Semi-worsted products are between worsted and woolen. At present, "semi-worsted" in the industry mostly uses wool spinning equipment and cotton spinning equipment to combine cotton spinning technology with wool spinning technology. Compared with worsted spinning process, the production process is shorter, and a new spinning process has been formed. Its yarn not only has the characteristics of good evenness and smoothness of combed yarn, but also has the characteristics of good handle, good elasticity and fluffy of carding yarn, and has a wide range of spinnable count and strong applicability of raw materials. Compared with carding yarn, the CV value of evenness decreases, and the anti-pilling index also improves.
Semi-worsted technology has taken shape in the industry after recent years of development. Now its products are not only wool yarn, but also cotton, silk and hemp blended yarn. It has penetrated into cotton and silk spinning industries. Semi-worsted yarns have the following characteristics: diversified varieties and miscellaneous raw materials; yarn twist is generally larger than that of cotton yarn and combed wool yarn of the same size, and some products are strong twist yarn, which makes it difficult to untwist when twisting; after dyeing, the strength of single fibre is mostly damaged to varying degrees, especially cotton, wool and cashmere products. Short velvet will be produced during carding, resulting in more frequent defects of yarn, higher shear rate of electro-cleaning and more joints, so the demand for knots is higher; some special semi-worsted yarns have very low single yarn strength, which has a great impact on the quality of knots and the starting tension and speed of windings; yarns are of high grade and customers have a great influence on yarns. The requirement of appearance defect is very high, and the requirement of strength and appearance of the knot is also higher.
In view of the above characteristics, the production of semi-worsted yarn by automatic winder is easy to cause poor twisting and internal quality problems of the bobbin. As far as semi-worsted yarn with high grade and high price is concerned, the control of return rate of automatic winder can not be ignored.
