رضا ثقفی

Needle-Punching process is the main mechanical method used for increasing the strength of fibrous web. The increase in strength is due to an increase in the degree of fiber entanglement within the fibrous web. In this work, the effect of needle-punching parameters such as punch-density and needle penetration depth on tensile properties of needled fabrics has been investigated by assessing fiber orientation.Four samples of needle-punched fabrics were produced using appropriate Carding/Cross-lapping machines. The orientation of the fibers in the samples was determined by use of Radon transform of images of the samples. Breaking strength of the samples in both machine direction and cross-machine direction were determined by using strip method. Results indicate that an increase in amount of punch-density generally leads to variation in orientation of the fibers in the fabrics along its principle directions. It was also found that an increase in the amount punch-density causes a corresponding increase in fiber orientation in machine direction; additionally it was found that the amount of punch-density affects the breaking strength of the fabrics