The Experts below are selected from a list of 6663 Experts worldwide ranked by ideXlab platform
Costas P Grigoropoulos - One of the best experts on this subject based on the ideXlab platform.
-
Laser Cleaning of surface contaminants
Applied Surface Science, 1998Co-Authors: Axel Kramer, Hee K Park, Costas P GrigoropoulosAbstract:Laser Cleaning effect can be produced on a surface using pulsed Laser irradiation, with pulse duration typically 1 to 100 ns, fluence typically tens to hundreds of mJ/cm2, and wavelengths typically in the 200 to 300 nm range. A thin liquid film can be used to enhance the removal efficiency of small particulates; this is called `steam Laser Cleaning'. A manufacturing-worthy tool that can provide both steam Laser Cleaning as well as dry Laser Cleaning is built and tested successfully. The basic mechanism of steam Laser Cleaning is studied.
-
Laser Cleaning of surface contaminants
Applied Surface Science, 1998Co-Authors: Andrew C. Tam, Hee K Park, Costas P GrigoropoulosAbstract:Laser Cleaning effect can be produced on a surface using pulsed Laser irradiation, with pulse duration typically 1 to 100 ns, fluence typically tens to hundreds of mJ/cm 2 , and wavelengths typically in the 200 to 300 nm range. A thin liquid film can be used to enhance the removal efficiency of small particulates; this is called 'steam Laser Cleaning'. A manufacturing-worthy tool that can provide both steam Laser Cleaning as well as dry Laser Cleaning is built and tested successfully. The basic mechanism of steam Laser Cleaning is studied. © 1998 Elsevier Science B.V.
T C Chong - One of the best experts on this subject based on the ideXlab platform.
-
Real-time monitoring of Laser Cleaning by an airborne particle counter
Applied Surface Science, 2003Co-Authors: Wen Dong Song, Minghui Hong, S.h. Lee, T C ChongAbstract:Abstract A method to monitor Laser Cleaning is presented in this paper. During Laser Cleaning of contamination, particles are generated and/or ejected from a substrate based on Laser ablation and Laser-induced fast thermal expansion of contaminants and/or the substrate. An airborne particle counter is used to detect the particles ejected from the substrate during Laser Cleaning at the same time as the irradiation of the Laser beam. The Cleaning threshold, Cleaning efficiency, cleanliness of substrate and ablation threshold of substrate can be monitored by particle detection.
-
Laser Cleaning of printed circuit boards
Applied Surface Science, 2003Co-Authors: W.d. Song, Yong Feng Lu, M.h. Hong, T C ChongAbstract:Laser Cleaning of printed circuit boards (PCB) has been studied in this paper. It is demonstrated that Laser Cleaning is a powerful tool to remove resin contaminants from printed circuit boards. A Nd:YAG Laser is used as a light source for Laser Cleaning. The beam profile of the YAG Laser is reshaped and homogenized into a square beam with uniform energy distribution in the focal plane of the focusing lens by using an optical system. The printed circuit board surfaces before and after Laser Cleaning were inspected by an optical microscope, analysed by X-ray photoelectron spectroscopy and monitored by an acoustic wave detection method. The Cleaning threshold is about 75mJ/cm2 and no damage is observed below 400mJ/cm2.
-
Laser Cleaning technology and its application
Second International Symposium on Laser Precision Microfabrication, 2002Co-Authors: W.d. Song, Minghui Hong, L. Zhang, T C ChongAbstract:Laser Cleaning technology has been demonstrated to be an effective Cleaning technique for removing particulate and film-type contaminants from solid surfaces in this paper. Dry and steam Laser Cleaning mechanisms and applications in semiconductor and disk drive industry will be addressed.
