Optimizing mold design and molding conditions can often be a very inefficient, time-consuming and costly process. Simulation is one approach to improve this undesireable situation. However, most simulations have focused on selecting molding conditions to minimized the harmful effects of weld lines, prevent short shots, reduce warpage, etc. Few studies have targetted reduced cycle times and volumetric shrinkage. In this study we have developed a simulation technique to minimize cycle time and improve dimensional tolerance. A new algorithm to relate injection temperature and pressure to cycle time and shrinkage will be described.

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This report describes tests of polymer-filler mixing in a co-rotating twin screw extruder using polypropylene (pp) and talk and investigations of ways to increase the throughput.
The throughput was found to decrease with increasing filler content and decreasing filler particle size.
On the other hand, the melt flow rate of the polymer was found to have little influence on the throughput. Further understanding of the mechanism of mixing in the twin screw extruder was obtained by pulling out the screws from the barrel and observing the mixing process along the screws.

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