JLA Vol:25 Iss:5 (Stoichiometric 6H-SiC thin films deposited at low substrate temperature by laser ablation)

Authors:
J. G. Quin˜ones-Galva´n
Physics Department, CINVESTAV-IPN, Apdo. Postal 14-740 Me´xico, D.F. 07360, Mexico

J. S. Arias-Cero´n
CICATA-IPN, Unidad Legaria, Me´xico D.F. 11500, Mexico

F. de Moure-Flores
Facultad de Qui´mica, Materiales, Universidad Auto´noma de Quere´taro, Quere´taro 76010, Mexico

A. Herna´ndez-Herna´ndez
A. Guille´n-Cervantes
J. Santoyo-Salazar
J. G. Mendoza-Alvarez
M. Mele´ndez-Lira
Physics Department, CINVESTAV-IPN, Apdo. Postal 14-740 Me´xico, D. F. 07360, Mexico


...

JLA Vol:25 Iss:5 (Heat transfer and fluid flow in additive manufacturing)

Authors:
A. Raghavan
H. L. Wei
T. A. Palmer
T. DebRoy
Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802

In laser-based direct energy deposition additive manufacturing, process control can be achieved through a closed loop control system in which thermal sensing of the melt pool surface is used to adjust laser processing parameters to maintain a constant surface geometry. Although this process control technique takes advantage of important in-process information, the conclusions drawn about the final solidification structure and mechanical properties of the deposited material are li...

JLA Vol:25 Iss:5 (Numerical and experimental study of the effect of groove on plasma plume during high power laser welding)

Authors:
Cai Yan
Xie Wen-Jing
Wu Yue
Sun Da-Wei
Wu Yixiong
Shanghai Jiao Tong University, Dongchuan Road 800, Shanghai 200240, China and Shanghai Key Laboratory of Materials Laser Processing and Modification, Shanghai 200240, China

The influence of groove on the static feature and dynamic behavior of plasma plume during high power CO₂ laser welding process was studied using a hydrodynamic three-dimensional model and corresponding experiments. The temperature, composition, and velocity of plasma plume along the incident path of laser beam were computed. The static morphology of plasma plume was analyzed through both models ...

JLA Vol:25 Iss:5 (Laser remote-fusion cutting with solid-state lasers)

Authors:
A. Wagner
M. Lu¨tke
A. Wetzig
Fraunhofer Institute for Material and Beam Technology IWS, Winterbergstraße 28, 01277 Dresden, Germany

L. M. Eng
Institute of Applied Photophysics, TU Dresden, George-Ba¨hr-Straße 1, 01062 Dresden, Germany

A laser remote cutting process is analyzed, which differs significantly from established laser cutting processes. On the one hand, no cutting gas is needed and a high working distance is realized. On the other hand—in opposite to conventional laser remote cutting—sheets of metal with thicknesses above 1 mm can be cut in one step. Examinations were carried out at the...

JLA Vol:25 Iss:5 (Use of track/layer morphology to develop functional parts by selective laser melting)

Authors:
I. Yadroitsev
Ph. Bertrand
Universite´ de Lyon, Ecole Nationale d'Inge´nieurs de Saint-Etienne (ENISE), DIPI Laboratory, 58 rue Jean Parot, 42023 Saint-Etienne Cedex 2, France

G. Antonenkova
S. Grigoriev
Moscow State University of Technology “STANKIN”; Vadkovsky per., 1, 127994 Moscow, Russia

I. Smurov
Universite´ de Lyon, Ecole Nationale d'Inge´nieurs de Saint-Etienne (ENISE), DIPI Laboratory, 58 rue Jean Parot, 42023 Saint-Etienne Cedex 2, France

Selective laser melting (SLM) is a powder-based additive manufacturing capable to produce parts layer-by-layer from...

JLA Vol:25 Iss:5 (Laser-induced thermoelectric voltage in La_0.9Pr_0.1MnO₃ thin films)

Authors:
Lisheng Zhang
Qianqian Hua
Yan Fang
Beijing Key Laboratory for Nano-Photonics and Nano-Structure, Capital Normal University, Beijing 100048, People's Republic of China

The laser-induced thermoelectric voltage (LITV) was observed in La_0.9Pr_0.1MnO₃ thin films grown on the vicinal cut LaAlO₃ substrate by pulsed laser deposition for the first time. The detected signals were demonstrated to be originated from the anisotropic Seebeck effect. The largest peak value of the voltage is about 2.4 V, the full width at half-maximum of the temporal voltage peak and the rising time are 300–500 and 40–50 n...

JLA Vol:25 Iss:5 (Investigation into the effects of process parameters on bending angle in the laser bending of tailor machined blanks based on a statistical analysis)

Authors:
Mehdi Safari
Mahmoud Farzin
Abbas Ghaei
Department of Mechanical Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran

In this paper, the effects of process parameters on bending angle in laser bending of tailor machined blanks are investigated experimentally. The Taguchi experimental design method is employed to study various parameters, which significantly affect the bending angle in the laser bending of tailor machined blanks. The start point of scan path, irradiating method, laser output power, beam diameter, and number of radiation passes are considered in the evaluations. A L₁₈(2¹×3⁴) Ta...

JLA Vol:25 Iss:4 (Random laser action with nanostructures in a dye solution)

JLA Vol:25 Iss:3 (Random testing reveals excessive power in commercial laser pointers)

Authors:
Joshua Hadler
Quantum Electronics and Photonics Division, NIST, Boulder, Colorado 80305

Edna Tobares
Office of Safety, Health and Environment, NIST, Gaithersburg, Maryland 20899

Marla Dowell
Quantum Electronics and Photonics Division, NIST, Boulder, Colorado 80305

In random testing of 122 commercial laser pointers, the authors observed that 90% of green pointers and 44% of red pointers were not in compliance with the Code of Federal Regulations (CFR), producing laser power in excess of the CFR-allowed limit at one or more laser wavelengths. The measurement results are presented and the authors describe the inexpensive test bed they ...

JLA Vol:25 Iss:3 (Evaluation of corneal and eye lens irradiance for optical aided viewing)

Authors:
Enrico Galbiati
GEST Labs, Via Kennedy, 20871 Vimercate, Italy

The use of a magnifying lens with a highly divergent laser beam may cause a big increase of the irradiance on the cornea and the eye lens. This study provides the analysis of several cases where the use of a lens lead to a corneal irradiance significantly higher than the naked-eye viewing. The examples analyzed in this study allow determining the factors that represent the increase of the corneal irradiance caused by the use of the lens. The results indicate that these factors of irradiance increase may be close to 100.