A study of polymer-mold contact during injection molding cycle
Résumé
Injection molded parts often show several types of surface defects. Different authors mentioned that those defects are due to the interaction between the mold and the melt. This contact has a strong influence on the flow front behavior, and depends on processing parameters like melt and mould temperatures, ram speed during injection, mould surface properties and roughness, mould thickness and polymer melt rheological properties … After a literature review of "flow marks" defect, it appears that the "alternate flow marks" are caused by an instability of the Fountain flow front. An assumption proposed by some researchers is that the slip is the formation mechanism of this instability. We assume that this mechanism is the start of the flow front instability during the filling stage. We use numerical simulations performed with Forge2 commercial software, in order to generate non-symmetrical contact boundaries conditions. We introduce some sliding conditions at the wall during a flow between two parallel plates. Our preliminary computations confirm that the instability is created in this way.
Domaines
Sciences de l'ingénieur [physics]
Origine : Fichiers produits par l'(les) auteur(s)
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