Optimization of speed frmne process paraIneters for better ... - NOPR

Indian Jo urnal of Fibre & Textile Research Vol. 29, March 2004, pp. 39-43

Optimization of speed frmne process paraIneters for better yarn quality and production S M ishtiaquc", R S Rcngasamy & A Ghosh Department o f Tex til e Techno logy, Indian Institut e of Technology, New Delhi 110 016. India

Received 3 April 2003; accepted 16 Jlllle 2003 The innu e nce of n yer speed, top roller pressure a nd size of middl e co ndense r in the drafting reg ion o n v:Jriou s characte ristics of rov ing and ya rn has been studied. The 130x and Behnken factorial design h:JS been used to opti mi ze th ese speed fram e m:Jchine va riab les. In eac h case, the o ptimum co nditi o ns within the industrially acceptabl e limits of the process are establi shed. It is observcd that the n ye r spccd hi g he r than 1040 rpm and the top roller pressure hi g he r Ihan 2.2 k g/c m~ are not s uita ble wi thin the ex pe rime ntal zo ne ex plored. The optim um middle condenser wid th is fou nd to be 8 mm w ith th e present experimental set-up. Keywords: Co nde nser width , Cotl o n, Factorial design , Flycr spccd , Top ro ll e r press ure 7 IPC Code: Int. C I D02G 3/00

1 Introduction It is a recognized fac t th at more than 60% of world yarn production is currently done by ring spinning method. An important machine involved in thi s method continues to be the speed frame . It is desirable to prod uce high quality roving at high production rate under flexible processing conditions. This can be achieved by means of process optimization in speed frame. The literature hardly reports any study regarding the optimization of speed frame parameters. In the present work, an attempt has been made to optimize speed frame process parameters, viz. flyer speed, top roller pressure and size of middle condenser by using Box and Bhenken factorial design I. These factors have been exclusively selected as they influence the machine productivity to a greater extent than other factors, viz. draft distribution and roller setting.

2 Materials and Methods 2.1 Preparation of Samples

The Sankar-6 cotton was processed on a modern Rieter blow room line and Rieter C-4 card. The carded slivers were given two passages through sliver lap former and ribbon lap former and then processed on Rieter E7/5 comber. The combed slivers were

drawn on a Rieter RSI3-8S1 draw frame to produce finisher slivers of 0. 12s Ne. As per as the factoria l design (Table 1), the 15 rovings with 0.9s Ne and 1.34 twi st multiplier were prepared on Lakshmi LF l400A speed frame. The actual levels of variables are given in Table 2. To study the different yarn properties, each roving sampl e was spun into a 30s Ne yarn with 3.79 twi st multipli er on Lakshmi LG/5 rin g frame. The yarn samples were tested for various properties. 2.2 Tes ting of Samples

The Uster tester 3 was ll sed to meas ure the evenness of roving and yarn, yarn imperfections and Table I-Box and l3ehnken des ign for three variables Expt. No

XI

.1'2

X, 0 0 0 0 -I

I

-I

-I

2 3 4 5 6 7

- I

I

8

I 0 0 0 0 0 0 0

9 10

II "To whom all the correspondence sho uld be addressed. Phone: 26591410; Fax: +91-11-26581103; E-mai l: inshtiaque54@ ho tmail.co m

Le vel of variables

12 13 14 15

-I -I -I

I 0 0

0 0 -I

- I I - [

-I I 0 0 0

- I I 0 0 0

INDIAN J. FIBRE TEXT. RES ., MARCH 2004

40

hairiness index. The yarn samples were tested on the Uster Tensorapid 3 for yarn tenacity and elongationat-break. Starting from th e initia l doff to full doff the total breakage was observed for each run of the sa mples in speed frame. The breakage rate was calculated as number of roving breaksll 00 spindle / h.

3 Resul ts and Discussion Experimental res ults for all the 15 samples are given in Table 3. The response surface equation for various roving and yarn characteristics as well as roving breakage rate are g iven in Table 4 along with the square of correlation coefficients between the ex perimental values and the calculated values obtained from the response-surface equations. The ex perimental results have been exp lained with respect Table 2-Actual levels corresponding to coded levels Variable

Flyer speed (XI)' rpm Top roller press ure (xz). kg I cm z Middl e condenser width (x, ), mill

- I

Coded le vel 0

900 1.9

1040 2 .2

8

II

+1

11 80 2.5 14

to the experimental zone considered within th e industrially acceptable limits of each process variable. 3.1 Roving Irregu larity

Figure 1 shows the influence of flyer speed and condenser width on roving in-egu l