Influence of Fiber Geometry on the Punching-Force Characteristics of Webs During Needle Felting

Abstract

This study describes the effects of fiber surface and geometric properties on the punching-force characteristics of webs during the needling process. A small needle loom assembly (consisting of a needle board, stripper, and a bed plate unit) mounted on an Instron tensile tester was used to measure the punching forces generated during the needling process. The punching speed used in this investigation was much lower than that employed in industrial needle looming. The punching force encountered during the second cycle (with and without recovery times between the successive cycles) was used to characterize the efficiency of the needling and fiber reorientation process. It was found that fiber linear density has a profound effect on the punching force of polyester fiber webs, while surface roughness, cross-sectional shape, length and crimp seemed to have little or no effect on the punching-force values. How ever, the interaction of crimp and length, linear density and crimp, and linear density and length had a significant influence on the punching force. Measurements of the punching force in successive cycling experiments showed that, in addition to fiber linear density, fiber length, crimp and cross-sectional shape also significantly affected the recovery behavior of the reoriented fibers.