JLA Vol:17 Iss:4 (Temperature distributions due to annular laser beam heating)

Authors:
D. Zeng
Laser-Aided Manufacturing, Materials and Micro-Processing (LAMMMP) Laboratory, College of Optics and Photonics, Center for Research and Education in Optics and Lasers (CREOL), Mechanical, Materials and Aerospace Engineering Department, University of Central Florida, Orlando, Florida 32816-2700

W. P. Latham
Air Force Research Laboratory, Directed Energy Directorate, 3550 Aberdeen, Avenue SE, Kirtland Air Force Base, New Mexico 87117-5776

A. Kar
Laser-Aided Manufacturing, Materials and Micro-Processing (LAMMMP) Laboratory, College of Optics and Photonics, Center for Research and Education in Optics and Lasers (CREOL), Mechanical, Materials and ...

JLA Vol:18 Iss:1 (An experimental and theoretical investigation of combined gas- and water-atomized powder deposition with a diode laser)

Authors:
Andrew J. Pinkerton
Waheed Ul Haq Syed
Lin Li
Laser Processing Research Centre, School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, Sackville Street Building, PO Box 88, Manchester M60 1QD, United Kingdom

Functionally graded or composite components (FGCs) have been recognized as having immense potential for many industries. So far, deposition of compositionally graded alloys is the only method that has been shown to be a practical way to produce FGCs. In this work, a second way, that allows graded structures of a single material to be formed by direct metal deposition, is investigated. Simple component samples are bui...

JLA Vol:18 Iss:1 (Cladding of Stellite-6 and vanadium carbide on carbon steel using a yttrium–aluminum–garnet laser robot system)

Authors:
Guojian Xu
Graduate School of Engineering, Nagoya University, 1 Furo-cho Chikusa-ku, Nagoya 464-8603, Japan

Muneharu Kutsuna
Manoj Rathod
School of Engineering, Nagoya University, 1 Furo-cho Chikusa-ku, Nagoya 464-8603, Japan

In the present work, a laser robot system was setup for cladding and repairing machinery parts using pulsed 300 W Nd:yttrium–aluminum–garnet laser facility, six-axis robot, optical fiber, powder feeding system with a special nozzle for powder supply. A mild steel plate was deposited with powder mixtures of Stellite-6 alloy and vanadium carbide (VC). The shape of clad layer, microstructure, and its wear perfo...

JLA Vol:18 Iss:1 (Effect of oxygen in ambient atmosphere on penetration characteristics in single yttrium–aluminum–garnet laser and hybrid welding)

Authors:
Yasuaki Naito
Masami Mizutani
Seiji Katayama
Joining and Welding Research Institute (JWRI), Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan

Welding with a yttrium–aluminum–garnet (YAG) laser only or with hybrid source combined with a YAG laser and a TIG arc was carried out on Type 304 stainless steel plate with low S content in the air or in the chamber with Ar gas including 0%–15% oxygen gas. It was confirmed in both laser and hybrid welding that the penetration and geometry of welds depended upon the volume of the oxygen in the ambient atmosphere, and that a pronounced “nail head” disappeared in a weld...

JLA Vol:18 Iss:1 (Finite element modeling of laser forming of aluminum matrix composites)

Authors:
F. R. Liu
K. C. Chan
C. Y. Tang
Department of Industrial and Systems Engineering, Advanced Manufacturing Technology Research Centre, The Hong Kong Polytechnic University, Hung Hom, Hong Kong

Much work has been done on modeling of laser forming over the past decades, but most of the models were developed for monolithic materials. In this article, a microstructure integrated finite element model is developed for the first time to predict the deformation behavior of composite materials in laser forming. A unit cell model is used to analyze the thermo-physical properties of an aluminum matrix composite. Spherical particles are assumed, and the particles ...

JLA Vol:18 Iss:1 (Magnetic stirring during laser welding of aluminum)

Authors:
Frank Vollertsen
Claus Thomy
BIAS Bremer Institut fu¨r angewandte Strahltechnik GmbH, D-28359 Bremen, Federal Republic of Germany

The use of magnetic fields to influence melt flow is a well-established method, e.g., in foundry technology. For arc welding processes (especially tungsten inert gas welding), a process called magnetic stirring was first proposed, patented, and investigated in the 1970s. The central aim was to improve (by the help of an alternating magnetic field coaxial with the arc axis) weld quality especially in aluminum by the combined effects of arc current and magnetic field. It was established that such fields are indeed capable of influenc...

JLA Vol:18 Iss:1 (Modeling of the melted bath movement induced by the vapor flow in deep penetration laser welding)

Authors:
E. H. Amara
CDTA-Laser Material Processing Group, P.O. Box 17, 16303 Baba-Hassen, Algiers, Algeria

R. Fabbro
LALP (CNRS)-GIP GERAILP, 16 bis Avenue Prieur de la Coˆte d'Or, F-94114 Arcueil Cedex, France

F. Hamadi
CDTA-Laser Material Processing Group, P.O. Box 17, 16303 Baba-Hassen, Algiers, Algeria

In this article we are interested in a moving mechanism occurring in the melted bath that is produced during the deep penetration laser welding process. It concerns the displacement of the melted metal induced by the friction effect due to the interaction with the metallic vapor when it flows toward the keyhole exit. Boundary conditi...

JLA Vol:18 Iss:1 (Optical viewport assembly for eye-safe monitoring of thin film deposition)

Authors:
Kevin Robbie
Cristina Buzea
Olivier Landry
Cory Dean
Department of Physics, Queen’s University, Kingston, Ontario K7L 3N6, Canada

This article discusses the design and application of a simple eye-safe monitoring assembly of thin film deposition and its advantages over the existent eye protection filters. This assembly prevents users from being exposed to the radiation field caused by lasers or incandescent objects during thin film deposition. Its design is simple, the device being reliable and easy to operate.

JLA Vol:18 Iss:1 (Pulsed laser welding of metal-polymer sandwich materials using pulse shaping)

Authors:
H. L. Gower
R. R. G. M. Pieters
I. M. Richardson
Netherlands Institute for Metals Research, Rotterdamseweg 137 2628 AL Delft, The Netherlands

Increasing interest has been expressed in the application of hybrid metal/polymer materials for automotive applications, both to reduce weight and to improve performance. To date, the only joining methods available are mechanical fastening and adhesive bonding, both requiring an overlapping joint configuration to generate sufficient bond strength. This article describes how laser spot-welding and SHADOW™ (stepless high speed accurate and discrete one pulse welding) welding can be used to minimize degradat...

JLA Vol:18 Iss:1 (Simultaneous wire- and powder-feed direct metal deposition: An investigation of the process characteristics and comparison with single-feed methods)

Authors:
Waheed Ul Haq Syed
Andrew J. Pinkerton
Lin Li
Laser Processing Research Centre, School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, Sackville Street Building, Manchester M60 1QD, United Kingdom

Many direct laser deposition processes utilize metallic powders to obtain near net shape objects. Wire feeding has also been used in many laser-cladding and other material-addition applications. Each feeding method has its own advantages and disadvantages: wire feeding laser deposition typically has higher deposition rate and higher material usage rate than the powder feeding deposition process, while powder feeding gives bette...