Fibre Migration in Short-Staple Spinning Systems

Fibre migration — the cyclic radial movement of fibres between the core and surface of a yarn during twist insertion — is fundamental to the performance of short-staple spun yarns. This article presents a comprehensive treatment of the physics and mathematics underlying migration, augmented with tribological analysis of the fibre–traveller interface and statistical evidence linking migration parameters to yarn quality. Eight quantitative figures illustrate: (1) helix geometry, (2) migration velocity vs. twist, (3) population balance along the yarn axis, (4) wrap count vs. twist, (5) tensile strength vs. wrap count (with regression statistics), (6) tribological friction models, (7) hairiness index vs. migration balance, and (8) evenness CV% vs. twist multiplier. Practical implications, model limitations, and future research directions are discussed.