Research on twists in core and sheath layers of staple core-spun yarn produced by coaxial roller with different diameters

A novel method for producing cotton/polyester staple core-spun yarns was introduced in this study to fully exploit the advantages of composite staple yarns. A coaxial roller with different diameters was installed on the ring spinning machine to assist in the production of the staple core-spun yarn. In addition, given the challenge of accurately measuring the twist of the staple core-spun yarn using a traditional twist tester, image technology was employed to measure the twists in the core and sheath layers. Models were established to correlate the process twist (the twist set on the spinning machine) with twists in the core and sheath layers of the staple core-spun yarn. The effects of the core proportion and process twist on the yarn properties were studied and statistically examined using analysis of variance. The results indicated that the twists in the core and sheath layers were linear functions of the process twist. The core exposure ratio of the staple core-spun yarn increased with an increase in the core proportion and first decreased and then increased with an increase in the process twist. The tensile properties, yarn evenness, and hairiness of the staple core-spun yarn improved with an increasing core proportion. The analysis of variance results confirmed that the core proportion and process twist significantly influenced the tensile properties, yarn evenness, and hairiness of the staple core-spun yarn. Furthermore, there were statistically significant differences in the properties of the staple core-spun yarn and ring-spun yarn at the 95% confidence interval.