The wool fiber length is generally divided into natural length and straight length. The natural length is the linear distance between the two ends of the fiber in the natural crimp state, also known as the wool length. The tuft length of raw wool and washed wool is generally measured. The length of wool fiber after eliminating bending is called straightening length. The fiber length in the wool top is generally measured as the straight length. There are two methods to measure the fiber length in wool top: comb length analyzer method and hand array method.
The length of wool varies with the variety, sex and feeding conditions of sheep. The length of fine wool is 5-12 cm, the length of semi fine wool is 5-15 cm, and the length of hybrid wool is 7.5-15 cm. The length of male wool is longer than that of female wool, and the length of wool under good feeding conditions is longer.
Wool length not only affects the quality of wool textile products, but also determines the spinning system and process parameters. When the number of spinning yarn is fixed, the wool length is long, the strength of spun yarn is high, the evenness is good, and the spinning breakage rate is low. When the short wool percentage in wool length index is low, the yarn evenness and yarn defects are few.
