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Sept.-Oct. 2014

SITRA News

This issue of SITRA NEWS

covers the fol low ing topics:

Page no.

PRODUCTIVITY AND COSTS

30thCosts, operational performance and yarn

quality: Inter-mill study of key factors

(April - June 2014) 1

TECHNICAL NOTES

1. Impurities in a finishing chemical- A case study 5

2. Factors to be considered while selecting needle lubricant

for modern knitting machines 8

3. Cotton stickiness - Issues and solutions

- Part 1 10

CONSULTANCY SERVICES OFFERED BY SITRA

DURING SEPTEMBER OCTOBER 2014 13

STAFF NEWS 14

CONFERENCES AND SEMINARS 16

TRAINING PROGRAMMES 17

ABSTRACTS OF TECHNICAL ARTICLES 19


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SITRA News 1

30thCosts, operational performance and yarn

quality: Inter-mill study of key factors

(April - June 2014)

This study is thirtieth in the series on inter-mill study on Costs,

Operational Performance and Yarn Quality. In this study, 142 mills

had participated. The following are some of the main findings of the

study.

Comparison with last study (April-June 2013)

A comparison has been made with respect to 8 costs and operational

parameters against the last study. Based on the deviations in the

average values, relative changes in the individual mills performance

have been identified with respect to 86 mills which had participated in

both the studies.

In the 2nd quarter of 2014, mills on the whole faced a setback in the

performance by recording a significant fall of Rs 840 per spindle per

year in the contribution (by 14%) as compared to the correspondingquarter of 2013 (Table 1), which was mainly due to the substantial

increase in the raw material cost (by Rs 2940 per spindle per year).

The sale value, however, registered a huge increase of Rs 2280 per

spindle per year which was mainly due to the increase in the yarn

selling price (by 60%) and partly because of the jump in the machine

productivity (40%). The production per spindle and spindle utilisation

respectively registered a marginal increase of 2% and one percentage

point. While the power cost recorded a marginal drop (by Rs 110 per

spindle per year), the salaries and wages cost registered a significantincrease of Rs 290 per spindle per year.


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SITRA News 2

The huge increase in the yarn sale value and a marginal reduction inthe power cost, however, could not off-set the increase registered by

the raw material cost and salaries and wages cost, due to which the

mills had experienced a significant drop in the contribution.

It is interesting to note that almost none of these common mills had

registered a negative contribution in both the studies. Though, on the

whole, these mills had experienced a drop in the contribution in the

30th study, nevertheless, the average contribution earned by them in

the 2nd

quarter of 2014 was fairly high at Rs 5260 per spindle per year.

Further analysis shows that out of the 86 common mills, only one-

third (28 mills) registered an increase in the contribution (by Rs 990

per spindle per year), the increase ranging from Rs 90 to Rs 4470

between mills (Figure 1). The remaining mills recorded a drop of Rs

1760 per spindle per year in the contribution, the drop ranging from Rs

40 to Rs 4930 between mills which was due to the increase in the two

major input costs viz., raw material cost and salaries and wages cost

which more than off-set the increase in the yarn sale value. On theother hand, the increase in the contribution in the 28 mills was largely

due to the increase in the sale value (by Rs 4030 per spindle per year)

and reduction in the power cost (by Rs 150 per spindle per year) which

more than off-set the increase in the two other major input costs (by

Rs 3190 per spindle per year).

Figure 1 Differences in the contribution between the two studies

(Q2 of 2013 and Q2 of 2014)


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Table 1 Comparison of costs and operational parameters betweenthe two studies

Coun t-wise raw m ater ial cost, yarn sel l ing price and NOV

The YSP, RMC and NOV of 18 common counts for which 5 and above

mills had furnished the data in both 29th and 30th studies are given in

Table 2. It can be seen that except in two counts (20s OE and 60s C-

Comp.- Ex.), the mills had faced a setback in the performance during

Q2 of 2014, as compared to Q2 of 2013, by recording about 15% drop

in the NOV. The raw material cost in these 16 counts had registered a

whopping increase of 19% which overshadowed the increase registered

by the YSP (by 3.8%), thereby resulting in the above drop in the NOV.

