• JLA Vol:14 Iss:2 (Human behavioral factors in laser safety)

    Rick Mannix
    Environmental Health & Safety Office, University of California, Irvine, California 92697-2725

    While training, engineering controls, warning signs/systems, and protective eyewear are emphasized in laser safety programs, laser-related accidents do occur in facilities without obvious deficiencies in those areas. Problems still occur because of insufficient attention to administrative safety issues directly related to human nature and behavioral factors. Common safety problems associated with behavioral factors are discussed. Personal experiences of the author, including lessons learned, are included. The issues are discussed within the context of laser safety, bu...


  • JLA Vol:14 Iss:2 (Influence of oxide film on weld characteristics of mild steel in CO<sub>2</sub> laser welding)

    Kazuhiko Ono
    Kaoru Adachi
    Manufacturing Engineering Development Center, Komatsu Ltd., Hirakata, Osaka 573-1011, Japan

    Isamu Miyamoto
    Takashi Inoue
    Department of Manufacturing Science, Osaka University, Suita, Osaka 565-0871, Japan

    The influence of oxide film, such as laser cutting edge or mill scale, on CO2 laser welding phenomena and weld characteristics of mild steel was investigated. Laser welding of butt joints, which were different in location and thickness of oxide film, were performed. Examinations were made on the weld characteristics which were: bead geometry, defect, and microstructure. Light emitted from la...


  • JLA Vol:14 Iss:2 (Monitoring of laser weld penetration using sensor fusion)

    Allen Sun
    Elijah Kannatey-Asibu
    Department of Mechanical Engineering, The University of Michigan, Ann Arbor, Michigan 48109

    Mark Gartner
    Ford Motor Company, Dearborn, Michigan 48121

    Depth of penetration is a critical parameter in laser welding. In many applications, full penetration is desired, but difficult to detect in real time. A sensor fusion system using infrared, ultraviolet, audible sound, and acoustic emission has been implemented for real time monitoring of CO2 laser lap welds in both laboratory and industrial production settings. Signals from the welds were analyzed by: (1) singular value decomposition with data fusion,...


  • JLA Vol:14 Iss:2 (On the mechanisms of wetting characteristics modification for selected metallic materials by means of high power diode laser radiation)

    J. Lawrence
    L. Li
    Department of Mechanical Engineering, Laser Processing Research Centre, Manufacturing Division, University of Manchester Institute of Science and Technology (UMIST), Manchester M60 1QD, United Kingdom

    This work elucidates and analyzes the factors responsible for modifications to the wettability characteristics of metallic materials after high power diode laser (HPDL) treatment. It was found that interaction of EN3 and EN8 mild steel with HPDL radiation resulted in the wettability characteristics of the mild steels altering to various degrees depending upon the laser processing parameters. Such changes in the wettability characteristics of the mi...


  • JLA Vol:14 Iss:2 (Thermomechanical effects in laser microprocessing for dieless metal wire drawing)

    Yonggang Li
    School of Optic/CREOL (Center for Research and Education of Optics and Lasers), Mechanical, Materials and Aerospace Engineering Department, University of Central Florida, Orlando, Florida, 32816-2700

    Nathaniel R. Quick
    USF Filtration and Separations Group, Inc., 1750 Filter Drive, DeLand, Florida 32724-2045

    Aravinda Kar
    School of Optic/CREOL (Center for Research and Education of Optics and Lasers), Mechanical, Materials and Aerospace Engineering Department, University of Central Florida, Orlando, Florida, 32816-2700

    A new dieless metal fiber drawing process is developed in which a high-precision laser is used to heat the...


  • JLA Vol:14 Iss:3 (Application of experimental-based modeling to laser cladding)

    Ehsan Toyserkani
    Amir Khajepour
    Steve Corbin
    Department of Mechanical Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada

    This article addresses experimental-based modeling of the powder injection laser cladding process. An accurate model for the process is essential for controller design and process automation. There are few dynamic and static models for the process, however, due to the limitations and intensive numerical calculations, their application to real-time process control are not practical. Two model structures, the Hammerstein–Wiener model and Elman recurrent neural network are implemented to identify the laser cl...


  • JLA Vol:14 Iss:3 (Appropriate regimes of laser drilling models containing melt eject mechanisms)

    S. S. Kudesia
    Department of Physics, Heriot-Watt University, Riccarton, Edinburgh EH14 4AS, United Kingdom

    P. Solana
    Departamento de Matema´tica Aplicada, Universidad Polite´cnica de Madrid, Spain

    W. S. O. Rodden
    D. P. Hand
    J. D. C. Jones
    Department of Physics, Heriot-Watt University, Riccarton, Edinburgh EH14 4AS, United Kingdom

    The significance of melt ejection during various drilling regimes of laser drilling is investigated. The predictions of two analytical models of the drilling process, with and without the melt ejection mechanism, are compared with experimental measurements made using a ...


  • JLA Vol:14 Iss:3 (Assessment of laser Doppler perfusion imager&rsquo;s <em>in vivo</em> reliability: Can it be used for a prospective analysis?)

    Antonella Caselli

    Damanpreet Singh Bedi
    Colleen O’Connor
    Chirag Shah
    Aristidis Veves
    Joslin–Beth Israel Deaconess Foot Center, Department of Surgery, and Microcirculation Laboratory, Beth Israel–Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts

    The aim of this study was to assess the reliability of the laser Doppler perfusion imager (Lisca PIM 1.0; Lisca development, Linkoping, Sweden) for longitudinal analysis. We measured the skin blood flow under a biological zero condition at the forearm level in 84 patients enrolled in a 12 week prospective interventional trial. Sin...


  • JLA Vol:14 Iss:3 (Characterizing keyhole plasma light emission and plasma plume scattering for monitoring 20 kW class CO<sub>2</sub> laser welding processes)

    J. Tu
    School of Industrial Engineering, Purdue University, West Lafayette, Indiana 47907

    I. Miyamoto
    T. Inoue
    Department of Manufacturing Science, Osaka University, Osaka, Japan

    In very deep penetration, the plasma inside the keyhole exhibits complicated behavior and the plasma plume covering outside the keyhole can also affect the observation of keyhole plasma. Measuring the light emission from keyhole plasma is an effective method to monitor laser welding processes in thin sheets; however, in welding thick sheets, several critical phenomena must be observed. In this article, we provide experimental investigations using a 20 kW CO2


  • JLA Vol:14 Iss:3 (Effects of laser welding parameters on magnetic materials with the aid of a mechatronic measuring system)

    Hussein A. Abdullah
    School of Engineering, University of Guelph, Guelph, Ontario N1G 2W1, Canada

    Chris R. Chatwin
    School of Engineering, University of Sussex, Brighton BN1 9QT, United Kingdom

    This article reports results from an experimental investigation into laser welding of ferromagnetic material, which, for example, is of interest to the European Space Agency. The effects of laser welding power and translation velocities on the magnetism of ferromagnetic materials were studied. An automated system using a Hall effect transducer was constructed to measure the magnetic field transverse to the laser weld before welding, immediately after welding and thr...



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