JLA Vol:22 Iss:2 (Influence of Mie-scattering on high-speed micro-perforation considering brilliant laser radiation)
Authors:
M. Baumeister
T. Scholz
K. Dickmann
Laser Center University of Applied Sciences Muenster (LFM), Stegerwaldstrasse 39, Steinfurt 48565, Germany
F. Vollersten
Bremer Institut fuer Angewandte Strahltechnik (BIAS) GmbH, Klagenfurter Strasse 2, Bremen 28359, GermanyHigh-speed laser micro-perforation (“on-the-fly” technique) represents a processing technique for the time-efficient and cost-effective production of microsieves. In order to increase the perforation rate this process is researched with use of a brilliant laser source. These laser sources combine ample output power with an excellent beam quality. The high perf...
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JLA Vol:22 Iss:2 (Keyhole behavior in deep penetration CO<sub>2</sub> laser welding)
Authors:
Hiroshi Honda
Susumu Tsukamoto
Isao Kawaguchi
Goro Arakane
Structural Metals Center, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, JapanA slender keyhole formed by deep penetration laser welding fluctuates violently and is apt to form porosity. To reveal the keyhole depth behavior, the authors observed the keyhole images simultaneously by using a microfocus x-ray transmission imaging system and plasma plume images in deep penetration CO2 laser welding at various welding speeds. Plasma light emission was also measured by using photodiodes. The upper part of the keyhole was found to fluctuat...
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JLA Vol:22 Iss:2 (Nd:YAG laser welding of titanium alloys using a directed gas jet)
Authors:
Jonathan Blackburn
Laser Processing Research Centre, The University of Manchester, Manchester M60 1QD, United Kingdom
Chris Allen
Paul Hilton
TWI Ltd., Granta Park, Abington, Cambridge CB21 6AL, United Kingdom
Lin Li
Laser Processing Research Centre, The University of Manchester, Manchester M60 1QD, United KingdomThe increasing utilization of titanium alloys in the aerospace industry, a direct result of socioeconomic pressures, has created the need for a production process which can produce high quality near-net-shape titanium alloy components. Keyhole laser welding is a joining technology which could be utilized for t...
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JLA Vol:22 Iss:2 (Studies on characteristics of CO<sub>2</sub> laser-GTAW hybrid welding of austenitic stainless steel)
Authors:
Rakesh Kaul
Harish Kumar
B. T. Rao
L. M. Kukreja
Laser Material Processing Division, Raja Ramanna Centre for Advanced Technology, P.O. CAT, Indore 452 013, India
Nageshwar Singh
H. S. Vora
Laser System Engineering Division, Raja Ramanna Centre for Advanced Technology, P.O. CAT, Indore 452 013, IndiaThe present paper describes an experimental hybrid welding study, involving CO2 laser and gas tungsten arc welding, on 6 mm thick austenitic stainless steel sheet. The study focused on real-time plasma monitoring during welding and metallographic examination of the resultant weldments. Coupling of...
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JLA Vol:22 Iss:3 (Analysis of the hybrid pulsed MAG-YAG laser plasma with synchronization of multiple signals)
Authors:
Li Zhiyong
College of Material Science and Engineering, North University of China, Taiyuan 030051, China
Yang Lijun
Gao Ying
Li Huan
School of Material Science and Engineering, Tianjin University, Tianjin 300072, China
Wang Wei
Harbin Welding Institute, Harbin 150080, ChinaIn this paper, a synchronization system is developed for collecting multiple signals of arc plasma which is generated by the hybrid pulsed metal active gas (MAG)-YAG laser welding process. The synchronization system can collect spectra of the plasma, arc voltage, welding current, and high speed video simultaneously. Because the hybrid ar...
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JLA Vol:22 Iss:3 (Evaluation criterion and closed-loop control of penetration status during laser-MIG hybrid welding)
Authors:
Yongqiang Zhang
Shougang Research Institute of Technology, Beijing 100043, Peoples Republic of China
Peng Wen
Jiguo Shan
Yuanqing Shuang
Wuzhu Chen
Department of Mechanical Engineering, Tsinghua University Beijing 100084, Peoples Republic of ChinaLaser-MIG hybrid welding is an advanced joining process and is widely applied in various industries. It is important to make sure the plate is fully penetrated with an appropriate weld formation in practical applications. In this paper, 3 kW CO2 laser and pulse MIG machine were used to compose the laser-MIG hybrid welding equipment to make butt weld of stainless...
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JLA Vol:22 Iss:3 (Evaluation of the shear bond strength of a composite resin in sound, demineralized and hypermineralized bovine dentin after irradiation with Er:YAG and Nd:YAG lasers, employing a self-etching adhesive system)
Authors:
Andressa Pereira da Silva Kuwana
Leily Macedo Firoozmand
Maria Ame´lia Maximo de Arau´jo
Department of Restorative Dentistry, Sa˜o Jose´ dos Campos School of Dentistry–UNESP, Sa˜o Jose´ dos Campos, SP, BrazilBackground and Objectives. The adhesion of dental materials is important for the success of treatment. The aim of this study is to evaluate the bond strength of a composite resin applied with a self-etching adhesive system in different dentins after irradiation with Er:YAG and Nd:YAG lasers, observing their morphologic pattern using Scanning Electronic Microscopy (SEM). Materials and Methods...
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JLA Vol:22 Iss:3 (Laser lap welding of zinc coated steel sheet with laser-dimple technology)
Authors:
Hongping Gu
Stronach Centre for Innovation, Magna International Aurora, Canada L4G 7L6Laser beam welding technology has been widely used to weld automobile components, especially for tailored blank welding. In order to provide best corrosion resistance to the welded sheet metal parts, zinc coated steel sheets are normally used. The zinc coating poses no issues to the butt joining of the sheet metals. However, when laser welding technology is applied to lap joint of these sheets, the welding process is not straightforward. Special techniques must be employed to allow the venting of the zinc vapor that is generated at the interface between the paired sheets. Many efforts have ...
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JLA Vol:22 Iss:3 (Weld strength improvement for Al alloy by using laser weaving method)
Authors:
Kwang-Deok Choi
Young-Nam Ahn
Cheolhee Kim
Advanced Welding & Joining Technology Research Team, Korea Institute of Industrial Technology, 7-47 Songdo-Dong, Yeonsu-Gu, Incheon 406-840, KoreaLaser welding of aluminum alloys usually produces linear welds that have shear-tensile strength lower than that of the base metal. This is usually due to porosity resulting from an unstable keyhole and cracking which is related to the high crack sensitivity of many of these alloys. In this work laser weaving is used to improve the joint strength of laser welds. In this research, lap welds and bead-on-plate welds were produced on 1 mm thick aluminum alloy sheet...
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JLA Vol:22 Iss:4 (A fast method for morphological analysis of laser drilling holes)
Authors:
M. Schneider
L. Berthe
M. Muller
R. Fabbro
Laboratoire PIMM (CNRS) ARTS et METIERS ParisTech, 151 Boulevard de l’Hopital, 75013 Paris, FranceThis paper presents an original method for analyzing laser drilled holes. The so-called Direct Observation of Drilled hOle (DODO) method is introduced and its applications. The hole characterization that’s been made is compared with x-ray radiography and cross-section analysis. Direct Observation of Drilled hole provides instantaneously surface state, geometric shape, as well as recast layer structure, without additional operation. Since no mounting resin is used to embed the sample, th...
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