PRODUCTIVITY AND COSTSPackage defects in automatic cone winding: reasons and remedies......1TECHNICAL NOTES

1. Sample average of cots vs lot averages of cots.....42. Cotton Stickiness issues and solutions: Part 6........63. Different types of packing materials and the problems

associated with PVC....8PROJECTSMoisture management properties of compact yarn fabrics.... 13STAFF NEWS....18TRAINING......20ABSTRACTS.......22

In this issue

SITRA News is a bi-monthly magazine, circulated to member mills.SITRA NEWS - July - August 2015, Vol. 56, No.4

2015, The South India Textile Research Association13/37, Avinashi Road, Coimbatore Aerodrome Post, Coimbatore - 641 014, Phone: 0422-2574367-9, 4215333, Fax: 0422-2571896, 4215300E-mail:info@sitra.org.in, Website: www.sitra.org.in

This issue can also be downloaded from

SITRA.ORG.IN scan code for web link

SITRA News

July - Aug. 2015

PRODUCTIVITY AND COSTS

1

Package defects in automatic cone winding: reasons and remedies

Besides intrinsic quality of yarn, package defects also play a significant role in deciding yarn breaks during warping. SITRA has recently brought out a Focus publication on How to resolve customer complaints in spinning mills? A case study (Volume 33, No.3, September 2015), which deals with suggestions that were offered to a spinning mill to resolve a customer complaint viz. higher warping breaks. Various package defects that were covered in the Focus include i) cone tip damages, ii) base cut ends/nose cut ends/drum cuts and iii) yarn entanglement, wild yarn and weak splice. This note covers reasons for some other package defects (given below) along with remedial measures.

1) Bunch winding2) Bunch at middle of the cone3) Variations in package densities4) Slough-off at critical zones5) Weight variation between cones

1) Bunch windingReasons

- Poor condition of base adaptor, brake shoes and brake piston gaskets.

- Bends and burr formations in the upper arm comb.- Accumulation of dust in inner surface of the upper arm.- Absence of package lifting action.- Suction air leakage in package arms in idle condition (zero

position).

Increase work load by

Changing machinery layout Imparting multi- skill training Providing higher assignments Incorporating additional duties Enabling team work

SITRA News2

July - Aug. 2015

Corrective actions- Attend to solenoid failure, counter weight piston gasket

failure and air reducer valve failure.- Ensure correct positioning of the pneumatic connections

1after removing and fixing a spindle .- Check the suction arm settings and condition of comb.- Ensure no upper arm air leakages in the zero position.- Check for good inner surface in the cone adaptors (no step

formation).- Check the braking action of the cone adaptors.

2. Bunch at middle of the coneReasons

- Knife cut marks in the drum grooves.- Lifting plates touching drums due to double cones on the

plates and loosened plate screws.- Improper selection of drum pattern settings.- Higher number of upper arm attempts.- Dust/powder accumulation/scale formation in the drum

grooves.

Corrective actions- Remove sharp cut marks/scratches on the drum grooves

using steel wool.- Clean the grooves with suitable solvent.- Ensure correct selection of drum pattern setting.- Select optimum number of upper arm attempts so as to

avoid disturbance in the yarn layers during reverse run of cone.

- Ensure proper positioning of lifting plates.

3. Variations in packing densitiesReasons

- Improper selection of tension and cradle pressure.- Improper maintenance and servicing of pneumatic circuits.

1) denotes an entire drum assembly

SITRA News 3

July - Aug. 2015

Corrective action- Check all the pneumatic circuits and replace worn-out

hoses.- Ensure proper opening and closing of tension discs.

4. Slough-off at critical zonesReasons

- Improper working of anti-ribbon control device motor.- Improper selection of drum pattern settings.- Improper cone holder arm setting.- Selection of higher number of upper arm attempts.- Improper tension application.

