Experimental validation of polymer composite injection moulding process simulation
Jacek Nabiałek, Dariusz Kwiatkowski, Adam Gnatowski
Quarterly No. 4, 2011 pages 283-287
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abstract The paper presents the chosen results of investigations on polymer flow during the mould cavity filling phase of the injection moulding process. The process is characterized by high dynamics, which causes several technological difficulties, both during injection mould design and during product implementation to the production stage. Greater understanding of the phenomena which occur during filling of the injection mould may lead to more effective design of processing tools and shortening of the time for implementation and production time. The results of computer simulations of the injection process have been compared with the results of video recording of the plastic flow during the filling phase. A specialized injection mould which enables observation and registration of the plastic flow during processing has been employed. The mould enables direct monitoring of the course of the phenomena inside the mould cavity in two planes. Transparent sight-glasses have been used, made of a material called Zerodur® which is characterized by a coefficient of thermal expansion close to zero. To record the flow, a digital video camera has been employed. The camera enabled registration of the flows with the rate of 25 fps. This reduced the scope of the investigations, since at higher plastic flow speeds the registered image became less clear. The video sequences registered during the investigations were later digitally processed in order to ensure in-depth analysis. For the simulation investigations, professional computer software, Autodesk Moldflow Insight 2011, has been employed. The results of the investigations enabled the documentation of specific phenomena which occur during the plastics or their composites injection process. The registered video sequences have been compared to the results of numerical calculations and then it was estimated to what degree the computer simulation of the injection process may be useful in practice. The investigations were performed on a wide scale, however, only chosen results have been presented. As an example, the issue of flowing around a rectangular obstacle of the plastic stream has been described. The obtained results of the investigations are so encouraging that they made the authors continue such experiments.