3D-printed minimalists / Heinz Gross in KUNSTSTOFFE INTERNATIONAL, Vol. 109, N° 1-2 (01-02/2019)  

[article]  inKUNSTSTOFFE INTERNATIONAL > Vol. 109, N° 1-2 (01-02/2019) . - p. 40-43 Titre : 3D-printed minimalists : Improved extrusion head designs thanks to additive manufacturing Type de document : texte imprimé Auteurs : Heinz Gross, Auteur ; Sebastian Gross, Auteur ; J. M. Nóbrega ; Joao P. O. Vidal Année de publication : 2019 Article en page(s) : p. 40-43 Langues : Anglais (eng) Catégories : Fusion sélective par laser La fusion sélective par laser (selective laser melting en anglais) est une technique de fabrication additive capable de produire des pièces métalliques à l'aide de lasers de haute puissance, faisant fusionner progressivement et localement, c'est-à-dire de façon sélective, une poudre métallique dans une atmosphère contrôlée. Impression tridimensionnelle Malaxeurs et mélangeurs Matières plastiques -- Extrusion Simulation par ordinateur Têtes d'extrusion Index. décimale : 668.4 Plastiques, vinyles Résumé : The development of additive manufacturing processes, such as selective laser melting (SLM), has significantly extended the options for manufacturing extrusion heads. Extrusion head designs can now be realized with very slender geometries, which not only have integrated mixer functions, thereby improving the melt homogeneity, but can also be used to attach the mandrel to the head. This allows compact heads to be manufactured with a very high potential for saving operating costs. Note de contenu : - An innovative head design avoids weld marks and reduces the number of invidual parts - Design challenges - Head for a small-diameter tube - Blow molding for a parison - Head for thin tubes - Figure : Size comparison: the mixer spider-type head mounted on the extruder, which is manufactured by an additive process, without the heating tapes, weighs 480 g ; the conventional head lying below it in the catch basin weighs 32 kg - Fig. 1 : A spider-type head manufactured conventionally, with radial adjusting screws for centering the die - Fig. 2 : Section through the innovative pipe head in perspective view - Fig. 3 : Air channel that follows the profile of the wall of the honeycomb system - Fig. 4 : Tube head with tilt die and axial setting screws during the testing at Siro-Plast GmbH - Fig. 5 : Mixer-spider-type head with counterrotating spiral mixer spider legs : 3D view and mounted on the trial extruder - Fig. 6 : Simulation results of a color exchange trial after 5 s ; figures top left : with supporting air channel ; figures bottom left : channel section rotated through 90 degrees without the disruption of the melt stream by the supporting air channel. Blue : original color; red: color purged out of the channel with the blue melt - Fig. 7 : Color exchange trials : the improved mixer spider-leg system results in uniform colors over the entire cross-section of the samples, which were removed at different times during color exchange trials - Fig. 8 : Cutaway view of a one-piece mixer-spider-type head with an innovative Integrated supporting air-channel system and a sensitively adjustable tilt die En ligne : https://drive.google.com/file/d/1CtB4_4kYnN_-sTEmwiaIHeKZ_aZVpB5s/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=31825 [article]

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A 3D simulation analysis of reactive flow in screw elements of closely intermeshing twin screw extruders / Ederley Ortiz-Rodriguez in INTERNATIONAL POLYMER PROCESSING, Vol. XXVII, N° 4 (08/2012)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXVII, N° 4 (08/2012) . - p. 442-451 Titre : A 3D simulation analysis of reactive flow in screw elements of closely intermeshing twin screw extruders : Scale-up calculations Type de document : texte imprimé Auteurs : Ederley Ortiz-Rodriguez, Auteur ; C. Tzoganakis, Auteur Année de publication : 2012 Article en page(s) : p. 442-451 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Ecoulement permanent Extrudeuse bi-vis Modélisation tridimensionnelle Peroxydes Polypropylène Rhéologie Simulation par ordinateur Index. décimale : 668.9 Polymères Résumé : The peroxide-initiated degradation of polypropylene in conventional screw elements of closely intermeshing twin-screw extruders is analyzed by means of a three-dimensional (3D) simulation approach. The 3D simulations of the reacting flow are implemented under the assumption of steady-state flow conditions, and scale-up considerations are addressed by simulating screw elements of two different size extruders. The effects of the initial peroxide concentration and reference mass throughputs on processing parameters are analyzed in terms of the specified extruder size. In this study, the scaled-up mass throughput is determined under the assumption of constant residence time. For the implemented processing conditions, the final values of the weigh-average molecular weight (Mw) and polidispersity index (PDI) for both the reference and scaled-up screw elements are similar when the flow rate is close to that corresponding to the maximum conveying capacity of the screw elements. For more restricted flow conditions, however, lower values of both the Mw and PDI are obtained for the larger screw element. Additionally, a previously proposed scale-up procedure from one-dimensional (1D) simulations is evaluated by means of a 3D simulation analysis. The results of this evaluation show a good agreement between the trend of the 3D and 1D simulation results. Note de contenu : - Modeling considerations - Set up of the simulations and processing conditions - Discussion and results : Genral scale-up calculation analysis - Thermal time analysis DOI : 10.3139/217.2568 En ligne : https://drive.google.com/file/d/1X1cNmVTFhJmSjh-difgAne0WIojvpuB0/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=15767 [article]

