International Journal of Textile Science 2015, 4(1): 9-19 DOI: 10.5923/j.textile.20150401.02 The Influence of Some Process Parametres on Rotor Spun Yarn Quality Produced from Recycled Cotton Spinning Wastes Md. Khalilur Rahman Khan 1 , Ronobir Chandra Sarker 2 , Habibur Rahman 1,* 1 Department of Textile Engineering, Bangladesh University of Business and Technology (BUBT), Dhaka, Bangladesh 2 Department of Mathematics, Bangladesh University of Business and Technology (BUBT), Dhaka, Bangladesh Abstract Rotor spun yarns from recycled cotton spinning wastes were manufactured by means of rotor spinning process and tested for yarn imperfections and strength.Results of studies are examined the effect of cleaning intensity,cylinder speed and combing roller speed of rotor frame by using box and behnken experimental design. Observing the value of co-efficent of determination,it can be said that the properties of yarn imperfections affectedsignificantly by our selected parametres in compared with the incidence of yarn strength. Yarn imperfections (Thick place and Neps) results improve with increasing cylinder speed although higher cylinder speed shows slightly different results in case of yarn neps. Increase of opening roller speed improves yarn imperfections quality at lower cleaning intensitysetting of UNIclean and although further increase of opening roller speed hardly improves the results of yarn neps(+280%) but increases the value of thick place in yarn. Lower cleaning intensity setting gives better rotor yarn strength produced by using 100% recycled cotton wastes. Experiments based on a 60 tex rotor yarn indicate that our selected independent variables influence rotor yarn quality not linearly but quatradically with few exceptions. Keywords Rotor Spun Yarn, Recycled Waste, Imperfection, Strength, Box and Behnken Design 1. Introduction The open-end rotor system is the only real alternative to ring spinning for producing coarser yarn counts with the successful processing of fiber at significantly higher speeds [1]. In rotor spinning it is common to spin useful yarns from waste or by adding waste to the normal raw material [2]. It is of interest to note that waste spinning units are being installed. This indicates that profits are better in them, since the raw material, namely wastes from spinning mill, is relatively cheaper to give better returns [3]. It is very common in spinning mill to produce rotor spun yarn using recycled fibers. Since recycled fibres have limitations in aspects of processing, so it can be said that it is necessary to reach a compromise when setting the parametres of process those depend on mainly raw materials, desired yarn quality and machine running conditions. Beater speed has a positive correlation with fibre quality,that is, fibre rupture and fibre neps [5]. The beater speed is directly proportional to the relative amount of waste viz. grid bar setting & its cleaning intensity [6]. The efficient * Corresponding author: mhr_ratu@yahoo.com (Habibur Rahman) Published online at http://journal.sapub.org/textile Copyright © 2015 Scientific & Academic Publishing. All Rights Reserved opening at blow room stage not only improves fiber cleaning but also yarn properties such as yarn tenacity and total imperfections [7]. We had selected the setting of cleaning intensity in UNIclean machine for as one of the process parametres in our investigation to spin yarn from 100% cotton recycled fibre. The process of carding drastically changes the fibre orientation in sliver. Card cylinder speed is one of the influencing factor of carding machine to perform the better carding action. Fibre individualization,neps removing efficiency and hooked fibre formation has a relation with cylinder speed. Since fibre arrangement in sliver leads to eventually good or bad yarn quality,so card cylinder speed behaviour with recycled wastes in which most of the short fibre are present should be known during spinning of cotton recylced wastes. In rotor spinning optimum opening is a prerequisite for yarn quality and running behavior. [8] The task of opening roller in rotor frame is to open the carded or drawn sliver fed to the spinning box into individual fibers and at the same time to separate the fibers from the trash. Pinar N. Duru et al reported that the opening roller in the OE rotor spinning system, influences yarn quality and spinning performance [9]. Certain raw materials, especially when using 100% cotton recycled wastes, careful selection of opening roller speed is required. The most suitable speed can be chosen on