K. G. Watkins - One of the best experts on this subject based on the ideXlab platform.
-
In-process monitoring techniques for Laser Cleaning
Optics and Lasers in Engineering, 2000Co-Authors: J M Lee, K. G. WatkinsAbstract:Diverse in-process monitoring techniques based on acoustic, chromatic and intelligent approaches have been developed for Laser Cleaning not only to achieve the sound-cleaned surface but also to control the process in an automatic manner. The Cleaning of various materials such as copper, marble, paper have also been carried out by using Q-switched Nd:YAG radiation. The process was successfully monitored by detecting the acoustic emission induced by Laser-surface interactions during Laser Cleaning. Novel surface monitoring was achieved by chromatic modulation technique. The monitoring of Laser fluence based on neural network logic was carried out by means of the recognition of acoustic spectrum patterns. The prediction system of surface damage has been also developed using fuzzy rule base in the same way as a human expert. These techniques may provide unique information for characterizing the process as well as a promise of successful applications for Laser Cleaning techniques in real practical fields.
-
Real-time monitoring and expert control of Laser Cleaning
International Congress on Applications of Lasers & Electro-Optics, 2000Co-Authors: J M Lee, K. G. Watkins, W. M. SteenAbstract:In order to achieve the sound cleaned surface as well as to control the process with an automatic manner, real-time monitoring based on acoustic, optical and chromatic approaches have been carried out in the Laser Cleaning processes. Diverse materials such as copper, marble, paper have been used for the removal of the surface contaminants by a Q-switched Nd:YAG Laser in this study. The process was monitored by detecting the acoustic wave emitted from the surface during Laser Cleaning. Direct surface monitoring was carried out by sensing the reflected light from the surface. Chromatic modulation technique based on tristimulus detection was also used for investigating the Laser-induce plume during Cleaning. In addition, the expert system based on fuzzy rule base has been developed not only to predict the surface damage beforehand but also to control the Laser Cleaning process effectively. These techniques may provide unique information for characterising the process as well as a promise of successful applications of Laser Cleaning in real practical fields.In order to achieve the sound cleaned surface as well as to control the process with an automatic manner, real-time monitoring based on acoustic, optical and chromatic approaches have been carried out in the Laser Cleaning processes. Diverse materials such as copper, marble, paper have been used for the removal of the surface contaminants by a Q-switched Nd:YAG Laser in this study. The process was monitored by detecting the acoustic wave emitted from the surface during Laser Cleaning. Direct surface monitoring was carried out by sensing the reflected light from the surface. Chromatic modulation technique based on tristimulus detection was also used for investigating the Laser-induce plume during Cleaning. In addition, the expert system based on fuzzy rule base has been developed not only to predict the surface damage beforehand but also to control the Laser Cleaning process effectively. These techniques may provide unique information for characterising the process as well as a promise of successful applic...
-
Angular Laser Cleaning for the enhancement of Cleaning efficiency
Conference Digest. 2000 Conference on Lasers and Electro-Optics Europe (Cat. No.00TH8505), 2000Co-Authors: Jong-myoung Lee, C. Curran, K. G. WatkinsAbstract:Summary form only given. Laser Cleaning has begun to attract a considerable amount of interest recently as a new Cleaning technique among scientists and engineers. Due to its unique characteristics as a selective, precise, controllable and environmentally-friendly process, the Laser Cleaning technique is finding a wide range of successful applications both in industry and in the world of art conservation. In this paper, Laser removal of small particles on metal surface is carried out by changing the incidence angle of Laser beam. It is found that dramatic improvement of Cleaning efficiency is observed at the glancing angle of incidence on the surface compared to the perpendicular incidence of Laser beam. Furthermore substrate damage is greatly reduced and probably eliminated at the glancing angle of incidence.
-
Laser Cleaning in Art Restoration: A Review
Laser Processing: Surface Treatment and Film Deposition, 1996Co-Authors: K. G. Watkins, J. H. Larson, D. C. Emmony, W. M. SteenAbstract:This paper presents a review of previous work on Laser Cleaning from the perspective of conservation and restoration in the art world. Particular attention is given to Laser Cleaning mechanisms, including selective vaporisation, ablation, selective removal of small particles, steam Cleaning and special features for metals.
Stephen Dilworth - One of the best experts on this subject based on the ideXlab platform.