Even during the adverse trading condition in the Q2 of 2014, in the

combed compact yarns, the drop in the NOV was at lower level (by

about 10%) when compared to that recorded by the remaining varieties

of yarns viz. carded, combed and combed hosiery - both domestic

and export. In fact, the combed hosiery export yarns registered a huge

drop of about 20% in the NOV.

Parameter

Common mills (86) average

29th study

(Apr.- June 2013)

30th study

(Apr.- June 2014)

Contribution - Rs/spindle/year 6100 5260

Salaries and wages cost - Rs/spindle/year 1870 2160

Power cost - Rs/spindle/year 3370 3260

Raw material cost - Rs/kg of yarn

- Rs/spindle/year

135

15150

158

18090

Yarn selling price - Rs/kg 256 268

Yarn sale value - Rs/spindle/year 26490 28770

Prodn./spl./8 hrs.(adj.to 40s) in g 101 103

Spindle utilisation (%) 93 94

Average count 46s 47s


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Table 2Count-wise yarn selling price, raw material costand NOV in the two studies (Q2 of 2013 and 2014)

.

*INCREASE

Raw material cost relat ive to yarn sel l ing pric e

All the 17 ring spun yarns registered an increase in the cotton cost

relative to yarn selling price (by 6 to 12 percentage points) (Table 3).

Count

Yarn selling price(Rs/kg)

Raw material cost(Rs/kg of yarn)

NOV(Rs/kg of yarn)

April -June

2013

April-June

2014

%

inc.

April-June

2013

April-June

2014

%

inc.

Apri -June

2013

April -June

2014

%

reduction

20s OE 135.5 143.6 6.0 94.5 96.3 1.9 41.0 47.3 15.4*

40s K 207.1 212.7 2.7 122.9 142.4 15.9 84.2 70.3 16.5

40s C 234.0 239.0 2.1 138.9 162.0 16.6 95.1 77.0 19.0

60s C 287.4 290.0 0.9 143.5 165.5 15.3 143.9 124.5 13.580s C 351.5 363.0 3.3 154.6 189.9 22.8 196.9 173.1 12.1100s C 441.5 457.8 3.7 174.4 231.6 32.8 267.1 226.2 15.3

40s C-Comp. 245.7 250.5 2.0 141.5 158.2 11.8 104.2 92.3 11.4

50s C-Comp. 295.8 304.1 2.8 146.1 173.0 18.4 149.7 131.1 12.460s C-Comp. 321.0 339.1 5.6 150.0 185.7 23.8 171.0 153.4 10.3

80s C-Comp. 402.3 445.8 10.8 169.2 223.9 32.3 233.1 221.9 4.8

30s CH 205.8 216.4 5.2 136.8 157.7 15.3 69.0 58.7 14.9

34s CH 215.6 226.0 4.8 136.3 156.6 14.9 79.3 69.4 12.540s CH 228.2 232.6 1.9 139.2 163.3 17.3 89.0 69.3 22.1

60s C-Comp.-Ex. 309.7 390.8 26.2 152.3 215.8 41.7 157.4 175.0 11.2*

26s CH-Ex. 221.9 224.8 1.3 143.9 172.4 19.8 78.0 52.4 32.830s CH-Ex. 207.1 221.5 7.0 133.1 162.7 22.2 74.0 58.8 20.540s CH-Ex. 236.2 245.7 4.0 140.9 166.1 17.9 95.3 79.6 16.5

50s CH-Ex. 256.4 262.5 2.4 143.1 162.9 13.8 113.3 99.6 12.1


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Table 3Count-wise raw material cost relative to yarn selling price inthe two studies

* drop

- D.Shanmuganandam & J.SreenivasanLiaison and Consultation Division

1. Impurities in a finishing chemical A case study

A finisher buys a certain chemical on the understanding that it should

not contain more than 3% impurities. When a batch was delivered, five

independent determinations of percentage impurity in the chemical

were made and the results are given in Table 1.

