12—THEORETICAL CONSIDERATIONS IN OPEN-END SPINNING

Two problems are discussed in this paper. In the first, the effect of the deposition of fibres in open-end-spinning systems on the yarn irregularity produced is considered. The drafting operations are divided into two types, that is, System I and System II. System I is the type in which fibres are accelerated when the leading ends arrive at a point or a specified area, and System II is the type in which the trailing ends are accelerated in the same way as those of System I. System II is more profitable if the fibres have non-uniform length, and the leading-fibre-end-density function contains most of the irregularity. The rotating-drum spinning method is also considered from the viewpoint of yarn irregularity, and the range of wavelengths that should be decreased by this method is calculated. The conclusion is that the total draft must be smaller than 2πR/[lbar], where R is the inner radius of the drum and [lbar] is the mean fibre length. The second problem concerns the separation draft. Open-end drafting ...