Development of high pressure injection technology for normal hydraulic injection molding machines / M. C. Song in INTERNATIONAL POLYMER PROCESSING, Vol. XXXIII, N° 1 (03/2018)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXXIII, N° 1 (03/2018) . - p. 52-59 Titre : Development of high pressure injection technology for normal hydraulic injection molding machines Type de document : texte imprimé Auteurs : M. C. Song, Auteur ; Y. Liu, Auteur ; H. Chang Année de publication : 2018 Article en page(s) : p. 52-59 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Elastomères -- Moulage par injection -- Appareils et matériels Hautes pressions Machines hydrauliques Matières plastiques -- Moulage par injection Polypropylène Presses à injecter Terpolymère acrylonitrile butadiène styrène Index. décimale : 668.4 Plastiques, vinyles Résumé : Previous studies have shown that enhancing injection pressure can help improve the precision and mechanical properties of molding products, and reduce their shrinkage. But for now the ordinary hydraulic injection molding machine cannot generally meet the requirements of high pressure injection. To improve the injection pressure, the pressurizing module and the hydraulic circuit were designed, and their influence on the product quality was explored via molding experiments. The relationship between the system pressure of injection molding machine and the injection pressure was demonstrated. The experimental results showed that the maximum injection pressure of the injection molding machine with the pressurizing module was improved from 204 MPa to 320 MPa, up 56.86 %. The lack of materials, bubbles, sags of products were gradually weakened until finally disappeared with increasing the injection pressure. The pressurizing module was convenient to be assembled into or removed from the injection molding machine without damaging the original structure, and the state of pressurizing or no pressurizing could be transformed easily during the injection molding process. These results indicated that this technology was easy to be popularized and applied. Note de contenu : - EXPERIMENTAL : Materials - Module structure and principle - Relationship between injection pressure and system pressure - Experimental instruments - Design and manufacture of the specimen - Experimental plan - RESULTS AND DISCUSSION : Effect of pressurizing module on density and crystallinity - Effect of pressurizing module on the tensile strength - Effect of pressurizing module on the impact strength - Effect of pressurizing module on the shrink mark - Effect of pressurizing module on the internal structure DOI : 10.3139/217.3364 En ligne : https://drive.google.com/file/d/1BjzKs3rqykYqsbuRfMlaYNP3sogIkhy3/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=30168 [article]

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In-line density monitoring of rigid PVC foam during extrusion process / N. H. Abu-Zahra in INTERNATIONAL POLYMER PROCESSING, Vol. XV, N° 4 (12/2000)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XV, N° 4 (12/2000) . - p. 348-354 Titre : In-line density monitoring of rigid PVC foam during extrusion process Type de document : texte imprimé Auteurs : N. H. Abu-Zahra, Auteur ; H. Chang, Auteur Année de publication : 2000 Article en page(s) : p. 348-354 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : An ultrasound-based sensor has been investigated to monitor the density of rigid PVC foam, in-line, during the extrusion process. A 2.25 MHz ultrasound transducer was used to measure the acoustic properties; i.e. speed of sound, acoustic impedance, and attenuation, in the polymer melt prior to exiting the extrusion die. A special transducer adapter and wave reflector were incorporated in the design of the extrusion die. The density of PVC foam was varied by varying the blowing agent content in the resin compound prior to extrusion. A mathematical derivation of the behavior of ultrasound waves in the melt is presented and used to calculate the attenuation coefficient of the polymer melt at various foam densities. An empirical relation was derived between the calculated attenuation coefficient of the polymer melt and the measured density of the foam extrudate. This relation can be used to estimate the foam density based on the acoustic measurement of the melt in the extrusion die. Further work is proposed to normalize for the effect of variations in the melt temperature and pressure on the ultrasound measurements. DOI : 10.3139/217.1614 En ligne : https://drive.google.com/file/d/1p_WdW-c4vlRZuAIeL8H6t85CRzqe-Y3D/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=16145 [article]

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