The analysis of the influence of fiber length distribution on the theoretical and additional unevenness of yarn

Fiber length distribution has an impact not only on the theoretical unevenness of yarn caused by random fiber alignment, but also upon the additional unevenness caused during processing, especially in drafting. For a given fiber length distribution, there is a discrepancy between the theoretical unevenness of yarn which is calculated with Martindale’s equation and the actual unevenness tested by instrument. In order to reflect the effect of fiber length distribution on the theoretical unevenness of yarn, in this research, a kernel function was used to estimate the probability density function of fiber length, therefore, calculation of Suh’s model for theoretical unevenness was realized. On this basis, the theoretical and additional unevenness of yarn were calculated. The statistical influence of fiber length parameters on yarn unevenness was discussed. It can be concluded that decreasing the values of effective length, length irregularity and 16 mm SFC by weight would improve the uniformity of yarn.