Indian Journal of Fibre & Textile Research Vol.18,March 1993,pp.14-l9 Influence of process parameters on the properties of friction-spun yarns A R Padmanabhan & N Ramakrishnan The South India Textile Research Association, Coimbatore 641 014, India Received 9 June 1992; revised received 23 October 1992; accepted 24 November 1992 The effects of spinning drum speed, yam delivery rate, core-wrapper ratio and number of wrapper slivers on the quality characteristics of yams spun on a laboratory model DREF-3 friction spinning ma- chine have been studied. It is observed that by and large, drum speed and per cent wrapper fibres deter- mine the yarn tenacity while the delivery rate and the per cent core fibre content influence the yam un- evenness. Keywords: Carding drum, Drum speed, Friction-spun yarn, Yarn tenacity, Unevenness, Wrapper fibres t Introduction drafting unit II with different core-to-wrapper ratios The quality of the yarn obtained from any spinn- and at different delivery rates. ing system depends on the quality of raw material In each count, 12 yarn samples, three for each of used as well as on the process parameters employed the four process variables, were produced by suit- during spinning. Friction spinning is no exception to ably altering the spinning parameters as listed in this. While many research workers have studied in Table 2. While varying the parameters, care was tak- detail the influence of process variables on yarn en to ensure that only one parameter was changed at quality in both ring and rotor spinning, such an in- a time, keeping the other three at the following opti- formation with regard to friction spinning appears mum level as suggested by the manufacturer. to be rather limited. Louis et al:' studied in detail the Spinning drum speed : 4000 rpm influence of fibre properties on yarn skein strength Yarn delivery rate : 200 m/min and single yarn characteristics in DREF-3 spinning Core-wrapper ratio : 70/30 and observed that fibre length, strength, elongation No. of wrapper slivers : 5 and micronairc together account for 74% of the yarn skein strength. Thierron and Hunter- studied Due to the poor spinning performance, counts be- the effect of process parameters on the properties of yond 16s could not be spun. About 1 kg sample of polyester and polyester-cotton DREF-3 yarns only. each yarn was produced. This paper reports the results of a detailed study carried out on a laboratory model DREF-3 friction 2.2 Test Methods spinning machine at SITRA to assess the influence of All the yarn samples were tested for-general yarn various process parameters on yarn quality and properties using the standard test procedures and spinning performance. Table I-Fibre properties of MECH cotton 2 Materials and Methods 2.5% Span length, mm 27.2 2.1 Raw Materials and Processing Details 50% Span length, mm 13.0 MECH cotton, whose fibre properties are given Uniformity ratio,% 47.8 in Table I, was processed through the conventional Fibre bundle strength blow room and carding machines at SITRA pilot (118 in. gauge), gltex 19.2 mill and converted into second passage drawframe Fineness, Mc 3.40 sliver of linear density 3 g/m. The drawing sliver Mature fibres, % 56 was then spun into core yarns of 6s, 12s and 16s Half-mature fibres, % 8 counts on a laboratory model DREF-3 spinning ma- Immature fibres, % 36 chine installed at SITRA at a fixed carding drum Maturity coefficient 0.752 speed of 12,000 rpm, keeping one sliver as the core Trash content, % 4.8 in drafting unit I and many slivers as the wrapper in PADMANABHAN & RAMAKRISHNAN: FRIcnON-SPUN YARNS 15 test conditions. Generally, the unevenness of DREF rate. At higher drum speed, the twist becomes more. yarns was found to be high as compared to that of However, the increase is significant in 12s and 16s ring yams. This is mainly due to the chockingofspinn- counts. With regard to single strand strength varia- ing drum by the high short-fibre content (24%) of biliry, no such particular trend is observed. MECH cotton. The average% elongation at break is around 4 for various DREF yarns and is not significantly affected 3 Results and Discussion by the speed of the spinning drums. However, it is The properties of DREF yams produced under always higher for fine count 16s than for 6s and 12s different spinning conditions are shown in Tables for any given drum speed. 