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Abstract
Plied yarns, which are considered as yarns with specific characteristics and properties, are important in many textile manufacturing processes and various applications.
Since, the single yarn is not expected to behave in the same manner in the plied state as it would behave outside the plied structure, therefore, it was important to investigate the effect of certain machine and yarn parameters on the final plied yarn properties.
So, an attempt was carried out in this work to investigate the effect of, the type of the plied yarn package winding unit, the variability due to the difference in the spindle positions and doffing stages, ply to single yarn twist ratio, single yarn twist, single yarn type, yarn count and plying direction, on plied yarn, turns/in, tensile strength, elongation, tenacity, evenness and number of imperfections. This was accomplished by producing four different plied yarn package sizes and testing them in terms of the previous mentioned properties.
It was found that, if no modification is applied to the feeding roller on the two-for-one twister machine, the produced plied yarn turns/in will suffer long and short term variation, unlike, the turns/in of the plied yarn, produced from ring twister machine, which was more or less the same as the required turns/in.
It could be concluded that plying has improved the plied yarn tested properties and reduced their coefficient of variation.
It can also be concluded that, the rate of improvement in tensile strength of cotton plied yarn with respect to twist, was almost the same for the ply yarn twist and the single yarn twist and that the increase of single yarn twist caused the plied yarn strength to increase. There was a continuous improvement in elongation with increase in plied yarn turns per unit length, however, the twist of singles and plying have to be raised to high values to increase substantially the elongation of the plied yarn. Regarding plied yarn evenness, in the scope of this study, single and ply twist levels didn’t affect the evenness of plied cotton yarn, as the increase in ply to single yarn twist ratio didn’t alter the incidence of thick places and neps in the different ply yarn constructions.
It was confirmed that, the variability, resulting from different spindle positions and doffing stages, caused statistical difference in plied yarn turns/in, when the turns/in of the four plied yarn packages, was compared. This difference was reflected as statistical difference in plied yarn tensile strength, elongation and tenacity.