Abstract
Abstract
The consistency of polymer melt production in the injection-moulding process has been studied using a Taguchi design-of-experiment method for acrylonitrile butadiene styrene (ABS) and high-density polyethylene. Systematic experimentation with injection-moulding machine settings helped to establish both qualitative and quantitative process understanding in attempting to control the melt quality, assessed here by the shot weight variability. Optimum machine settings were determined which gave the lowest variations in the shot weight. In the case of ABS, uncontrollable influences (noise factors; here the injection stroke and moisture content) were incorporated in the study in such a way that the optimum levels recommended by the analysis make the process (i.e. shot weight) insensitive to variations caused by the noise factors. The set melt temperature and screw-back pressure were observed to be the most influential control factors affecting the shot weight variability for both polymers.