Recently, Air jet textured yarns from polyester multi filaments are widely used in different field such as carpet industry. One of the most important matters in using, is durability and stability. Therefore, investigation the effect of air jet variables on filaments damages is very important in texturing process whereas the control of these effective parameters guarantees durability of yarn in different usage like carpets. The present research investigates the effect of air jet variables on filament damages by consideration of the cross section of polyester multifilament in different conditions of air jet processing. In this investigation, the air jet variables of feeding rate and air velocity were changed and different indexes of fiber cross section such as area, eccentricity, equivalence diameter, hydraulic diameter, perimeter and solidity were measured by image processing method. The conclusions have some remarkable implications in making decisions about choosing adjusting processing parameters for different consumptions.
