JLA Vol:18 Iss:3 (Thermal and microstructural aspects of the laser direct metal deposition of waspaloy)

Authors:
Andrew J. Pinkerton
Laser Processing Research Centre, School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, PO Box 88, Manchester M60 1QD, United Kingdom

Mallikarjun Karadge
Manchester Materials Science Centre, School of Materials, The University of Manchester, Grosvenor Street, Manchester M1 7HS, United Kingdom

Waheed Ul Haq Syed
Lin Li
Laser Processing Research Centre, School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, PO Box 88, Manchester M60 1QD, United Kingdom

A potential problem in applying the laser direct metal deposition (LDMD) technique to the f...

JLA Vol:9 Iss:6 (… .But is it really safe?)

Authors:
Peter A. Smith
DERA Centre for Human Sciences, Farnborough, Hampshire, U.K.

JLA Vol:3 Iss:2 (Laser Applications in Criminalistics)

Authors:
E. R. Menzel
Center for Forensic Studies, Department of Physics, Texas Tech University, Lubbock, Texas 79409

Lasers find application in numerous areas of criminalistics, such as fiber analysis, document examination and serology. Their widest use, however, is in detection of latent fingerprints. Several routine procedures for obtaining laser‐excited fingerprint fluorescence on a range of surfaces have been developed. However, many surfaces fluoresce so strongly themselves that they are not amenable to these procedures. Time‐resolved luminescence imaging is being investigated to permit detection of fingerprints on such surfaces.

JLA Vol:16 Iss:4 (Dimensional and material characteristics of direct deposited H13 tool steel by CO₂ laser)

Authors:
J. Choi
Y. Hua
Department of Mechanical and Aerospace Engineering and Engineering Mechanics, University of Missouri, Rolla, Missouri 65409-1060

Laser aided direct metal/material deposition process builds metal parts layer-by-layer directly from the computer aided design representation. Success of this technology in the die and tool industry depends on the parts quality to be achieved. To get designed geometric dimensions and material properties, delicate control of the process variables such as laser power, spot diameter, traverse speed, and powder mass flow rate is critical. With a closed loop optical height control system, the dimensional accuracy was achieved ...

JLA Vol:21 Iss:2 (Corrosion performance and restoration of laser-formed metallic alloy sheets)

Authors:
Z. Liu
C. Guzma´n
H. Liu
A. Anacleto
T. Francisco
M. Abdoalshafie
L. Ma
O. Abodunrin
P. Skeldon

Previous studies of laser forming have been focused on understanding the laser forming mechanisms, investigating the effects of important laser process parameters on deformed shape, and modeling the forming process. Although microstructures and mechanical properties have received some attention, no work has addressed corrosion behavior of laser-formed components. However, laser forming is a thermal process with substantial thermal cycles required; sensitization of microstr...

JLA Vol:26 Iss:1 (Periodic antireflection surface structure fabricated on silicon by four-beam laser interference lithography)

Authors:
Z. Zhang
CNM and JR3CN, Changchun University of Science and Technology, Changchun 130022, China and CHO, Changchun Observatory, National Astronomical Observatory, CAS, Changchun 130117, China

Z. Wang
D. Wang
CNM and JR3CN, Changchun University of Science and Technology, Changchun 130022, China and JR3CN, University of Bedfordshire, Luton LU1 3JU, United Kingdom

Y. Ding
CNM and JR3CN, Changchun University of Science and Technology, Changchun 130022, China

Silicon surface structures with excellent antireflection property arouse wide interest. Chemical and physical methods such as femtosecond, nanosecond, and picosecond la...

JLA Vol:24 Iss:2 (Energetic efficiency of remote cutting in comparison to conventional fusion cutting)

Authors:
M. Lu¨tke
J. Hauptmann
A. Wetzig
Fraunhofer IWS, Winterbergstraße 28, 01277 Dresden, Germany

E. Beyer
Fraunhofer IWS, Winterbergstraße 28, 01277 Dresden, Germany and University of Technology Dresden, 01062 Dresden, Germany

The remote cutting technique provides an enormous potential in terms of cutting speeds when working on thin sheets. Even on contour cutting speeds about 100 m/min are realizable. Working without any cutting gas, the material of the cutting kerf must be vaporized partially. It is evident that the energy input must be higher than for pure melting of the cutting kerf’s material. In order to ...

JLA Vol:6 Iss:4 (Hazardous chemicals produced by laser materials processing)

Authors:
John M. Kokosa
GMI Engineering & Management Institute, Flint, MI, U.S.A.

Despite evidence to the contrary, until recently many laser operators believed, or at least stated, that the only chemical by‐products of laser processing of any consequence were water and CO₂. During the last eight years, especially, several investigations have shown that hazardous materials are produced when cutting or welding nearly all substrates. In the following paper, the major chemical hazards associated with processing metals, inorganics, biomaterials, and polymers are outlined.

JLA Vol:15 Iss:2 (Laser surface processing of titanium in air: Influence of scan traces overlapping)

Authors:
A. Pe´rez del Pino
P. Serra
J. L. Morenza
Departament de Fı´sica Aplicada i Òptica, Universitat de Barcelona, E-08028 Barcelona, Spain

Laser surface treatments of titanium in air have been performed through a pulsed Nd:yttrium–aluminum–garnet (λ=1.064 μm) laser. Several samples have been obtained modifying the laser scan velocity and partial overlapping of consecutive traces, in order to study the influence of these parameters on the surface morphology. Scanning electron microscopy and profilometry measurements have revealed different surface morphologies depending on the physical processes involved in th...

JLA Vol:19 Iss:2 (Intrabeam viewing of extended-source lasers with telescopes)

Authors:
Wesley J. Marshall
E. Christopher Brumage
David H. Sliney
U.S. Army Center for Health Promotion and Preventive Medicine, AberdeenProving Ground, Maryland 21010-5403

Magnifying optics can increase the hazards for intrabeam viewing of lasers. Although it is rather straightforward to evaluate these increased hazards for point-source lasers at distance, limited information is available for determining the hazards from viewing extended-source lasers from within the beam when magnifying optics are used. Since intrabeam viewing of nearly all lasers results in an extremely small retinal image, commonly known as a “point source,” extended-source m...