Influence of process parameters on packing density of open-end and core-sheath friction spun yarns

The effect of opening roller speed, difference in drum speed and suction air pressure on packing density parameters of open-end and core-sheath friction spun yarns has been analyzed using the Box-Behnken method and response surface equations. The trends of change in packing density with process variables are found to be opposite to those of yarn diameter. Yarn diameter decreases, and helix angle and packing density increase with the increase in suction air pressure for open-end and core-sheath friction spun yarns. Core-sheath friction yarns have lower yarn diameter and helix angle, but higher packing density than open-end friction yarns.