Corrective actions- Ensure optimum selection of drum pattern settings.- Ensure correct cone holder arm setting in all the drums.- Proper selection of upper arm attempts.- Check tension discs' opening and closing action.

5. Weight variation between conesReasons

- Yarn count CV more than 1.5%.- Improper RH% in the department.- Defective encoder, PCB and inverter.- Improper cone holder arm setting.- Defective EYC unit.- More number of splicing cycles.

Corrective actions- Maintain yarn count CV at below 1.5%.- Maintain required RH in the department according to the

type of product-mix.- Ensure proper functioning of encoder, PCB and inverter.- Ensure correct setting in the cone holder arm.- Ensure proper functioning of EYC unit.

R.Soundararajan and J.Sreenivasan

Liaison and Consultation Division

4 SITRA News

July - Aug. 2015

A supplier of roller cots to mills claims that the average shore 0 0hardness of cots supplied by him is 80 with standard deviation of 1 .

When a lot was delivered, 9 cots from the lot were selected at random and tested for shore hardness. The results are given in Table1.

Cots No. Shore Hardness1 78.00

2 81.50

3 78.50

4 78.00

5 80.00

6 79.50

7 80.50

8 77.00

9 79.00

Table 1 Shore Hardness of cots

Is there any evidence to conclude that the sample average is same as that of lot average for the shore hardness of cots?

The problem pertains to testing the significance of a sample average X against a population average (), the standard deviation of the population () being known. In such cases, the sample average is normally distributed with a standard error of where n is the sample size.

Then, a parameter called 'variate' is calculated. The variate (U) is given by

?

TECHNICAL NOTEs

Sample average of cots vs lot average of cots

SITRA News 5

Dr. K.P. ChellamaniSpinning Division

July - Aug. 2015

= Sample average = Population average = Standard deviation of the population

At 95% significant level,

If U lies between -1.96 and 1.96 it means that the sample average do not statistically differ from each other.

In the present problem,

0Sample average (X) = 79.110Population average () = 80

0Standard deviation of the population ()= 1Sample size (n) = 9

Then, variate,

Since the variate 'U' is lower than - 1.96, the sample average and the population average (of shore hardness of cots) are statistically different.

It would mean that the average shore hardness of the lot osupplied to the mills is not 80 as claimed by the supplier.

X

X n

-= ( )( )U

( )

X n

-= ( )( )U

1 9=

=

( ) 79.11 - 80

- 2.7

6 SITRA News

2. Cotton Stickiness : Issues and solutions - Part 6

July - Aug. 2015

Wrap frequency (lapping tendency) of different fibres

SITRA has conducted a study to assess the level of wrap frequency (a measure of lapping tendency) in ten mills that were

s sproducing a wide range of counts (26 to 100 C) using cotton as well as polyester blends.

The individual values of wrap frequency are given in Table 1.

Table 1 Wrap frequency (P) values for different counts and blends.

Mill No.

Count

Wrap frequency

(Wraps / Spindle minute)(P) x 10-2

1

26s C

35s K

0.30

2.18

2 65s K

63s P/C 4.92

2.14

3 90s C

42s P 0.40

11.83 4 31s SF 0.13

5 45s P/V 20s P/V

14.36 3.60

6

45s P/V 60s P/V

13.43 43.85

7

40s C

100s C

0.00

0.16

8

60s P/V

42s P

36.72

3.63

9

63s P/ C

56s C

0.75

0.00

10

82s C74s C

0.000.39

SITRA News 7

July - Aug. 2015

The average values of wrap frequency for different materials / counts are given in Table 2.

Table 2 Wrap frequency for different materials / count range

Material

Yarn c ount range

Wrap frequency(Wraps / Spindle minute)

x (10-2)

Cotton

carded

yarns

35s

65s

2.0 to 5.0(3.6)*

Cotton

combed

yarns

26s

56s

74s

100s

0 to 0.3(0.1)*

0 to 0.4(0.24)*

P/V yarns 20s 60s 4.0 to 44.0(22.4)**Values in parenthesis are the average values.

