ORIGINAL ARTICLE Improving yarn quality through multi-response optimisation of electronic yarn clearer in winding machine Susanta Kumar Gauri Received: 10 December 2009 / Accepted: 13 December 2010 / Published online: 20 January 2011 # Springer-Verlag London Limited 2011 Abstract One of the essential post-spinning operations of yarn is winding. In winding machine, ring yarn (i.e. the yarn produced in ring frame) is passed through electronic yarn clearer (EYC) and wound into empty conical-shaped pack- ages called cones. The purpose of EYC is to improve the yarn quality as much as possible by eliminating the various types of faults or irregularities, e.g. thin places, thick places and neps from the ring yarn. The process engineer in an Indian spinning mill was facing the problem of inaccurate detection of faults by the EYC, which led to higher number of winding breaks as well as yarn irregularities. Aiming to tackle the problem, Taguchi’sL 27 orthogonal array experimentation was carried out. The experimental data are analysed using weighted principal component (WPC) method and principal compo- nent analysis-based grey relational analysis that take care of correlation among multiple responses. The WPC method is found to give better optimisation. By using the optimal settings, sensitivity of the EYC to detection of faults increased and thus, yarn quality improved substantially. Keywords Yarn quality . Correlated responses . Multi-response optimisation . Taguchi method . Electronic yarn clearer (EYC) 1 Introduction Raw cotton after processing at several stages of operations is converted to yarn of required count in ring frame (spinning machine) and wound into bobbins. One of the essential post-spinning operations is winding. At a time, several bobbins are fed into a winding machine. Yarn from each bobbin is passed through an electronic yarn clearer (EYC) with some tension given to the yarn and wound into an empty conical-shaped package called cone. Because of the given tension, the weak places that are present in the ring yarn are removed. On the other hand, the purpose of the EYC is to improve the ring yarn quality as much as possible by elimination of various types of faults or irregularities, e.g. thin places (TP), thick places (TKP) and neps (NP) (thick places of very high amplitude) from the ring yarn. Depending on the customer’s requirements, however, some additional post-spinning operations, e.g. assembly-doubler winding and two-for-one twister are carried out after winding operation and then packages of yarn are shipped to the customers. Quality of shipped yarn is characterised by the quantities of various types of faults or irregularities present in a given length of yarn [1]. More is the number of irregularities in the yarn, higher will be the end breakage rate during subsequent weaving/knitting operation and poorer will be the appearance of the woven/ knitted product. The woven/knitted product with poor appearance when dyed will produce uneven shades of colour [2, 3]. Researchers have carried out several investigations on the winding operations aiming to improve the yarn quality. Rae [4] has presented results of an investigation of some factors influencing the extension of a woollen yarn during winding and of its subsequent relaxation. Babaarslan et al. [5] have shown that an uncontrolled high winding tension in an open-end spinning system can cause yarn breakage and a non-uniform tension in the yarn at cone winding. They proposed a mathematical model of the system and demonstrated how the model can be used to predict the yarn S. K. Gauri (*) SQC and OR Unit, Indian Statistical Institute, 203 B.T. Road, Kolkata 700108, India e-mail: susantagauri@hotmail.com Int J Adv Manuf Technol (2011) 56:387–396 DOI 10.1007/s00170-011-3163-3