Strand oscillator assembly for choppers and method

A chopper for separating one or more rapidly moving items selected from a group consisting of fiber, filament, strands, string, wire, strip, and ribbon into short segments comprising a blade roll, a working surface on a backup roll for the blade roll to work against an idler roll for forceably pressing the one or more items against the working surface close to a nip between the blade roll and the working surface, a guide roll for guiding the one or more items, a shaft for supporting the guide roll, and an assembly for oscillating the guide roll back and forth along its axis, the improvement being that the oscillating assembly comprises a mechanism for translating a rotational motion into an oscillating lateral motion of said shaft in directions parallel to an axis of said shaft, an electric servo motor for providing the rotational motion and a programmable controller for said servo motor, the oscillating assembly located to guide the items onto the working surface at least about 0.75 circumferential inch upstream of a nip between the idler roll and the working surface and wherein the programmable controller is programmed to cause the servo motor to pause for at least 5 seconds at reversing points in the oscillating path of said shaft.