JLA Vol:24 Iss:1 (Laser texturization to improve absorption and weld penetration of aluminum alloys)

Authors:
J. M. Sa´nchez-Amaya
Titania, Ensayos y Proyectos Industriales S.L. Parque Tecnolo´gico TecnoBahi´a Edif. RETSE Nave 4. Ctra. Sanlu´car Km 7. 11510, El Puerto de Santa Mari´a, Ca´diz., Spain

Z. Boukha
L. Gonza´lez-Rovira
LABCYP. Departamento de C. Materiales e Ing. Metalu´rgica y Qui´mica Inorga´nica. CASEM. Avda. Repu´blica Saharaui s/n, Puerto Real, 11510. Universidad de Ca´diz., Spain

J. Navas
J. Marti´n-Calleja
Departamento de Qui´mica Fi´sica. Facultad de Ciencias. Universidad de Ca´diz. Avda. Repu´blica Saharaui s/n, P...

JLA Vol:24 Iss:1 (Possible explanations for different surface quality in laser cutting with 1 and 10 μm beams)

Authors:
Koji Hirano
PIMM Laboratory (Arts et Me´tiers ParisTech-CNRS), 151 Boulevard de l’Hoˆpital 75013 Paris, France and Nippon Steel Corporation, Marunouchi Park Building, 2-6-1 Marunouchi, Chiyoda Ward, Tokyo 100-8071, Japan

Remy Fabbro
PIMM Laboratory (Arts et Me´tiers ParisTech-CNRS), 151 Boulevard de l’Hoˆpital 75013 Paris, France

In laser cutting of thick steel sheets, quality difference is observed between cut surfaces obtained with 1 and 10 μm laser beams. This paper investigates physical mechanisms for this interesting and important problem of the wavelength dependence. First, striation generation process is descri...

JLA Vol:24 Iss:1 (Silicon(IV) phthalocyanine-loaded-nanoparticles for application in photodynamic process)

Authors:
Andreza Ribeiro Simioni
Fernando L. Primo
Antonio Claudio Tedesco
Array

The aim of this study was to evaluate the potential application of biodegradable nanoparticles containing a photosensitizer in photodynamic therapy. The poly (D,L lactic-co-glycolic acid) nanoparticles were studied by steady-state techniques, time-resolved fluorescence, and laser flash photolysis. The external morphology of the nanoparticles was established by scanning electron microscopy, and the biological activity was evaluated by in vitro cell culture by 3-(4,5 dimethyl-thiazol-2,5 biphenyl) tetrazolium bromide assay. The particles were spherical in shape exhibiting ...

JLA Vol:24 Iss:1 (Surgical treatment of squamous cell carcinoma of tongue with carbon dioxide laser radiation (CO₂))

Authors:
Walter Niccoli-Filho
Lu´cio Murilo-Santos
Aline R. C. Morosolli
Gerusa de Oliveira Moura Cardoso
Joa˜o Vitor dos Santos Canellas
Array

In this clinical study, we proposed to observe the efficacy of the treatment of squamous cell carcinoma of the tongue (SCCT) by carbon dioxide (CO₂) laser surgery. Twelve patients with SCCT were treated with excisional surgery using the CO₂ laser with a spot size of 0.8 mm, 10 W, power density of 2.5 W/cm² in continuous mode, and under constant vacuum removal of the plume. The post surgical clinical evaluations were done every day until the sutures...

JLA Vol:24 Iss:1 (Ultra-high speed disk laser cutting of carbon fiber reinforced plastics)

Authors:
Kwang-Woon Jung
Yousuke Kawahito
Seiji Katayama
Joining and Welding Research Institute (JWRI), Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan

Laser cutting of carbon fiber reinforced plastics (CFRPs) has been known to be difficult due to the thermal damage to CFRP material. Therefore, with the objectives of evaluating the cutting possibility for long- or short-fiber pellet CFRP sheets of 3 mm in thickness and obtaining narrower heat affected zone (HAZ) for better cut quality, ultra-high speed cutting was conducted by using a continuous-wave high brightness disk laser. The increase in the laser power rendered the cutting time shorter...

