JLA Vol:3 Iss:1 (Nursing Perspective: Clinical Laser Safety Issues Survey)

Authors:
Penny J. Smalley
Laser Resources & Consulting Services, Chicago, Illinois

JLA Vol:2 Iss:3 (Energy Coupling in Surface Treatment Processes)

Authors:
Friedrich Dausinger
Markus Beck
Jae H. Lee
Eckhard Meiners
Thomas Rudlaff
Jialin Shen
Institut fu¨r Strahlwerkzeuge, University of Stuttgart, Federal Republic of Germany

In cutting or welding processes with lasers, deep penetration mechanisms allow high energy coupling rates. In surface treatment processes such as martensitic hardening, cladding and alloying, deep penetration of the laser beam is mostly not applicable. This generally leads to insufficient coupling rates. In this contribution several ways of enhancing the coupling rate are summarized. Following some theoretical considerations, results of exp...

JLA Vol:2 Iss:3 (A Relationship between Laser Power, Penetration Depth and Welding Speed in the Laser Welding of Steels)

Authors:
L. Mannik
S. K. Brown
Ontario Hydro Research Division, 800 Kipling Ave., Toronto, Ontario M8Z 5S4, Canada

Experimental data have been generated for the bead‐on‐plate keyhole welding of mild steel using the TEM₀₀ beam from a 1.5 kW CO₂ laser and a range of material thickness from 0.64 to 2.6 mm. For each thickness, the maximum welding speed was measured for laser powers from 600 to 1500 W, using the criterion of full penetration along a 5 cm length. Analysis of the data has yielded a simple correlation between laser power (P,kW), penetration depth (d,cm) and welding speed (v,cm/s). When the specific welding energy per unit thic...

JLA Vol:2 Iss:3 (Fatigue Strength of Laser‐Welded Lap Joints)

Authors:
Charles E. Albright
Chris Hsu
R. Olan Lund
Edison Welding Institute, 1100 Kinnear Road, Columbus, Ohio 43212

This investigation demonstrates that weld pattern selection can significantly increase fatigue strength in laser‐welded lap joints. The study included evaluations of the effects of weld pattern, plate thickness, intersheet gap width and joint prebending on fatigue strength. All joints were tested in simple lap tensile shear. A weld pattern with multiple short welds parallel to the loading direction, and located within a band transverse to the loading direction, exhibited a fatigue strength 1.8 times higher (about 10 times longer fatigu...

JLA Vol:2 Iss:3 (Video Applications to Moire´ Metrology)

Authors:
Joel H. Blatt
Jeffery A. Hooker
Physics and Space Science Department, Florida Institute of Technology, 150 W. University Blvd., Melbourne, Florida 32901‐6988

Robert V. Belfatto
Eddie H. Young
Newport Electro‐Optics Systems, Inc., 4451B Enterprise Court, Melbourne, Florida 32935

Video technology is applied to the problem of moire´ metrology. In the past, moire´ metrology seemed a promising yet limited method in the measurement and comparison of surface shape. The use of video technology has widened the area of application of moire´ metrology by reducing the complexity of the optical set up and pro...

JLA Vol:2 Iss:3 (Current State‐of‐the‐Art of Contouring Techniques in Manufacturing)

Authors:
Kevin G. Harding
Industrial Technology Institute, Sensor Center for Improved Quality, Ann Arbor, Michigan 48106

A manager with a major automobile manufacturer once made the comment that “the best thing we ever did to improve quality was give the guys on the floor a caliper to measure the parts”. As the tolerances on manufacturing become tighter, the need for accurate measurement has also increased. Hand fitting of parts to each other does not work in modern automated factories. Gauges in the past have been built to provide a fixed set of measurements of a known part. This practice too has been changing due to the trend toward flexible manufacturing. Now the gages...

JLA Vol:2 Iss:3 (On Optical Methods in Particle Flow)

Authors:
I. Shimizu
Dept. of Mechanical Engineering, Ibaraki College of Technology, Katsuta 312, Japan

Wen‐Jei Yang
Dept. of Mech. Eng. and Applied Mech., University of Michigan, Ann Arbor, Michigan 48109

Some recently developed optical methods for the measurement, control and shape recognition of particle flow are presented including motion control of micro‐particles by optical pressure, identification of particle groups by matched spatial filters, bidirectional light scattering/image processing, bidirectional light scattering/real time measurement, dual beam type particle counter, and speckle photography.

JLA Vol:2 Iss:3 (The American Society for Laser Medicine & Surgery Presents the William B. Mark Award to Michael W. Berns)

Authors:
Caroline S. Mark

JLA Vol:2 Iss:3 (Laser Surgery: Organs to Organelles)

Authors:
Michael W. Berns
Beckman Laser lnstitute and Medical Center

JLA Vol:2 Iss:3 (Erbium:YAG (2.94 &mu;<em>m) Laser Effects on Dental Tissues</em>)

Authors:
James A. Hoke
E. Jeff Burkes
Edward D. Gomes
Myron L. Wolbarsht

Past trials with soft and calcified tissues have demonstrated that long pulse train (2.5 μs) Er:YAG (2.94 μm) laser may be used to ablate tooth structure of human teeth. Determination of physical and thermal damage to surrounding tissue during removal of enamel and dentin is a primary objective of this study. Extracted human teeth with thermal probes imbedded in the pulp chambers were submitted to cavity preparation using an Erbium YAG laser with water mist. Wavelength selection as well as use of a water mist during the procedure resulted in efficient tissue...