JLA Vol:8 Iss:3 (Theoretical and experimental studies of thick‐section cutting with a chemical oxygen–iodine laser (COIL))

Authors:
A. Kar
J. E. Scott
W. P. Latham

A simple mathematical model of thick‐section stainless steel cutting with a high power chemical oxygen–iodine laser (COIL) is presented and compared with experimental results obtained with a 10‐kilowatt COIL at the U.S. Air Force's Phillips Laboratory. This model uses a lumped‐parameter technique to relate the cutting kerf depth with various process parameters and can be used to predict scaled laser materials processing performance to very thick sections. The model is similar to an empirical model developed by researchers in Japan, but includes predictive capabilities for thick metal cutting...

JLA Vol:2 Iss:3 (Current State‐of‐the‐Art of Contouring Techniques in Manufacturing)

Authors:
Kevin G. Harding
Industrial Technology Institute, Sensor Center for Improved Quality, Ann Arbor, Michigan 48106

A manager with a major automobile manufacturer once made the comment that “the best thing we ever did to improve quality was give the guys on the floor a caliper to measure the parts”. As the tolerances on manufacturing become tighter, the need for accurate measurement has also increased. Hand fitting of parts to each other does not work in modern automated factories. Gauges in the past have been built to provide a fixed set of measurements of a known part. This practice too has been changing due to the trend toward flexible manufacturing. Now the gages...

JLA Vol:17 Iss:2 (Feedback control effects on dimensions and defects of H13 tool steel by direct metal deposition process)

Authors:
Y. Hua
J. Choi
Department of Mechanical and Aerospace Engineering and Engineering Mechanics, University of Missouri, Rolla, Missouri 65409-1060

As a promising and novel manufacturing technology, laser aided direct metal deposition (DMD) process produces near-net-shape functional metal parts directly from the computer aided design (CAD) model. In-process feedback control has been recognized as a critical element to ensure the dimensional accuracy as well as near-net-shape production. Furthermore, process parameters should be delicately controlled to produce defect-free parts with superior mechanical properties. A closed loop real-time optical height control system...

JLA Vol:21 Iss:4 (Numerical model of a laser-sustained argon plasma)

Authors:
R. Akarapu
A. R. Nassar
Department of Engineering Science and Mechanics, Penn State University, University Park, Pennsylvania 16802-6812

S. M. Copley
Applied Research Laboratory and Department of Mechanical and Nuclear Engineering, Penn State University, University Park, Pennsylvania 16802-6812

J. A. Todd
Department of Engineering Science and Mechanics, Penn State University, University Park, Pennsylvania 16802-6812

A steady state axi-symmetric model was developed to predict the size, shape and temperature of a laser-sustained plasma in flowing argon. The power of the carbon dioxide (CO₂) laser and the free s...

JLA Vol:24 Iss:4 (Morphology of nanoscale structures on fused silica surfaces from interaction with temporally tailored femtosecond pulses)

Authors:
Lars Englert
Matthias Wollenhaupt
Cristian Sarpe
Dirk Otto
Thomas Baumert
Institut fuer Physik and CINSaT, Universitaet Kassel, Heinrich-Plett-Str. 40, D-34132 Kassel, Germany

Laser control of two basic ionization processes on fused silica, i.e., multiphoton ionization and avalanche ionization, with temporally asymmetric pulse envelopes is investigated. Control leads to different final electron densities/energies as the direct temporal intensity profile and the time inverted intensity profile address the two ionization processes in a different fashion. This results in observed different thresholds for material modification o...

JLA Vol:5 Iss:2 (Experimental Method for Determining the Coherence Length of CW Lasers Using a Michelson Interferometer)

Authors:
Sami Alaruri
Allison Gas Turbine Division, General Motors Corporation, Sensor Development Group

Theoretical analysis of the relationship between coherence length and the resonant‐longitudinal modes in an optical cavity is given. A Michelson interferometer is used to measure the coherence lengths of two CW He‐Ne laser cavities. Analysis of the experimental measurements shows good agreement with the theoretically predicted values.

JLA Vol:15 Iss:3 (Preparation of polyperinaphthalenic organic semiconductive nanoparticles by excimer laser ablation and their application to optic and electronic devices)

Authors:
Satoru Nishio
Hiroshi Fukumura
Department of Chemistry, Graduate School of Science, Tohoku University, Aramaki, Sendai, Miyagi 980-8578, Japan

Kazuyuki Tamura
Jun Murata
Junko Kitahara
Teruhiko Kan
Akiyoshi Matsuzaki
Department of Chemistry for Materials, Faculty of Engineering, Mi’e University, 1515 Kamihama-cho, Tsu, Mi’e 514-8507, Japan

Nobuo Ando
Yukinori Hato
Kanebo LTD., 3-1, Kanebo-cho, Hofu, Yamaguchi 747-0823, Japan

Polyperinaphthalene (PPN) nanoparticles are prepared by excimer laser ablation (ELA) of a 3, 4, 9, 10-perylenetetracarbox...

JLA Vol:19 Iss:4 (Bench-top antigen detection technique that utilizes nanofiltration and fluorescent dyes which emit and absorb light in the near infrared)

Authors:
Vanessa A. Varaljay-Spence
Department of Biological, Geological and Environmental Sciences, Cleveland State University, Cleveland, Ohio 44115, NASA Glenn Research Center at Lewis Field, Brook Park, Ohio 44135, and Department of Microbiology, University of Georgia, Athens, Georgia 30602

Maximilian C. Scardelletti
NASA Glenn Research Center at Lewis Field, Brook Park, Ohio 44135

This article discusses the development of a bench-top technique to detect antigens in fluids. The technique involves the use of near infrared (NIR) fluorescent dyes conjugated to antibodies, centrifugation, nanofilters, and spectrometry. The system used to detect the antigens utili...

JLA Vol:24 Iss:5 (A comparative study of cut front profiles and absorptivity behavior for disk and CO₂ laser beam inert gas fusion cutting)

Authors:
Leonardo Daniele Scintilla
Luigi Tricarico
Dipartimento di Meccanica, Matematica e Management (DMMM), Politecnico di Bari, Viale Japigia, 182–70126 Bari, Italy

Achim Mahrle
Institute of Manufacturing Technology, Technische Universita¨t Dresden, 01062 Dresden, Germany and Fraunhofer IWS Dresden, Winterbergstraße 28, 01277 Dresden, Germany

Andreas Wetzig
Fraunhofer IWS Dresden, Winterbergstraße 28, 01277 Dresden, Germany

Eckhard Beyer
Institute of Manufacturing Technology, Technische Universita¨t Dresden, 01062 Dresden, Germany and Fraunhofer IWS Dresden, Winterbergstraße 28, 01277 Dres...

JLA Vol:22 Iss:4 (A fast method for morphological analysis of laser drilling holes)

Authors:
M. Schneider
L. Berthe
M. Muller
R. Fabbro
Laboratoire PIMM (CNRS) ARTS et METIERS ParisTech, 151 Boulevard de l’Hopital, 75013 Paris, France

This paper presents an original method for analyzing laser drilled holes. The so-called Direct Observation of Drilled hOle (DODO) method is introduced and its applications. The hole characterization that’s been made is compared with x-ray radiography and cross-section analysis. Direct Observation of Drilled hole provides instantaneously surface state, geometric shape, as well as recast layer structure, without additional operation. Since no mounting resin is used to embed the sample, th...