Since production of air-jet spun yarns began in the early 1980s, it has often been said that sliver cleanliness is of paramount importance in terms of both yarn quality and spinning performance. The target coarse trash percentage in a 50/50 polyester/cotton blend has usually been quoted as 0.05%. In order to achieve this level of sliver cleanliness, however, a textile plant must usually extract a fairly large percentage of waste in the cleaning line and at the card. This, of course, results in economic loss because good fiber is inevitably lost in the waste. In addition, the aggressive cleaning action required places stress on the fiber. This research was conducted to scientifically determine the effects of trash size and trash level in polyester/cotton sliver on air-jet spinning performance and yarn quality.

Two bales of cotton with varying amounts of trash content and trash size distribution were used in the study. For each bale, settings at the fine opener and card licker-in were changed in order to obtain three levels of trash content. Therefore, a total of 6 sliver conditions were created. Sliver from each condition was spun into 34/1 yarn. The total number of stops and the nature of the stops were recorded during spinning. Quality measurements were made on the yarn from each condition.