In cotton carded yarns, the wrap frequency averaged at 3.6 x -210 wraps / spindle minute with the values differing between counts

by about 2.5 times. In combed yarns, the wrap frequency is much th -2lower at 1/20 of carded yarn, the average value being 0.17 x 10

wraps/ spindle minute. Even 'zero' lapping is achievable in combed counts under good working conditions as per the data. Between combed and carded yarns, the reduction in lapping is attributed to,

I) removal of short fibres during combingii) preferential removal of bunches of immature fibres which

originate from immature cotton seeds (ovules) during combing

iii) removal of seed coats fragments during combing.

P/V yarns have exhibited the highest wrap frequency, the -2average value being 22.4 x 10 wraps/ spindle minute. When

compared with carded cotton yarns of equivalent count range, wrap frequency in P/V yarns was higher, on an average, by 6 times. The higher lapping tendency in P/V yarns are due to one or more of the following reasons.

Deposition of the tints (that are used for identification

8 SITRA News

July - Aug. 2015

purposes) over the cot surface which act as the catalyst for fibres to stick to the cots surface. It is preferable to avoid tinting in mills towards reducing roller lapping.

Optimum humidity conditions suitable for both the fibres, (in P/V blends) not being maintainable in ring spinning. For polyester fibres, to take care of its static charge forming nature, higher humidity levels need to be maintained. On the other hand, for viscose fibres, due to its hygroscopic nature, lower humidity levels are needed. The RH maintained in mills is a compromise between the two conflicting requirements and as a result P/V yarns show higher lapping tendency.

The average fibre length to be dealt by the top roller in P/V counts, being higher as compared to carded or combed cotton counts.

To be continued..K.P.Chellamani & M.K.Vittopa

Spinning Division

3. Different types of packing materials and the problems associated with PVC

Packaging is enclosing or protecting products for distribution, storage, sale, and use. Materials used for packaging are termed as Packing Materials.

Methods of packing followed in textile mills

1) Yarns in hank form are packed in bundles and bales.

2) Yarns in cone form are packed in carton boxes / bags/pallets

3) Fabrics / Cloth are packed in bales.

4) Fancy clothes are packed in wooden boxes / cardboard cases.

5) Other packing materials used are hessian cloth, paper board, polythene sheet, lining paper, iron/plastic hooks, nails, sewing thread, etc.

Types of packing materials and their properties

a. Polyethylene

Water proof, translucent plastic receptacles employed in a number of industrial, commercial and domestic settings for the protection, storage or transport of goods.

b. High Density Polyethylene (HDPE) 3A plastic material whose density ranges from 941 to 965 g/cm ,

HDPE is more expensive, but it maintains greater strength, resistance and stiffness than either LDPE or LLDPE.

c. Linear Low Density Polyethylene (LLDPE)

It is a plastic material that is produced at lower temperatures and pressures than LDPE through copolymerization, resulting in a crystalline structure responsible for greater stiffness and a higher melting point than LDPE. Although it is more difficult to process, LLDPE maintains greater tensile strength and a greater resistance to stress cracking than LDPE.

d. Low Density Polyethylene (LDPE)

It is a most common and least expensive plastic bag material 3that maintains a density of 910 to 925 g/cm , LDPE maintains its

durability, flexibility, water resistance and clarity under low temperatures and its low melting point makes it ideal for heat sealing.

e. Polypropylene

It is a completely transparent, strong and rigid material that doesn't stretch but provide a good vapor and moisture barrier. Light, durable thermoplastic with a high melting point that is often used in packaging.

9SITRA News

July - Aug. 2015

f. Printed plastic bags

They are mass manufactured or custom made storage containers to which permanent labels and designs are added.

g. Resealable plastic bag

It includes all bags designed with a closure mechanism that can open and be re-fastened for continued product containment.

h. Vinyl bags

They are sacks or pouches made of a specific thermoplastic polymer known as polyvinyl chloride, or PVC.

