying the zone of conformity of a particular component an adequate determination of the task-related measurement uncertainty relevant to the utilized measurement method is required, in accordance with part one of the standard “Geometrical Product Specifications” as well as with the “Guide to the Expression of Uncertainty in Measurement”. Although, measurement uncertainty is a central subject in the field of metrology and is certainly considered to be of significant importance, there is still a perceived lack of knowledge on the subject within employees in the field of quality management and industrial metrology. They are often neither familiar with procedures for the determination of measurement uncertainty nor with the interpretation and analysis of measurement results as well as economic consequences of decisions taken at the level of conformity. Furthermore, in times of increasing globalization relating to products, processes and development, in which ever more producers cooperate with institutes and companies from all over the world, there is a strong demand and need for a transnational vocational training on the topic of measurement uncertainty. For that reason, in the European project MUVoT (“Blended Learning course on measurement uncertainty for advanced vocational training” - Leonardo da Vinci – Transfer of Innovation 2011-1-PL1-LEO05-19870), a course for advanced vocational training on the topic of measurement uncertainty was established in cooperation with seven institutes from six European countries to provide an internationally harmonized education programme and thus guarantee a better quality of products through the training of metrologists. The training offer is based on a Blended Learning concept, combining self-dependent learning via a web-based eLearning platform and class teaching in face-to-face workshops. On the one hand, this allows the adaptation to individual knowledge and skills by self-controlled learning of abstract contents. On the other hand, the exercises enable the practical application of typical methods, which are generally considered as quite complex by many employees, and thus assure correct understanding. Furthermore, class teaching in manageable groups of participants offers the possibility of adaption to individual training needs. The integration of vocational training into a job-based application is facilitated, so that the idea of Lifelong Learning is promoted in new fields of application. Taking into consideration, that the target group of this training consists of participants with a very inhomogeneous qualification, including foremen, skilled workers, technicians and engineers, the course contents are provided in a modular structure with preparatory, basic and advanced chapters. By performing pilot courses at each project partner, the course content has been thoroughly tested and feedback has been sought and given allowing for a policy of continuous improvement. This article describes the results of these evaluations and the targeted improvements of the content and overall concept considering the identified competence requirements and needs of the participants