Signal Analysis of Dynamic Forces Experienced by Individual Needles in High Speed Needle Punching

Abstract

Dynamic forces experienced by individual needles are measured and investigated in time and frequency domains to deduce the needle force signal due to fiberweb resistance during penetration and withdrawal of the needles from the fiberweb. A technique de veloped to deduce a needle force signal due to fiberweb resistance for the entire nee dling cycle for any number of cycles enables the determination of peak penetration force, peak stripping force, and penetration and stripping energies due to fiberweb resistance. The force parameters are essential to loom and needle manufacturers for design purposes. Equally important, the force parameters are related to needled fabric end use performance. This relationship can be used to produce consistent fabric prop erties by controlling the process variables that influence needle force parameters.