Effect of runner and gate configuration on the performance of D-LFT composite parts
Notice bibliographique
Résumé
Direct long fibre thermoplastics (D-LFT) composites based on polypropylene and glass fibre (PP/GF) are widely used for the manufacturing of semi-structural and structural automotive applications that include front-end carriers, running boards and door carriers, among other parts. The D-LFT process has a number of advantages when compared to the two step pre-compounded LFT pellet process, of which the most relevant are the cost reduction associated to the elimination of an intermediate step of producing pellets, the flexibility of modifying material formulations in-house at convenience and the reduction of heat and shear history of the material. Among the various configurations commercially available for D-LFT systems, two processes were considered for the present project. In the first process reinforcing fibres are fed and mixed with a molten polymer in a twin screw compounder and then extruded into a rectangular cross-section profile. This extrudate (sometimes referred to as a "log") is automatically cut to a specific length and transferred by a robot arm to a vertical compression moulding press where the polymer/fibre compound is moulded to the desired shape. The moulding can be done by means of direct compression of the log or by its placement into a mould shot-pot device that actuates after the mould is completely closed. A second approach involves the use of an injection moulding compounding unit, comprised of a twin screw compounder and a shot-pot (incorporated this time into the compounding-injection unit) that discharges material through a long nozzle into the sprue of the mould in similar fashion as the conventional injection moulding process. This paper deals with the hypothesis that the differences in the geometry of the flow channels for these two approaches affect the length, dispersion and distribution of fibres in the polymer matrix. It has been well documented in literature that fibre length affects the mechanical properties of the composite material while dispersion and distribution affect the uniformity of these properties ['"]. A systematic analysis of composite material produced with the two processing methods described above was carried out. A Coperion-Dieffenbacher D-LFT system, using a shot-pot mould, and a Coperion-Husky, using the compounding-injection moulding process, were employed to mould identical parts under similar compounding conditions. Samples were taken from the parts for a comparison of the respective fibre lengths and distribution patterns of the two moulding technologies using the micro computed tomography (CT) scanning technique. A characterization of fibre length distribution was performed on the samples using image analysis software after pyrolysis. Resulting mechanical properties were compared to provide a comprehensive picture of the two processing technologies.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».