Theoretical Profile of Ring-Spun Slub Yarn and its Experimental Validation

A mathematical model for the yarn count of ring-spun slub yarn was established to predict the yarn profile based on process parameters such as the fibre length, the velocities of rollers and the time of over-feeding. The theoretical study shows that the slub length depends mostly on the process parameters above. The actual slub length is a fibre length greater than the slub length designed, and the actual length of basic yarn is a fibre length less than the length of basic yarn designed. The validity of the model was then verified using four sets of experiments. The experimental results agreed well with the model predictions and showed that the present model had high prediction accuracy, which may aid in the design and production of a desired slub yarn with controlling spinning parameters.