Studying the fiber positioning in the yarn structure is the essential point to understand the different characteristics of yarns that counted as alternatives to each other. This study explores the packing densities of single-ply, two-ply and Siro-spun spun yarns that have been stated as the alternative yarn types considering the production method or yarn structure. In the study, Modal, Tencel, polyethylene teraphtalete, and cotton fibers represent micro, regenerated, synthetic, and natural fibers were used for the production of the 29.50 Tex yarns. Cross-sectional views of the yarns were acquired according to the hard sectioning method, and the packing densities of yarns were calculated with image processing tools. Yarn packing densities were calculated as the ratio of total fiber area within the yarn cross-section to yarn cross-section. Results showed that single ply ring-spun and siro-spun yarns are in a more circular shape and have greater packing densities values than two-ply yarns. Besides, yarns produced from cotton fibers have the least packing density values in each spinning technology. Similar packing density values were obtained for micro Modal, Tencel, and PET single-ply and siro-spun yarns. Packing density values were also compared with USTER diameter and density values and significant relations between those values were found.

Studying the fiber positioning in the yarn structure is the essential point to understand the different characteristics of yarns that counted as alternatives to each other. This study explores the packing densities of single-ply, two-ply and Siro-spun spun yarns that have been stated as the alternative yarn types considering the production method or yarn structure. In the study, Modal, Tencel, polyethylene teraphtalete, and cotton fibers represent micro, regenerated, synthetic, and natural fibers were used for the production of the 29.50 Tex yarns. Cross-sectional views of the yarns were acquired according to the hard sectioning method, and the packing densities of yarns were calculated with image processing tools. Yarn packing densities were calculated as the ratio of total fiber area within the yarn cross-section to yarn cross-section. Results showed that single ply ring-spun and siro-spun yarns are in a more circular shape and have greater packing densities values than two-ply yarns. Besides, yarns produced from cotton fibers have the least packing density values in each spinning technology. Similar packing density values were obtained for micro Modal, Tencel, and PET single-ply and siro-spun yarns. Packing density values were also compared with USTER diameter and density values and significant relations between those values were found.