Influence of a Yarn Extractive Nozzle on the Apparent Loss of Twist in Rotor Open-End Acrylic Staple Spun Yarns

The influence of a yam extractive nozzle on the apparent loss of twist or "residual twist" has been studied for rotor open-end acrylic staple spun yarns. Four factors were studied: two quantitative factors - yam linear density at three levels and yarn twist multiplier at five levels, and two qualitative factors - three nozzle types and four rotor types. The analysis of results showed that both rotor type and extractive nozzle type exert a significant influence on residual twist, which tends to increase when the nozzle produces an increasing false twist effect on the yam and to decrease when yarn friction against the rotor increases. Residual twist increases significantly in a linear manner with both yarn linear density and twist multiplier. The nozzle type interacts significantly with all other factors (rotor type, yam linear density, and twist multiplier). An inter action between yarn linear density and twist multiplier has been also detected. Generally both nozzle type and twist multiplier exert a significant influence on the residual twist coefficient of variation.