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Suche nach „[H.] [Hansen]“ hat 2 Publikationen gefunden
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    DigitalMaschinenbau und Mechatronik

    Zeitschriftenartikel

    P. Müller, Jochen Hiller, Y. Dai, J. Andreasen, H. Hansen, L. Chiffre

    Quantitative analysis of scaling error compensation methods in dimensional X-ray computed tomography

    CIRP Journal of Manufacturing Science and Technology, vol. 10, no. August, pp. 68-76

    2015

    DOI: 10.1016/j.cirpj.2015.04.004

    Abstract anzeigen

    X-ray Computed Tomography (CT) has become an important technology for quality control of industrial components. As with other technologies, e.g., tactile coordinate measurements or optical measurements, CT is influenced by numerous quantities which may have negative impact on the accuracy and repeatability of dimensional and geometrical measurements. The aim of this paper is to discuss different methods for the correction of scaling errors and to quantify their influence on dimensional measurements. Scaling errors occur first and foremost in CT systems with no built-in compensation of positioning errors of the manipulator system (magnification axis). This article also introduces a new compensation method for scaling errors using a database of reference scaling factors and discusses its advantages and disadvantages. In total, three methods for the correction of scaling errors – using the CT ball plate, using calibrated features measured by CMM and using a database of reference values – are presented and applied within a case study. The investigation was performed on a dose engine component of an insulin pen, for which several dimensional measurands were defined. The component has a complex geometry and is made of brass, which makes its measurements with CT challenging. It is shown that each scaling error correction method results in different deviations between CT measurements and reference measurements from a CMM. Measurement uncertainties were estimated for each method, taking into consideration the contributions related to the applied correction method. The newly suggested approach using the database appeared to work well, indicating, that if the properties of a CT system under investigation are monitored using a reference object (ball bar in our case), a correction factor based on individual selected magnification factors can be applied for scaling error correction of any object, and thus no additional scanning of a reference object is needed.

    Maschinenbau und Mechatronik

    Zeitschriftenartikel

    P. Müller, Jochen Hiller, Y. Dai, J. Andreasen, H. Hansen, L. Chiffre

    Estimation of measurement uncertainties in X-ray computed tomography metrology using the substitution method

    CIRP Journal of Manufacturing Science and Technology, vol. 7, no. 3, pp. 222-232

    2014

    DOI: 10.1016/j.cirpj.2014.04.002

    Abstract anzeigen

    This paper presents the application of the substitution method for the estimation of measurement uncertainties using calibrated workpieces in X-ray computed tomography (CT) metrology. We have shown that this, well accepted method for uncertainty estimation using tactile coordinate measuring machines, can be applied to dimensional CT measurements. The method is based on repeated measurements carried out on a calibrated master piece. The master piece is a component of a dose engine from an insulin pen. Measurement uncertainties estimated from the repeated measurements of the master piece were transferred on to additionally scanned uncalibrated workpieces which provided the necessary link for achieving traceable measurements.