Abstract: The paper established a mathematical model of carding index of the top comb, and analyzed the relationship between the number of comb teeth for single fiber and the tooth density of top comb. The effect of tooth density of top comb on combing and yarn quality of long-staple cotton was studied via keeping the other process parameters of the comber unchanged and changing the tooth density of the top comb respectively. The results show that properly increasing the tooth density of top comb is beneficial to eliminate the short fibers and neps in the laps, improve the yarn evenness and enhance the yarn strength. If the tooth density of the top comb is too high, it will cause fiber damage, which will increase the content of short fibers and neps in combed sliver and weaken the yarn quality. The tooth density of top comb should be reasonably selected based on the grade of raw cotton and the type of spinning. In the production of 9.7 tex long-staple cotton combed yarn, when the tooth density of top comb is set to 32 teeth/cm, the yarn has both good combing quality and yarn quality.

Key words: comber; tooth density of top comb; carding index of the top comb; combing quality; yarn quality