Voids in short fibre-reinforced injection-moulded parts: density control vs. mass control
Résumé
Injection-moulded thick plates were produced using a short glass fibre-reinforced thermoplastic. We studied the effect of processing parameters on voids rate inside the parts. Voids rate was measured using an optical microscope. Mass and density measurements were compared with each other in order to define the most relevant method for voids detection. The hydraulic holding pressure level is the most relevant process parameter. As this parameter increases, we found a two-domain relationship between density and mass. In the first domain, injection-moulded parts include voids, and mass is proportional to density, with the volume of the part as slope. In the second domain, the slope is different from this volume, parts are void free, but residual stresses appear. We defined an optimum hydraulic holding pressure level, leading to voids free parts. This optimum cannot be detected using mass measurements, but it is easily detectable using density measurements.
Domaines
Sciences de l'ingénieur [physics]
Origine : Fichiers produits par l'(les) auteur(s)
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