Count

April-

June

2013

(A)

April-

June

2014

(B)

Increase

(percentagepoints)

(A-B)

Count

April-

June

2013

(A)

April-

June

2014

(B)

Increase

(percentagepoints)

(A-B)

20s OE 69.7 67.1 2.6* 40s CH-Ex. 59.7 67.6 7.9

40s C-Comp. 57.6 63.2 5.6 60s C-Comp. 46.7 54.8 8.1

60s C-Comp.-Ex. 49.2 55.2 6.0 80s C-Comp. 42.1 50.2 8.1

34s CH 63.2 69.3 6.1 80s C 44.0 52.3 8.3

50s CH-Ex. 55.8 62.1 6.3 40s C 59.4 67.8 8.4

30s CH 66.5 72.9 6.4 40s CH 61.0 70.2 9.2

60s C 49.9 57.1 7.2 30s CH-Ex. 64.3 73.5 9.2

50s C-Comp. 49.4 56.9 7.5 100s C 39.5 50.6 11.1

40s K 59.3 66.9 7.6 26s CH-Ex. 64.8 76.7 11.9


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Table 1 Impurity level in finishing chemical

Is there sufficient evidence to conclude that the batch contains too

much impurity?

In the present problem,

3.2 + 3.4 + 2.8 + 3.1 + 3.1

Mean value of the 5 impurity determinations =

5

= 3.12Standard Deviation of the 5 impurity values (SD) = 0.217

Standard Error of the impurity values (SE) =

where n is the number of determinations of percentage impurity

Standard Error of the 5 impurity values (SE) = = 0.097

Actual Mean Impurity - Expected Mean Impurity

t value =

Standard Error of Impurity Values

3.12 - 3

=

0.097

= 1.24

Test no. Impurity (%)

1 3.2

2 3.4

3 2.8

4 3.1

5 3.1


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A condensed version of the t table for different degrees of freedom isgiven in Table 2.

Table 2 t values for the different degrees of freedom

(95% significant level)

t value from the statistical table for 4 degrees of freedom (df = No. of

observations - 1 ie. 5 1 = 4) at 95% level of significance is 2.78.

Since the calculated value of t (1.24) is lower than the value given in

the statistical table (2.78), the difference between the two values under

question is not statistically significant.

Hence, it may be deduced that there is no evidence to conclude that

the level of impurities in the delivered batch is higher than the expected

level of 3%.

- Dr. K.P.Chellamani

Spinning Division

Degrees offreedom

t valueDegrees of

freedomt value

1 12.71 13 2.16

2 4.30 14 2.143 3.18 15 2.13

4 2.78 16 2.12

5 2.57 17 2.11

6 2.45 18 2.10

7 2.36 19 2.09

8 2.31 20 2.09

9 2.26 21 2.08

10 2.22 22 2.0711 2.20 23 2.07

12 2.18 24 2.06


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SITRA News 8

2. Factors to be considered while selecting a needle

lubricant for modern knitting machines

The basic function of a needle lubricant is to ensure that the needles

and knitting elements of the machine run smoothly with minimum wear

even under high temperature and pressure so that the optimum life of

the machine is realized. Some of the parameters that need to be

considered while selecting a lubricant oil for modern knitting machines

are discussed below.

a) Oil viscosity

Optimum viscosity of oil ensures that the oil has the appropriate

thickness at normal machine operating temperature. Too low oil

viscosity leads to quicker drain out of the oil from the machine surfaces

and does not warrant the presence of oil film on the machine parts

requiring lubrication. This could lead to premature wear of the knitting

elements. If the oil is too viscous, cold starting of the machine will be

difficult and the oil may not flow sufficiently between the moving parts

as clearances are reduced when the machine heats up and expands.

Too viscous oil can result in the machine running at a higher than

expected temperature, again possibly compromising the wear rate.

Mostly, the required viscosity levels are recommended by the knitting

machine manufacturers. ISO 22 viscosity grade oils are the most widely

recommended oils for modern machines though ISO 15 and 32 grade

oils are suggested in a few cases.

b) Oil additives

The choice of additives incorporated in oils is critical. Additives may

be used to modify the frictional properties of oil but primarily are used

to give improvements in the anti-wear performance, oxidation resistance

and corrosion resistance. Modern knitting machines are engineered

with close machine tolerances, have steep cam angles and high

peripheral speeds and potentially operate 24 hours a day, all demanding

a very high performance in terms of the anti-wear properties of the oil.

