Visualization analysis of asymmetric fountain flow phenomenon in injection molding of filler-reinforced resins by rotary runner exchange system / H. Yokoi in INTERNATIONAL POLYMER PROCESSING, Vol. XX, N° 2 (06/2005)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XX, N° 2 (06/2005) . - p. 157-161 Titre : Visualization analysis of asymmetric fountain flow phenomenon in injection molding of filler-reinforced resins by rotary runner exchange system Type de document : texte imprimé Auteurs : H. Yokoi, Auteur ; Y. Kanetoh, Auteur Année de publication : 2005 Article en page(s) : p. 157-161 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : In this study, we attempted to visualize the flow patterns inside molded samples of glass-fibers or talc reinforced GPPS and PP especially in the vicinity of the flow front, using a rotary runner exchange system which instantaneously switches melt flowing into the cavity. From the visualization results, an extremely characteristic flow behavior was seen at the flow front area for resins with fillers which was not observed for those without fillers. Especially in the case of resins with 40 wt.% talc or 30 wt.% GF, a-symmetric zigzag fountain flows were generated alternately upward and downward along the cavity width direction. Moreover along the outer layer of the flow front, one observed a large amount of residual resin remaining for a long time during the cavity filling process, in the case of 40 wt.% GF, primarily due to the increase of viscosity which restricts the occurrence of diverging flow. Based on the above visualization results, we proposed a generic model of zigzag fountain flow; an a-symmetric upward flow in a certain area starts preventing the fountain flow in the upper side of the adjacent area, causing the diverging center to sink. This phenomenon subsequently causes an a-symmetric flow in the opposite direction in the next adjacent area, which continuously propagates along the cavity width direction. DOI : 10.3139/217.1875 En ligne : https://drive.google.com/file/d/1VqXzreoqEXJDat_AznmBOZpOFGuW5Y-r/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3075 [article]

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Visualization analysis of resin flow behavior around a flow front using a rotary runner exchange system / Y. Kanetoh in INTERNATIONAL POLYMER PROCESSING, Vol. XXVII, N° 3 (07/2012)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXVII, N° 3 (07/2012) . - p. 310-317 Titre : Visualization analysis of resin flow behavior around a flow front using a rotary runner exchange system Type de document : texte imprimé Auteurs : Y. Kanetoh, Auteur ; H. Yokoi, Auteur Année de publication : 2012 Article en page(s) : p. 310-317 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Ecoulement visqueux Fluides, Mécanique des Matières plastiques -- Moulage par injection -- Appareils et matériel Moulage par injection -- Défauts Moules d'injection Polystyrène Index. décimale : 668.4 Plastiques, vinyles Résumé : In plastic injection molding, external defects such as flow marks are serious problems. These external defects are known to occur during cavity filling processes inside the mold, and are closely related to resin flow behavior in the flow front area. In this study, the authors propose a new method for visualizing in-mold resin flow behavior using a glass-inserted mold and rotary runner exchange system capable of instantaneously switching two types of melt at the runner just before the gate. This method is capable not only of dynamic visualization, but also static visualization by the observation of cross-sections of a sample, because colored resins switched multiple times at the gate spread in layers inside the sample and freeze. Using this method and general purpose polystyrene, visualization analysis of the flow behavior of inner layer resins near the flow front in simple rectangular cavities was carried out. As a result, it was found that resins reaching the flow front are not exposed at the molded product surface immediately after the fountain-flow process, but remain along the circumference of the flow front for a long period of time, and then stretch out into a thin filmlike shape to form the surface of the molded product. In addition, the inner layer resins near the flow front form a converging flow just before reaching the flow front and then form a fountain flow. It was also confirmed that this is a general phenomenon in the fountain-flow process during injection molding regardless of whether the resin is crystalline or noncrystalline. Based on these results, we built a model on the flow of inner layer resins near the flow front of general resins. DOI : 10.3139/217.2457 En ligne : https://drive.google.com/file/d/12C-9v6b6ma__sKVLqopueoqxp7OW7vvm/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=15576 [article]

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