초록
Ring spinning is a unit operation that is widely used in manufacturing staple yarn and is taken for granted in the textile industry as a standard method for manufacturing staple yarn because of its superior physical properties and its domination of the market share. Recent researches in ring spinning are conducted targeting to improve the yam qualities by introducing new accessory devices which lead to finer staple yarn without loss of linear density, to produce the so called compact yarn. This paper deals with developing a new method that can manufacture compact yarns, while using the conventional ring-spinning method, in that some samples of staple yam are prepared by introducing variously angled grooves to the front roll cylinder ant thus by realizing different nipping time to the fibers that are lying on the same cross-sectional position. This study suggests that the groove angle of front roll cylinder influences the compactness of the ring spun yarn and there exist optimal groove angles that can result in a most compact yarn, depending on the draft ratio. The optimal groove angle ranges from 5 to 10 degrees. In addition, we suggest an index that can be used to define the yarn compactness, i.e., the compactness index defined as the ratio of the yarn linear density to yam diameter. The apparent volume density can also be used as an alternative measure of the yam compactness.
