Enhancement of injection molding consistency by adjusting velocity/pressure switching time based on clamping force / J.-Y. Chen in INTERNATIONAL POLYMER PROCESSING, Vol. XXXIV, N° 5 (11/2019)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXXIV, N° 5 (11/2019) . - p. 564–572 Titre : Enhancement of injection molding consistency by adjusting velocity/pressure switching time based on clamping force Type de document : texte imprimé Auteurs : J.-Y. Chen, Auteur ; C.-Y. Liu, Auteur ; M.-S. Huang, Auteur Année de publication : 2019 Article en page(s) : p. 564–572 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Matières plastiques -- Moulage par injection Tags : 'Moulage  par  injection'  'Commutation  vitesse/pression'  Serrage Index. décimale : 668.4 Plastiques, vinyles Résumé : The velocity/pressure (V/P) switching time, the transition from the filling phase to the holding phase during the injection molding cycle, plays a crucial role in ensuring the quality of the injection molding. Improper settings can lead to a variety of defects, including oversize/undersize, excessive residual stress, flash, warpage, and the like. There are currently many V/P switching methods to choose from. For example, when the injection time or the screw position reaches a prescribed value, that is, when a specified percentage of the cavity is filled with the molten resin, the switching time can be started. These traditional V/P switching methods should work well using precision injection molding machines to ensure accurate and repeatable motion control. However, the quality of shot-to-shot injection molding still varies with environmental changes, such as varying mold/melt temperatures. In this study, we propose a V/P switching adjustment method involving part weight or maximum clamping force increments. It was found that the weight of the injection molded part was highly correlated with the maximum clamping force increment and the V/P switching time. Experimental verification by considering various settings such as V/P switching time, injection speed and holding pressure show that the adjustment method is a feasible means of assuring quality consistency. Note de contenu : - Correlation analysis - Experimental verification with different injection speeds. V/P switching times and holding pressures - Experimenmtal verification with different barrel temperatures DOI : https://doi.org/10.3139/217.3867 En ligne : https://www.hanser-elibrary.com/doi/pdf/10.3139/217.3867 Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=33619 [article]

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Study on crystal form transition and non-isothermal crystallization of glycidyl methacrylate grafted isotactic polybutene-1 / Y.-X. Zhao in INTERNATIONAL POLYMER PROCESSING, Vol. XXXII, N° 1 (03/2017)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXXII, N° 1 (03/2017) . - p. 26-33 Titre : Study on crystal form transition and non-isothermal crystallization of glycidyl methacrylate grafted isotactic polybutene-1 Type de document : texte imprimé Auteurs : Y.-X. Zhao, Auteur ; W. Xu, Auteur ; Y.-F. Zhou, Auteur ; J.-Y. Chen, Auteur ; L. Han, Auteur ; D. Li, Auteur Année de publication : 2017 Article en page(s) : p. 26-33 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Calorimétrie Copolymères greffés Cristallisation Diffractométrie de rayons X Fourier, Spectroscopie infrarouge à transformée de Méthacrylate de glycidyle Microscopie Polybutène-1 Le polybutène-1 (polybutylène-1, sigle PB-1), est un polymère thermoplastique qui appartient à la famille des polyoléfines. Il existe deux isomères du polybutène selon la ramification du monomère butène : le polybutène-1, de formule -[CH2-CH(CH2CH3)]n-, et le polyisobutène, de formule -[CH2-C(CH3)2]n-. Synthèse : Le polybutène-1 est préparé par le procédé de polymérisation avec catalyse de Ziegler-Natta à basse pression. Polymères isotactiques Index. décimale : 668.4 Plastiques, vinyles Résumé : We report the impact of grafting glycidyl methacrylate (GMA) at different degrees onto isotactic polybutene-1 (iPB-1) on the crystallization process. The study of the crystal form transition using FTIR and X-ray Diffraction (XRD) revealed that the conversion degree from form II to form I of the grafted iPB-1 (iPB-g-GMA) was higher than that of iPB-1 under the same experimental conditions and increased with increasing grafting degree. The spherulitic size of iPB-g-GMA was smaller compared to iPB-1 at the same amplification factor in Polarized Optical Microscopy (POM). The kinetic parameters of the non-isothermal crystallization process have been determined based on Differential Scanning Calorimetry (DSC) experiments and the Ozawa and Mo equation. The results showed that the crystallization rate of iPB-g-GMA was higher than that of iPB-1. The activation energy for the non-isothermal crystallization process of iPB-g-GMA (with a grafting degree of 1.54%) was lower than that of iPB-1, which further illustrated that grafting GMA on iPB-1 accelerated the crystallization rate. Note de contenu : - EXPERIMENTAL : Materials - FTIR - X-Ray diffraction analysis (XRD) - Differential scanning calorimetry (DSC) - Polarized optical microscopy (POM) - RESULTS AND DISCUSSION : - Crystal from transformation - Crystal morphology - Non-isothermal crystallization - Non isothermal crystallization kinetics DOI : 10.3139/217.3205 En ligne : https://drive.google.com/file/d/1aLeakvcO61vMS-kOyXHzL5t_E23nu_I9/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=27976 [article]

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