Abstract
In this article, we study the effect of various spinning and folding parameters on the yarn quality for ring, open-end and hybrid folded yarn. Statistical models are established to predict a total quality index and the optimum spinning and folding conditions. The results indicate that the folding twist factor has the most important effect on the open-end, hybrid and ring folded yarns quality. The yarn linear density has also the most significant effect on the ring folded yarns quality, but has no effect on the open-end and hybrid folded yarns one.