Search Results (2)

The dynamic regulation of fiber stress distribution in the yarn-forming triangle area is critical for controlling variable composite yarn structures, including siro and sirofil composite yarns. In this study, comparison analyses of the variable geometric structure and stress distribution during the yarn-forming process, which involves step rolls with asymmetrical fiber control, have been carried out using ring-spinning technology. The geometric analyses show that partly staple fibers are continuously controlled while other fibers intermittently lack stress restraint, resulting in cyclically changed helical angles and wrapping density in the yarn-forming triangle area. The yarn structure model displayed that periodically distributed staple fibers occur in siro composite yarn, while sirofil composite yarn shows gradual periodic changes with uniform thickness variations, caused by cyclical changes in the stress distribution between filaments, and the strand altered the yarn-forming zone shapes from symmetrical to offset. Then, a systematic comparison of variable composite yarns with different frequencies (high, medium and low frequency) revealed that low-frequency step roll with wider grooves resulted in an intermittent output of staple fibers with less stress restraint, resulting in more pronounced structural variation in the siro and sirofil composite yarns with a slight yarn quality deterioration. Full article

Stainless-steel fibre hybrid spun yarns are becoming increasingly popular due to their wide range of applications. In this aspect, the cost-effective and scalable processing of such yarns is highly important. Stainless-steel staple fibres are relatively heavier and weaker compared to conventional textile fibres. As a result, the staple spinning processing of these fibres showing higher tensile strength and productivity both at the same time is quite challenging. In this manuscript, we explored a number of spinning techniques to find the optimised method of producing low-twist and high-strength stainless-steel fibre hybrid spun yarns offering the advantage of both quality and productivity. Conventional ring spinning, folding and twisting, and advanced ring spinning techniques (ARSTs) such as pneumatic compact ring spinning and pneumatic compact SIRO spinning were employed in this study. Additionally, the plain and SIRO yarns were produced in two forms using the compact spinning method, one with pneumatic suction active (compact plain, compact SIRO) and other with pneumatic suction inactive (noncompact plain, noncompact SIRO). The tensile properties of yarns were tested and analysed. The results reveal that the tensile properties of conventional ring-spun and plied yarns can be enhanced to some extent by increasing the twist coefficient (TC) and the number of yarn plies, respectively. In contrast, by finding optimised spinning parameters, a substantially higher tensile strength (up to 16%) of yarns, produced at ARSTs, was observed even at the minimum level of TC used in experiments. The findings of the study are extremely valuable in terms of scaling up the production of high-quality metallic fibre hybrid spun yarns at a higher productivity level. Full article