Predicting the Actual Strength of Open-End Spun Yarn Using Mechanical Model Resty Mayseptheny Hernawati 1, a ,Valentinus Galih Vidia Putra 2,b and Irfandhani Fauzi 3,c 1, 2, 3 Sekolah Tinggi Teknologi Tekstil, Bandung, Indonesia a resty.mayseptheny.h@gmail.com, b galih_vidia@yahoo.com, c fauzi.fandhani@gmail.com Keywords:predicting, yarn, strength, rotor speed, rotor diameter, rotor, take-off nozzle, Open-End spun yarn Abstract On this journal, modeling relation of rotor speed and rotor diameter toward yarn tension on take-off nozzle has been validated by theoretical approach and numeric computation.It shows that value of yarn tension is F=(1,4.10 -13 )Tt n R 2 d R 2 [cN]. Excessively high spinning tension always results in an intolerable increase in yarn breakage. This paper presents a comparative study of theoretical and reference-based experimental result for predicting the actual strength of open-end spinning system. 1. Introduction According to Lawrence[1], Open-End (OE) spinning has several advantages over ring spinning, such as increased production rate, separation of twisting and winding, possibilities of full automation of yarn spinning, and elimination of speed frame and winding. Rotor spinning, friction spinning and vortex spinning systems are three major methods of yarn manufacture developed on the principle of open end spinning. According to Gunter Trommer[3], the characteristic of all OE spinning processes is the teasing out of the sliver into individual fibres, followed by reassembly of the fibres and their twisting into the end of the yarn, enabling the twist imparting and yarn winding processes to be performed independently by two different mechanisms. The essential features of the open end spinning process are thus drafting, fibre transport, fibre alignment, cleaning (if necessary), fibre condensation, twisting, yarn removal and winding[1]. Individual fibres are being twisted at the yarn peel-off point. According to Vaclav Rohlena[2] and Gunter Trommer[3], tenacity [cN] has tendency to arise until take-off nozzle point. According to Gunter Trommer[3], value of yarn tension is (1,4.10 -13 )Tt n R 2 d R 2 [cN]. Spinning tension, which inevitably increases as rotor speed increases with constant rotor diameter in the rotor spinning process, is ultimately limited by fibre strength. Excessively high spinning tension always results in an intolerable increase in yarn breakage. Tension yarn breaks take place in the already spun yarn, normally between the take-off nozzle and take-up rollers, leaving a short, broken yarn end in the rotor groove. The cause of tension yarn breaks is always excessive spinning tension, which affects the weakest yarn point i.e. the point, between the take-off nozzle and the take-up roller. According to Gunter Trommer[3], yarn tension in the centre of the take-off nozzle should therefore no exceed from 1/10 until 1/15 of the fibre strength. In addition to yarn quality, running performance plays a major role in evaluation of a spinning process. Running behavior is often expressed in terms of the number of yarn breaks per unit mass of yarn. According to Lawrence[1], the stability of the rotor spinning process decides whether a problem such as trash particles, foreign fibres, dust,etc., will result in a yarn break or not. Spinning stability in rotor spinning is largely influenced by the following four factors. One of those factors is Σ the numbers of fibres in the yarn cross-section. According to Gunter Trommer[3], finer fibres permit a correspondingly finer yarn count in accordance with the minimum number of around Z > 900-110 fibres necessary on average in the yarn cross-section in rotor spinning. Applied Mechanics and Materials Vol 780 (2015) pp 69-74 Submitted: 2015-02-25 © (2015) Trans Tech Publications, Switzerland Accepted: 2015-04-16 doi:10.4028/www.scientific.net/AMM.780.69 All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans Tech Publications, www.ttp.net. (ID: 36.72.133.106-07/05/15,11:49:10)