Additives used in the manufacture of packing materials

These are substances added to a polymer to increase the effectiveness, but not the strength, of the polymer. Plastic bags are made from polyethylene. During processing, the polyethylene might be treated with a number of additives, such as:

Pigments, carbon black -for ultra violet resistance

Anti-block - prevents the plastic layers from sticking together (blocking).

Slip additives - To lower coefficient of friction of film and helps the plastic bag open easier and allows items to slide in smoothly.

Ultraviolet inhibitor (UVI) - Protects the plastic from ultraviolet radiation, which can weaken the plastic's strength and fade its color.

Antistatic additives - To reduce dust attraction caused by buildup of static changes.

Antioxidants - To prevent degradation during processing and during service life of the article.

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July - Aug. 2015

Plasticizer - A chemical added to plastic resins to increase the flexibility of the plastics

In addition to creating safety problems during production, many chemical additives that give plastic products desirable performance properties also have negative environmental and human health effects. These include,

Direct toxicity, as in the cases of lead, cadmium, and mercuryCarcinogens, as in the case of diethylhexyl phthalate (DEHP)Endocrine disruption, which can lead to cancers, birth defects,

immune system supression and developmental problems in children.

People are exposed to these chemicals not only during manufacturing, but also by using plastic packages, because some chemicals migrate from the plastic packaging to the environment.

Polyvinyl chloride, or PVC, is a major source of phthalates which are the same dangerous plastic softeners that are banned. Polyvinylchloride can cause cancer, birth defects, genetic changes, chronic bronchitis, ulcers, skin diseases, deafness, vision failure, indigestion and liver dysfunction

What is polyvinyl chloride (PVC)?

and a class of chemicals called phthalates which disrupt the endocrine system among many other health problems. These additives off-gas and leach during product use, and are also known to seep into groundwater once the product goes to landfill. PVC itself does not biodegrade and remains on the shelf, in the environment, or in the landfill. Sometimes landfills catch fire, and the PVC release

Polyvinyl chloride (or PVC, also known as vinyl) is an environmental toxin. Polyvinyl chloride is widely considered to be the most toxic plastic. Vinyl chloride, the base ingredient in PVC, is a known carcinogen, and those who work in PVC plants suffer elevated health risks. Dioxins and other carcinogens are byproducts of it. For example in making yoga mats, plasticizers are added to make the PVC soft and sticky. It's not usually possible to know the exact ingredients of any given mat, but the most common additives include lead, cadmium

11SITRA News

July - Aug. 2015

dioxin, hydrochloric acid, and other toxins. PVC is difficult to recycle, which is why so little of it is recaptured. PVC is made softer and more flexible by the addition of phthalates. Bisphenol A (BPA) is also used to make PVC plastics. PVC contains high levels of chlorine.

How can PVC affect our health?

Exposure to PVC often includes exposure to phthalates, which are used to soften PVC and may have adverse health effects. Because of PVC's heavy chlorine content, dioxins are released during the manufacturing, burning, or landfilling of PVC. Exposure to dioxins can cause reproductive, developmental and other health problems and at least one dioxin is classified as a carcinogen.

Dioxins, phthalates, and BPA are suspected to be endocrine disruptors, which are chemicals that may interfere with the production or activity of hormones in the human endocrine system. Exposure to PVC dust may cause asthma and affect the lungs.

Certification Bodies

Certification bodies for textiles like GOTS & Oeko-Tex have listed guidelines for selection of packaging materials. The use of packaging materials having PVC is listed under 'prohibited items for use' in the requirements of these certifications. Hence, they insist on PVC free certificates for packing materials used in the textile manufacturing. Alternatives to PVC

There are alternatives for most uses of PVC. Some cost more at the counter, but if we add in the health and environmental costs of producing PVC, it becomes the most expensive choice. Prices of alternatives will come down as demand increases.

