Absorption coefficient measurement in laser transmission welding of thermoplastics / M. Chen in INTERNATIONAL POLYMER PROCESSING, Vol. XXX, N° 1 (03/2015)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXX, N° 1 (03/2015) . - p. 38-43 Titre : Absorption coefficient measurement in laser transmission welding of thermoplastics Type de document : texte imprimé Auteurs : M. Chen, Auteur ; G. Zak, Auteur ; Phil J. Bates, Auteur Année de publication : 2015 Article en page(s) : p. 38-43 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Absorption Composites à fibres de verre Matières plastiques -- Soudage Noir de carbone Polyamide 6 Soudage laser Index. décimale : 668.9 Polymères Résumé : Laser transmission welding involves joining of transmitting and absorbing thermoplastic polymer components. Absorption is normally controlled by addition of small amounts of carbon black (CB). In thermal modelling of the process, the laser-light absorption coefficient is an important parameter that controls the rate and distribution of heat generation in the absorbing component. This paper introduces a novel experimental method to conveniently and accurately measure the absorption coefficient in the absorbing component. In this method, a laser beam scans rapidly over the surface of the CB-filled polymer. The laser power resulting in the onset of surface melting can be obtained and used to calculate the absorption coefficient based on an analytical model presented in this paper. To validate the proposed method, the experimental results were compared with those obtained by the spectrophotometer and the power-meter methods using unreinforced and glass-fiber reinforced nylon 6. The results indicate that there is a linear relationship between the absorption coefficient and carbon black level for these two polymers. The influence of glass fibers and laser scan speed on the measurement are also discussed. Note de contenu : - BACKGROUND : Laser transmission welding - Bouguer-Lambert law - Absorption coefficient measurement - PRINCIPLE AND EXPERIMENTAL SETUP OF THE DIRECT-SCAN METHOD : Measurement principle - Test materials - Experimental setup - EXPERIMENTAL RESULTS AND ANALYSIS : Absorption coefficient vs. CB level - Test methods comparison DOI : 10.3139/217.2820 En ligne : https://drive.google.com/file/d/1EQU7GfazF9ZZ1vm3z4s6msj7J-5MA5wH/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=23416 [article]

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Simulation of heat transfer in laser transmission welding / R. Prabhakaran in INTERNATIONAL POLYMER PROCESSING, Vol. XX, N° 4 (12/2005)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XX, N° 4 (12/2005) . - p. 410-416 Titre : Simulation of heat transfer in laser transmission welding Type de document : texte imprimé Auteurs : R. Prabhakaran, Auteur ; Marianna Kontopoulou, Auteur ; G. Zak, Auteur ; Phil J. Bates, Auteur ; V. Sidiropoulos, Auteur Année de publication : 2005 Article en page(s) : p. 410-416 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : A numerical simulation of the heat transfer during laser transmission welding is presented. A finite difference approach was used to solve the one-dimensional unsteady-state heat conduction problem and to investigate the effect of welding conditions on the time-dependent temperature profiles for PA 6. For the needs of the simulation, the process was divided into heating and heat redistribution periods. The absorption coefficient of the laser-transparent part was measured experimentally and that of the laser-absorbing part was fitted using experimental data. The predicted temperature profiles were combined with experimental meltdown data to estimate the heat-affected zone thickness in the welded specimens. Good agreement was found between the estimated and measured heat-affected zone thickness values. En ligne : https://drive.google.com/file/d/1EPZG66vHoA0ClrbNJZ4jBb-15CA8U5yA/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=2966 [article]

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