Mechanical Engineering Department, Michigan State University, East Lansing, Michigan 48824-1226
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...
JLA Vol:21 Iss:4 (Use of dispersive Raman spectroscopy to detect the cytotoxic action of <em>viscum album</em> in adenocarcinoma of colon)
Daniela Franco Lopes
Institute of Research and Development (IP&D), Universidade do Vale do Parai´ba (UNIVAP), Av. Shishima Hifumi, 2911 Urbanova, 12244-000 Sa˜o Jose´ dos Campos, SP, Brazil
Group of Biomedical Engineering, Universidade Camilo Castelo Branco (UNICASTELO), Rod. Pres. Dutra, Km 138, Eugeˆnio de Melo, 12247-004 Sa˜o Jose´ dos Campos, SP, Brazil
Marcelo Nobuo Sibata
Aloi´sio Cunha de Carvalho
Institute of Research and Development (IP&D), Universidade do Vale do Parai´ba (UNIVAP), Av. Shishima ...
JLA Vol:8 Iss:2 (Trepan drilling of fuel injection nozzles with a TEM<sub>00</sub> Nd:YAG slab laser)
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% were achieved. One hole is drilled in 7–25 seconds in dependence of the drilling strategy.
Joel H. Blatt
Jeffery A. Hooker
Physics and Space Science Department, Florida Institute of Technology, 150 W. University Blvd., Melbourne, Florida 32901‐6988
Robert V. Belfatto
Eddie H. Young
Newport Electro‐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:15 Iss:3 (Process characteristics and effects of gas- and water-atomized stainless steel powders in laser-based rapid tooling)
Andrew J. Pinkerton
Department of Mechanical, Aerospace, and Manufacturing Engineering, Laser Processing Research Centre, UMIST, P.O. Box 88, Sackville Street, Manchester M60 1QD, United Kingdom
In rapid tooling using the direct laser deposition process and stainless steel materials, only powders prepared using the gas-atomization method have been used because of their presumed superior flow characteristics. In this article, the use of water-atomized powder is investigated by comparing the behavior of the two types of 316 L powders, deposited using a CO2 laser and coaxial head. Results show little difference in the pneumatic conveyance of the po...
David H. Sliney
Wesley J. Marshall
E. Christopher Brumage
Laser/Optical Radiation Program, U.S. Army Center for Health Promotion and Preventive Medicine, Aberdeen Proving Ground, Maryland 21010-5403
The basic concept of laser hazard classification with four fundamental risk groups and several subclasses is well understood by most laser users. However, many readers of laser safety standards are frequently puzzled by the rigid measurement conditions applied for hazard classification, even if this is normally a task performed by the laser manufacturer and not by a laser user or a Laser Safety Officer. The historical rationale for the measurement conditi...
X. Y. Zhang
J. Y. Guo
W. W. Duley
Nanojoining, a burgeoning research area, becomes a key manufacturing of complicated nanodevices with functional prefabricated components. In this work, various nanojoining methods are first reviewed. For nanojoining of Ag/Au nanoparticles, three methods are investigated comparatively. Thermal annealing shows a two-step solid state diffusion mechanism. Laser annealing by millisecond pulses displays the thermal activated solid state diffusion. Meanwhile, two effects have been identified in femtosecond laser irradiation with diffe...
JLA Vol:5 Iss:2 (Characterization of Laser Produced High Molybdenum Surface Alloys on Stainless Steel Substrates)
A. R. Biswas
G. L. Goswami
M. B. Deshmukh
High Mo surface alloys on stainless steels 304L and 316L were produced by laser surface alloying. For this, a layer of 60 μm thickness was overlaid on the substrates by plasma spraying of Mo powders. These were further treated by a Nd:YAG pulsed laser for alloying. Depths of alloying in the range of 440–1110 μm were achieved. Concentration in the range of 5.2–15.0 wt% Mo within the laser alloyed zone was, in general, uniform throughout. During alloying, in‐situ heating at 700°C was required to prevent cracking in samples wi...
JLA Vol:18 Iss:1 (An experimental and theoretical investigation of combined gas- and water-atomized powder deposition with a diode laser)
Andrew J. Pinkerton
Waheed Ul Haq Syed
Laser Processing Research Centre, School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, Sackville Street Building, PO Box 88, Manchester M60 1QD, United Kingdom
Functionally graded or composite components (FGCs) have been recognized as having immense potential for many industries. So far, deposition of compositionally graded alloys is the only method that has been shown to be a practical way to produce FGCs. In this work, a second way, that allows graded structures of a single material to be formed by direct metal deposition, is investigated. Simple component samples are bui...
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