• JLA Vol:16 Iss:2 (Quality and costs analysis of laser welded all steel sandwich panels)

    Henrikki Pantsar
    Antti Salminen
    Lappeenranta University of Technology, FIN 53850 Lappeenranta, Finland

    Anssi Jansson
    VTT Industrial Systems, FIN 53850 Lappeenranta, Finland

    Veli Kujanpa¨a¨
    Lappeenranta University of Technology, FIN 53850 Lappeenranta, Finland

    Laser welding is a fast and flexible way to manufacture all steel sandwich panels. Economically the most feasible solution is often to weld as large panels as possible. In corrugated core all steel sandwich panel applications the effect of an air gap in welding is difficult to eliminate when welding large panels. A system for welding large panels with a las...


  • JLA Vol:20 Iss:3 (Three-dimensional biomimetic microchannel network by laser direct writing)

    Dong Hyuck Kam
    Jyoti Mazumder
    Center for Lasers and Plasmas for Advanced Manufacturing (CLPAM), University of Michigan, Ann Arbor Michigan 48105

    Application of laser direct writing to the fabrication of microchannel networks for tissue engineering was presented. A Q-switched Nd:YAG laser with fundamental wavelength was used. Multidepth, multiwidth microstructures on silicon were machined without photolithography-based methods. The molten material inside the microchannel was ejected with a modified assist gas, and thus the volume of laser ablation was increased. The debris build-up due to the strong thermal reaction of silicon to the nanosecond IR laser pulse was ...


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  • JLA Vol:23 Iss:4 (Femtosecond laser machined microfluidic devices for imaging of cells during chemotaxis)

    L. Costa
    A. Terekhov
    D. Rajput
    W. Hofmeister
    Center for Laser Applications, University of Tennessee Space Institute, Tullahoma, Tennessee 37388

    D. Jowhar
    G. Wright
    Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37240

    C. Janetopoulos
    Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37240 and Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee 37240

    Microfluidic devices designed for chemotaxis assays were fabricated on fused silica substrates using femtosecond laser micromachining. These devices hav...


  • JLA Vol:6 Iss:1 (Standardization in the field of lasers in Europe—Towards common international standards)

    Ernst Sutter
    Physikalisch‐Technische Bundesanstalt, Bundesallee 100, D‐38116 Braunschweig, Germany

    Different standards in different European countries have given rise to technical trade barriers. The European Community made a great effort to establish a single market before the end of 1992 in which the free movement of goods is ensured. The first approach was to adopt directives setting up detailed requirements for all products. This has proved to be such a slow and difficult process that the New Approach has been adopted: the essential requirements are established by directives, whereas the technical specifications are detailed in harmonized standards....


  • JLA Vol:14 Iss:4 (Process study for laser-induced surface coloration)

    H. Y. Zheng
    G. C. Lim
    X. C. Wang
    J. L. Tan
    Gintic Institute of Manufacturing Technology, 71 Nanyang Drive, Singapore 638075

    James Hilfiker
    J. A. Woollam Company, Inc., 645 M Street, Suite 102, Lincoln, Nebraska 68508

    A KrF excimer laser beam is used to induce controllable and high-contrast colors on a stainless-steel surface under different processing conditions. The laser beam acts as a localized heating source that promotes the formation of semitransparent oxide films of varying thicknesses and morphologies on the sample surface. Ellipsometry and atomic force microscopy were employed to understand the laser-induce...


  • JLA Vol:18 Iss:4 (Simulated fabrication of off-axis microlens array using excimer laser dragging process)

    Shuh-Yi Wang
    Department of Mechanical Engineering, Chengshiu University, 840 Cheng Ching Road, Niaosung, Kaoushiung, 833, Taiwan, Republic of China

    A computer simulation of the fabrication of an off-axis aspheric microlens array using excimer laser dragging with variously shaped masks is performed. Traditionally, a semicircular mask is used during dragging to yield an on-axis microlens array. However, a quarter-circular mask can generate an off-axis microlens array using this dragging process. Unlike the more common centered or on-axis system, this off-axis microlens array can process focused light without obstructing the lens. Variously shaped masks were computer simulated. ...


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

    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.


  • JLA Vol:2 Iss:3 (Video Applications to Moire&acute; Metrology)

    Joel H. Blatt
    Jeffery A. Hooker
    Physics and Space Science Department, Florida Institute of Technology, 150 W. University Blvd., Melbourne, Florida 32901&hyphen;6988

    Robert V. Belfatto
    Eddie H. Young
    Newport Electro&hyphen;Optics Systems, Inc., 4451B Enterprise Court, Melbourne, Florida 32935

    Video technology is applied to the problem of moire´ metrology. In the past, moire´ metrology seemed a promising yet limited method in the measurement and comparison of surface shape. The use of video technology has widened the area of application of moire´ metrology by reducing the complexity of the optical set up and pro...


  • JLA Vol:17 Iss:2 (Numerical simulation of femtosecond laser interaction with silicon)

    Hyungson Ki
    Mechanical Engineering Department, Michigan State University, East Lansing, Michigan 48824-1226

    Jyoti Mazumder
    Center for Laser Aided Intelligent Manufacturing, University of Michigan, Ann Arbor, Michigan 48109-2125

    A numerical model for simulating femtosecond laser interaction with silicon is presented. This model simulates laser beam propagation by directly solving Maxwell’s equations using the finite-difference time-domain method, so that complete electromagnetic nature of a laser beam is simulated accurately. Accurate computation of laser beam passage ensures realistic heat generation pattern in the target material. The two-temperat...



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