Spirality of weft-knitted fabrics: Part I—Descriptive approach to the effect

55-59The nature, origin and characteristics of the spirality effect have been examined in detail. The distinction between the spirality effect and other fabric distortions contributes towards the verification, by experiment, that the prime reason for spirality is the yarn twist liveliness

Direct determination of yarn snarliness

23-28The formation of snarls that takes place in the yarns in post-spinning processes, such as winding, warping, weaving and knitting, has been studied. This defect is due to the excessive yarn twist liveliness (torsional buckling) and causes great trouble to the manufacturers of yarns and fabrics. Biased testing techniques are used for the measurement of this defect. A snarling testing apparatus PRIANIC and an unbiased testing technique have been developed and are reported. The investigation of factors such as yarn package form, yarn twist factor, time elapsed between production and processing stages of yarns and yarn conditioning show the significant role they play in the reduction of yarn snarliness. </span

Spirality of weft-knitted fabrics: Part II—Methods for the reduction of the effect

60-64The effect of yarn steam setting and fabric washing on spirality has been studied and a brief description of a yarn treatment, based on the false twisting process, worked out towards the solution of this problem is given. The results indicate that a possible method for the reduction of the spirality effect should include a real reduction in the twist liveliness or torque existing in the yarns

Spirality of weft knitted fabrics: Part IV—Effect of yarn partial detwisting on yam and fabric properties

209-215The alteration in the yarn properties that possibly occurs during the detwisting process has been experimentally studied. A small reduction in yarn tenacity and hairiness and slight changes in other yarn properties have been observed. It is shown that the yarn steam setting is essential for getting the best results in spirality reduction. The avoidance of any time delay between yarn detwisting and fabric knitting contributes positively to the minimization of fabric spirality

Spirality of weft knitted fabrics: Part III— An innovative method for the reduction of the effect

202-208The effect of partially detwisting steam-set yarns on spirality is studied. It is observed that partial detwisting reduces significantly and in some cases eliminates the spirality of weft knitted fabrics produced from singles ring-spun yarns. As this technique is applied, two phenomena appear that disobey the rules concerning the relationship of yarn twist direction, twist liveliness and fabric spirality, indicating that these three factors are inter-related with the yarn torque