-S. Kowsalya and S. SivakumarTextile Chemistry Division

12 SITRA News

July - Aug. 2015

SITRA News 13

July - Aug. 2015

PROJECTS

Moisture management properties of compact yarn fabrics

When drops of water fall on the surface of any textile material, the water spreads into the fabric radially in multiple directions. Its precise movement depends upon the chemical and physical nature of the textile material. Thus, the ability of a fabric to control movement of moisture associated with it is called moisture management of the textile material. Moisture management of fabric draws moisture away from the skin and disperses it over a large surface area away from the skin where it evaporates, thereby reducing the chill factor and improving comfort.

A study was conducted at SITRA to assess the influence of type of weave of compact yarn fabrics on the moisture management properties. Fabrics with 4 different weaves, viz plain, drill (3/1 Twill), Satin (5 end) and honey comb were produced using 40s compact yarn.

The moisture management properties of the conditioned fabric samples were determined according to AATCC 195-2009 on an SDL Atlas Moisture Management Tester. The apparatus is based on the physical principle that the surface contact electrical resistance of a fabric changes with the content of a water based liquid solution near the surface. The resistance value depends on two factors: the electrical conductivity of the liquid and the water content in the local areas of the fabric. As the electrical conductivity of the liquid is fixed, the electrical resistance measure on the surface of the fabric is

2determined by the water content. All specimens (8.0 x 8.0 0.1cm ) were washed and ironed to remove excessive water and wrinkles. They were then conditioned for at least 24h prior to testing. Sweating was simulated with 0.21 x 0.01 g of synthetic sweat, which was introduced onto the top surface of the fabric. The liquid would now begin to get transmitted in three directions, i.e. spreading

14 SITRA News

July - Aug. 2015

radially outwards on the upper surface of the fabric, wicking through the fabric from the upper to the lower surface and spreading radially outwards on the lower surface of the fabric. Moisture Management Tester (MMT), contained upper and lower concentric moisture sensors that enclosed the test-specimen. Based on the signals measured, a set of indices is calculated. The indices are graded according to AATCC Test method 195-2009 and converted from a numerical value to a grade on a five point grade scale.

The fabrics with different weaves made in this investigation were tested for the various quality indices obtained in the Moisture Management Tester and they are given in Table 1.

Table 1 Grading of fabrics with different weaves for Moisture Management quality indices

Quality Index Fabric weave type Grade1

2 3 4 5

Wetting Time Top Surface

(WTt)

A

?B

?

C ?

D ?

Wetting Time BottomSurface (WTb)

A ?B z ?C

?

D

?

Absorption Rate Top Surface

(ARt)

A

?

B

?C

?D

?

Absorption Rate Bottom Surface

(ARb)

A

?

B

?C

?

D

?

Maximum Wetted Radius

Top Surface (MWRt)

A

?B

?C

?D

?

Maximum Wetted Radius Bottom Surface

(MWRb)

A

?

B ?C ?D ?

Spreading Speed Top Surface (SS t)

A ?B ?C ?D ?

SITRA News 15

July - Aug. 2015

Quality Index Fabric weave type Grade1

2 3 4 5

Spreading Speed Bottom Surface

(SSb)

A

?

B

?C

?

D ?Accumulative

One-Way Transport Index

(R)

A ?B ?C ?D ?

Over all Moisture

Management Capability(OMMC)

A ?B ?C ?

D ?

Table 1 Contd..

