JLA Vol:7 Iss:1 (Electrical hazards associated with lasers)

Authors:
Arthur G. Varanelli
Raytheon Co., 141 Spring St., Lexington, MA 02173, U.S.A.

The range and degree of electrical hazards associated with lasers is generally greater than encountered with other forms of equipment in the industrial, commercial, or scientific sectors. In laser equipment the electrical energy conversion to ‘optical’ wavelength energy is achieved by many methods, each method having differing electrical safety hazard exposures. Laser output is described in terms of beam power, energy, wavelength, and spatial characteristics, enabling common points of comparison and beam hazard characterization. In contrast, the methods of electrical energy conversion ha...

JLA Vol:7 Iss:2 (Fiber optic equipment to supplement today's laser electro‐optic laboratories and global communication highway)

Authors:
Thomas A. Cellucci
Newport Corporation, 1791 Deeve Ave., Irvine, CA 92714, U.S.A.

As the key technology of the Information Superhighway, fiber optics is poised for explosive growth in the next decade. This paper identifies some of the major obstacles involved in establishing a university‐level fiber optics laboratory, and suggests time‐and money‐saving solutions with an emphasis on pre‐packaged fiber optic laboratory kits.

JLA Vol:7 Iss:2 (Laser processing centers and their research projects in Japan)

Authors:
Akira Matsunawa
Welding Research Institute, Osaka University, 11‐1 Mihogaoka, Ibaraki, Osaka 567, Japan

In Japan, R&D activities on laser materials processing are mainly conducted in universities, public research institutions, and technical centers in private enterprise. Among them the Welding Research Institute and the Department of Welding and Production Engineering, both at Osaka University, have taken the initiative in conducting fundamental studies on laser materials processing as well as training experts and engineers in laser technology since the mid 1960s. In 1990, a new laser center called the Applied Laser Engineering Center (ALEC) was established in Naga...

JLA Vol:7 Iss:2 (Fraunhofer‐Institut fu¨r Lasertechnik)

Authors:
Eckhard Beyer
Fraunhofer‐Institut fu¨r Lasertechnik, Aachen, Germany

JLA Vol:7 Iss:2 (Fraunhofer resource center for laser technology ‐ USA)

Authors:
Frank W. Kuepper
Fraunhofer Resource Center for Laser Technology, Ann Arbor, MI, U.S.A.

JLA Vol:7 Iss:3 (Characterization of chromium bearing surface alloys produced by laser alloying on low carbon steel substrates)

Authors:
G. L. Goswami
Dilip Kumar
A. L. Pappachan
A. K. Grover
K. Sridhar
Array

High‐chromium ferritic alloys were produced on mild steel substrates by laser surface alloying. For this, chromium‐plated mild steel samples were treated with a pulsed Nd:YAG laser (300 W maximum power) by varying the average power level from 21.6 W to 30.0 W. The chromium content of the surface alloys was in the range of 3.0–27.0 wt%, with fairly uniform depth of alloying. Microscopy showed very fine austenite needles within elongated/equiaxed ferrite grains in the laser‐alloyed zone (LAZ). X‐ray diffraction indi...

JLA Vol:7 Iss:3 (Institut de Soudure Laser Center)

Authors:
J. C. Goussain
A. Chehaibou
Institut de Soudure, 4 Boulevard Henri Becquerel, 57110 Yutz, France

JLA Vol:7 Iss:3 (Study of liquid and vapor ejection processes during laser drilling of metals)

Authors:
Bekir S. Yilbas¸
Department of Mechanical Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia

In an experimental investigation of laser–metal interaction, one of the important parameters is the propagation velocity of the liquid–vapor interface. The quantity appears as a direct result of the theoretical examination of the interaction and may be used to test the accuracy of the theory. Consequently, in the present study, the nature of the interaction mechanism between a pulsed laser beam and metals is examined using streak photographs of the ejecta from four metals: titanium, tantalum, nickel, and EN58B stainless steel. It...

JLA Vol:7 Iss:3 (Institut fu¨r Strahlwerkzeuge (IFSW), University of Stuttgart)

Authors:
Helmut Hu¨gel
Institut fu¨r Strahlwerkzeuge, University of Stuttgart, Pfaffenwaldring 43, D‐70569 Stuttgart, Germany

JLA Vol:7 Iss:3 (Determination of energy absorption during laser welding by an iterative conduction method)

Authors:
Junji Mimatsu
Jeannine A. Bos
Elijah Kannatey‐Asibu
Michael M. Chen
Department of Mechanical Engineering and Applied Mechanics, The University of Michigan, 2146 G. G. Brown, Ann Arbor, MI 48109‐2125, U.S.A.

Energy absorption is a key process in laser welding. While there is now good qualitative empirical knowledge of the dependence of the effective absorptivity on laser power level, detailed quantitative understanding is poor. In recent years there has been considerable interest in computational modeling of the heat transfer and fluid flow phenomena during laser welding, in order to have a better understanding of the physic...