Anti-oxidants reduce the rate of oil deterioration and prevent the rapid

formation of sticky or resinous deposits. Corrosion resistance is


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SITRA News 9

important for the protection of the machine.

c) Compatibility with machine components

The oil selected should have good compatibility with the materials

used in the manufacture of modern machines viz., plastic components,

electric cabling, rubber seals, electronic actuators and not the least,

machine paints.

d) Scourability

The needle oil in consideration should not only lubricate and protect

the machine but also have a part to play in ensuring the production of

good quality fabric. Hence, the oil should be selected keeping in mind

the type of fibres / yarn being knitted and the processing / finishing

route of the fabric when it leaves the knitting machine. In case of

splashing onto the fabric, the oil stain thus formed on the fabric should

be easily scourable. The lubricant oil should display superior

scourability from cotton, cotton / synthetic or 100% synthetic fabricsand effective scouring performance from fabrics knitted from dyed yarns,

mlange yarns and protein fibres such as wool / silk.

e) Suitability for elastane yarns

Special type of oils are to be used in the knitting of fabrics containing

elastane yarns, where the fabric is heat-set prior to the scouring

process. Ordinary oils disintegrate and stain the fabric at high

temperatures applied during heat-setting. Hence, the need for suchspeciality oils.

f) Presence of heavy metals

Lubricant oils should be free from heavy metals such as Lead, Nickel,

Manganese, Arsenic, Copper, Chromium, etc in order to be environment

friendly. Also, this is one of the requirements of organic certification

and a few other Eco labels that the lubricant oils used in manufacturing

site should be free from heavy metals or if present, the metals shall bewithin the allowable limits that are prescribed in the respective

standards.


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The typical characteristics of a needle lubricant shall be as given below:

ISO viscosity grade : 22

Viscosity @ 400C : Approx. 22 cSt

Viscosity Index : 95 to 96

Density @ 150C : Approx. 0.86 to 0.89 kg /l

Cloud point : Below 00C

Flash Point : Above 1300C (SETA)

Ionic nature : Non-ionic / Anionic

The oils suitable for Elastane yarns can be of Non-ionic / Cationic in nature

pH Value : Approx. 4.5 as 10% emulsion

Emulsifiability : Self emulsifiable in water

Colour : Pale to Dark yellow

- S. Sivakumar

Textile Chemistry Division

Stickiness of cotton is an universal problem. Cotton being an important

fibre crop for many developing countries like India, several attempts

were made all over the world to overcome this problem. With the advent

of fourth generation high speed processing machines, the problem of

stickiness has assumed greater significance. SITRA has conducted alarge number of studies towards processing cottons with a relatively

higher level of sticking tendency.

Understanding the importance of this parameter in the processing of

cottons, we are commencing from this issue a new series to focus on

these aspects.

The sticking tendency of cotton is mainly due to the non-cellulosic

matter present in cotton. The chemical constituents of a typical cottonfibre are given below in Table 1.

3. Cotton Stickiness - Issues and solutions

- Part 1


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SITRA News 11

Table 1 Chemical constituents of cotton fibre*

Sticky cottons are troublesome at the ginning stage itself by way of

reduced throughput. In the spinning process, deposits form on the

card crush rolls, drawing and comber rolls, and also on the top and

bottom drafting rollers of speed frames and ring frames. These deposits,

in due course of time, build up sufficiently to cause roller lapping andcause disruption of the production process.

At the carding stage, the most acute problem while processing sticky

cottons is the lapping on the card crush rolls and sometimes loading

of fibres on card cylinder. Generally, as thickness of fibre batt passing

between rollers decreases, the sticking tendency of cotton increases.

