Statistical modeling of polyester filament yarn evenness with respect to some melt spinning parameters

This study deals with employing central composite design (CCD) as a design of experiment (DoE) tool for finding an appropriate model representing the evenness of polyester fully drawn yarn (FDY). Main effects of parameters like melt temperature, quenching air velocity, winding speed, draw ratio, and the position of the bobbin on the coefficient of variation (CV) of the FDY were examined. The interactions between significant factors were detected by the analysis of variance. CCD model showed that the quenching air velocity has no significant effects on the CV values. The special effects of the winding speed and melt temperature are higher than that of draw ratio and the position of the bobbin. Final model predicted the minimum CV values of 1.72–1.78% at 15 melt spinning conditions. Optimal CV value (1.72%) was achieved at the melt temperature of 283.8 °C, quenching air velocity of 41.0 m/s, winding speed of 4391.7 m/min, draw ratio of 2.89, and the position of 0°. It was also revealed that the average tensile strength of the PET filament yarns decreases from 44.73 ± 1.13 to 40.50 ± 0.81 cN/tex as the unevenness increases from 1.8 to 3.0. These results indicated that the CCD is well capable of analyzing, modeling, and optimizing the evenness of the PET filament yarns.

Graphical abstract

A lay out of melt spinning process and the variation of CV versus quenching speed and temperature.