M. H. Cho
D. F. Farson
Welding Engineering Department, The Ohio State University, Columbus, Ohio 43221
J. I. Kim
The Faculty of Marine Engineering, Mokpo National Maritime University, Mokpo, Chonnam 530-729, Korea
Vapor capillaries associated with deep penetration laser welding (keyholes) are inherently unstable and it is well known that the bounded evolution of unstable modes of nonlinear dynamic systems can lead to complex fluctuations of state and/or output variables. In the case of keyholes, the magnitude of self-induced fluctuations is sometimes large enough to cause occasional closure (“collapse”) and trapping of voids in t...
Gillian C. Walker
Anthony J. Fitzgerald
Academic Unit of Medical Physics and Centre of Medical Imaging Research, University of Leeds, Wellcome Wing, Leeds General Infirmary, Leeds LS1 3EX, United Kingdom
N. N. Zinov’ev
Institute of Microwaves and Photonics, University of Leeds, Leeds LS2 9JT, United Kingdom
Stephen W. Smye
Department of Medical Physics and Engineering, Leeds Teaching Hospitals NHS Trust, St. James’s University Hospital, Leeds LS9 7TF, United Kingdom
Robert E. Miles
Institute of Microwaves and Photonics, University of Leeds, Lee...
JLA Vol:15 Iss:3 (Experimental and numerical analyses of the mechanism for decreasing hydrogen-embrittlement sensitivity of aged Inconel 718 by laser surface annealing)
School of Materials Science and Engineering, Shanghai Jiao Tong University, Huashan Road 1954, Shanghai 200030, China
Kojiro F. Kobayashi
Department of Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
Laser surface annealing (LSA) treatments were conducted to decrease the hydrogen embrittlement (HE) sensitivity of Inconel 718. Hydrogen was charged into the alloy by a cathodic-charging process. The LSA treatment significantly reduced the strength loss of the hydrogen-precharged notched specimen. Tensile tests and elasto–...
Department of Physics, Structure Research Laboratory, University of Science and Technology of China, Hefei, Anhui, 230026, People’s Republic of China
GE Corporate Research and Development Shanghai Center, 421 Hongcao Road, Shanghai 200233, People’s Republic of China
Holes were percussion drilled in Inconel 718 plates by a high intensity pulsed ultraviolet laser (266 and 355 nm) with 8 ns pulse width. It showed that shortening the laser wavelength resulted in thinner recas...
JLA Vol:15 Iss:3 (Preparation of polyperinaphthalenic organic semiconductive nanoparticles by excimer laser ablation and their application to optic and electronic devices)
Department of Chemistry, Graduate School of Science, Tohoku University, Aramaki, Sendai, Miyagi 980-8578, Japan
Department of Chemistry for Materials, Faculty of Engineering, Mi’e University, 1515 Kamihama-cho, Tsu, Mi’e 514-8507, Japan
Kanebo LTD., 3-1, Kanebo-cho, Hofu, Yamaguchi 747-0823, Japan
Polyperinaphthalene (PPN) nanoparticles are prepared by excimer laser ablation (ELA) of a 3, 4, 9, 10-perylenetetracarbox...
JLA Vol:15 Iss:3 (Process characteristics and effects of gas- and water-atomized stainless steel powders in laser-based rapid tooling)
Andrew J. Pinkerton
Department of Mechanical, Aerospace, and Manufacturing Engineering, Laser Processing Research Centre, UMIST, P.O. Box 88, Sackville Street, Manchester M60 1QD, United Kingdom
In rapid tooling using the direct laser deposition process and stainless steel materials, only powders prepared using the gas-atomization method have been used because of their presumed superior flow characteristics. In this article, the use of water-atomized powder is investigated by comparing the behavior of the two types of 316 L powders, deposited using a CO2 laser and coaxial head. Results show little difference in the pneumatic conveyance of the po...
CLFA, 16 bis Avenue Prieur de la Côte d’Or, 94114 Arcueil Cedex, France
OPTIS, ZE la Farlède, BP 275, 83078 Toulon Cedex 9, France
We present a global self-consistent model of the laser cutting process where we have taken into account the main parameters of the process that are the laser beam intensity distribution, the thermal phenomena controlling the melt parameters, the fluid, both cutting gas and melt hydrodynamics, and the local equilibrium of the geometry of the cutting front. This steady state approach provides us with different fluid velocities, surface ...
JLA Vol:15 Iss:3 (Three-dimensional finite element modeling of laser cladding by powder injection: Effects of powder feedrate and travel speed on the process)
University of Waterloo, Department of Mechanical Engineering, Waterloo, Ontario N2L 3G1, Canada
This article addresses a novel three-dimensional transient finite element model of the laser cladding by powder injection process. The proposed model can predict clad geometry as a function of time and process parameters including beam velocity, laser power, powder jet geometry, laser pulse shaping, and material properties. In the proposed method, the interaction between powder and melt pool are assumed to be decoupled and as a result, the melt pool boundary is first obtained in the absence of powder spray....
V. V. Prabhu
N. I. Shaikh
J. T. Schriempf
J. H. McDermott
The Pennsylvania State University, University Park, Pennsylvania 16802
Lasers are being successfully applied to a variety of manufacturing processes, including cutting, welding, cladding, and free forming. Part of their success is due to the high quality beam that is directly related to the condition of components involved in the lasing process. However, maintaining the requisite beam quality requires frequent and time-consuming intervention by maintenance operators, specifically, for dismounting, inspection, servicing, and reassembly. Preventive maintenanc...
JLA Vol:15 Iss:4 (Design and performance of multilevel phase fan-out diffractive optical elements for laser materials processing)
Itami R&D Laboratories, Sumitomo Electric Industries, Ltd., 1-1-3 Shimaya, Konohana-ku, Osaka 554-0024, Japan
A multilevel phase fan-out diffractive optical element (DOE) has been developed and introduced into various kinds of laser materials processing such as drilling, cutting, welding, and soldering. The larger the number of arrayed spots the DOE generates on the surface of the workpiece, the more sensitive the intensity uniformity of the spots becomes to fabrication errors, which are deviations between designed and fabric...