Flow behavior of sandwich injection molding in sequential and simultaneous injection / D. Watanabe in INTERNATIONAL POLYMER PROCESSING, Vol. XVIII, N° 2 (06/2003)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XVIII, N° 2 (06/2003) . - p. 199-203 Titre : Flow behavior of sandwich injection molding in sequential and simultaneous injection Type de document : texte imprimé Auteurs : D. Watanabe, Auteur ; U. S. Ishiaku, Auteur ; T. Nagaoka ; K. Tomari ; H. Hamada Année de publication : 2003 Article en page(s) : p. 199-203 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : The flow behavior of skin and core materials in co-injection molding was investigated to understand the flow patterns that could lead to core breakthrough in sequential and simultaneous injection molding. A spiral-flow mold was used and the core material was loaded with a black master batch to facilitate the monitoring of the core material. PC/ABS blend was used as the skin material and ABS was the core material. It was revealed irrespective of simultaneous injection time, sandwich injection molding display the four flow regions identified earlier i.e. primary injection region, core advance region, core expansion region and core breakthrough region. The flow length of core expansion region lengthened with increasing simultaneous injection time of skin and core material while the overall injection time decreased. It was also observed that the core became thinner and wider with increasing simultaneous injection time. DOI : 10.3139/217.1735 En ligne : https://drive.google.com/file/d/1OoPgF6TJiC5lDOU-6BjdZ_P3Ie_I5GCt/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3312 [article]

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The flow behavior of core material and breakthrough phenomenon in sandwich injection molding / D. Watanabe in INTERNATIONAL POLYMER PROCESSING, Vol. XVIII, N° 4 (12/2003)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XVIII, N° 4 (12/2003) . - p. 398-404 Titre : The flow behavior of core material and breakthrough phenomenon in sandwich injection molding : Part 1 : Dependence on viscosity and injection speed of skin/core materials Type de document : texte imprimé Auteurs : D. Watanabe, Auteur ; U. S. Ishiaku, Auteur ; T. Nagoaka ; K. Tomari, Auteur ; H. Hamada, Auteur Année de publication : 2003 Article en page(s) : p. 398-404 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : Molding - The processing variables that control the occurrence of break-through phenomenon in sandwich injection molding were investigated. Particular attention was paid to the conditions that would yield an optimum sandwich molded part. The effects of variation of core volume ratio that would yield optimum core shot size, injection speed and the skin/core viscosity ratio were examined. The flow morphology at the various stages of flow was also explored. The study was conducted with a bar-flow mold mounted on a twin-barrel injection machine fitted with a common nozzle. It was noted that the core material flow distance depends on the core cylinder screw metering position (core shot size). At the stage at which the core material completely penetrated through the skin material (breakthrough), four distinct regions of flow could be identified. The flow distance of the core material is controlled by the injection speed of the core material while the injection speed of the skin material is of little significance. In order to increase the flow distance of the core material, it is effective to increase the core material injection speed albeit limited by an optimum value of screw metering position. It was found that the flow distance of the core material was longer when the core material viscosity was lower than that of the skin material but breakthrough occurred much earlier so core volume is limited. Breakthrough failed to occur when the viscosity of the core material was higher than that of the skin material. It was found that optimum core volume and core distribution occurred when skin/core viscosities were intermediate. The morphology of the skin material leading to breakthrough was also analyzed. Note de contenu : - EXPERIMENTAL : Materials - Sample preparation - Measurement of flow distance and break point - Morphology observation of PC/ABS alloy - RESULTS : Effect of core volume ratio - Injection speed of skin-core - Effect of viscosity ratio of skin/core - Breakthrough - Morphology DOI : 10.3139/217.17522 En ligne : https://drive.google.com/file/d/1GHXW7JVYwTFLIEvFSRqAUdR0_f4J4adN/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=15824 [article]

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The flow behavior of core material and breakthrough phenomenon in sandwich injection molding / D. Watanabe in INTERNATIONAL POLYMER PROCESSING, Vol. XVIII, N° 4 (12/2003)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XVIII, N° 4 (12/2003) . - p. 405-411 Titre : The flow behavior of core material and breakthrough phenomenon in sandwich injection molding : Part 2 : Influence of mold cavity thickness and core cylinder temperature Type de document : texte imprimé Auteurs : D. Watanabe, Auteur ; U. S. Ishiaku, Auteur ; T. Nagoaka, Auteur ; K. Tomari, Auteur ; H. Hamada, Auteur Année de publication : 2003 Article en page(s) : p. 405-411 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : Molding - The processing conditions that exert influence on the occurrence of breakthrough during sandwich injection molding were investigated. A spiral flow mold mounted on a twin-barrel injection machine fitted with a single nozzle was used. The effect of mold cavity thickness and the effects of skin material cylinder temperature on skin material viscosity, melt strength, and drawing ratio were considered. Scanning electron microscopy was used to study the morphology of the skin material at the flow front. It was found that the flow length at core expansion region increased and breakthrough phenomenon was delayed as the thickness of the mold cavity increased. When cylinder temperature is increased, the viscosity is lowered and the flow front of the skin material extends with greater ease when pushed by the core material, thus, a greater core volume can be accommodated. As the flow front progresses, the tendency is that the skin material becomes thinner. Polishing and etching followed by SEM examination of the skin material at the flow front revealed that the skin material is oriented perpendicular to the flow direction and the extent of orientation increases with increasing cylinder temperature. This further supported the observation that the deformation ratio and drawing ratio increased with increasing cylinder temperature. Note de contenu : - EXPERIMENTAL : Material - Sample preparation - Sample observation - Melt tension test - RESULTS : Effect of cavity thickness on flow length - Effect of cylinder temperature of skin material - Effect of melt viscosity of skin material - The change in skin layer thickness of flow front at core expansion region - Melt tension test DOI : 10.3139/217.1787 En ligne : https://drive.google.com/file/d/1Y_4HuKDvM2vSEWDkYBqai2G0RtXinv_y/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=15825 [article]

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