A study of influence of the delivery rubber roller on yarn properties

In this study, a mechanical model was introduced to analyze the hair wrapping via a contact surface in the yarn formation zone. Worsted and ramie/cotton rovings were then used to produce yarns on an experimental ring frame with and without a delivery rubber roller to validate the theoretical analysis. Yarn properties, including hairiness, unevenness, and tensile properties were tested and the results indicated that the delivery roller could stop fibers from escaping from the twisting process in the spinning triangle and wrap most of them onto the stem of the yarn. In particular for worsted spinning, yarn unevenness CV, as well as tensile properties, was improved significantly due to an improved arrangement of the worsted strand when using the front delivery rubber roller. However, yarn evenness and tensile properties deteriorated for ramie/cotton yarn spun with a delivery rubber roller. This was mainly because of the high modulus of the ramie/cotton blend strand, as upstream twists were blocked and a weak spinning zone was formed to incur an unexpected drawing.