Yarns produced from sticky cottons are in general, weak, uneven,

neppy and are rated poor in appearance than yarns produced from

non-sticky cottons. Results of experiments conducted at SITRA confirmthe poor spinning performance of sticky cottons in terms of higher

ends down in spinning, higher values of yarn unevenness &

imperfections, etc.

The apparent effect of the sticky nature of cotton is reflected as the

number of roller lappings at various stages of spinning. In other words,

cotton stickiness and roller lapping are respectively the cause and

effect of a particular problem. The causes for roller lapping can be

broadly classified as (i) fibre factors and (ii) machinery factors.

* Henry H.Perkins., Some observations on sticky cottons, Textile

industries, Vol. 3, 1991, pp. 365-373.

Constituent % Dry weight

Cellulose 94.0

Proteins 1.3

Pectic Substances 0.9

Ash 1.2

Wax 0.6

Organic Acids 0.8Sugars 0.3

Others 0.9

Total 100.0


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SITRA News 12

The inherent cotton fibre characteristics like maturity, micronaire value,wax content and other non cellulosic constituents play a greater role

in making the cotton fibres sticky in nature. In addition, certain

contaminants like crushed seeds, immature seeds, oily substances,

etc., also influence the sticking tendency of cotton during processing.

Fibre Fineness

Fibre fineness is an intrinsic property of the type of cotton and it varies

from as low as 2.8 to as high as 6.2 micronaire. As the fibre micronairevalue decreases (fineness increases), the bending rigidity decreases

proportional to the square of micronaire and consequently, the fibre

exhibits greater tendency to follow the curvature of the rollers. Therefore,

loose fibres not held by the twist inserted in the yarn are most likely to

lap over the top or bottom drafting rollers and try to gather enough

fibres from the yarn to cause an end break and subsequently lapping.

It follows from this that finer fibres are more prone to lapping. Moreover,

the lapping tendency increases as the number of fibres coming in

contact with either the top or bottom rollers (area of contact) increases.This also implies that finer fibres will have higher lapping tendency and

vice versa. Cotton fibres with micronaire value lower than 3.0 are

generally found to be lap-prone.

Fibre Maturity

Maturity is a factor indicating the degree of development of a cotton

fibre. Like fibre fineness, the maturity also varies among different types

of cottons and also within a cotton type depending upon the growingand harvesting conditions. Low maturity cottons generally record lower

micronaire values and vice versa. Hence, the mechanism of lapping for

finer fibres also holds good for cotton with low maturity values. Cotton

fibres with number of mature fibres less than 60%, normally exhibit

higher level of roller lapping.

Immature cotton fibres, in addition to low bending rigidity, have higher

concentration of monosaccharides (mainly fructose and glucose), which

are directly related to the sticking nature of cotton. Presence of large


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SITRA News 13

MEDICAL TEXTILES - 11 S.no. Type of study No. of mills

Consultancy services offered by SITRA

during September - October 2014

1. Machinery valuation 1

2. Techno-economic viability study 1

3. A study on MIS 1

4. Performance improvement study 1

5. Productivity and maintenance audit 1

6. Steam energy audit 1

7. Power consumption analysis for air compressor 18. ACS for humidification plants & compressors 1

9. Energy audit 1

10. A study on the water consumption of soft flow

dyeing machines while processing bleaching

and washing lots 1

11. A solution to prevent dusting-off on burn-out

printed garments 1

12. Process route to eliminate oil line marks on

fleece knitted fabrics 1 13. Elimination of crease marks while processing

grey mlange fabrics 1

14. Process route to minimize roll to roll shade

variation in knitted fabrics dyed using reactive

dyes 1

Besides the above consultancy studies, SITRA also offered solutions

to two adhoc problems in the area of spinning. Sixty nine instruments

were calibrated and 255 accessory samples were tested.

absolute amounts of B D fructose, X D glucose and B D glucosemakes the cotton fibre lap-prone.

To be continued

- K.P.Chellamani & M.K.Vittopa, Spinning Division


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SITRA News 14

Meetings attended

Dr. Prakash Vasudevan, Director, attended the following meetings at

Ministry of Textiles, New Delhi on 8th

September, 2014:

- Eighth meeting of Empowered Committee constituted under

Technology Mission on Technical Textiles (TMTT).

