Mapa da pilosidade H de fios de algodão em sistemas de fiação de anel/viajante trados por nitretação à plasma

摘要

This experimental investigation concerning to cotton yarn quality was conductedin two different textile industries according to USTER® yarn qualitybenchmarks. The results of the Hairiness H of yarn samples representing eachdiary production were tested using ANOVA by means of Statgraphics®Centurion XVI statistical tool. A hairiness H map was designed andsystematically constructed for evaluate the quality of NE 30/1 Cotton CardedKnitting Yarns produced during all the life of travelers running continuously at28 m/s and 42 m/s in two ring spinning machines, with 528 and 1,480 spindles,so constituting two systems, A and B, respectively. Tribological abrasion testswere designed and performed in Laboratory at 3.5 m/s in order to simulateHertzian contact pressures since severe to moderate range for simulate thecontact zone of the ring-traveller system and analyze by Scanning ElectronMicroscopy their main wear mechanisms. Ion nitrided travellers were obtainedby two different processing conditions, C and D, to compose lots of 100 nitridedtravellers for A spinning machine system and 740 nitrided travellers (C and Dschemes) for B system and were experimentally tested in comparison withconventional travellers. Periodical Surface Roughness, Rsm, and NonperiodicalRa, Rq and Rz parameters of nitrided and conventional travellers, inthe Position of Yarn Bath, i.e., the contact zone between the traveller and theyarn, were measured by Atomic Force Microscopy (AFM), in two conditions,new and worn after their service life. The Hairiness H Map developed in thisthesis showed is a useful tool for a broad visualization of the travellerfunctionality, the relevance of its surface treating and the evolution of thesurface roughness during its service life. The nitrided travellers demonstratedlonger life and they produced NE 30/1 Cotton Carded Knitting Yarns with lowerH hairiness that those obtained by conventional travellers.