A-Plain B- Drill C- Satin D- Honey comb

Definition of the various indices given in Table 1

i) Wetting Time (WT ) Top Surface tandWetting time (WT ) bottom surfaceb- The time in seconds when the top and bottom surfaces of the specimen begin to be wetted after the test is started.

ii) Adsorption rate (AR ) Top Surfacet and

Adsorption rate (AR ) Bottom Surfaceb- The average speed of liquid moisture absorption for the top and bottom surfaces of the specimen during the initial change of water content during a test.

iii) Maximum Wetted Radius (MWR ) Top tand Maximum Wetted Radius (MWR ) Bottom b- The greatest ring radius measured on the top and bottom surfaces of the test specimen.

iv) Spreading speed (SS ) Top tand

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July - Aug. 2015

Spreading speed (SS ) Bottom b- The accumulated rate of surface wetting from the centre of the specimen, where the test solution (Saline solution) is dropped to the maximum wetted radius.

v) Accumulative one-way transport capability - The difference between the area of the liquid moisture content curves of the top and bottom surfaces of the test specimen with respect to time.

Overall Moisture Management Capability (OMMC) is calculated using the formula

OMMC = C1 x AR + C x R + C3 x Ssb 2 b

Where AR is the absorption rate (bottom surface)bR is the one way transport capabilitySS is the spreading speed (bottom surface)b

and C , C & C are system constants. 1 2 3

The system constants used in the formula are C = 0.25, C = 1 20.5 and C = 0.25 based on human perception studies in which the 3one-way transport capability was found to be twice as important as absorption rate and spreading speed.

According to the grades (Table 1), the fabrics with different weaves taken for the study were ranked for OMMC and are given in Table 2.

Table 2 Ranking of fabrics with different weaves as per the OMMC

Fabric Weave Type

Rank (as per OMMC)

Plain

Excellent Drill

Very Good Satin Excellent Honey Comb Fair

17SITRA News

July - Aug. 2015

Depending on the grades obtained by different fabrics during moisture management testing, the fabrics can be classified into 7 categories and they are given in Table 3.

Sl.No Moisture Management Grade Classification of

the fabric1)

: Absorption

: Spreading : One Way

Transport

Very slow

Slow

No

Water Proof Fabric

2)

: Absorption

: Spreading

: One Way Transport

: Wetting

No

No

Poor

No

Water Repellent Fabric

3)

: Absorption

: Spreading

: One Way Transport

Slow

Slow

Poor

Slow Absorbing & Slow Drying Fabric

4)

: Absorption

: Spreading

: One Way Transport

: Wetting time

Medium to Fast

Slow

Poor

Medium to Fast

Fast Absorbing & Slow Drying Fabric

5)

: Absorption

: Spreading

: One Way Transport

: Wetting time

Medium to Fast

Fast

Poor

Medium to Fast

Fast Absorbing & Quick Drying Fabric

6)

: One Way Transport

: Spreading Area

Excellent

Small

Water Penetration Fabric

7) : Absorption: Spreading: Spreading Area: One Way Transport: Wetting time

Medium to Fast Fast Large Good to Excellent Medium to Fast

Moisture Management

Fabric

Table 3 Fabric classification as per Moisture Management Grade

K.P.Chellamani & J.SudharsanSpinning Division

1. Viscosity cup fabrication 10 2. Study on Mantex Spinning Tubes 13. Consultancy on 40s conversion factors list 3 4. Energy audit 2 5. Consultancy on Machinery valuation 16. Technical efficiency audit 17.

Study of capacity and water consumption of soft flow fabric dyeing machines 1

10. Study on the production capacity of precision soft package winding machines 1

11. Improvement of rubbing fastness of Indigo dyed denim fabrics 1

Besides the above consultancy studies, SITRA also offered solutions to 10 adhoc problems in the area of spinning and 9 in the area of chemical testing, 92 instruments were calibrated, 351 accessory samples were tested and 10 samples were woven and knitted .

Production per spindle improvement study 18. Work assignment study 19.

S.no. Type of study No. of mills

Consultancy services offered by SITRA during July - August 2015

NewsSTAFF

Meetings attended

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

- State Planning Commission (SPC)-Textile Sector Workshop on Current Scenario of Textile Industries in Tamil Nadu Challenges and Policy initiative at the State Planning Commission, Chennai on 01.07.2015.

