Gear Pump Performance in Polypropylene Filament Yarn Uniformity

Abstract We report the development of a high resolution computerized monitoring system for fiber melt spinning and the results of its application to polypropylene fiber production. Variation in pack pressure caused by the melt pump was found to significantly affect the uniformity of the filament linear density. In this study, the variation in the pack, or gear pump outlet, pressure during polypropylene fiber melt spinning is correlated with various process parameters and the resulting fiber characteristics. We found the coefficient of variation in pump discharge pressure to decrease with increasing pump capacity and pump speed. The coefficient of variation in pack pressure was directly correlated with the coefficient of variation in filament yarn uniformity. Pump wear was found to have a marked impact on the variance in pack pressure.