During clearing and winding the yarn for warping, weaving or knitting it has been found that there is deterioration of certain yarn characteristics like strength, elongation, hairiness etc, and the process parameters thus have substantial influence on the final properties of the yarn, concludes Vaibhav Rane.
The transformation of yarn from small ring cops to wound cone includes removal of yarn defects, ie, about 31 in number (excluding classified) or above in case of latest yarn clearing sensors. If these defects are not removed, it can result in:
- Breakage of yarn at every subsequent process, ie, warping to weaving.
- Defective packages at warping and sizing.
- Lowering of efficiency at all stages.
- Introducing the fabric faults at weaving, and
- Poor fabric appearance
Thus, during clearing and winding the yarn for warping, weaving or knitting it has been practically experienced by industry that there is deterioration of certain yarn characteristics like strength, elongation, hairiness, etc [1, 3, 4, 5 & 7]. The process parameters thus have substantial influence on the final properties of the yarn.
Inappropriate tension in winding deteriorates some yarn properties. The yarn in latest automatic winding machines is accelerated from zero metres per minute (mpm) to 1,500 mpm just, in a few seconds and reach up to 2,500 mpm. While being pulled off the bobbin, dragged across several machine elements of different metallurgy & friction coefficients, and forced into a traverse motion at accelerated speed may affect yarn properties.
The claims made by most of the winding machine manufacturers regarding quality of wound yarn, efficiency and overall performance, the industry has experienced deviation in performances on various machines as against that claimed by machinery manufacturers.
Machine geometry aspects like: numbers of yarn bending (deviation from vertical) points, angles of yarn bending throughout the yarn path length, extent of free yarn lengths between bending points and number of free yarn length zones; which affects yarn properties critically according to this research, ie, never been studied earlier by any researcher, which becomes inevitable once the machine is commissioned. But, still on other hand the factor, which is controllable is optimisation of winding process parameters, ie, definable  in terms of the following factors:
- Quality of ring frame yarn.
- Type of fabric construction.
- Acceptance standard for fabric fault.
- Method of fabric manufacturing.
This article is the outcome of a research attempt made to study which machine (or machine geometry) affects the yarn properties most and how.
The experimentation of this kind will be able to resolve following factors:
- Machinery selection
- Settings to be kept for desired yarn properties
Materials and methods
Experimental plan and sample preparation
Five different counts were used: 27s, 32s, 39s, 60s and 95s Ne as standard raw material on three different winding machines which are widely used in Indian textile industry, having respective machine geometries codified as: M1, M2 & M3.
That is done by Taguchi design of experiment (Taguchi DOE) as explained in Table 1, which shows 25 treatment combinations for single machine. These combinations were replicated three times on three winding machines, a total of 75 wound samples were prepared and eight yarn properties were tested by taking ten readings of each (1,00,000 mtr in case of Classimat) and analysis of samples was done by general full factorial design with ANOVA using adjusted SS, keeping a = 0.05
For execution of such experiment equivalent settings were kept on all machines.
In Table 1: S1 to S5 and T1 to T5 are codes of clearer settings and tension, details of which are given in Table 2.
Result and discussion
1. Single yarn strength (SYS)
It has been depicted from Graphs 1, 2 & 4 that M3 gives highest performance, ie, 295.7, 224.7 and 168.3 gm SYS for L5, L23 and L12 group of settings (GS) for respective yarn counts. M1 gives highest performance (Graphs 3 & 5) 174.7 gm & 94.5 gm SYS for L6, L17 & L19 GS for respective counts.
The reason attributed to this are the machine geometries of M3 & M1 (Figures 1 & 3), which shows more number of yarn deflections (bending) from vertical compared to M2, negative sign shows deflection towards left from vertical. Among M3 & M1, M3 shows higher bending angles. The results show mean value 181.6 gm (max) for M3 and effect of machine geometry on SYS found significant having value P = 0.000.
The effect of process parameters did not show any significance for CSP. Though, M3 showed better performance comparatively.
Yarn path on winding machine M1
Yarn path on winding machine M2
Yarn path on winding machine M3
3. Elongation retention%
From Graphs 6, 8 & 9 it is observed that M1 gives superior performance, ie, 5.514, 4.692 & 3.702% elongation retention for L1, L9 & L17 GS regarding respective counts.
M3 gives superior performance (Graphs 7 & 9), ie, 4.167 & 4.217% elongation retention for L23 & L11 GS. The reasons attributed to this are similar to SYS because, SYS and elongation are interrelated. The results show mean value 4.05 % (max) for M3 and effect of machine geometry on elongation retention percent age found significant having value P = 0.000.
M3 shows least hairiness values (Graphs 11 & 12) 7.18 & 7.3 for L3 & L24 GS. M2 shows least hairiness values (Graphs 13 & 15) 6.65 & 3.6 for L6, L16, L17 & L19 GS regarding respective counts. M1 gives least hairiness values (Graph 14), ie, 3 for L11 GS for 60s Ne.
The reason for such performance with respect to machine geometry can be explained by comparing respective machine geometries and design, M2 has straight yarn path up to extent of 81.5 cm from k to g (Figure 2) and in addition Balloon controller systemís interaction produces least hairy yarns, despite having 11 (max) yarn contact points including tensor-box.
The results show mean value 5.17 (min) for M2 and effect of machine geometry and design on hairiness found significant having value P = 0.012.
5. Critically thin places eliminated during winding (CTPE)
The effect of tension levels found significant having value P = 0.022 for CTPE. The results show mean value 44.20 (max) for tension level T2, which clearly means that tension level T2 is most efficient in eliminating critically thin places.
6. Objectionable short thick places eliminated during winding (OSTPE)
The effect of variables used: machine, speed clearer settings and tension did not show any significant effect on OSTPE. Though, M3 and M2 showed better performance comparatively.
The effect of process parameters used did not show any significance but, effect of machine showed some signs by having value P = 0.063 which is nearer to significance level this may be most probably because, during foreign matter and contamination clearing neps are also removed.
8. U% (Unevenness)
The effect of process parameters did not show any significance for U%. Though, M1 showed least unevenness.
1. M3 winding machine produces yarn of highest SYS and highest elongation retention percentage. While M2 produces lowest of both.
2. For CSP, M3 shows highest performance and M1 shows lowest.
3. However, for hairiness M2 gives best performance and M3 gives lowest.
4. M3 and M2 show almost same values for OSTPE.
5. M1 shows maximum CTPE amongst three of the winding machines and M2 shows minimum.
6. As far as neps are concerned, M1 removes highest neps and M2 lowest.
7. M1 produces yarn with minimum U% (unevenness) and M2 produces yarn with maximum U%.
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Note: For detailed version of this article please refer the print version of The Indian Textile Journal March 2012 issue.
DKTES Textile & Engg Institute