JLA Vol:7 Iss:2 (Laser and optics activities at CREOL)

Authors:
C. Martin Stickley
Center for Research and Education in Optics and Lasers (CREOL), University of Central Florida, Orlando, FL, U.S.A.

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 (Understanding laser hazard evaluation)

Authors:
Wesley J. Marshall
U.S. Army Center for Health Promotion and Preventive Medicine (Provisional), Aberdeen Proving Ground, MD 21010‐5422, U.S.A.

The current 1993 version of the ANSI Z136.1 standard for the safe use of lasers provides maximum permissible exposures which more closely match available biological injury data. Interpreting the standard can be more difficult at times than with previous versions. By keeping the biological injury mechanism in mind, the reasoning behind the multitude of rules contained in the standard are more understandable.

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 (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...

JLA Vol:7 Iss:3 (Impact resistance of adhesive joints using laser‐induced shock waves)

Authors:
I. Gilath
R. Englman
Z. Jaeger
A. Buchman
H. Dodiuk

The impact resistance of aluminum–aluminum joint bonded with FM‐73 (American Cyanamid) structural adhesive was studied using laser‐induced shock waves. The adhesive joint failed in a ductile mode, showing shock absorbtion ability through plastic deformation. All stages of the impact damage were identified from threshold damage through complete sample perforation. In the theoretical study, the damage induced in the target is obtained as follows. The shock wave is modeled by an expanding stress front, which creates a void population in the laser‐im...

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 (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 (Laser beam surveying, refractive index measurements and the making of a 360° reflection hologram)

Authors:
David Foster
Notre Dame High School, 596 South Second St., San Jose, California 95112, U.S.A.

Triangulation measurements, using a laser to find the height of a room and of buildings, will be described first. This will be followed by triangulation and laser beam divergence measurements for range finding. The use of a hollow prism to hold liquids, whose refractive indicies are to be found, will then be described. The final topic will describe how a 360° reflection hologram was made at Notre Dame High School, utilizing three lasers and beam spreaders and four lasers and beam spreaders. The 360° hologram, made by a student, will be available for viewing.

JLA Vol:7 Iss:3 (Laser operator training and competency assessment in the community hospital setting)

Authors:
Michael A. Connor
Allan F. Cook
Marymount Hospital, Cleveland, Ohio, U.S.A.

At the 279 bed Marymount community hospital, Cleveland, Ohio, the importance of providing a safe laser environment for patients as well as staff was identified. The decision was made to cross‐train all full‐time RNs, LPNs, and SAs to allow flexibility in staffing all laser procedures with a qualified operator. A competency based training program was implemented, utilizing a combination of techniques to assist the adult learner. Selected video tapes were used to teach laser physics and applications. Comprehension was assessed through written and oral quizzing. Individual time...