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3D simulation of nanostructures replication via injection molding / Jordi Pina-Estany in INTERNATIONAL POLYMER PROCESSING, Vol. XXXII, N° 4 (08/2017)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXXII, N° 4 (08/2017) . - p. 483-488 Titre : 3D simulation of nanostructures replication via injection molding Type de document : texte imprimé Auteurs : Jordi Pina-Estany, Auteur ; Andres-Amador Garcia-Granada, Auteur Année de publication : 2017 Article en page(s) : p. 483-488 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Imagerie tridimensionnelle Matières plastiques -- Moulage par injection Nanostructures Polypropylène Simulation par ordinateur Index. décimale : 668.4 Plastiques, vinyles Résumé : The purpose of this paper is to shed light on how and when 3D simulations are preferable over 2D simulations in order to predict the replicated height of nanocavities via plastic injection moulding. Simulations are necessary since not all the cavity is copied depending on geometrical and injection conditions. A 3D simulation is preferable over a 2D simulation in two cases: (i) when the heat transfer through the walls parallel to the simulated domain is not negligible and (ii) when the polymer final shape is relevant. This work explains when 2D simulations like the more commonly found in the literature are not enough to obtain reliable results and how to obtain such results by means of a 3D simulation. Note de contenu : - SIMULATION PROCEDURE : Macro simulation settings - Nano simulation settings - RESULTS AND DISCUSSION : Replicated height - Frozen polymer shape DOI : 10.3139/217.3383 En ligne : https://drive.google.com/file/d/1SyC9bxVmgAEEyoO01aOGkm930r4-TL3l/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=28905 [article]

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Absorption of water by molded plastics / Maik Brehm in KUNSTSTOFFE INTERNATIONAL, Vol. 110, N° 7 (2020)  

[article]  inKUNSTSTOFFE INTERNATIONAL > Vol. 110, N° 7 (2020) . - p. 43-46 Titre : Absorption of water by molded plastics : Numerical simulations help to describe and understand diffusion processes Type de document : texte imprimé Auteurs : Maik Brehm, Auteur ; Achim Frick, Auteur Année de publication : 2020 Article en page(s) : p. 43-46 Langues : Anglais (eng) Catégories : Déformations (mécanique) Diffusion (physique) Humidité -- Absorption:Eau -- Absorption Polyamide 66 Résistance des matériaux Simulation par ordinateur Index. décimale : 668.4 Plastiques, vinyles Résumé : What does the simulation of a diffusion process have to do with the simulation of a temperature field ? Simply put, they share the same differential equation. This property can be exploited in such a way that diffusion processes can be simulated with the aid of finite element programs. Such numerical simulation vividly reveals how such processes take place and how water absorption can influence the design of molded plastics. Note de contenu : - Change in mechanical properties - Standards and guidelines - Analogy between diffusion and heat transfer - Validation illustrated with the example of a plate - Demonstrator part - An open housing - Figure : Test setup and simulation: How does a component behave after three years of water absorption? A simulation quickly provides information, e. g. about water saturation, deformation and (in the figure on the right) the von Mises equivalent stress - Fig. 1 : Water absorption of polyamide 66 over time when aged in 40 °C warm water according to : The change in water absorption over time varies with the thickness of the specimen, but the saturation value remains the same. A simulation conducted on a specimen thickness of 2 mm shows good agreement with the experimental curve - Fig. 2 : FE model of the demonstrator: The meshing was carried out with ten hexahedral elements across the wall thickness. The more elements provided across the thickness, the better the transient diffusion process can be modeled. The simulations were carried out on a quarter model with symmetry boundary conditions - Fig. 3 : True stress-strain curves for PA66 at 20 °C : As the water content increases, the rigidity and strength of the material decrease - Fig. 4 : Water saturation, deformation and stress over time (shown as a quarter model) : Maximum deformation occurs after 116 days, while maximum stress in the steady state occurs only after 1157 days - Table 1 : Comparison of the equations for diffusion and heat transport - Table 2 : Material properties for PA66 immersed in water at 40 °C: these are required for a diffusion simulation En ligne : https://drive.google.com/file/d/1A8iWNphqOMEm2sMIflO542q5fVYKOH36/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34817 [article]

