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The effects of various variotherm processes and their mechanisms on injection molding / C.-T. Huang in INTERNATIONAL POLYMER PROCESSING, Vol. XXVI, N° 3 (07/2011)
[article]
Titre : The effects of various variotherm processes and their mechanisms on injection molding Type de document : texte imprimé Auteurs : C.-T. Huang, Auteur ; I.-S. Hsien, Auteur ; C.-H. Tsai, Auteur ; Y.-C. Chiou, Auteur ; C.-C. Tang, Auteur Année de publication : 2011 Article en page(s) : p. 265-274 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Matières plastiques -- Moulage par injection
Moules d'injectionTags : Moules 'Rapid heat cycle molding' RHCM 'Induction heating molding IHM 'Conventional injection CIM 'Electricity mold' E-mold 'Conservation énegie' Index. décimale : 668.4 Plastiques, vinyles Résumé : To eliminate surface defects and improve the quality of molded parts, increasing the mold temperature is one of the solutions. Using high mold temperature can eliminate weld lines, reduce molding pressure, residual stress and clamping force and improve part surface quality. However, with the increasing of mold temperature, the cycle time will also be increased. Hence, people have paid the attention to mold temperature control technologies. Among them, the variotherm molding technologies, including Rapid Heat Cycle Molding (RHCM), Induction Heating Molding (IHM), and Electricity Heating Mold (Emold), are some effective methods. Although those variotherm technologies have been proposed, how does the external or internal heating source affect the injection molding process and the final product? The true function and the efficiency study of each technology still remain vague. Hence, in this paper, we have systematically conducted various technologies, including Conventional Injection Molding (CIM), RHCM, IHM, and Emold, by using true 3D transient cool technology. Through the inside mechanism investigation at various moments in time, the functions and the heating-cooling efficiency for each technology can be visualized. Besides, experimental study and verification of IHM are also performed. Note de contenu : - Theory and assumptions
- Initial condition for energy conservation
- Boundary conditions for energy conservation
- Numerical discretization method
- Investigation proceduresDOI : 10.3139/217.2436 En ligne : https://drive.google.com/file/d/15wEwbQ7pbTp8FfOUsmfrichpp5DZXN_E/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=12405
in INTERNATIONAL POLYMER PROCESSING > Vol. XXVI, N° 3 (07/2011) . - p. 265-274[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 013159 - Périodique Bibliothèque principale Documentaires Disponible Effect of mold temperature on structure and property variations of PBT injection moldings in the thickness direction / M. Shibaya in INTERNATIONAL POLYMER PROCESSING, Vol. XIX, N° 3 (09/2004)
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Titre : Effect of mold temperature on structure and property variations of PBT injection moldings in the thickness direction Type de document : texte imprimé Auteurs : M. Shibaya, Auteur ; C. Nonomura, Auteur ; N. Yoshihara, Auteur ; K. Yamashita, Auteur ; H. Ishibara, Auteur Année de publication : 2004 Article en page(s) : p. 303-307 Note générale : Bibliogr. Langues : Anglais (eng) Tags : Injection molding Polybutylene terephthalates Microstructure Modulus of elasticity Tensile tests Crystallization Moldings Index. décimale : 668.9 Polymères Résumé : During injection molding process, the surface of flowing resin in contact with the mold surface is cooled first followed by the cooling of inner part. This results in the variation of microstructure in moldings through the thickness direction. It has been reported that these phenomena result in the layered structure of injection moldings. Particularly, because of the rapid rate of crystallization, PBT injection moldings have well-defined skin and core layers. The purpose of this study is to investigate the effect of mold temperature on the development of structure and property variations of PBT injection moldings in the thickness direction. Tensile tests were performed using
dumbbell specimens that were stamped out from the sliced specimens of moldings. Neck phenomenon occurred irrespective of mold temperature and distance from the surface of moldings. The start point of neck propagation shifted to higher strain with increasing distance from the surface. Tensile modulus increased with increasing distance from the surface. In order to discuss these results from a structural viewpoint, the microstructure of each layer was evaluated by density, wide-angle X-ray diffraction and Fourier transform infrared absorption measurements. The delay in necking start points with increasing distance from the surface is due to the higher crystallinity of the inner layer compared to that of the layer near the surface. Two crystal forms of PBT ( alpha- and béta-forms) were developed in injection moldings. The region near the surface, where content of alpha-form is larger than that of béta-form, becomes thinner with increasing mold temperature. It is known that the crystal modulus of alpha-form is lower than that of béta-form. Therefore the portion of moldings with lower tensile modulus and yield strength becomes smaller. It is suggested that the border between the skin and core layers, where tensile property changes, shifts to the surface of PBT injection moldings as mold temperature increases.DOI : 10.3139/217.1827 Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3114
in INTERNATIONAL POLYMER PROCESSING > Vol. XIX, N° 3 (09/2004) . - p. 303-307[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 001029 - Périodique Bibliothèque principale Documentaires Disponible