Variations in Yarn Properties Caused by a Series of Design Changes in a Friction Spinning Machine

Abstract

The structure of friction open-end yarns made with a much modified DREF 3 friction spinning unit with replaced suction rolls and equipped with a comber roll assembly from a Platt 881 rotor spinning unit was studied and found to be dissimilar to that of ring spun yarns. Migration theory, as it is known in ring spinning, was inadequate for friction spun yarns. Classical tracer fiber studies allowed yarn structure to be characterized, and fiber extent was poor. Of the three fiber shapes found in the yam, two had characteristics of very poor fiber extent. A series of design changes was evaluated by characterizing yarn structure and measuring yarn properties. Two methods of fiber feed were compared: applying the fibers first to the ingoing roll with subsequent transfer to the yarn tail, and applying the fibers directly to the rotating yarn tail. Changes in comber roll design led to improved fiber orientation prior to assembly onto the yarn tail and, ultimately, to improved fiber length utilization in the yarn. The design of a blank beneath the nip of the suction rolls was used to restrain fluid turbulence in the nip. The fiber feed angle had distinct effects on yarn structure and properties.