- Review of progress in transition to new MIS launched in ISDS.

Dr. K.P.Chellamani, General Manager - Projects, attended the following

meetings:

- Purchase Committee meeting of the COEIndutech at P.S.G.

College of Technology, Coimbatore on istand 19thSeptember, 2014.

- Conducted the viva-voce examination of Mrs.Vijayalakshmi, Ph.D.

scholar of Anna University, Chennai at P.S.G. College of

Technology, Coimbatore on 29thSeptember, 2014.

- Conducted the viva-voce examination of Mr.C.Prakash, Ph.D.

scholar of Anna University, Chennai at Kumaraguru College of

Technology, Coimbatore on 9thOctober, 2014.

Seminars / Conferences attended

Dr. Prakash Vasu devan, Director, attended National Handloom

Development Corporation (NHDC) buyer seller meet at Jenneys

Residency, Coimbatore on 5thSeptember, 2014.

Mr. Sakthiv el Perum alsamy, Head - Centre of Excellence for Medical

Textiles, attended a workshop conducted by Department of HealthResearch (DHR) / Indian Council of Medical Research (ICMR) on Medical

Diagnostics and Devices Innovation held at New Delhi on 19th& 20th

September, 2014.


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SITRA News 15

Paper published

Dr.K .P.Chel laman i, M.K .Vi t to pa an d S.Sivakumar, Studies on

quality attributes of Bt-cottons Asian Textile Journal, October 2014,

Volume 23, Issue 10, pp. 68-72.

Papers presented / Lectures given

Dr.K.P.Chellamanidelivered the following lectures at Gandhigram

Deemed University, Dindigul:

- Total Quality Management in an R & D Set-up at the programme

entitled Managerial Strategies on 2ndSeptember 2014.

- Process-Re-engineering at the Enterpreneurs Development

Programme on 7thOctober 2014.

- Small Group Activities in a Decentralized Sector at the conference

held on 14thOctober 2014

Mr.S.Sivakumar, Head Incharge (Textile Chemistry) delivered a

guest lecture on Defects in knitted fabrics and their remedies at the

16thAnnual General body Meeting of the South India Imported Machine

Knitters Association (SIIMKA) on 13th September, 2014.

Overseas visit

Dr. Prakash Vasudevan, Director, visited the following Institutes inTaiwan and Hongkong during his one week overseas visit:

- Taiwan Textile Research Institute (TTRI), Taiwan .

- The Hongkong Research Institute of Textiles and Apparel (HK

RITA).

- SDL ATLAS, Hongkong.


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SITRA News 16

Research Projects Review

Dr.K.P.Chellamani, has reviewed the Terminal Report of the Research

Project Development of low cost jute bags for food grains and sugar

submitted by Indian Jute Industries Research Association (IJIRA),

Kolkata.

Seminar on Energy conservation in industry

With an aim to create an awareness among industry personnel the

importance of conservating energy, SITRA organised a seminar on

Energy conservation in Industry on 27thOctober, 2014 at SITRA.Around 300 participants representing various textile mills and other

industries, apart from faculty and students from different colleges

attended the seminar. A SITRA publication entitled Fundamentals of

Electricity Management in Industry was released on the occassion.

Six different technical papers of relevance and current interest in the

field of energy conservation were presented in the seminar.

Mr.N.Vasanthakumar, Junior Scientific Officer, Textile Engineering &

Instrumentation Division presented a paper on Selection of energyefficient electrical utilities.

International workshop on Biocompatibility evaluation of

medical devices

An International workshop on biocompatibility evaluation of medical

devices Sponsored by the Ministry of Textiles, Govt. of India was

organised by the Centre of Excellence for Medical Textiles, SITRA at

SITRA, from 15th

- 18th

October, 2014. Expert speakers from the De-partment of Microbiology and Mutagenicity, Bioneeds, Bangalore

and the Skin Ethic Laboratory, France delivered lectures relating to

CONFERENCES AND SEMINARS


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SITRA News 17

biocompatable evaluation of medical devices with a focus on ISO 10993.Totally, 25 persons took part in the workshop.