-
Numerical Simulation of Excimer Laser Cleaning of Film and Particle Contaminants
Journal of Heat Transfer, 2013Co-Authors: Sampath Marimuthu, a. Mhich, Zhanke Liu, Dave Whitehead, Sonia Cheetham, Clive Grafton-reed, Paul Mativenga, L .c. Li, I. S. Molchan, Z B Wang, Stephen DilworthAbstract:Laser Cleaning is a promising surface preparation technique for applications in high value manufacturing industries. However, understanding the effects of Laser processing parameters on various types of contaminants and substrates, is vital to achieve the required Cleaning efficacy and quality. In this paper, a two-dimensional transient numeri-cal simulation was carried out to study the material ablation characteristics and sub-strate thermal effects in Laser Cleaning of aerospace alloys. Element birth and death method was employed to track the contaminant removal on the surface of the material. The result shows that contaminant ablation increases with Laser power and number of pulses. The finite element method (FEM) model is capable enough to predict the optimum number of pulses and Laser power required to remove various contaminants. Based on the simulation results, the mechanism of the excimer Laser Cleaning is proposed. Thus, the use of numerical simulation can be faster and cheaper method of establishing the op-timum Laser Cleaning window and reducing the number of experimental tests. [ABSTRACT FROM AUTHOR]
J M Lee - One of the best experts on this subject based on the ideXlab platform.
-
In-process monitoring techniques for Laser Cleaning
Optics and Lasers in Engineering, 2000Co-Authors: J M Lee, K. G. WatkinsAbstract:Diverse in-process monitoring techniques based on acoustic, chromatic and intelligent approaches have been developed for Laser Cleaning not only to achieve the sound-cleaned surface but also to control the process in an automatic manner. The Cleaning of various materials such as copper, marble, paper have also been carried out by using Q-switched Nd:YAG radiation. The process was successfully monitored by detecting the acoustic emission induced by Laser-surface interactions during Laser Cleaning. Novel surface monitoring was achieved by chromatic modulation technique. The monitoring of Laser fluence based on neural network logic was carried out by means of the recognition of acoustic spectrum patterns. The prediction system of surface damage has been also developed using fuzzy rule base in the same way as a human expert. These techniques may provide unique information for characterizing the process as well as a promise of successful applications for Laser Cleaning techniques in real practical fields.
-
Real-time monitoring and expert control of Laser Cleaning
International Congress on Applications of Lasers & Electro-Optics, 2000Co-Authors: J M Lee, K. G. Watkins, W. M. SteenAbstract:In order to achieve the sound cleaned surface as well as to control the process with an automatic manner, real-time monitoring based on acoustic, optical and chromatic approaches have been carried out in the Laser Cleaning processes. Diverse materials such as copper, marble, paper have been used for the removal of the surface contaminants by a Q-switched Nd:YAG Laser in this study. The process was monitored by detecting the acoustic wave emitted from the surface during Laser Cleaning. Direct surface monitoring was carried out by sensing the reflected light from the surface. Chromatic modulation technique based on tristimulus detection was also used for investigating the Laser-induce plume during Cleaning. In addition, the expert system based on fuzzy rule base has been developed not only to predict the surface damage beforehand but also to control the Laser Cleaning process effectively. These techniques may provide unique information for characterising the process as well as a promise of successful applications of Laser Cleaning in real practical fields.In order to achieve the sound cleaned surface as well as to control the process with an automatic manner, real-time monitoring based on acoustic, optical and chromatic approaches have been carried out in the Laser Cleaning processes. Diverse materials such as copper, marble, paper have been used for the removal of the surface contaminants by a Q-switched Nd:YAG Laser in this study. The process was monitored by detecting the acoustic wave emitted from the surface during Laser Cleaning. Direct surface monitoring was carried out by sensing the reflected light from the surface. Chromatic modulation technique based on tristimulus detection was also used for investigating the Laser-induce plume during Cleaning. In addition, the expert system based on fuzzy rule base has been developed not only to predict the surface damage beforehand but also to control the Laser Cleaning process effectively. These techniques may provide unique information for characterising the process as well as a promise of successful applic...
