Causes of the Gloss Transition Defect on High-Gloss Injection-Molded Surfaces

Jinsu Gim, Eunsu Han, Byungohk Rhee, Walter Friesenbichler, Dieter P. Gruber

    Research output: Contribution to journalArticleResearchpeer-review

    6 Citations (Scopus)


    The gloss transition defect of injection-molded surfaces should be mitigated because it
    creates a poor impression of product quality. Conventional approaches for the suppression of the
    gloss transition defect employ a trial-and-error approach and additional equipment. The causes of
    the generation of a low-gloss polymer surface and the surface change during the molding process
    have not been systematically analyzed. This article proposes the causes of the generation of a
    low-gloss polymer surface and the occurrence of gloss transition according to the molding
    condition. The changes in the polymer surface and gloss were analyzed using gloss and
    topography measurements. The shrinkage of the polymer surface generates a rough topography
    and low glossiness. Replication to the smooth mold surface compensates for the effect of surface
    shrinkage and increases the surface gloss. The surface stiffness and melt pressure influence the
    degree of mold surface replication. The flow front speed and mold temperature are the main factors
    influencing the surface gloss because they affect the development rate of the melt pressure and the
    recovery rate of the surface stiffness. Therefore, the mold design and process condition should be
    optimized to enhance the uniformity of the flow front speed and mold temperature.
    Original languageEnglish
    Article number2100
    Number of pages16
    Issue number9
    Publication statusPublished - 15 Sept 2020

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