• JLA Vol:8 Iss:1 (Laser technology at the Oak Ridge National Laboratory)


    Authors:
    Marc L. Simpson
    John C. Miller
    Doug H. Lowndes
    Oak Ridge National Laboratory, PO Box 2008 Oak Ridge, TN 37831, U.S.A.


    Researchers at the Department of Energy (DOE) facilities at Oak Ridge perform a variety of basic and applied research involving lasers and laser technology. One of the major strengths at Oak Ridge is the combination of core capabilities in optical materials, optical diagnostics, and sensors. Communities benefiting from these core capabilities include environmental, biomedical, and industrial sponsors. Industry can interact with Oak Ridge in a variety of ways: with Cooperative Research and Development Agreements (CRADAs), through Work ...

    $25.00

  • JLA Vol:8 Iss:1 (Recent progress in laser surface treatment: <emph type="4">I</emph>. Implications of laser wavelength)


    Authors:
    W. Bloehs
    B. Gru¨nenwald
    F. Dausinger
    H. Hu¨gel
    Institute fu¨r Strahlwerkzeuge, Universita¨t Stuttgart, Pfaffenwaldring 43, 70569 Stuttgart, Germany


    The coupling mechanisms of laser radiation and the mechanisms of heat transport in the workpiece are considered. Starting from the well&hyphen;known basics of Fresnel absorption — valid only for smooth and clean surfaces — further effects of coupling are examined. Studies on the effects of surface modifications inherent to all industrial parts and process conditions are presented. The more appropriate term coupling rate is introduced: This describes the r...

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  • JLA Vol:8 Iss:2 (Enhancement of adhesion in coated steels through excimer laser surfacing)


    Authors:
    M. Olfert
    R. E. Mueller
    W. Duley
    T. North
    J. Hood
    D. Sakai



    Galvanize and galvanneal steel sheet are used extensively by the automotive industry. Through a process of excimer laser surface treatment, we have succeeded in significantly enhancing the adhesion characteristics of these coated steels. Preliminary adhesion tests have been carried out via simple ‘T’ peel testing, using a hot melt nylon resin as the adhesive substrate. The peel test results indicate that, for particular processing conditions, enhanced adhesion exceeding the cohesive strength of the nylon adhesive can be obtained. The results...

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  • JLA Vol:8 Iss:2 (High power calibration of commercial power meters using an NIST&hyphen;traceable secondary standard)


    Authors:
    Michael L. Lander
    John O. Bagford
    Daniel B. Seibert
    Robert J. Hull



    For the past 19 years, the Laser Hardened Materials Evaluation Laboratory (LHMEL), located at Wright&hyphen;Patterson AFB, OH, has maintained a number of calibrated high energy power measurement devices capable of measuring CO2 powers up to 150 kW. These devices, calibrated annually to the National Institute for Standards & Technology (NIST) high energy standard calorimeters, serve as secondary standards for in&hyphen;house calibration of LHMEL's commercial power heads and calorimeters. Recent discussions with academic and industrial laser users have ident...

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  • JLA Vol:8 Iss:2 (Laser materials processing at Sandia National Laboratories)


    Authors:
    James L. Jellison
    Michael J. Cieslak
    Sandia National Laboratories, Albuquerque, NM 87185, U.S.A.


    This paper describes the laser materials processing capabilities at Sandia National Laboratories. Some of the advances in the understanding of various aspects of laser materials processing which have been made by the laser materials processing team at Sandia are discussed.

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  • JLA Vol:8 Iss:2 (Low power laser heat treatment to improve fatigue life of low carbon steel)


    Authors:
    David E. Fly
    J. T. Black
    Ben Singleton



    An industrial laser cutting machine tool was used to harden 1117 and 1144 steel to examine effects on fatigue life. Transformation hardening leaves residual compressive stresses at the surface, which greatly enhance fatigue life in addition to increasing the hardness. The laser, which creates localized heating, allows faster cooling rates than conventional heat treatment methods. As a result, the application of the laser facilitates the hardening of low carbon steel which is not hardenable by conventional methods.

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  • JLA Vol:8 Iss:2 (Obtaining laser safety at a synchrotron radiation user facility: The Advanced Light Source)


    Authors:
    Kenneth Barat
    Lawrence Berkeley National Laboratory, MS 90&hyphen;2148, 1 Cyclotron Road, Berkeley, CA 94720, U.S.A.


    The Advanced Light Source (ALS) is a United States national facility for scientific research and development located at the Lawrence Berkeley National Laboratory in California. The ALS delivers the world's brightest synchrotron radiation in the far ultraviolet and soft X&hyphen;ray regions of the spectrum. As a ‘user facility’ it is available to researchers from industry, academia, and laboratories from around the world. Subsequently, a wide range of safety concerns become involved. This article relates not only to synchrotron facilities but to any ...

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  • JLA Vol:8 Iss:2 (Recent progress in laser surface treatment: <emph type="4">II</emph>. Adopted processing for high efficiency and quality)


    Authors:
    W. Bloehs
    B. Gru¨nenwald
    F. Dausinger
    H. Hu¨gel
    Institut fu¨r Strahlwerkzeuge, Universita¨t Stuttgart, Pfaffenwaldring 43, 70569 Stuttgart, Germany


    In Part I of this contribution, energy coupling and transport mechanisms were considered in detail. The second part concentrates on the effect of the spatial distribution of the energy in the laser beam, which will be discussed in connection with applications of laser surface technologies. Along these lines, a variety of beam shaping facilities is presented for laser hardening and cladding. Their purpose is to adapt the irradiated area to the workpiece ge...

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  • JLA Vol:8 Iss:2 (Trepan drilling of fuel injection nozzles with a TEM<sub>00</sub> Nd:YAG slab laser)


    Authors:
    H. Rohde
    E. Meiners



    Holes of 160 μm diameter were trepan drilled in fuel injection nozzles of 1 mm thickness by means of a TEM00 fundamental mode Nd:YAG slab laser. Two different types of holes have been trepan drilled: at an angle of 90°, and at an angle of 60° to the metal surface. The influence of nozzle distance, focal position, gas pressure, pulse repetition frequency and trepanning velocity on the hole diameter and on the conicity are investigated. A diameter accuracy of ±10 μm and a conicity of 3&percnt; were achieved. One hole is drilled in 7–25 seconds in dependence of the drilling strategy.

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  • JLA Vol:8 Iss:3 (A study of laser&hyphen;based removal of polymethylmethacrylate bone cement)


    Authors:
    W. O'Neill
    P. Kapadia
    T. Thomas



    Complications are often produced with the removal of bone cement from the femoral cavity in the treatment of a failed hip prosthesis. Apart from being slow and difficult the conventional process runs the risk of producing damage to the femur. Ultrasonic techniques have been suggested to achieve these ends but removal of the cement by this approach is not entirely easy. The alternative laser&hyphen;based approach would seem to have significant advantages over conventional techniques. The laser is capable of delivering energy to a specific region or surface under close control. The choice of laser is determined by its a...

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