• 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...


  • JLA Vol:14 Iss:3 (Evaluation of nozzle geometries for laser surface alloying)

    Terri L. Tramel
    Mary H. McCay
    John A. Hopkins
    T. Dwayne McCay
    The University of Tennessee Space Institute, Tullahoma, Tennessee

    Five general types of nozzles and nine configurations were tested in a water tunnel and using gas pressure analysis to determine their effectiveness at reducing entrained air from the outside environment during laser surface alloying. Two orientations with regard to the work piece were employed: The optics and nozzle being normal, the optics and nozzle being at a 15° oblique angle. Both argon and nitrogen were studied. In the impingement region, they produced roughly the same results regardless of the nozzle...


  • JLA Vol:14 Iss:3 (Laser-assisted chemical etching for embedded microchannels and overhanging microstructures on Si/SiO<sub>2</sub> substrates)

    George P. Vakanas

    Ampere A. Tseng
    Department of Mechanical and Aerospace Engineering, Arizona State University, Tempe, Arizona 85287

    Paul Winer
    Silicon Debug Tools Development, SC9-09, Intel Corporation, Santa Clara, California 95054

    The feasibility of fabricating buried (embedded or subsurface) microstructures between silicon and silicon oxide using laser-assisted chemical etching (LACE) in chlorine atmosphere is demonstrated in this article. An associated LACE ablation model and sample calculations based on one-dimensional thermal analysis and chemical kinetics are presented. A strategy for optimizing the laser process for 3...


  • JLA Vol:14 Iss:3 (Prevention of welding defect by side gas flow and its monitoring method in continuous wave Nd:YAG laser welding)

    Kenichi Kamimuki
    Takashi Inoue
    Applied Laser Engineering Research Institute, 2085-16 Uenoyama, Fukasawamachi, Nagaoka, Niigata 940-2135, Japan

    Kouzou Yasuda
    Mikio Muro
    Tokuhiro Nakabayashi
    Technical Institute, Kawasaki Heavy Industries, 118 Futatsuzuka, Noda, Chiba 278-8585, Japan

    Akira Matsunawa
    Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan

    In the Nd:yttrium–aluminum–garnet (YAG) laser welding of thick plates, reduction of porosity and monitoring the keyhole/molten metal behavior are very important issues to assure the high...


  • JLA Vol:14 Iss:3 (Pulsed laser driven deposition of spattered molten particles and its application to the manufacturing of wear-resistant coatings)

    Toru Nagai
    Takashi Inoue
    Applied Laser Engineering Research Institute, 2085-16 Uenoyama, Fukasawa, Nagaoka 940-2135, Japan

    Hirofumi Shimura
    Mechanical Engineering Laboratory, Agency of Industrial Science and Technology, 1-2 Namiki, Tsukuba 305-8564, Japan

    In this article, we report on a new process for manufacturing metal coatings with submillimeter thickness by pulsed laser driven deposition of molten metal particles. The process of “laser spattering of molten particles” using a high pulse-energy laser is considered to be effective compared to the conventional physical vapor process based on vaporized ultrafine particle generati...