Hybrid moulds with epoxy-based composites – effects of materials and processing on shrinkage and warpage / P. G. Martinho in INTERNATIONAL POLYMER PROCESSING, Vol. XXVI, N° 3 (07/2011)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXVI, N° 3 (07/2011) . - p. 256-264 Titre : Hybrid moulds with epoxy-based composites – effects of materials and processing on shrinkage and warpage Type de document : texte imprimé Auteurs : P. G. Martinho, Auteur ; A. Sabino Netto, Auteur ; C. H. Ahrens, Auteur ; G. V. Salmoria, Auteur ; A. S. Pouzada, Auteur Année de publication : 2011 Article en page(s) : p. 256-264 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Matériaux -- Déformations géométriques et dimensionnelles Moulage par injection -- Défauts Moules d'injection Polymères amorphes Polymères semi-cristallins Thermocinétique Thermoplastiques -- Moulage par injection Index. décimale : 668.4 Plastiques, vinyles Résumé : This paper contributes with the analysis of the case of a complex three-dimensional shape that was moulded in a standard steel mould and an alternative hybrid mould with steel cavity and epoxy-based composites cores. The mouldings were produced in semicrystalline and amorphous polymers. Pressure and temperature were recorded at two locations in the cavity. The processing conditions were simulated. The effect of the processing was observed on some dimensions of the part that were used for assessment of the shrinkage and warpage. The results suggest the importance of predicting the regime mould temperature when low thermal conductivity materials are used in moulding blocks. Results also evidenced that in hybrid moulds with resin blocks the shrinkage of the mouldings is a consequence of the specific polymer shrinkage and the deformation of the non-metallic core deformed by the processing pressure. The warpage occurring on these parts is also larger in comparison with conventional steel moulds. DOI : 10.3139/217.2435 En ligne : https://drive.google.com/file/d/1wXHy38Kn2T_X1NFFNEQuP_WVsgglzKic/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=12404 [article]

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Solidification criterion on shrinkage predictions for semi-crystalline injection moulded samples / A. J. Pontes in INTERNATIONAL POLYMER PROCESSING, Vol. XV, N° 3 (09/2000)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XV, N° 3 (09/2000) . - p. 284-290 Titre : Solidification criterion on shrinkage predictions for semi-crystalline injection moulded samples Type de document : texte imprimé Auteurs : A. J. Pontes, Auteur ; R. Pantani, Auteur ; G. Titomanlio, Auteur ; A. S. Pouzada, Auteur Année de publication : 2000 Article en page(s) : p. 284-290 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : The phenomenon of shrinkage in injection moulding is particularly evident in semi-crystalline polymers. During cooling, these materials experience a transition from a completely amorphous to a partially crystalline status, which results in a severe change of all material characteristics, including volumetric parameters. In this study an iPP was injection moulded in a rectangular impression (120mm x 630mm x 62 mm) with a 1.5mm thick line gate. The influence of holding pressure and time, and geometry constraints on linear shrinkage was explored. In-mould shrinkage was measured by means of a recent method based on strain gauges. Experimental results are compared with predictions for shrinkage obtained by C-Mold and a code developed at the University of Salerno, which takes into account crystallisation kinetics. The solidification criterion resulted to be extremely relevant for shrinkage predictions. DOI : 10.3139/217.1594 En ligne : https://drive.google.com/file/d/1ODoaWDUb7LGE1p3TEFUrsf1VD0ZEYdf0/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=15833 [article]

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