AUTEX Research Journal, Vol. 7, No 1, March 2007 © AUTEX http://www.autexrj.org/No1-2007/0188.pdf 1 A STUDY ON SPINNING LIMITS AND YARN PROPERTIES WITH PROGRESSIVE CHANGE IN YARN COUNT IN FRICTION SPINNING R. Chattopadhyay and S. K. Sinha* Department of Textile Technology, Indian Institute of Technology, Delhi, India, *Department of Textile Technology, National Institute of Technology, Jalandhar, India Abstract: The spinning limit for three different fibres (cotton, viscose rayon and polyester) on a Dref-3 friction spinning machine has been investigated. The change in yarn properties with progressive change in count has also been reported. The count range has been seen to be dependent on fibre type. As one progresses from very coarse to fine counts, the yarn tensile property remain fairly unaltered for cotton, but changes for polyester and viscose yarns. Key words: spinning limit, Dref-3, friction spinning, yarn property, twist Introduction Every spinning system produces yarn over a certain count range, and the limit of this range varies from system to system. As an example, in ring spinning the technologically possible range is 295 tex (2 s N e ) to 3 tex (200 s N e ) and for rotor spinning 590 tex (1 s N e ) to 10 tex (60 s N e ). However, the technologically possible count range differs from the economic or commercially viable count ranges. The commercial count range is usually narrower, and is limited by quality and cost considerations. The range of count that can be successfully spun and the type of fibres that can be processed testifies to the capability of the spinning system and possibilities of its commercial success. Modern machine manufacturers constantly aim to extend this count range so that it overlaps the medium count range (between 20 s Ne and 30 s Ne) where maximum production takes place for better market penetration. The following figure shows the economic count ranges of different spinning systems [5]: The spinning limit usually refers to the production of the finest yarn count from a given fibre with acceptable qualities and an end breakage rate below a tolerable threshold. The commercial value of a fibre depends upon its spinning limit. It is important to know why a system fails to spin beyond a certain count on both the coarser and finer sides. A clear understanding of the mechanism of yarn formation and the way the fibre parameters interact with the spinning process can lead to further improvement in the machine design with a view to widening the count range. Many people have