JLA Vol:24 Iss:2 (Energetic efficiency of remote cutting in comparison to conventional fusion cutting)

Authors:
M. Lu¨tke
J. Hauptmann
A. Wetzig
Fraunhofer IWS, Winterbergstraße 28, 01277 Dresden, Germany

E. Beyer
Fraunhofer IWS, Winterbergstraße 28, 01277 Dresden, Germany and University of Technology Dresden, 01062 Dresden, Germany

The remote cutting technique provides an enormous potential in terms of cutting speeds when working on thin sheets. Even on contour cutting speeds about 100 m/min are realizable. Working without any cutting gas, the material of the cutting kerf must be vaporized partially. It is evident that the energy input must be higher than for pure melting of the cutting kerf’s material. In order to ...

JLA Vol:24 Iss:2 (Laser ablation of polyetheretherketone films for reversible wafer bonding)

Authors:
Lauren E. S. Rohwer
James E. Martin
Thomas A. Friedmann
Sandia National Laboratories, P.O. Box 5800, MS1425, Albuquerque, New Mexico 87185-1425

John Heck
Intel Corporation, M/S SC9-09, 2200 Mission College Blvd., Santa Clara, California 95054

A reversible wafer bonding method has been developed that enables high-temperature processing of thinned silicon wafers. The silicon wafers are bonded to Pyrex carriers using a polyetheretherketone (PEEK) film, which melts at 343 °C, and provides a very strong bond. Debonding is accomplished by UV laser ablation through the Pyrex carrier and can be facilitated by coating the Pyrex wafer...

JLA Vol:24 Iss:2 (Laser dressing of metal bonded diamond blades for cutting of hard brittle materials)

Authors:
Philipp von Witzendorff
Anas Moalem
Rainer Kling
Ludger Overmeyer
Laser Zentrum Hannover e.V., Hollerithallee 8, 30419 Hannover, Germany

In this study, the authors investigate the laser dressing of metal bonded diamond blades by means of laser pulses with different pulse durations and wavelengths. Conventional dressing suffers from excessive blade wear, whereas laser dressing enables precise removal of the bonding metal to generate the required chip space of protruding diamond grains. The challenge for processing this composite material is to find appropriate level of ablation for the bonding metal without damaging the diamond grains thr...

JLA Vol:24 Iss:2 (Laser induced backside wet and dry etching of solar glass by short pulse ytterbium fiber laser irradiation)

Authors:
He Chao
Liu Furong
Wang Min
Yuan Jianwen
Chen Jimin
Institute of Laser Engineering, Beijing University of Technology, Chaoyang District, Beijing 100124, China

Microstructures fabricated on the surface of solar glass have the potential to improve the performance of solar cells. In this paper, in order to overcome the high transmittance to 1064 nm center wavelength fiber laser irradiation and realize high efficiency process on transparent glass substrates, different absorber materials, including alumina powder, alumina ceramic wafers, and copper sulphate solutions, were applied for dry and wet etching under the irradiation of ...

JLA Vol:24 Iss:2 (Synthesis of nitrogen-doped diamond films using vibrational excitation of ammonia molecules in laser-assisted combustion flames)

Authors:
L. S. Fan
Z. Q. Xie
J. B. Park
X. N. He
Y. S. Zhou
Department of Electrical Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0511

L. Jiang
Department of Mechanical and Automation Engineering, Beijing Institute of Technology, Beijing 100081, People’s Republic of China

Y. F. Lu
Department of Electrical Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0511

Nitrogen-doped diamond was synthesized in open air using laser-assisted combustion flame method. A wavelength-tunable CO₂ laser was used to resonantly excite the vibration mod...