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Accurate simulation of the four modes of post-die extrudate shape distortion / M. Gupta in INTERNATIONAL POLYMER PROCESSING, Vol. 36, N° 1 (2021)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. 36, N° 1 (2021) . - p. 69-78 Titre : Accurate simulation of the four modes of post-die extrudate shape distortion Type de document : texte imprimé Auteurs : M. Gupta, Auteur Année de publication : 2021 Article en page(s) : p. 69-78 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Chlorure de polyvinyle Filières d'extrusion Fluides, Mécanique des Matières plastiques -- Extrusion Rhéologie Simulation par ordinateur Terpolymère acrylonitrile butadiène styrène Index. décimale : 668.4 Plastiques, vinyles Résumé : A combined flow, thermal and structural analysis is employed to simulate post-die extrudate distortion in different profile dies. All four factors which can cause extrudate distortion, namely, non uniform exit velocity distribution, extrudate shrinkage, extrudate draw down, and deformed shape of the calibrator or sizer profile, are simulated. To analyze the effect of exit velocity variation on extrudate distortion, the parameterized geometry of a simple profile die is optimized using an extrusion die optimization software. The simulation results presented for a bi-layer profile die successfully demonstrate how gradually changing profile shape in successive calibrators/sizers can be used to simplify the die design for extrusion of complex profiles. The predicted extrudate shape and layer structure for the bi-layer die are found to accurately match with those in the extruded product. Note de contenu : - INTRODUCTION : Non-uniform exit velocity - Cooling shrinkage - Extrudate draw down - Calibrator or sizer profile - GOVERNING EQUATIONS : Fluid flow and structural mechanics equations - Extrusion die optimization - MATERIAL PROPERTIES - RESULTS AND DISCUSSION : Effect of velocity distribution at die exit on extrusion distortion - Effect of cooling shrinkage on extrusion distortion - Effect of post-die draw down on extrudate distortion - Effect of calibrator or sizer profile on extrudate distortion - Table 1 : Properties of ABS and PVC used in this work DOI : https://doi.org/10.1515/ipp-2020-3995 En ligne : https://drive.google.com/file/d/1qY_XNA26AXe00d8KSO7vnQzaDLURTLLl/view?usp=shari [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36352 [article]

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Adidas : le PUR au coeur d'une démarche innovante / V. Rouiller in CAOUTCHOUCS & PLASTIQUES, N° 814 (06-07/2003)

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Advanced geometry modelling for 3D woven fabrics in composites processing and performance analysis / Xuesen Zeng in JEC COMPOSITES MAGAZINE, N° 82 (07/2013)  

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Air permeability and moisture penetration performance of leather from a microscopic view / Zhong Anhua in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 99, N° 1 (01-02/2015)  

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All about plasticizing screws / Filipp Pühringer in KUNSTSTOFFE INTERNATIONAL, Vol. 111, N° 4 (2021)  

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Améliorere la simulation des pièces à fibres de verre / Valérie Hosdez in PLASTIQUES & CAOUTCHOUCS MAGAZINE, N° 862 (11/2008)

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An aeronautics and space-oriented research group / Bruno Castanié in JEC COMPOSITES MAGAZINE, N° 122 (07/2018)  

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An engineering model that simulates pantographing occurring in the shaping process of reinforced uncured rubber parts / B. Debbaut in INTERNATIONAL POLYMER PROCESSING, Vol. XXXII, N° 1 (03/2017)  

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An integration of microstructure predictions and structural analysis in long-fiber-reinforced composite with experimental validation / Huan-Chang Tseng in INTERNATIONAL POLYMER PROCESSING, Vol. XXXII, N° 4 (08/2017)  

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Analyses des sillons viscoélastiques lors d'un contact entre une pointe rigide et la surface d'un polymère / H. Pelletier in MATERIAUX & TECHNIQUES, Vol. 96, N° 3 (2008)  

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Analysis of hybrid structures : easy and efficient / Christian Witzgall in ADHESION - ADHESIVES + SEALANTS, N° 1/2016 (2016)  

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Analysis of superimposed influence of double layer gas flow on gas-assisted extrusion of plastic micro-tube / T.-K. Liu in INTERNATIONAL POLYMER PROCESSING, Vol. XXXV, N° 2 (05/2020)  

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Analysis of the no-flow criterion based on accurate crystallization data for the simulation of injection molding of semi-crystalline thermoplastics / V. Hondros in INTERNATIONAL POLYMER PROCESSING, Vol. XXXIII, N° 3 (07/2018)  

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Anisotropic simulation of short fiber-reinforced plastics / Vanessa Kett in KUNSTSTOFFE INTERNATIONAL, Vol. 112, N° 2 (2022)  

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Annular extrudate swell of a fluoropolymer melt / Evan Mitsoulis in INTERNATIONAL POLYMER PROCESSING, Vol. XXVII, N° 5 (11/2012)  

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Application of molecular dynamics computer simulations to evaluate polymer–solvent interactions / Armando Gama Goicochea in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 9, N° 3 (05/2012)  

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