JLA Vol:21 Iss:4 (Seam-tracking for high precision laser welding applications—Methods, restrictions and enhanced concepts)

Authors:
Boris Regaard
Stefan Kaierle
Reinhart Poprawe

Laser beam welding bears evident advantages regarding precision, quality, productivity, low heat input, and feasibility of automation. At the same time the process calls for high precision of the beam positioning on the workpiece, which therefore imposes high requirements of welding trajectory and feed rate accuracy; e.g., for butt welding the focal point of the laser beam with respect to the joint must be maintained within a typical accuracy better than 20–150 μm, depending on the focused beam radius. To meet these requirements, seam-tracking devices are used. A sensor measures the joint p...

JLA Vol:21 Iss:4 (Use of dispersive Raman spectroscopy to detect the cytotoxic action of <em>viscum album</em> in adenocarcinoma of colon)

Authors:
Daniela Franco Lopes
Institute of Research and Development (IP&D), Universidade do Vale do Parai´ba (UNIVAP), Av. Shishima Hifumi, 2911 Urbanova, 12244-000 Sa˜o Jose´ dos Campos, SP, Brazil

Landulfo Silveira
Group of Biomedical Engineering, Universidade Camilo Castelo Branco (UNICASTELO), Rod. Pres. Dutra, Km 138, Eugeˆnio de Melo, 12247-004 Sa˜o Jose´ dos Campos, SP, Brazil

Marcelo Nobuo Sibata
Aloi´sio Cunha de Carvalho
Cristina Pacheco-Soares
Jamil Saade
Institute of Research and Development (IP&D), Universidade do Vale do Parai´ba (UNIVAP), Av. Shishima ...

JLA Vol:22 Iss:1 (Control of penetration depth fluctuations in single-mode fiber laser welds)

Authors:
Matt J Reiter
Dave F Farson
Welding Engineering Program, Laboratory for Multiscale Processing and Characterization, The Ohio State University, 1248 Arthur E Adams Drive, Columbus, Ohio 43221

M Mehl
Honeywell FM&T, 2000 E 95th St., Kansas City, Missouri 64131

Circular focus spot oscillation was investigated as a means of suppressing penetration spiking and related defects in partial penetration single-mode fiber laser welds. Initially, partial penetration welds in stainless steel square-butt joints with linear travel were made to quantify weld and weld spiking characteristics. Then, welds were made with linear travel and superimposed circ...

JLA Vol:22 Iss:1 (Finite volume model for laser-soot interaction for a laser transmission welding process)

Authors:
L. S. Mayboudi
A. M. Birk
G. Zak
Mechanical and Materials Engineering, Queen’s University, Kingston, Ontario K7L 3N6, Canada

P. J. Bates
Chemistry and Chemical Engineering, Royal Military College, Kingston, Ontario K7K 7B4, Canada

Laser transmission welding, a technique to join thermoplastic components, involves a laser beam passing through a laser-transmitting part being absorbed by a laser-absorbing part at the weld interface. The heat generated at the interface melts a thin layer of the plastic in both parts and forms a joint. Laser-absorbing agents such as dyes or soot particles are added to the laser-absorbing part to...

JLA Vol:22 Iss:1 (Laser roll welding of dissimilar metal joint of zinc coated steel to aluminum alloy)

Authors:
Hitoshi Ozaki
Muneharu Kutsuna
Graduate School of Engineering, Nagoya University, 1, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan

Shigeyuki Nakagawa
Kenji Miyamoto
Research Center, Nissan Motor Co., Ltd., 1, Natsushima-cho, Yokosuka-shi, Kanagawa 237-8523, Japan

There is a subject to reduce the weight of car body by replacing steel to aluminum alloys as some structural body parts for improving fuel consumption and suppressing CO₂ generation. As one of the solutions, the hybrid body structure concept using aluminum alloys and high strength steels is proposed recently. However, it is well known that fusion welding of st...

JLA Vol:22 Iss:1 (Photodynamic therapy of cariogenic agents: A systematic review)

Authors:
Patri´cia Valente Araujo
Maria Esperanza Cortes
Luiz Thadeu de Abreu Poletto
Restorative Dentistry Department (ODR-FO-UFMG), Federal University of Minas Gerais, Av. Antonio Carlos, 6627 Pampulha, Belo Horizonte, CEP 31270-901 Minas Gerais, Brazil

The purpose of this systematic review was to evaluate the current status of the photodynamic therapy (PDT) against cariogenic micro-organisms. Publications with abstracts, published in English and available online in PubMed, were included. To identify relevant publications, all abstracts obtained from the search in PubMed were read independently by the authors. In total, 19 studies were reviewed. It wa...

JLA Vol:22 Iss:1 (Surface effects of alumina ceramics machined with femtosecond lasers)

Authors:
J. Meeker
A. E. Segall
V. V. Semak
Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania 16802

Laser machining is now an accepted method for shaping and modifying ceramics and is rapidly replacing other methods such as grinding and etching. In fact, new innovations such as short pulsed or femtosecond lasers have drastically decreased the amount of unwanted damage associated with laser machining. However, laser machining does still alter the surface and can change the flaw populations and the strength. In order to investigate this effect, the flaw populations and strengths of both unaltered and femtosecond...

JLA Vol:22 Iss:1 (Thermal stress analysis on laser cross scribe of glass)

Authors:
Koji Yamamoto
Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, Japan

Noburu Hasaka
Hideki Morita
Mitsuboshi Diamond Industrial Co., Ltd., 1-4-37 Minami-kaneden, Suita, Osaka, Japan

Etsuji Ohmura
Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, Japan

In CO₂ laser scribe processing of glass, an initial crack on the start edge of the glass is indispensable. When carrying out laser cross scribe, there is no initial crack on the edge of the first scribed line. However, the second scribing progresses across the first scribed line. In this research, in orde...

JLA Vol:22 Iss:2 (Characterization of the melt removal rate in laser cutting of thick-section stainless steel)

Authors:
Catherine Wandera
Department of Mechanical Engineering, Lappeenranta University of Technology, Tuotantokatu 2, Lappeenranta FIN-53850, Finland

Veli Kujanpaa
Department of Mechanical Engineering, Lappeenranta University of Technology, Tuotantokatu 2, Lappeenranta FIN-53850, Finland and VTT Technical Research Centre of Finland, Tuotantokatu 2, Lappeenranta FIN-53850, Finland

The efficiency of the laser cutting process depends on both the rate of melting and rate of melt removal from the cut kerf. The depth of flow separation and the dross attachment on the lower cut edge relate to the efficiency of the melt removal process and can be used to characterize t...

JLA Vol:22 Iss:2 (CO₂ laser beam welding of AM60 magnesium-based alloy)

Authors:
Asma Belhadj
Me´caSurf Laboratory, Arts et me´tiers ParisTech, 13617 Aix en Provence, France and Me´canique Applique´e, Inge´nierie et Industrialisation (MA2I), E´cole Nationale d'Inge´nieurs de Tunis, 1002 Tunis, Tunisia

Jean-Eric Masse
Laurent Barrallier
Me´caSurf Laboratory, Arts et me´tiers ParisTech, 13617 Aix en Provence, France

Mahmoud Bouhafs
Jamel Bessrour
Me´canique Applique´e, Inge´nierie et Industrialisation (MA2I), E´cole Nationale d'Inge´nieurs de Tunis, 1002 Tunis, Tunisia

Magnesium alloys have a 33% lower den...