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: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:24 Iss:1 (Surgical treatment of squamous cell carcinoma of tongue with carbon dioxide laser radiation (CO₂))

Authors:
Walter Niccoli-Filho
Lu´cio Murilo-Santos
Aline R. C. Morosolli
Gerusa de Oliveira Moura Cardoso
Joa˜o Vitor dos Santos Canellas
Array

In this clinical study, we proposed to observe the efficacy of the treatment of squamous cell carcinoma of the tongue (SCCT) by carbon dioxide (CO₂) laser surgery. Twelve patients with SCCT were treated with excisional surgery using the CO₂ laser with a spot size of 0.8 mm, 10 W, power density of 2.5 W/cm² in continuous mode, and under constant vacuum removal of the plume. The post surgical clinical evaluations were done every day until the sutures...

JLA Vol:6 Iss:2 (Laser safety notes)

Authors:
Robert Weiner
Weiner Associates, Manhattan Beach, California, U.S.A.

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:8 Iss:4 (The role of oxygen pressure in laser cutting mild steels)

Authors:
A. Ivarson
J. Powell
C. Magnusson

This paper presents the results of an experimental program investigating the effects of using high pressure oxygen as assist gas in combination with a pulsed laser while cutting medium thick mild steel plates. It was discovered that if the pulse conditions are optimized, the maximum cutting speed for a set average laser power could be increased by up to 10% compared to low oxygen pressure continuous wave (CW) laser cutting. The assist gas was found to have two optimum pressure ranges between which the material suffered from burning on the cut edge. The paper presents a phenomenological model to explain the ch...

JLA Vol:2 Iss:2 (A Comparison of Methods for Accurate Image Centroid Position Determination with Matrix Sensors)

Authors:
Paul G. Backes
Warren H. Stevenson
School of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47907

Optical methods for the measurement of position, part dimensions, or alignment are finding increased application in manufacturing operations. Several of these methods utilize analog or digital position sensitive detectors to find the centroid of an illuminated spot on the detector. The objective of this study was to determine the accuracy with which the centroids of a direct laser beam and a circular incoherent image could be determined using a matrix array sensor. Centroids were found using five different analytical methods. The results showed t...

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...

JLA Vol:21 Iss:1 (Microstructural analysis and oxidation protection behavior of Cr–Ni surface coatings of 347 stainless steel by rapid mirror scanning of a high power CO₂ laser)

Authors:
Jorge A. Ramos-Grez
Departamento de Ingenieri´a Meca´nica y Metalu´rgica, Pontificia Universidad Cato´lica de Chile, Vicun˜a Mackenna 4860, Santiago, Chile

David L. Bourell
University of Texas at Austin, Mechanical Engineering Department, Austin, Texas 78712

Madhav Rao Govindaraju
Karta Technologies, Inc., San Antonio, Texas 78249

A surface coating technique that uses a 1 kW CO₂ laser beam actuated by two high-speed raster-scanning mirrors was utilized to selectively consolidate predeposited powder coatings consisting of 50%Cr-50% Ni (wt %) over the surface of 347 austenitic stainless st...