JLA Vol:19 Iss:3 (Single-Pass and Multi-Pass Laser Cutting of Si–SiC: Assessment of the Cut Quality and Microstructure in the Heat Affected Zone)

Authors:
F. Quintero
J. Pou
F. Lusquin˜os
A. Riveiro
M. Pe´rez-Amor
Departamento Fi´sica Aplicada, E.T.S. Ingenieros Industriales, University de Vigo, 36310 Vigo, Spain

A. J. S. Fernandes
Department of Physics, University of Aveiro, 3810-193 Aveiro, Portugal

Experimental investigations on the laser cutting of thick silicon infiltrated silicon carbide (Si–SiC) elements are presented. Si–SiC is a fully dense ceramic composite with high hardness and chemical and thermal stability, which makes it a valuable material in severe conditions. However, machining is still a challenging task. A...

JLA Vol:24 Iss:3 (2D longitudinal modeling of heat transfer and fluid flow during multilayered direct laser metal deposition process)

Authors:
Simon Morville
Muriel Carin
LIMATB, Universite´ de Bretagne-Sud/UEB, Centre de recherche Ch. Huygens, Rue de Saint Maude´, BP 92116, 56321 Lorient cedex, France

Patrice Peyre
Myriam Gharbi
PIMM, UMR 8006 CNRS-Arts et Me´tiers Paris Tech, 151 Boulevard de l’Hoˆpital, 75013 Paris, France

Denis Carron
Philippe Le Masson
LIMATB, Universite´ de Bretagne-Sud/UEB, Centre de recherche Ch. Huygens, Rue de Saint Maude´, BP 92116, 56321 Lorient cedex, France

Re´my Fabbro
PIMM, UMR 8006 CNRS-Arts et Me´tiers Paris Tech, 151 Boulevard de l’Ho&ci...

JLA Vol:6 Iss:4 (Holographic optical elements (HOEs): A serious application of holography)

Authors:
Gareth T. Williams
Jeff Fredrick
Physics Department, San Jose State University, San Jose, CA, U.S.A.

Without disputing the excitement and sense of accomplishment associated with the production of display holograms, this paper suggests equal rewards from the production of holographic optical elements (HOEs). The elements described here are zone plates, diffraction gratings, interference filters and mirrors, and lenses. Ways of making each of these in an optics teaching laboratory are described, but the main emphasis will be on positive lens HOE.

JLA Vol:25 Iss:4 (Analysis of Yb:YAG thin disk laser resonator considering thermal lens effects: Experimentally and by Laser Cavity Analysis and Design)

JLA Vol:18 Iss:1 (Three-dimensional analytical model on laser-powder interaction during laser cladding)

Authors:
Yan-Lu Huang
Jian Liu
Nai-Heng Ma
Jian-Guo Li
School of Materials Science and Engineering, Shanghai Jiaotong University, Shanghai, China 200030

To compute the attenuation of laser power by powder stream and the temperature distribution of the powder particles arriving at different sites on the surface of the workpiece, a three-dimensional analytical model was presented based on Lambert-Beer theorem, Mie’s theory, and heat equilibrium principle. The obtained results revealed that for a given stream spread and speed of powder particles, the laser intensity distribution of laser spot and the temperature distribution of the powder part...

JLA Vol:7 Iss:1 (Development of laser finishing for non‐circular profiles)

Authors:
Ko‐Wang Liu
Paul S. Sheng
Department of Mechanical Engineering, University of California, Berkeley, CA 94720‐1740, U.S.A.

A laser‐based technique for finishing of non‐circular cylindrical parts is presented. In this process, the frequency characteristics of a desired non‐circular shape is extracted from a CAD through a Fast Fourier Transform algorithm and implemented through a CO₂ laser machining system. A galvanometer‐based scanner is used in the process to achieve programmable beam trajectories and high‐speed finishing. An error estimation scheme can be developed to determine the final dimensional erro...

JLA Vol:16 Iss:1 (Influence of surface preparation and process parameters on the porosity generation in aluminum alloys)

Authors:
A. Haboudou
P. Peyre
CLFA, avenue Prieur de la Côte d’or, 94114 Arcueil, France

A. B. Vannes
Ecole Centrale de Lyon, Ecully, France

The 4 kW cw Nd:yttrium–aluminum–garnet laser welding of solid solution hardened A5083 (5% Mg) and precipitation-hardened A356 (7% Si) alloys, sensitive to porosity formation was carried out at different welding speeds, under He gas shielding, and for partial penetration conditions, on bead on plate configuration. The porosity formation was examined through observation and evaluation of weld beads, based on x-ray radiography inspection coupled with image analysis, and quantification of gas...

JLA Vol:20 Iss:2 (Design and validation of a hybrid laser/water-jet machining system for brittle materials)

Authors:
Dinesh Kalyanasundaram
Gamal Shehata
Clayton Neumann
Pranav Shrotriya
Pal Molian
Department of Mechanical Engineering, Laboratory for Lasers, MEMS and Nanotechnology, Iowa State University, Ames, Iowa 50011-2161

A unique laser/water-jet (LWJ) cutting head has been designed, built, and interfaced with a CO₂ laser for cutting and scribing of hard and brittle ceramic materials. Alumina samples were used to validate the effectiveness of the LWJ cutting head in thermal fracture mode. The results were compared with vaporization mode (focused beam) as well as thermal fracture mode (defocused beam) of air-assisted laser c...

JLA Vol:9 Iss:1 (Laser cladding of Al‐Sn alloy on a mild steel)

Authors:
Z. Liu
J. L. Sun
W. M. Steen
K. G. Watkins
C. Lee
W. P. Brown

Direct laser cladding of Al alloy on mild steel produces continuous brittle intermetallic Fe_xAl_y layers at the interface resulting in weak bonding of the clad and the substrate. To overcome this problem, both Ni and Al were investigated as intermediate coatings. Although a Ni coating with a thickness of 70 μm was successful in eliminating the formation of continuous Al‐Fe intermetallics, the bonding at the Al alloy/Ni interface was not strong enough to survive a bending test. A pure Al coating was found to be a better ...

JLA Vol:4 Iss:3 (Where We Are Today: International Update)

Authors:
Jerry Glen
Union, Kentucky