Determining Residual Torsional Energy Limits in Plied versus Alternate Feed Single Jersey Knits
Plied yarns neutralize torsional spirality within the strand cross-section, while alternate feeds distribute opposed stresses across alternating courses.
Z-Twist
Angular Alignment
Structural orientation where surface fibers incline toward the right when held vertically forms the predominant twist direction for ring-spun single yarns. Spinning frames impart z-twist by rotating travelers clockwise around ring spindles during drafting and package winding. The visual spiral corresponds to the central diagonal stroke of the letter Z.
Structural Torque
Rotational force imparted during twisting gives single yarns structural integrity, holding short staple fibers together against tensile loads. Higher twist levels increase yarn tenacity up to an optimum critical limit, beyond which excessive fiber strain reduces tensile strength. Right-hand torque in single yarns creates spirality tendencies in knitted structures, requiring balancing during fabric formation.
Plying z-twist singles with opposing twist vectors cancels internal torque, yielding dimensionally stable ply yarns.
Fabric Slant
Woven fabric structures utilizing z-twist warp yarns produce pronounced diagonal twill lines when paired with right-hand twill weave patterns.
Verification Standard
Laboratory technicians measure twist direction and turns per inch using automated untwist-retwist instruments per ASTM D1423. Inspectors verify that single cotton yarns meet specified twist multiplier values prior to warping or knitting operations. Deviations in twist angle alter fabric hand feel, dye pick-up rates and surface sheen across finished fabric lots.