Seminar on Coating and laminating technologies

Module - I

Centre of Excellence for Medical Textiles, SITRA organized a 5-day

seminar on Coating and laminating technologies Module - I from 23rd

to 27th September, 2014 at SITRA. Specialist speakers from Pune

conducted the sessions. Topics like, polymers used for the manufactureof adhesive, adhesive types, additives for PSA, combination of various

resins, anti oxidants for adhesive, poly isobutene as tackifier and fire

retardant additives were discussed in the seminar. Totally, 26 persons

took part in the seminar.

Training Programme on Low Voltage Switchgear Selection &

Maintenance

With the objective of enhancing the knowledge of electrical personnelworking in various industries on key aspects involved in the selection,

operation and maintenance of low voltage switchgears, SITRA, in

collaboration with L&T (the pioneers in switchgears) planned 5 one-

day training programmes as independent modules - i) Circuit breakers,

ii) Contactors & OLR, HRC fuses, iii) Motor starters & MPCBs, iv)

MCBs, ELCBs & DBs and v) Fault level calculations, Numerical relays,

BBT and MV switchgear. The first two modules were held during June

and July, 2014 wherein 14 persons participated. The last three modules

were held during September and October 2014 wherein a total of 36persons participated.

TRAINING


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SITRA News 18

Technical Entrepreneur Development programme on

Shuttleless weaving

The programme was organised with the objective of educating young

entrepreneurs on the technologies involved in weaving, case studies

relating to woven fabric defects and remedial measures, TUF scheme,

various sources of availing loans, the modalities involved in setting up

new units etc. Nine persons comprising Managing Directors, senior

executives and technical personnel attended the programme.

Training programme on Shuttleless weaving machines

An Engineering College in Tamil Nadu availed SITRAs services to

conduct a training programme for its students on Shuttleless weaving

machines. The programme covered topics like basics of weaving

machines, modern developments, shuttleless weaving principles and

practical training on shuttleless looms. Totally, 60 students and 8 staff

were trained in 3 batches from 27.9.2014 to 30.9.2014.

Awareness programme on Eco-parameters

SITRA conducted an awareness programme on Eco-parameters at

Workshed, PLSC - Salem for supervisory and middle managerial staff

working in processing mills, job work units and garment exporters.

The programme was conducted in September, 2014 and covered topics

like sources for banned chemicals in textile supply chain, testing of

eco-parameters and certification procedures, methods to removehazardous substances from finished textile products apart from dealing

with case studies. Totally, 20 persons took part in the programme.

Pre-employment training and retraining programmes for textile

workers

Two out-station mills and one local mill availed SITRAs training services

for their workers. Two hundred and seventy operatives in preparatory,

spinning, auto cone winding and doubling departments were trained in15 batches. The training programmes were conducted in Tamil and

Kannada.


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SITRA News 19

AN INNOVATIVE TWISTING MECHANISM BASED ON

SUPERCONDUCTING TECHNOLOGY IN A RING-SPINNING

SYSTEMMahmud Hossain et al, Textile Research Journal, May 2014,

Volume 84, Issue 8, pp. 871 - 880.

Twist plays an important role to impart tensile strength in yarn during

the spinning process. In the most widely used ring-spinning machine

for short staple yarn production, a combination of ring and traveler is

used for inserting twist and winding the yarn on cops. The main limitation

of this twisting mechanism is the friction between the ring and traveler,

which generates heat at higher speeds and limits the productivity.This limitation can be overcome by the implementation of a magnetic

bearing system based on superconducting technology, which replaces

completely the existing ring/traveler system of the ring-spinning

machine. This superconducting magnet bearing consists of a circular

superconductor and permanent magnet ring. After cooling the

superconductor below its transition temperature, the permanent magnet

ring levitates and is free to rotate above the superconductor ring

according to the principles of superconducting levitation and pinning.

Thus the superconducting magnetic bearing (SMB) ensures a friction-free operation during spinning and allows one to increase spindle

speeds and productivity drastically.

