JLA Vol:16 Iss:1 (Influence of surface preparation and process parameters on the porosity generation in aluminum alloys)
CLFA, avenue Prieur de la Côte d’or, 94114 Arcueil, France
A. B. Vannes
Ecole Centrale de Lyon, Ecully, France
The 4 kW cw Nd:yttrium–aluminum–garnet laser welding of solid solution hardened A5083 (5% Mg) and precipitation-hardened A356 (7% Si) alloys, sensitive to porosity formation was carried out at different welding speeds, under He gas shielding, and for partial penetration conditions, on bead on plate configuration. The porosity formation was examined through observation and evaluation of weld beads, based on x-ray radiography inspection coupled with image analysis, and quantification of gas...
JLA Vol:20 Iss:2 (Design and validation of a hybrid laser/water-jet machining system for brittle materials)
Department of Mechanical Engineering, Laboratory for Lasers, MEMS and Nanotechnology, Iowa State University, Ames, Iowa 50011-2161
A unique laser/water-jet (LWJ) cutting head has been designed, built, and interfaced with a CO2 laser for cutting and scribing of hard and brittle ceramic materials. Alumina samples were used to validate the effectiveness of the LWJ cutting head in thermal fracture mode. The results were compared with vaporization mode (focused beam) as well as thermal fracture mode (defocused beam) of air-assisted laser c...
Departamento Fı´sica Aplicada Universidade de Vigo, Lagoas Marcosende 9, E-36200 VIGO, Spain
Laser Engineering Group, Department of Engineering, The University of Liverpool, Liverpool L69 3GH, United Kingdom
Slate is a natural stone which has the characteristic that shows a well-developed defoliation plane, allowing to easily split it in plates parallel to that plane which are particularly used as tiles for roof building. At present, the manufacturing of slate is mostly manual, bein...
JLA Vol:18 Iss:2 (Investigation of the effects of nonconventional beam geometries in laser surface treatment of ceramics: Theoretical analysis)
Laser Processing Research Centre, School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, Manchester M60 1QD, United Kingdom and Corrosion and Protection Centre, School of Materials, The University of Manchester, Manchester M60 IQD, United Kingdom
Laser Processing Research Center, School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, Manchester M60 1QD, United Kingdom
F. H. Stott
Corrosion and Protection Centre, School of Materials, The University of Manchester, Manchester M60 1QD, United Kingdom
Laser surface treatment of ceramics by melting and re...
JLA Vol:25 Iss:3 (Surface tension stabilized laser welding (donut laser welding)—A new laser welding technique)
Department of Engineering Sciences and Mathematics, Luleå University of Technology and Westinghouse Electric Sweden AB, SE-721 63 Va¨sterås, Sweden
Department of Engineering Sciences and Mathematics, Luleå University of Technology
A new laser welding process is presented which delivers a porosity free, spatter free weld. The process involves a donut shaped melt with a central hole of the same order of magnitude as the material thickness. The laser illuminates only the leading section of this melt. The hole is kept open by the melt surface tension.
JLA Vol:24 Iss:1 (Silicon(IV) phthalocyanine-loaded-nanoparticles for application in photodynamic process)
Andreza Ribeiro Simioni
Fernando L. Primo
Antonio Claudio Tedesco
The aim of this study was to evaluate the potential application of biodegradable nanoparticles containing a photosensitizer in photodynamic therapy. The poly (D,L lactic-co-glycolic acid) nanoparticles were studied by steady-state techniques, time-resolved fluorescence, and laser flash photolysis. The external morphology of the nanoparticles was established by scanning electron microscopy, and the biological activity was evaluated by in vitro cell culture by 3-(4,5 dimethyl-thiazol-2,5 biphenyl) tetrazolium bromide assay. The particles were spherical in shape exhibiting ...
B. A. Tozer
Lasermet Ltd and City University, London, U.K.
This paper reviews the present state of the standards‐making process in Europe, explaining such arcane terms as ‘CEN’, ‘CENELEC’, ‘Euronorm’ and ‘directive’. Standards‐making bodies in Europe work to strict guidelines with regard to their relationship to member countries of the EEC and EFTA, and work closely with the international standards bodies, IEC and ISO, to minimize duplication of effort and to ensure minimum conflict with international standards. The current situation with regard to laser safety standards in Europe is reviewed, and the author specul...
JLA Vol:16 Iss:3 (A procedure for the estimation of intrabeam hazard distances and optical density requirements under the ANSI Z136.1-2000 Standard)
Robert J. Thomas
Benjamin A. Rockwell
Air Force Research Laboratory, Brooks AFB, Texas 78235-5215
Wesley J. Marshall
USACHPPM, Aberdeen Proving Ground, Maryland 21010-5422
Robert C. Aldrich
Mary F. Gorschboth
Sheldon A. Zimmerman
Dahlgren Division, Naval Surface Warfare Center, Dahlgren, Virginia 22448-5100
R. James Rockwell
Rockwell Laser Industries, Cincinnati, Ohio 45243
Over the past few years, a comprehensive rewrite of the American National Standard for Safe Use of Lasers (ANSI Z136.1) has been conducted [American National Standards Institute, Z136.1-2000 America...
Politecnico di Milano, Dipartimento di Meccanica Via La Masa 1, I-20156 Milan, Italy
This paper studies the effect of different typologies of surface treatment by diode laser on the local formability of dual phase steel. An analytical thermal model allowed the temperature and cooling rate curves to be predicted and used to select the process parameter conditions. Microhardness measurements, microstructure observations, mechanical tensile test, and Erichsen cup test allowed the positive effect of the heat treatment on dual phase steel formability to be quantified.
B. S. Yilbas
A. Z. Al‐Garni
Mechanical Eng. Dept., KFUPM, P.O. Box 1913, Dhahran, Saudi Arabia
Laser induced heating processes are important when a laser is used as a machine tool in industry, since the quality of the machining process strongly depends on the heating mechanism. The present study examines a heat transfer model that provides useful information on the laser induced interaction mechanism. Steady state and time dependent heating models are introduced and temperature profiles inside the materials are predicted. Using appropriate assumptions, the time for the surface temperature to reach 90% of its steady state value is estimated. To valid...
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