JLA Vol:18 Iss:4 (Aluminum alloy welding by using a high power direct diode laser)

Authors:
N. Abe
M. Tsukamoto
Joining and Welding Research Institute, Osaka University, 11-1, Mihogaoka, Ibaraki, Osaka 567-0047, Japan

K. Maeda
K. Namba
Research and Development Center, Sumitomo Light Metal Industries, Ltd., 3-1-12 Chitose, Minato-ku, Nagoya 455-8670, Japan

J. Morimoto
School of Science and Engineering, Kinki University, 3-4-1, Kowakae, Higashiosaka, Osaka 577-8502, Japan

Aluminum alloys are the focus of increasing attention from the automobile industry because of their light weight, high formability, and easy recyclability. In this report, a 4 kW high power direct diode laser was used to exami...

JLA Vol:23 Iss:3 (Spatter in laser welding)

Authors:
A. F. H. Kaplan
J. Powell
Department of Engineering Sciences and Mathematics, Luleå University of Technology, SE-971 87 Luleå, Sweden

Spatter, the ejection of melt from a weld pool, is a major problem whenever it occurs in a welding process. The ejection of droplets from the weld metal results in a weld with underfill, undercuts, craters, blowholes, or blowouts—all of which can have a detrimental effect on the mechanical properties of the weld. This paper presents a systematic description of the different types of spatter phenomena which occur during laser welding. A categorization system is proposed to facilitate the comparison and combination ...

JLA Vol:6 Iss:1 (Mass transport during laser welding of stainless steels and alloys used by US Navy)

Authors:
Anand J. Paul
Parwaiz A. A. Khan
Manufacturing and Materials Division, Concurrent Technologies Corporation, 1450 Scalp Avenue, Johnstown, PA 15904, U.S.A.

Lasers, though developed only about a quarter century ago, are now being routinely used in the automotive, aerospace and other industries to produce superior quality, high‐speed autogenous welds with narrow heat‐affected zones in a number of alloys. However, they cannot at present be used to successfully weld certain important structural alloys due to a change in weld composition resulting from selective mass transport of certain alloying elements from the laser‐melted region. The loss of a...

JLA Vol:17 Iss:1 (Fracture control of unsupported ceramics during laser machining using a simultaneous prescore)

Authors:
A. E. Segall
G. Cai
R. Akarapu
A. Romasco
Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania 16802

B. Q. Li
Department of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164

While lasers offer many advantages when machining ceramics, costly premature fractures and related damage is the tradeoff often faced by manufacturers. This tradeoff is especially apparent for higher-speed machining of complex shapes where traditional “nail-bed” supports are not always practical. To help overcome these problems, re...

JLA Vol:21 Iss:3 (Laser welding of galvanized DP980 steel assisted by the GTAW preheating in a gap-free lap joint configuration)

Authors:
Shanglu Yang
Radovan Kovacevic
Center for Advanced Manufacturing, Southern Methodist University, Dallas, Texas, USA 75205

With the increasing need for reducing the vehicle’s weight, improving fuel efficiency and safety, as well as the corrosion resistance, more and more galvanized high-strength steels have been used in the automotive industry. However, the successful laser welding of galvanized steels in gap-free lap joint configuration is still a big challenge. The high-pressurized zinc vapor is readily developed at the interface of the two metal sheets due to the lower boiling point of zinc (around 906 °C) than the melting point of steel (over 13...

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...

JLA Vol:1 Iss:1 (High‐Speed Laser Welding Discontinuities)

Authors:
Charles E. Albright
Shichan Chiang
Department of Welding Engineering, Ohio State University, Columbus, Ohio

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.