A Mold Surface Treatment for Improving Surface Finish of Injection Molded Microcellular Parts

Micro-cellular foaming technology draws attention due to the enhancement of mechanical strength, which has been considered as a weak point of current plastic foaming technology. Foam materials produced by this technology offer improved consistency and homogeneity of cell structure, which can result in products with superior properties and uniformity ⁽¹⁾ . Thus it is widely used for commercial purposes and its market is now growing significantly. However, since the foamed injection parts have swirl marks on its surface, this technology has limited uses such as interior products, in spite of its diverse merits. In this paper, we propose surface treatment of the mold as a way to remove the swirl mark. We injected simple shape specimens with PP and PC/ABS materials and measured the surface quality values such as roughness and gloss. Also we researched the foaming characteristics of both treated and untreated surface using SEM analysis.