Impact Cutting of Wool

Abstract

Wool fibers are “impact cut” with a rotating blade made from piano wire at various positions along the fibers. The force transmitted to the base of the fibers decreases markedly when a critical velocity (from 140 to 270 m/s) is exceeded, with corresponding improvement in the cut surface. The velocity of the wire required for impact cutting varys according to the length of the fiber above and below the impact position; fibers with long lengths above the wire impact position are impact cut at lower wire velocities than shorter fibers. Fibers impact cut above the critical wire velocity are cut by tensile failure of the fiber, produced by the inertia of the fiber being accelerated by the impacting wire. To prevent damage to the fiber tip, the feed rate of the cutter into the wool should be high. Impact cutting may be a viable means of harvesting wool from skins or even live sheep.