Estimation of Cotton Yarns Complex Quality Index Based on the Uster Statistics

One of main tasks in characterization of cotton yarn complex quality index is proper combination of individual yarn properties according to their usefulness in weaving mills. This index can be simply created based on the complex quality indices. The degree of quality (complex

criterion) is here expressed as utility value U [1]. Evidently, general quality of cotton yarns is characterized by various utility properties Ri (i = 1,…m) obtained  from Uster statistics (variation coefficient of yarn fineness, CV Uster, hairiness, variation coefficient of yarn strength, yarn  strength,  deformation at break, deformation work, thick places, thin places, neps). Utility value UÎ<0, 1> aggregates then in some certain way these properties [2].

The purpose of the paper is to describe the construction of this type criterion by using weighting based on the Uster statistics. The application of U will be demonstrated on the example of rotor cotton yarns with different fineness and twist coefficients produced in Czech Republic. The program CQTEX written in MATLAB will be briefly mentioned.

The influence of cotton fiber quality index on the quality index of cotton yarns will be discussed as well.