JLA Vol:20 Iss:3 (Three-dimensional biomimetic microchannel network by laser direct writing)
Authors:
Dong Hyuck Kam
Jyoti Mazumder
Center for Lasers and Plasmas for Advanced Manufacturing (CLPAM), University of Michigan, Ann Arbor Michigan 48105Application of laser direct writing to the fabrication of microchannel networks for tissue engineering was presented. A Q-switched Nd:YAG laser with fundamental wavelength was used. Multidepth, multiwidth microstructures on silicon were machined without photolithography-based methods. The molten material inside the microchannel was ejected with a modified assist gas, and thus the volume of laser ablation was increased. The debris build-up due to the strong thermal reaction of silicon to the nanosecond IR laser pulse was ...
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JLA Vol:20 Iss:3 (Wear behavior of laser clad surfaces of Cr<sub>3</sub>C<sub>2</sub>, WC and Mo on austenitic AISI 304L steel)
Authors:
Dheeraj Gupta
Department of Mechanical and Industrial Engineering, Indian Institute of Technology, Roorkee-247667, Uttaranchal, India
C. P. Paul
Industrial CO2 Laser Section, Raja Ramanna Centre for Advanced Technology, Indore-452012, Madhya Pradesh, India
Bhupendra K. Gandhi
S. R. Gupta
Department of Mechanical and Industrial Engineering, Indian Institute of Technology, Roorkee-247667, Uttaranchal, India
A. K. Nath
Industrial CO2 Laser Section, Raja Ramanna Centre for Advanced Technology, Indore-452012, Madhya Pradesh, IndiaWear resistance of austenitic steels is low and needs to be improved for ...
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JLA Vol:20 Iss:4 (Considerations for reflective laser eye protection against ultrafast lasers)
Authors:
J. Tribble
Human Systems Department, Naval Air Warfare Center—Aircraft Division, Patuxent River, Maryland 20670-1906The inherently broad spectral bandwidth of ultrafast (mode locked) lasers can potentially exceed the protection bandwidth of laser eye protection. This is a particular concern for reflective laser eye protection technologies which by design possess sharp often narrow spectral protection notches. The purpose of this paper is to report spectral transmittance of an ultrafast laser through an interference filter typifying those currently used in laser eye protection and to examine the impact of spectral and angular leakage on the level of protection provided.
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JLA Vol:20 Iss:4 (Effect of Nd:Yttrium-aluminum-garnet laser radiation on Ti6Al4V alloy properties for biomedical applications)
Authors:
M. E. Khosroshahi
M. Mahmoodi
J. Tavakoli
M. Tahriri
Biomaterial group, Faculty of Biomed. Eng., Amirkabir University of Technology, Tehran, IranThe effect of Nd:yttrium-aluminum-garnet laser on the microtopography and physicochemical properties of Ti6Al4V alloy are investigated in the view of biomedical applications. The surface roughness and hardness for laser treated samples (LTS) at 140 J cm−2 were measured 7±0.02 and 825 vickers hardness number, respectively. This superior microhardness value is attributed to grain refinement associated with laser melting and rapid solidification. The electrochemic...
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JLA Vol:20 Iss:4 (Keyhole welding studies with a moderate-power, high-brightness fiber laser)
Authors:
R. T. Brown
Robert T. Brown, LLC, Technical Consulting, 74 South Farms Drive, Manchester, Connecticut 06040 and Department of Mechanical Engineering, University of Hartford, West Hartford, ConnecticutBead-on-plate welding tests were performed using a 600 W fiber-delivered fiber laser. Uniform, high-aspect-ratio keyhole welds were observed in 1018 low-carbon steel, 1100 aluminum, and 304 stainless steel. The Rosenthal two-dimensional thermal model for a moving-line heat source was effective in predicting weld width for both partial-penetration and full-penetration welds. By setting the temperature at the perimeter of the keyhole equal to the vaporization temperature, thi...
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JLA Vol:20 Iss:4 (Laser cutting of 2024-T3 aeronautic aluminum alloy)
Authors:
A. Riveiro
F. Quintero
F. Lusquin˜os
J. Pou
M. Pe´rez-Amor
Departamento de Fi´sica Aplicada, Universidade de Vigo, ETS Ingenieros Industriales, Vigo, 36310, SpainSince the beginning of the aeronautic industry, aluminum alloys have played a crucial role in its development. Nowadays, different aluminum alloy families are the base material of many pieces of aerospace vehicles. In this work, a novel approach to process aluminum alloys is explored. The authors efforts are aimed to cut 2024-T3 plates by a CO2 laser. They used a novel laser cutting head assisted by a gas jet working in supersonic regim...
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JLA Vol:20 Iss:4 (Laser-enhanced electroless plating of silver seed layers for selective electroless copper deposition)
Authors:
Nicholas S. Dellas
Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802
Kenneth Meinert
Applied Research Laboratory, The Pennsylvania State University, University Park, Pennsylvania 16802
Suzanne E. Mohney
Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802Copper (Cu) has been patterned using a laser direct-write metallization technique for fabrication of printed wiring boards. The approach consists of writing a silver (Ag) seed layer with a subsequent step of electroless Cu plating to increase thic...
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JLA Vol:20 Iss:4 (Tailored hybrid blank production—New joining concepts using different solders)
Authors:
C. von der Haar
L. Engelbrecht
O. Meier
A. Ostendorf
H. Haferkamp
Laser Zentrum Hannover e.V., Hollerithallee 8, 30419 Hannover, GermanyA consistent lightweight concept necessitates the combination of different lightweight materials. Because of the significant weight reduction, multimaterial design is becoming more and more interesting for the transportation industry. Mixed material concepts are partially limited because of the insufficient deformation behavior of the joining seams. To overcome this limitation, a brazing process has been developed in which aluminium and steel can be joined, with an enhanced deformation beha...
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JLA Vol:20 Iss:4 (Thermal stress analysis on laser scribing of glass)
Authors:
Koji Yamamoto
Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, Japan
Noboru Hasaka
Hideki Morita
Mitsuboshi Diamond Industrial Co., Ltd., 2-12-12 Minami-Kaneden, Suita, Osaka, Japan
Etsuji Ohmura
Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, JapanIn the laser scribing of glass a thermal stress is introduced into a glass substrate by means of a CO2 laser irradiation. The glass substrate is then rapidly cooled down by water jet immediately after the irradiation. For the purpose of theoretical clarification of the factors ruling the scribable condit...
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JLA Vol:21 Iss:1 (Automatic calibration of a scanner-based laser welding system)
Authors:
Nicolaj C. Stache
Andre´ Stollenwerk
Institute of Imaging & Computer Vision, RWTH Aachen University, 52056 Aachen, Germany
Jens Gedicke
Alexander Olowinsky
Fraunhofer Institute for Laser Technology, Steinbachstr. 15, 52074 Aachen, Germany
Achim Knepper
Til Aach
Institute of Imaging and Computer Vision, RWTH Aachen University, 52056 Aachen, GermanyIn precision engineering scanners are widely used for laser beam positioning. Equipped with cameras, scanners enable process monitoring or even position recognition of the parts to be welded. To allow precise welding or position recognition,...
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