JLA Vol:6 Iss:3 (Safety concerns about laser pointers)

Authors:
David H. Sliney
Jerome E. Dennis

In the past two years considerable concerns have been expressed about the safety of Class 3A laser pointers. The concern has been that Class 3A diode–laser pointers have replaced the safer helium–neon (He–Ne) Class 2 laser pointers. Hundreds of thousands of small He–Ne visible‐wavelength lasers have been traditionally used for alignment and pointing, laser demonstrations and laser displays in science, education and industry, but can the diode laser be as safe and effective? Not infrequently, some people associate “lasers” with Buck Rogers and “Star Wars”, and are concerned wh...

JLA Vol:14 Iss:2 (Human behavioral factors in laser safety)

Authors:
Rick Mannix
Environmental Health & Safety Office, University of California, Irvine, California 92697-2725

While training, engineering controls, warning signs/systems, and protective eyewear are emphasized in laser safety programs, laser-related accidents do occur in facilities without obvious deficiencies in those areas. Problems still occur because of insufficient attention to administrative safety issues directly related to human nature and behavioral factors. Common safety problems associated with behavioral factors are discussed. Personal experiences of the author, including lessons learned, are included. The issues are discussed within the context of laser safety, bu...

JLA Vol:18 Iss:3 (Modified dual-beam method for welding galvanized steel sheets in lap configuration)

Authors:
M. M. S. Gualini
S. Iqbal
Faculty of Applied Sciences, International I University, Islamabad, Pakistan

F. Grassi
Convergent Prima Industrie, Collegno (Turin), Italy

The dual laser beams method to lap weld galvanized steel sheets is being discussed, modeled, and analyzed, involving a precursor beam and a higher-power actual beam used in tandem and generated independently or otherwise split from the same source (Nd:yttrium-aluminum-garnet or CO₂ laser). The first beam cuts a slot, thus making an exit path for the zinc vapors, while the second beam welds as required. The article also presents and discusses some experiments performed ...

JLA Vol:25 Iss:3 (Evaluation of corneal and eye lens irradiance for optical aided viewing)

Authors:
Enrico Galbiati
GEST Labs, Via Kennedy, 20871 Vimercate, Italy

The use of a magnifying lens with a highly divergent laser beam may cause a big increase of the irradiance on the cornea and the eye lens. This study provides the analysis of several cases where the use of a lens lead to a corneal irradiance significantly higher than the naked-eye viewing. The examples analyzed in this study allow determining the factors that represent the increase of the corneal irradiance caused by the use of the lens. The results indicate that these factors of irradiance increase may be close to 100.

JLA Vol:8 Iss:5 (Laser drilling of advanced materials: Effects of peak power, pulse format, and wavelength)

Authors:
X. Chen
W. T. Lotshaw
A. L. Ortiz
P. R. Staver
C. E. Erikson
M. H. McLaughlin
T. J. Rockstroh

The quality of laser‐drilled holes is significantly influenced by the laser peak power, pulse format, and wavelength. Three advanced materials are used to demonstrate the importance of choosing the correct laser parameters for a specific material. The materials are: (1) intermetallic single crystal nickel aluminide (NiAl) alloy; (2) N5, a single crystal nickel‐based superalloy; and (3) a silicon carbide (SiC) ceramic matrix composite (CMC). The laser peak power is varied in terms of the pulse...

JLA Vol:2 Iss:1 (On Laser Vibrometry of Rotating Targets: Effects of Torsional and In‐Plane Vibration)

Authors:
S. J. Rothberg
J. R. Baker
N. A. Halliwell
ISVR, University of Southampton, Highfield, Southampton S09 5NH, England

Vibration measurements on rotating surfaces are often referred to in the commercial literature as a major application of laser Doppler vibration transducers. This paper examines such use of these instruments and shows how the presence of a velocity component due to the rotation itself leads to spurious measurement dependence on both torsional vibration and motion perpendicular to the line of incidence of the laser beam. In addition, the scale of this dependence increases with both rotation speed and perpendicular distance between the l...

JLA Vol:16 Iss:4 (Microstructural aspects of laser dissimilar welds of hard metals to steels)

Authors:
A. Costa
IDMEC, Av. Rovisco Pais, 1049-001 Lisboa, Portugal

L. Quintino
IDMEC, Av. Rovisco Pais, 1049-001 Lisboa, Portugal and Instituto Superior Te´cnico, Secc¸a˜o de Tecnologia Mecaˆnica, Av. Rovisco Pais, 1049-001 Lisboa, Portugal

R. M. Miranda
IDMEC, Av. Rovisco Pais, 1049-001 Lisboa, Portugal and Universidade Aberta, R. Escola Polite´cnica 147, 1269-001 Lisboa, Portugal

Laser beam welding has been widely used in industry in the past decade. Recently, applications in dissimilar welds involving hard metals have been investigated. Hard metals are commonly used in tool manufacturing and this application...

JLA Vol:21 Iss:1 (Local susceptibility of the retina, formation and duration of afterimages in the case of Class 1 laser products, and disability glare arising from high-brightness light emitting diodes)

Authors:
Hans-Dieter Reidenbach
Cologne University of Applied Sciences, Research Laboratory on Medical Technology and Non-Ionizing Radiation, Betzdorfer Str 2, 50679 Koeln, Germany

According to the new European Directive on Artificial Optical Radiation, the employer has to determine the exposure and the assessment of risks and in addition, he shall give particular attention to any indirect effects, such as temporary blinding, when carrying out the risk assessment. Up to now, secondary effects such as temporary blinding have not been regarded in safety standards and there exist but a few data on this topic as far as modern artificial high-brightness (HB) light sources are concerned. Te...

JLA Vol:24 Iss:4 (Cellular reactions toward nanostructured silicon surfaces created by laser ablation)

Authors:
K. Wallat
Institute of Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, Universitaetsstr. 5-7, 45117 Essen, Germany

D. Do¨rr
R. Le Harzic
F. Stracke
D. Sauer
Fraunhofer Institute for Biomedical Engineering (IBMT) and Chair for Molecular and Cellular Biotechnology (University of Saarbruecken), Ensheimer Str. 48, 66386 St. Ingbert, Germany

M. Neumeier
A. Kovtun
Institute of Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, Universitaetsstr. 5-7, 45117 Essen, Germany

H. Zimm...

JLA Vol:4 Iss:3 (Recommendations for Safe and Appropriate Use of Lasers in Dentistry in Face of Rising Concerns)

Authors:
Leo J. Miserendino
Elliot Abt
David Harris
Harvey Wigdor
The Chicago Dental Laser Institute