The SMB is comprised of a superconducting material and a magnetic

component. In general, the two well known designs of SMB can be

applied as twisting and winding devices in the conventional ring

spinning machine:

1. SMB1, where a magnetic ring rotates coaxially over a

superconductor ring;

2. SMB2, where a magnetic ring rotates coplanarly inside the

superconductor ring.


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SMB 1 is composed of a neodymium-iron-boron (NdFeB) magnet ringprovided by IBS Magnet and a superconductor ring yarn YBCO (Yttrium

barium Copper Oxide) provided by evico GmbH. NdFeB is one of the

strongest PMs (Permanent Magnet) with very good magnetic

properties. The density of NdFeB is 7.4 g/cm3and the fracture strength

is 80 MPa. For a magnet with a diameter of 10cm, a maximum rotation

speed of Ca. 28,400 rpm is possible, taking into account the tensile

stress and fracture strength. In order to realize higher rotation speeds,

the PM ring has to be reinforced. YBCO (YBa2Cu

3O

7-x), on the other

hand, is a crystalline chemical compound and a popular high-temperature superconductor, achieving superconductivity at transition

temperature, Tc= 1840C above the boiling point of liquid nitrogen (-

196.150C). For the technical application, the pining force must be as

strong as possible. Strong pinning forces can be realized in melt-

textured bulk YBCO material. It is possible to manufacture

superconducting YBCO magnets that can produce magnetic fields of

16 Tesla at 2490C and attractive or repulsive levitation forces up to

5000 N/cm2.

The authors report that they have spun 31 Tex 100% polyester yarn

using SMB as well as conventional ring spinning with the ring/traveler

system.

The SMB yarn was found to be more even with fewer projecting hairs.

According to the authors, the SMB can revolutionize the twisting

principle of yarn formation and can help to increase the spindle speed

substantially.

- R.S.Vignesh BalajiSpinning Division

YARN PERFORMANCE WITH COLD SIZING

Hrishikesh V. Chavan, Suraj S. Patil, D.K.T.E.S. Textile & Engineering

Institute, Ichalkaranji / India

Melliand International, June, 2014, No. 2, pp 84 to 86.

Energy conservation has received a high recognition these days. The

sizing department mainly consumes steam energy for preparation ofsize paste and drying of warp sheet. In this paper, the authors have


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studied and compared the performance of yarn sized through normalhot sizing process vis--vis the cold sizing process. Cold sizing is the

process in which the spun yarn (grey or dyed) in the form of a cone or

cheese is single end sized at room temperature during winding using

a special attachment for sizing and drying before winding onto a cone.

This process eliminates the need for preparation of warp beams and

hot sizing thus saving time, energy and cost. More importantly, it aids

the small scale industries which cannot afford to have warping and

sizing ranges to facilitate their yarn preparation for weaving.

Cold sizing has certain advantages over conventional hot sizing in

terms of savings in energy and time, requires less labour, reduces

dead loss, end breaks and machine downtime in the loom shed, etc.

The authors found that cold size can be preserved for 3-4 days without

deterioration in its properties and with no lump formation, thus giving

excellent results in end breaks at loom shed with less dust formation

and less pollution.

In this study, 40s carded 100% cotton ring spun yarn was used by theauthors to conduct trials by sizing the yarn through various methods

viz., hot sizing with Maize, Tapioca starches and cold sizing. The

authors report that the yarn co-efficient of friction against metal was

reduced by almost 50% in cold sized yarns when compared to that of

normal sized yarn, hence, breakage due to excessive friction between

reed eyes and travelling yarn can be reduced. Cold sized yarns gave

higher breaking force and elongation at break than the normal sized

yarns. The authors had inferred that the cold sized yarns had shown

higher abrasion resistance than the normal sized yarns and hencerendered improved weavability. Cold sized yarns recorded much less

hairiness than the normal sized yarns, hence problems in shed opening

during shed formation are expected to be less. Finally, the authors

concluded that, cold sized yarns gave better performance compared

to the normal sized yarn in terms of properties like strength, elongation,

hairiness and abrasion resistance.

- S. Sivakumar & S. Kowsalya

Textile Chemistry Division

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