JLA Vol:15 Iss:4 (Laser-assisted etching of titanium foil in phosphoric acid for direct fabrication of microstructures)

Authors:
Y. S. Shin
S. H. Jeong
Department of Mechatronics, Kwangju Institute of Science and Technology, 1 Oryong-dong Puk-gu, Kwangju 500-712, Republic of Korea

Characteristics of laser-induced thermochemical wet etching of titanium foil in phosphoric acid were investigated to examine the feasibility of this method for direct fabrication of microstructures. Variations of etch width, depth, and profile were examined for different combinations of laser power density, scanning speed of the beam focus, and etchant concentration which are the major process parameters governing temperature distribution on the sample surface and the reaction rate. Etch width increased almost li...

JLA Vol:20 Iss:1 (Surface preparation by using laser cleaning in thermal spray)

Authors:
H. Li
S. Costil
H-L. Liao
C. Coddet
LERMPS, Universite´ de Technologie de Belfort-Montbe´liard, 90010 Belfort Cedex, France

V. Barnier
R. Oltra
LRRS, Universite´ de Bourgogne, 21078 Dijon, France

Pulsed laser cleaning has emerged as a promising technology to challenge traditional surface preparation methods. This paper introduces the PROTAL® process, which combines an in situ pulsed laser cleaning with thermal spraying techniques. This laser surface preparation avoids some drawbacks of the traditional degreasing and sand-blasting stages prior to thermal spraying, which is ...

JLA Vol:23 Iss:1 (Mechanical and microstructural characteristics of the dissimilar materials butt joints by hybrid CO₂ laser-gas metal arc welding)

Authors:
HeeSeon Bang
HanSur Bang
Department of Naval Architecture and Ocean Engineering, Chosun University, Gwangju 501-759, Republic of Korea

YouChul Kim
Joining and Welding Research Institute, Osaka University, Osaka 567-0047, Japan

IkHyun Oh
Automotive Components Center, Korea Institute of Industrial Technology, Gwangju 500-480, Republic of Korea

BackSub Sung
Eco-friendly Components and Materials Education Center for Automobile, Gwangju 501-759, Republic of Korea

This paper intends to present the applicability of hybrid [CO₂ laser+gas metal arc (GMA)] welding process to dissimilar materials A...

JLA Vol:7 Iss:2 (Hazardous emissions: characterization of CO₂ laser material processing)

Authors:
H. Haferkamp
M. Goede
K. Engel
J.‐S. Wittbecker
Laser Zentrum Hannover e.V., Hollerithallee 8, D‐3000 Hannover 21, Germany

Parallel to the growth of laser technology is a high interest in safety in industrial surroundings. The characteristics of hazards resulting from laser processing are complex and highly interdependent. In addition, very little fundamental scientific research on this topic exists. The Laser Zentrum Hannover e.V. (LZH) is working on a research project subsidized by the BMFT (German Federal Ministry for Research and Technology) concerning the characterization and reduction of hazardous emissions resulting ...

JLA Vol:14 Iss:1 (A procedure for laser hazard classification under the Z136.1-2000 American National Standard for Safe Use of Lasers)

Authors:
Robert J. Thomas
Benjamin A. Rockwell
Air Force Research Laboratory, Brooks AFB, Texas 78235-5215

Wesley J. Marshall
USACHPPM, Aberdeen Proving Ground, Maryland 21010-5422

Robert C. Aldrich
Sheldon A. Zimmerman
Dahlgren Division, Naval Surface Warfare Center, Dahlgren, Virginia 22448-5100

R. James Rockwell
Rockwell Laser Industries, Cincinnati, Ohio 45243

Over the past few years, a comprehensive rewrite of the American National Standard for Safe Use of Lasers (ANSI Z136.1) has been conducted. The ANSI Z136.1 is a user standard, as opposed to a manufacturer standard like the Federal Las...

JLA Vol:18 Iss:2 (Marking of lines on clay brick pavers by vitrification with a Nd:YAG laser)

Authors:
J. W. Restrepo
J. M. Ferna´ndez-Pradas
M. A. Go´mez
P. Serra
J. L. Morenza
Universitat de Barcelona, Departament de Fi´sica Aplicada i Òptica, Marti´ i Franquès 1, E-08028 Barcelona, Spain

Laser marking of architectural materials is nowadays an attractive technique for industrial and decorative applications. We report the clay brick pavers marking by vitrification with a continuous-wave Nd:YAG laser (λ=1.064 μm), at different output powers and scan speeds of the laser beam. The marked lines resulted in a dark green glassy phase. The width, depth, and cross-section area of ...

JLA Vol:25 Iss:1 (Investigation on multi-track multi-layer epitaxial growth of columnar crystal in direct laser forming)

Authors:
XuanTuoi Do
State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, No. 28, Xianning West Road, Xi'an 710049, China and Le Quy Don University, No. 100, Hoang Quoc Viet Street, Hanoi 7EN-218, Vietnam

Dichen Li
Anfeng Zhang
Bin He
Haiyang Zhang
State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, No. 28, Xianning West Road, Xi'an 710049, China

Tatkhoa Doan
State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, No. 28, Xianning West Road, Xi'an 710049, China and Le Quy Don Technical Univers...

JLA Vol:9 Iss:5 (Threshold laser beam irradiances for melting and welding)

Authors:
K. H. Leong
H. K. Geyer
K. R. Sabo
P. G. Sanders
Technology Development Division, Argonne National Laboratory, Argonne, IL 60439, U.S.A.

A model based on the conservation of energy for a moving heat source incident on a flat plate is used to predict the threshold laser beam irradiance required to initiate melting on a metal surface. With the use of a non‐dimensional variable and its solution, the threshold irradiance can be predicted with the use of a simple equation. This equation is a function of the absorptivity of the surface, thermal conductivity of the metal, temperature increase for melting, diameter of the laser beam at th...

JLA Vol:3 Iss:3 (Determining Weld Quality in Pulsed Nd:YAG Laser Spot Welds)

Authors:
H. N. Bransch
Z. Y. Wang
J. T. Liu
D. C. Weckman
H. W. Kerr
Department of Mechanical Engineering, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1

For pulsed Nd:YAG laser spot welding applications, the development of optimum welding procedures ought to include various measures of weld size and quality, such as weld diameter, depth, surface contour and porosity. A split‐specimen technique has been developed that, despite the small size of the welds, allows such measurements to be made faster and more accurately than the traditional metallurgical technique involving sectioning, polishing and etching. In the sp...

JLA Vol:16 Iss:3 (Laser synthesizing NiAl intermetallic and TiC reinforced NiAl intermetallic matrix composite)

Authors:
Minlin Zhong
Laser Processing and Rapid Prototyping Research Center, Department of Mechanical Engineering, Tsinghua University, Beijing, 100084, China

Xiangyang Xu
Laboratory for Surface Modification, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100080, China

Wenjin Liu
Hongqing Sun
Laser Processing and Rapid Prototyping Research Center, Department of Mechanical Engineering, Tsinghua University, Beijing, 100084, China

The NiAl intermetallic layers and NiAl matrix composite layers with TiC particulate reinforcement were successfully synthesized by laser cladding with coaxial powder feeding of Ni/Al clad p...