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Auteur S.-W. Chang |
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Determination of thermal response on mold surface and recommendation of feasible heating time and gas flow rate for a circular cavity by gas preheating / S.-W. Chang in INTERNATIONAL POLYMER PROCESSING, Vol. XXVII, N° 1 (03/2012)
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Titre : Determination of thermal response on mold surface and recommendation of feasible heating time and gas flow rate for a circular cavity by gas preheating Type de document : texte imprimé Auteurs : S.-W. Chang, Auteur ; Y. H. Lee, Auteur Année de publication : 2012 Article en page(s) : p. 30-39 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Moules d'injection Tags : 'Surface moule' 'Temps chauffage' 'Préchauffage haute température gaz' 'Réponse thermique' 'Modèle mathématique' 'Transfert masse' bi-fluide' 'Analyse dimensionnelle' Index. décimale : 668.9 Polymères Résumé : This paper studies the thermal response on the mold surface of a circular cavity in the preheating process by high-temperature gas via a numerical approach, where the heat and mass transfer inside the cavity and mold are predicted by a two-fluid model. The dimensionless parameter group is identified from a dimensional analysis of the gas preheating problem. The correlations among dimensionless parameters are established by a least square method applied to the numerical predictions. The upper limit of the temperature rise on the cavity surface at a given gas flow rate is found approximately proportional to the square root of Q* and h*, respectively. The lower limit of gas flow rate to achieve a given temperature rise on the cavity surface is inversely proportional to h* but grows with (Q*)1.5. The first limiting line to describe the dependence of Q* on t* is independent of h* and T*, but the second one is governed by Q*c. For reaching a specified temperature rise on the cavity surface, the growth in the thickness of thermal resistive layer reduces the required preheating time but increases the corresponding gas flow rate. The dependence of (t∗ƒ, Q∗ƒ) on the parameter group (T*, h*) is given in this study to obtain the reasonable combinations of (t*Æ’ , Q*Æ’) based on the balance between the allowable preheating time and heating capacity. Note de contenu : - MATHEMATICAL MODEL : Governing equations - Boundary conditions - Numerical scheme
- DESCRIPTION OF STUDIED CASEDOI : 10.3139/217.2500 En ligne : https://drive.google.com/file/d/1Ek2BafMIA1ak7SI7Jm5gXPBhWvYVbtNc/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=13719
in INTERNATIONAL POLYMER PROCESSING > Vol. XXVII, N° 1 (03/2012) . - p. 30-39[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 13722 - Périodique Bibliothèque principale Documentaires Disponible Shrinkage analysis on convex shell by injection molding / C.-C. Chen in INTERNATIONAL POLYMER PROCESSING, Vol. XXIII, N° 1 (03/2008)
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Titre : Shrinkage analysis on convex shell by injection molding Type de document : texte imprimé Auteurs : C.-C. Chen, Auteur ; S.-W. Chang, Auteur Année de publication : 2008 Article en page(s) : p. 65-71 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Matières plastiques -- Moulage par injection Index. décimale : 668.9 Polymères Résumé : Injection molding of a convex shell has induced divergent flow front directions and therefore the shrinkage of a convex shell is difficult to controll. In some optical applications, such as ophthalmic devices of soft contact lens, that can be cast molded with a set of two convex shells made by injection molding there is a demand in maintaining dimensional stability. This research investigates the optimization of injection molding parameters for the minimum shrinkage of a convex shell of polypropylene (PP). The MPI 5.0 software is used first to simulate the filling stage of the convex shell and find the feasible operational ranges of parameters. Experiments were performed by an electric injection machine. Short shot experiments have been tested to compare with results of mold flow simulation. Taguchi's method is then used to find the optimal parameters for the minimum shrinkage of convex shell. Four parameters or factors, including mold temperature, injection temperature, holding pressure, and cooling time are considered in this study. An ANOVA table has been obtained for checking the significance of parameters. Results of simulation and experiments have been compared and the holding or packing pressure is found as the most significant parameter for the minimum shrinkage of a convex shell. Cooling time and injection temperature have been found as the second and third most significant parameters in this study. The optimal parameters have been established and then verified by the optimal injection molding experiment and the minimum shrinkage of convex shell was obtained as 72 µm. DOI : 10.3139/217.2044 En ligne : https://drive.google.com/file/d/1XtzqP8KvKDpCccG4AiYYlfm1AnFNmBlI/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=2662
in INTERNATIONAL POLYMER PROCESSING > Vol. XXIII, N° 1 (03/2008) . - p. 65-71[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 009860 - Périodique Bibliothèque principale Documentaires Disponible