A Continuous Monitor of Yarn Uniformity During Melt Spinning

Abstract

A yarn-mass variation instrument is described that can be used to provide a continuous monitor of yarn uniforn ity directly on a melt-spinning machine. The mass uniformity of melt spun yarns is a parameter of commercial importance. but uniformity has traditionally been measured off line, at low speeds, and on only a small portion of the yarn package with a Uster evenness tester. The on-line instrument, an Asahi GQ system, gives an indication of yarn uniformity during spinning via 3 readings that are calculated from the varying yarn modulation of a constant AC signal. 'I'he Asahi readings can be related to the conventional Uster values obtained after the yarn has been spun. The uniformity readings can also determine the nature of the mass nonuniformities arising during spinning and can relate the disturbances to specific portions of the process. The mass variation instrument can therefore be used for on line optimization of varn uniformity in the melt spinning process.