INTERACTION OF PROCESS AND MATERIAL PARAMETERS IN AIR-JET SPINNING

The first part of this paper deals with the interaction of first and s econd nozzle pressures in air-jet spinning of microdenier polyester/co tton blended yarns. The results show that the first and second nozzle pressures interact with each other to determine yarn strength. This is because both the number of wrapper fibers and the length of wrappings formed at a particular first nozzle pressure depend on the level of t he second nozzle pressure and vice versa. There is an optimum number o f wrapper fibers and wrapping lengths that yields the maximum yam stre ngth, and this optimum level can be obtained at several different nozz le pressure combinations because first and second nozzle pressures int eract with each other. However, it would be advantageous to use the lo west of these nozzle pressure combinations because of significant savi ngs in energy costs. The second part of this paper investigates the ef fect of yam delivery speed, first nozzle pressure, and blend ratio on the hairiness profile of microdenier polyester/cotton blended air-jet spun yarns. The results show that yam hairiness increases with increas ed yam delivery speed and first nozzle pressure, but decreases with in creasing amounts of polyester in the yarn. Also, the three factors (ya rn delivery speed, first nozzle pressure, and blend ratio) interact wi th one another in determining yarn hairiness.