Determination of Optimum Twist Equation for the Long Staple Combed Cotton Ring-Spun Yarn

The aim of this research was to determine the optimum twist equation for ring-spun yarns. The yarn twist can be calculated by different equations. With the research, we tried to find the appropriate equation to determine the yarn twist, which is determined by the values of yarn strength and hairiness. In the research, yarns from long staple combed cotton rovings and of different fineness (10 tex, 11.8 tex, 20 tex and 29.4 tex) were analyzed. The yarn twist was calculated using the equations of Koechlin and Laetsch. The analyzed yarns were produced in the spinning mill on the laboratory ring spinning machine Spinntester. In the second part of the investigation, yarn strength and hairiness were analyzed as a function of yarn twist. The results showed that Laetsch’s equation is suitable for determining the twist for yarns with a fineness of 10 tex, 11.8 tex, 20 tex and 29.4 tex, since, in this case, the calculated number of yarn threads is higher and thus the strength and elongation at break are also higher. The yarn hairiness is higher in analyzed samples for yarns with the twist calculated according to the Koechlin’s equation.