Sánchez Brea, Luis Miguel

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First Name
Luis Miguel
Last Name
Sánchez Brea
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Físicas
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Now showing 1 - 5 of 5
  • Publication
    Optical technique for the automatic detection and measurement of surface defects on thin metallic wires
    (The Optical Society Of America, 2000-02-01) Sánchez Brea, Luis Miguel; Siegmann, Philip; Rebollo, María Aurora; Bernabeu Martínez, Eusebio
    In industrial applications of thin metallic wires it is important to characterize the surface defects of the wires. We present an optical technique for the automatic detection of surface defects on thin metallic wires (diameters, 50–2000 µm) that can be used in on-line systems for surface quality control. This technique is based on the intensity variations on the scattered cone generated when the wire is illuminated with a beam at oblique incidence. Our results are compared with those obtained by atomic-force microscopy and scanning-electron microscopy.
  • Publication
    Comparison between optical techniques and confocal microscopy for defect detection on thin wires
    (Elsevier Science B. V., 2004-11-15) Siegmann, Philip; Sánchez Brea, Luis Miguel; Martínez Antón, Juan Carlos; Bernabeu Martínez, Eusebio
    Conventional microscopy techniques, such as atomic force microscopy (AFM), scanning electron microscopy (SEM), and confocal microscopy (CM) are not suitable for on-line surface inspection of fine metallic wires. In the recent years, some optical techniques have been developed to be used for those tasks. However, they need a rigorous validation. In this work, we have used confocal microscopy to obtain the topography z(x,y) of wires with longitudinal defects, such as dielines. The topography has been used to predict the light scattered by the wire. These simulations have been compared with experimental results, showing a good agreement.
  • Publication
    In-line detection and evaluation of surface defects on thin metallic wires
    (The International Society for Optical Engineering (SPIE), 2001) Martínez Antón, Juan Carlos; Siegmann, Philip; Sánchez Brea, Luis Miguel; Gómez Pedrero, José Antonio; Canabal Boutureira, Héctor; Bernabeu Martínez, Eusebio; Hoefling, Roland; Jueptner, Werner P. O.; Kujawinska, Malgorzata
    We have developed a prototype for in-line detection of surface defects in metallic wires, specially for scratches. A simple geometrical relationship between surface topography and conical reflection, permits to correlate the defects with intensity patterns in a simple way. The presented apparatus consists basically in a grating-divided laser beam incident on angular equidistant points. A CCD and an associated optics capture the information of the whole wire perimeter at once. Analytic rudiments are provided in agreement with the experimental results.
  • Publication
    Diffraction in wide slits with semi-cylindrical edges
    (Gustav Fischer Verlag, 2002) Siegmann, Philip; Sánchez Brea, Luis Miguel; Martínez Antón, Juan Carlos; Bernabeu Martínez, Eusebio
    We present an analytical model to obtain the diffraction pattern in far field of a metallic, thick slit based on the Geometrical Theory of Diffraction. The edges of the slit are modelled as semicylinders. We have considered that the thickness of the slit is sufficiently small compared to the width, so that the influence of multiple reflections between the edges may be neglected. The material in which the slit is made, as well as the polarization and angle of the incident beam, are considered. Notorious differences are obtained when compared to the classical diffraction from flat slits.
  • Publication
    Classification of surface structures on fine metallic wires
    (Elsevier Science B. V., 2001-08-16) Bernabeu Martínez, Eusebio; Sánchez Brea, Luis Miguel; Siegmann, Philip; Martínez Antón, Juan Carlos; Gómez Pedrero, José Antonio; Wilkening, Günter; Koenders, Ludger; Müller, Franz; Hildebrand, M.; Hermann, Harti
    In this report a classification of the main surface structures found on fine metallic wires is carried out (between ∼20 and 500 μm in diameter). For this, we have analyzed a series of wires of different metallic materials, diameters and production environments by scanning electron microscopy, atomic force microscopy, and confocal microscopy. A description and the images of the structures is given and, in addition, a nomenclature to be used by manufacturers, customers and researches is proposed. With this information the surface quality of fine metallic wires may be improved in a fabrication level. One of the objectives of this catalogue of defects is to serve as a basis for measuring the quality of the surface of the wires during the production process and the development of a measuring device for that purpose.