Abstract:

In order to explore the factors affecting the wrapping twist and twist distribution, the additional twists produced by the yarn unwinding of the outer wrapping yarn and the twist of the core yarn under the wrapping tension, as well as the size and fluctuation of the additional twist were analyzed. Twist test and comparative analysis of the covered yarn spun with different core yarn speed, linear density, tension and uneven thickness core yarn were carried out. The results show that the twist direction of the additional twists generated by the unwinding of the outer wrapping yarn is the same as the wrapping twist direction, while the twist direction of the additional twist generated by the twisting of the core yarn is opposite to the wrapping twist direction. Depending on the spinning process, the combined effect of the two types additional twists determines the deviation size and distribution uniformity of the wrapping twist. The wrapping twist has the similar twist distribution characteristics to the yarn twist, and the unevenness of core yarn significantly affects the evenness of short-term twist distribution, with less twisting at thick places and more twisting at thin places.

Key words: hollow spindle covered spinning, wrapping twist, additional twist, unevenness of core yarn, evenness of short-term twist distribution