3-6. The unevenness of DREF yams varies between 13.7 and 17.3 in 6s, 16.8 and 18.6 in 12s and 19.9 3.1 Eft'ectofSpinningDrumSpeed and 23.8 in 16s for the three drum speeds chosen It is observed from Table 3 that the yam count CV for this study (Fig. 2). In general, yam unevenness % shows no consistent trend With increase in spinn- and imperfections do not show any particular trend ing drum speed in all the three counts. The count with regard to increase in drum speed and yam line- CV of 6.3% noticed at a drum speed of 3000 rpm is ar density. All DREF yams are found to be hairy quite high. This is because sufficient quantity of yam and the average hairiness is around 48 hairs/m. could not be spun at this speed due to frequent end breaks in spinning. On the other hand, the tenacity of DREF yams 10 generally increases With increase in drum speed standablefrom 3000 as to in 5000 friction rpm spinning, (Fig. 1). Thisthe amount is quite ofunder- twist )( :.i insertedspeed of inthe the spinning yam is directly drums influencedand the yam by bothdelivery the ~ ~ : ,~-~-:.=---" >~ ~- l- t:; 4 ~ Table2-Detailsofspinningparameters ~ --6s(98tex) Parameter Processlevels 00 0 12s(~9 tex) X ~ 16s(33 tex) Spinningdrum speed, rpm 3000 4000 5000 Yarndelivery rate, m/min 150 200 250 0 3000 4000 5000 Core/wrapperratio 60/40 70/30 80/20 DRUMSPEED, rpm No. of wrapperslivers 3 4 5 Fig. I-Drum speedvs yarn tenacity Table3 -Influence of drumspeed on DREF yarn quality [Deliveryrate, 200 m/min; Core/wrapper ratio, 70/30; and No. of wrapperslivers, 5] Drum Count Yarnproperties speed Ne (tex) rpm Count U % Imperfections/km ASTM Tenacity StrengthElongation No. of CV % appear- g/tex CV % % hairs/m Thin Thick Neps ancegrade places places 6 (98) 0.61 13.7 0 15 8 C+ 8.00 12.6 3.9 20 3000 12 (49) 0.81 16.8 8 69 46 D 4.78 12.2 3.5 68 16 (33) 6.30 23.8 138 209 176 D 5.85 11.9 5.2 51 6 (98) 1.20 17.3 12 82 135 B 8.33 12.8 3.8 42 4000 12 (49) 0.72 17.5 9 77 46 C+ 6.44 16.4 3.5 46 16 (33) 1.20 19.9 70 188 144 D 6.50 12.1 4.3 59 6 (98) 0.58 14.4 2 28 22 C+ 8.59 10.0 4.1 37 5000 12 (49) 0.75 18.6 18 87 56 C 7.03 14.6 3.4 63 16 (33) 0.92 20.6 70 238 202 D 7.18 13.6 4.5 43 --- 16 INDIANJ. FmRE TEXT. RES., MARCH 1993 30 D d Drum speed and yam linear density seemto have no .3~ rs::e- significant influence on yam hairiness. Appearance 2 0 4(xx)rpm ofDREF yarns IS not significantly affected by drum ~ 5<XX>rpm speed. 1 3.2 Effectof YamDelivery Rate ;! Count CV % is generally low for all DREF yams =' 1 and does not show any particular trend with regard to delivery rate and yam linear density (Table 4 ). The tenacity of DREF yams decreases invariably in all counts as the delivery rate increases from 150 m/rnin to 250 m/rnin (Fig. 3). This is because in DREF spinning, the twist becomes low at higher de- 65(98lex) 125(49tex) 165(33I~x) livery rate due to slippage. But single yam strength COUNT CV % shows an opposite trend with respect to deliv- Fig.2-Drumspeed vsU% ery rate. However, CV % of strength increases signi- ficantly as the count becomes finer barring few cases and assumes minimum value at a delivery rate of 12 150 m/rnin. -65(98 I~x) The % elongation at break is found to decrease 10 0-.-0 .125(49lex) with increase in delivery rate up to 200 m/min and .:; ~--x 165(33lex) thereafter it increases. It also increases gradually as ~ the count becomes finer. ; 8 ~" In general, yam unevenness decreases as the de- S "~_v '" livery rate increases from 150 m/min to 200 m/min ~ ~"" (Fig. 4), but thereafter it shows an increasing trend. ~ 6 ' :--'X For a given delivery rate, yam unevenness increases ~ as the count becomes finer, but the deterioration ap- ~ I, pears to be quite significant at higher delivery rates. Yam imperfections do not exhibit any particular 2 trend with regard to yam delivery rate and yam 150 200 250 count. DELIVERYRATE, m/min Yam appearance, in general, deteriorates gradu- Fig. 3-Delivery rate vsyamtenacity ally by about four grades from B to D between the Table4- Influenceof deliveryrate on DREFyam characteristics [Drumspeed, 4000 rpm; Core/wrapper ratio, 70/30; and No. of wrapperslivers, 5] Delivery Count Yamproperties rate Ne (tex) rn/min Count U % Imperfections/kin ASTM Tenacity StrengthElongation No. of CV % appear- g/tex CV % % hairs/m Thin Thick Neps ancegrade places places 6 (98) 0.56 18.2 28 18 6 B 9.65 10.6 4.2 34 150 12 (49) (}.90 17.6 16 89 32 C+ 8.64 11.0 4.6 22 16(33) 0.95 22.3 181 324 166 D 8.10 12.6 4.9 28 6 (98) 1.20 17.3 12 82 135 B 8.33 12.8 3.8 42 200 12 (49} 0.72 17.5 9 77 46 C+ 6.44 16.4 3.5 46 16 (33) 1.20 19.9 70 188 144 D 6.50 12.1 4.3 59 6 (98) 0.54 14.7 7 26 25 D 4.71 16.3 2.9 116 250 12 (49) 1.07 23.1 251 275 132 D 4.88 15.8 4.2 74 16 (33) 0.80 20.5 83 207 91 D+ 5.47 12.4 4.2 74 PADMANABHAN & RAMAKRISHNAN: FRICTION-SPUN YARNS 17 delivery rates of 150 m/min and 250 m/min.