JLA Vol:16 Iss:4 (Laser transmission welding of polymer and wood composites: Material and joint mechanism related studies)
A. von Busse
Laser Zentrum Hannover e.V., Hollerithallee 8, 30419 Hannover, Germany
Laser beam transmission welding is an innovative and promising technology for many industries such as the automotive, electronic, and medical industry. Extension to application of this technology to wood components makes it also interesting for the woodworking and furniture industry. Therefore, several investigations in the field of welding of fiber reinforced thermoplastic and wood composites with polymers have been carried out. Focus is given to the determination of the weldability and weld ...
JLA Vol:16 Iss:4 (Micromelting and its effects on surface topography and properties in laser polishing of stainless steel)
T. A. Mai
G. C. Lim
Machining Technology Group, Singapore Institute of Manufacturing Technology, Singapore 638075, Singapore
This article presents the results of an investigation into using laser for polishing 304 stainless steel (SS) surfaces. The effects on surface topography, reflectivity, hardness, and corrosion resistance of 304 stainless steel were analyzed. An in-house developed finite difference heat conduction model was used to simulate the rapid melting and solidification process. The nonlinear problem of the solid/liquid moving boundary was solved by a novel hybrid numerical method. Melting depth was in the order of submicrons and polishing rate in a r...
IDMEC, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
IDMEC, Av. Rovisco Pais, 1049-001 Lisboa, Portugal and Instituto Superior Te´cnico, Secc¸a˜o de Tecnologia Mecaˆnica, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
R. M. Miranda
IDMEC, Av. Rovisco Pais, 1049-001 Lisboa, Portugal and Universidade Aberta, R. Escola Polite´cnica 147, 1269-001 Lisboa, Portugal
Laser beam welding has been widely used in industry in the past decade. Recently, applications in dissimilar welds involving hard metals have been investigated. Hard metals are commonly used in tool manufacturing and this application...
JLA Vol:17 Iss:1 (An experimental and numerical study of the influence of diode laser beam shape on thin wall direct metal deposition)
Andrew J. Pinkerton
School of Mechanical, Aerospace, and Civil Engineering, The University of Manchester, Sackville Street, Manchester, M60 1QD U.K.
Use of the high powered diode laser (HPDL) for direct metal deposition enables multiple layer cladding to be performed with a nominally rectangular beam, traversed at different angles to the fast axis, or with a fiber-coupled, circular beam. These factors may provide an advantage over the traditional beam profiles of CO2 and Nd:YAG lasers, so there is a need to examine the effect that they have on the process and final product characteristics. This article reports such an examination. A 1.5 kW ...
JLA Vol:17 Iss:1 (Excimer laser ablation of glass-based arrayed microstructures for biomedical, mechanical, and optical applications)
Department of Mechanical Engineering, Chung Cheng Institute of Technology, Tashi, Taiwan 33508, Republic of China
Department of Mechanical Engineering, Chung Hua University, Hsinchu, Taiwan 30067, Republic of China
Jack G. Zhou
Department of Mechanical Engineering, Drexel University, Philadelphia, Pennsylvania 19104
Ampere A. Tseng
Department of Mechanical and Aerospace Engineering, Center for Solid State Electronics Research, Arizona State University, Tempe, Arizona 85287-6106
An excimer laser has been used for ablation of glass-based substrates for making arrayed microstructures. T...
JLA Vol:17 Iss:1 (Fracture control of unsupported ceramics during laser machining using a simultaneous prescore)
A. E. Segall
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:17 Iss:1 (In-process monitoring and adaptive control for stable production of sound welds in laser microspot lap welding of aluminum alloy)
Joining and Welding Research Institute (JWRI), Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
A new procedure of in-process monitoring and adaptive control has been developed for laser microspot lap welding of A3003 aluminum alloy sheets of 0.1 and 1 mm in thickness. The objective is to consistently produce sound laser partial-penetration lap-joint welds. It was revealed that the reflected laser beam and the radiated heat from the welding area were effective as in-process monitoring signals in detecting melting, keyhole generation, and through-hole formation in the upper sheet during laser irradiation. Laser pulse...
JLA Vol:17 Iss:1 (Microstructural characterization of dissimilar laser weld between austenitic and ferritic stainless steels)
A. K. Nath
Industrial CO2 Laser Section, Centre for Advanced Technology, P. O. CAT, Indore 452 013, India
The present work involved microstructural characterization of thin sheet dissimilar laser welds between type 304 austenitic stainless steel and stabilized 17% Cr ferritic stainless steel and their comparison with welds produced by autogenous gas tungsten arc welding (GTAW). Low heat input of laser welding (LW) effectively reduced the size of fusion zone (FZ) and heat affected zone (HAZ). LW with focused laser beam (LB), preferentially displaced towards austenitic stainless steel (ASS), produced FZ with uniform and highly ref...
Flemming O. Olsen
IPU, Institute for Product Development, Technical University of Denmark, Building 425, DK-2800-Lyngby, Denmark
In this article, an overview of the hybrid welding process is given. After a short historic overview, a review of the fundamental phenomenon taking place when a laser (CO2 or Nd:YAG) interacts in the same molten pool as a more conventional source of energy, e.g. tungsten in-active gas, plasma, or metal inactive gas/metal active gas. This is followed by reports of how the many process parameters governing the hybrid welding process can be set and how the choice of secondary energy source, shielding gas, etc. can a...
J. K. Chen
W. P. Latham
J. E. Beraun
Laser Effects Research Branch, Directed Energy Directorate, Air Force Research Laboratory, Kirtland AFB, New Mexico 87117
Most of the ultrafast laser heating analysis to date has been accomplished with a constant electron–phonon coupling factor (G). Due to the significant changes in the electron and lattice temperature caused by high-power laser heating, G could be temperature dependent. In this article a phenomenological temperature-dependent G is introduced to simulate ultrafast laser heating in metals. The electron temperature and the ablation depth computed with the temperature-dependent G compare well w...
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