• JLA Vol:9 Iss:6 (Scaling laws for thick‐section cutting with a chemical oxygen–iodine laser)


    Authors:
    A. Kar
    J. A. Rothenflue
    W. P. Latham



    Almost all laser‐assisted materials processing involves melting, vaporization and plasma formation which affect the utilization of laser energy for materials processing. To account for the effect of these phases, an effective absorptivity is defined, and a simple mathematical model is developed for the cutting of thick‐section stainless steel using a high power chemical oxygen—iodine laser (COIL). The model is based on an overall energy balance, and it relates the cutting depth with various process parameters that can be used to predictively scale the laser materials processing performance to ...

    $25.00

  • JLA Vol:3 Iss:3 (Safety of Medical Excimer Lasers with an Emphasis on Compressed Gases)


    Authors:
    David H. Sliney
    Laser Microwave Division, US Army Environmental Hygiene Agency, Aberdeen Proving Ground, MD 21010‐5422

    Terrance N. Clapham
    VISX, Inc., 919 Kifer Road, Santa Clara, CA 94086


    Excimer lasers which emit short ultraviolet radiation (UVR) are currently being used in experimental and developmental surgical applications. Although UVR exposure is possible, it is not normal in laser angioplasty (cardiovascular surgery) and is insignificant in photokera‐toplasty (ophthalmic surgery). However, significant potential hazards exist with the use of excimer laser gases such as fluorine and HCI. Stringent safeguards for handling and use are ...

    $25.00

  • JLA Vol:16 Iss:3 (Solidification model of laser cladding with wire feeding technique)


    Authors:
    Chien-Fu Hung
    Jehnming Lin
    Department of Mechanical Engineering, National Cheng Kung University, Tainan 701, Taiwan


    The object of this study is to investigate the solidification problem in laser cladding with the wire feeding technique. The solidification phenomenon of laser cladding was analyzed by numerical simulation and experimental visualization. Good agreement has been obtained for 304 stainless steel wires cladding on round tubes and it transpires that there were three basic modes of clad profiles: thinning, thickening, and wavering of the clad thickness at different velocity settings between the feeding wire and the substrate in laser wire cladding. &copy...

    $25.00

  • JLA Vol:20 Iss:4 (Laser cutting of 2024-T3 aeronautic aluminum alloy)


    Authors:
    A. Riveiro
    F. Quintero
    F. Lusquin˜os
    J. Pou
    M. Pe´rez-Amor
    Departamento de Fi´sica Aplicada, Universidade de Vigo, ETS Ingenieros Industriales, Vigo, 36310, Spain


    Since the beginning of the aeronautic industry, aluminum alloys have played a crucial role in its development. Nowadays, different aluminum alloy families are the base material of many pieces of aerospace vehicles. In this work, a novel approach to process aluminum alloys is explored. The authors efforts are aimed to cut 2024-T3 plates by a CO2 laser. They used a novel laser cutting head assisted by a gas jet working in supersonic regim...

    $25.00

  • JLA Vol:1 Iss:3 (CO<sub>2</sub> Laser Engraving System for Relief Plate to Print Corrugated Cardboard)


    Authors:
    K. Wakabayashi
    N. Sugishima
    NEC Corporation, Laser Equipment Div., 1120, Shimokuzawa, Sagamihara, JAPAN


    A very compact and economical CO2 laser engraving system to make relief plates for the purpose of printing corrugated cardboard has been developed. This system consists of a highly stable 500W CO2 laser and a high speed, easy handling image processing sub&hyphen;system. In this paper several new developments are described. This image processing technique for CO2 laser raster scanning and engraving has been newly developed. Every binary image is converted to the relief plate more easier than other reported engraving systems.

    $25.00

  • JLA Vol:8 Iss:3 (Laser Hardened Materials Evaluation Laboratory (LHMEL))


    Authors:
    R. J. Hull
    M. L. Lander



    Since 1976, the Laser Hardened Materials Evaluation Laboratory (LHMEL) has been characterizing material responses to laser energy in support of national defense programs and the aerospace industry. Now that capability is available to commercial industry as well. LHMEL's power levels, beam uniformity, and diagnostics capabilities make it an ideal facility for proof&hyphen;of&hyphen;concept testing or process development. Located at Wright&hyphen;Patterson Air Force Base, Ohio, LHMEL is managed by the Wright Laboratory Materials Directorate and operated by Lawrence Associates, Incorporated. The facility's advanced hardware is centered aroun...

    $25.00

  • JLA Vol:2 Iss:2 (Binary Phase Gratings for Materials Processing)


    Authors:
    Paul J. Patt
    Array


    The feasibility of using a diffractive optical element, a phase grating, as a beam handling device for use in industrial laser material processing is examined. The binary phase grating is an efficient beam splitting device and is useful in many materials processing operations (welding, cutting, soldering, drilling) where a high degree of parallelism could significantly improve process throughput. Overall efficiency of etched quartz binary gratings agrees well with published predictions (nominal 70–90&percnt;). Copies of the grating formed in PMMA (acrylic) survived preliminary life tests (more than 1000 9&hyphen;J pulses from a commercial multimode N...

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  • JLA Vol:14 Iss:4 (Visible and invisible laser radiation&mdash;problems in laser safety terminology)


    Authors:
    David H. Sliney
    U.S. Army Center for Health Promotion and Preventive Medicine, Aberdeen Proving Grounds, Maryland 21010

    David J. Lund
    U.S. Army Medical Research Detachment, Brooks Air Force Base, Texas 78235

    Wesley J. Marshall
    U.S. Army Center for Health Promotion and Prevention Medicine, Aberdeen Proving Grounds, Maryland 21010


    The spectral band between 400 and 700 nm is termed “visible” in laser safety standards, this is not the full extent of the visible spectrum. Light, or visible radiation, is that which is perceived by the human eye, and the spectral bandwidth for vision is really larger, extending into what some r...

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  • JLA Vol:19 Iss:1 (Three-dimensional numerical approach for geometrical prediction of multilayer laser solid freeform fabrication process)


    Authors:
    Masoud Alimardani
    Ehsan Toyserkani
    Jan P. Huissoon
    Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada


    This article presents the development of a three-dimensional numerical method for predicting transient geometrical and thermal characteristics of multilayer laser solid freeform fabrication as a function of process parameters and material properties. In the proposed method, the thermal domain is numerically obtained, assuming the interaction between the laser beam and powder stream is to be decoupled. Once the melt pool boundary is obtained, the physical domain is discretized in a cross-se...

    $25.00

  • JLA Vol:24 Iss:4 (Laser-assisted nanofabrication of carbon nanostructures)


    Authors:
    Yun Shen Zhou
    Wei Xiong
    Jongbok Park
    Department of Electrical Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0511, USA

    Min Qian
    Department of Electrical Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska, 68588-0511, USA and Department of Physics, East China Normal University, Shanghai 200062, People’s Republic of China

    Masoud Mahjouri-Samani
    Yang Gao
    Department of Electrical Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0511, USA

    Lan Jiang
    Department of Mechanical and Automation Engineering, Beijing Institute of Technology, Bei...

    $25.00

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