• JLA Vol:15 Iss:3 (Three-dimensional finite element modeling of laser cladding by powder injection: Effects of powder feedrate and travel speed on the process)

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

    This article addresses a novel three-dimensional transient finite element model of the laser cladding by powder injection process. The proposed model can predict clad geometry as a function of time and process parameters including beam velocity, laser power, powder jet geometry, laser pulse shaping, and material properties. In the proposed method, the interaction between powder and melt pool are assumed to be decoupled and as a result, the melt pool boundary is first obtained in the absence of powder spray....


  • JLA Vol:19 Iss:3 (Characteristics of the laser clad metal made with powder mixture of Co-based alloy and vanadium carbide)

    Guojian Xu
    Munaharu Kutsuna
    Zhognjie Liu
    Graduate School of Engineering, Nagoya University, 1 Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan

    A powder mixture of Co-based alloy (Stellite-6) and vanadium carbide (VC) was deposited to substrates of SM400B mild steel and SUS304 stainless steel using a 2.4 kW cw CO2 laser. The mechanism of crack for clad metal was investigated by changing the VC weight fraction in the range of 0%–56%. The microstructures of the clad layer for matrix of Co-based alloy can be classified into two types—hypoeutectic structure (0–12 wt % VC) and hypereutectic structure (13–56&ens...


  • JLA Vol:24 Iss:3 (Investigation of the effects of basic laser material interaction parameters in laser welding)

    W. J. Suder
    S. W. Williams
    Welding Engineering and Laser Processing Centre, Cranfield University, MK43 0AL, United Kingdom

    The depth of penetration achieved in continuous wave (CW) laser welding results from a balance of many complicated phenomena, which are linked with the characteristics of the heat source. In this work, the laser welding process has been investigated in terms of basic laser material interaction parameters: power density and interaction time. It has been shown that these two parameters are insufficient to characterize the laser welding process. Thus, a third parameter, specific point energy, has been introduced, which along with the power densi...


  • JLA Vol:6 Iss:4 (Effective laser applications in high school physics)

    Jeff Sweet
    North Salinas High School Salinas, CA 93906, U.S.A.

    Laser light is an instant attention‐getter in the classroom; thus any activity which uses the laser as an instructional tool is sure to enhance student motivation. This paper discusses two demonstrations and one experiment involving laser applications that the author has found to be particularly beneficial in terms of (1) instructional effectiveness and (2) arousing the interest of high school physics students. Brief descriptions follow. Refraction through lenses can be nicely illustrated by splitting laser light into several parallel beams and directing them through a fish tank filled with a scatt...


  • JLA Vol:18 Iss:1 (Cladding of Stellite-6 and vanadium carbide on carbon steel using a yttrium–aluminum–garnet laser robot system)

    Guojian Xu
    Graduate School of Engineering, Nagoya University, 1 Furo-cho Chikusa-ku, Nagoya 464-8603, Japan

    Muneharu Kutsuna
    Manoj Rathod
    School of Engineering, Nagoya University, 1 Furo-cho Chikusa-ku, Nagoya 464-8603, Japan

    In the present work, a laser robot system was setup for cladding and repairing machinery parts using pulsed 300 W Nd:yttrium–aluminum–garnet laser facility, six-axis robot, optical fiber, powder feeding system with a special nozzle for powder supply. A mild steel plate was deposited with powder mixtures of Stellite-6 alloy and vanadium carbide (VC). The shape of clad layer, microstructure, and its wear perfo...


  • JLA Vol:7 Iss:1 (Safe laser system design for production)

    Ami Kestenbaum
    Richard J. Coyle
    Patrick P. Solan
    AT&T Bell Laboratories Engineering Research Center, Princeton, NJ 08542‐0900, U.S.A.

    The majority of industrial lasers used in manufacturing are Class IV lasers. Engineering and administrative control measures appropriate to that class of lasers must be enforced to ensure their safe use in production environments, i.e. they should be designed into Class 1 laser systems. In addition, several other design characteristics unique to industrial applications are normally incorporated into these Class I systems, such as interlocked enclosures, process mon...


  • JLA Vol:16 Iss:2 (Laser short pulse heating of copper: Thermo–elasto–plastic analysis)

    A. F. M. Arif
    B. S. Yilbas
    ME Department, KFUPM. Dhahran, Saudi Arabia

    Laser short pulse heating of metallic substrates results in excessive electron temperatures in the surface vicinity. This gives rise to nonequilibrium energy transport in the region irradiated by a laser beam. Moreover, the thermomechanical coupling effect should be incorporated into the energy transport equation as lattice site temperature increases. In the present study, laser short pulse heating of copper is considered. The electron kinetic theory approach is employed to model the nonequilibrium heating process while thermomechanical coupling is introduced in the energy transport equation t...


  • JLA Vol:20 Iss:3 (Diode-pumped solid state laser light sources for confocal laser scanning fluorescence microscopy)

    Mårten Stjernstro¨m
    Department of Applied Physics, Royal Institute of Technology, SE-106 91 Stockholm, Sweden and Department of Chemistry, Royal Institute of Technology, SE-100 44 Stockholm, Sweden

    Fredrik Laurell
    Hjalmar Brismar
    Department of Applied Physics, Royal Institute of Technology, SE-106 91 Stockholm, Sweden

    Diode-pumped solid-state lasers (DPSSLs) have been integrated as light sources in confocal laser scanning microscopy (CLSM). The standard argon ion laser at 488 nm is compared with a DPSSL operating at 473 nm in terms of noise and CLSM image characteristics. The equally high fluorescence image quality togeth...


  • JLA Vol:9 Iss:3 (High power laser welding in hyperbaric gas and water environments)

    G. J. Shannon
    W. McNaught
    W. F. Deans
    J. Watson

    A hyperbaric laser welding facility has been constructed and the feasibility of high power CO2 and Nd:YAG laser welding in both high pressure gas and water environments, to simulated water depths of 500 m, has been established. From initial trials on welding through water at atmospheric pressure, it was found that the different absorption characteristics of water to 10.6 μm (CO2 laser) and 1.06 μm (Nd:YAG laser) radiation proved crucial. The Nd:YAG laser was totally unsuitable as the beam was largely diffused in the water, whereas the CO2 beam was rea...



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