- Meeting of the Project Screening Committee for evaluation / examination of Detailed Project Report (DPR) for setting up of Focus Incubation Center (FIC) in Technical Textiles under TMTT - under the

18 SITRA News

July - Aug. 2015

Chairmanship of Textile Commissioner at the Office of the Textile Commissioner, Mumbai on 23.07.2015.

- Meeting of the Project Approval Committee (PAC) for selection of Focus Incubation Center (FIC) in Technical Textiles under Technology Mission on Technical Textiles (TMTT) at MoT, Udyog Bhavan, New Delhi on 10.08.2015.

- Meeting of Textile Sector Skill Council at Texprocil, Mumbai on 25.07.2015.

Dr. K.P.Chellamani, General Manager Projects, attended the Doctoral Committee meetings of Anna University for:

Mr.C.Mohan Bharathi, Ph.D. scholar, P.S.G.College of Technology, thCoimbatore on 14 July 2015 and Mr.J.Veeraprabahar, Ph.D. scholar

thKumaraguru College of Technology, Coimbatore on 24 July 2015.

Paper published

J.Sreenivasan, N.K.Nagarajan and D.Shanmuganandam, Can a textile mill achieve 6 HOK in spinning? Spinning Textiles, July-August, 2015.

Paper presented

Mr. S. Sivakumar, Incharge-Textile Chemistry presented a plenary paper on thEco-friendly textiles and Greener processing of textile materials at the 5

International Conference on 'Emerging Trends in Textile Industry New Innovations' organized by SSM College of Engineering, Komarapalayam during August' 15.

SITRA News 19

July - Aug. 2015

20 SITRA News

July - Aug. 2015

Management Development programme for TNTC, Chennai

Under a request from the Directorate of Handlooms and Textiles. Govt. of Tamilnadu, SITRA conducted a two-day Management Development programme for the MDs and Administrators of the

th thvarious units of the Directorate on 15 and 16 July, 2015.

The focus of the programme was to provide an exposure to the participants on areas like present textile scenario, cotton selection process, raw material properties, productivity, Critical areas of Process control in spinning, etc., Twenty two persons attended the programme. Ms.Gokula Indra, Hon. Minister of Textiles, Govt. of Tamilnadu attended the valedictory session of the programme and distributed the course completion certificates to the participants.

Training Programme on Low Voltage switchgear Selection & Maintenance

With the objective of enhancing the knowledge of electrical personnel working 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) conducted a 3-day training programme on the Selection and Maintenance of Low Voltage Switchgears during August 10-12, 2015. The programme covered various topics like introduction to switchgears, circuit breakers, contactors & OLR, HRC fuses, motor starters & MPCBs, MCBs" ELCBs & DBs, selection and operation of MCCBs, operation and maintenance of ACBs, numerical relays, BBT and MV switchgear and fault level calculations. A total of 20 participants from various industries attended the programme. The programme, apart from covering theoretical sessions, provided a good opportunity for the participants to have hands-on working on model switchgears.

SITRA News 21

July - Aug. 2015

Training of Trainers programme

The Textile Sector Skill Council (TSC) has been a body created under the auspices of the National Skill Development Council, New Delhi, with the specific task of skilling persons in the textile sector. Under the Prime Minister's Kaushal Vikas Yaogna (PMKVY) scheme of TSC, SITRA has been designated as one of the agencies to impart the mandatory training to the trainers from mills that are empanelled as training providers. SITRA has been contacted by mills to conduct a series of ToT programmes under the scheme. During July-August, SITRA completed 3 batches of the 3-day programmes, wherein a total of 59 trainers from 44 mills participated. The focus of the programme was to sensitize the participants on the scheme's guidelines and reach, right work methods for the operatives in textile mills, role of trainers in imparting knowledge to workmen, technical and behavioural skills required for trainers, records to be maintained in the process of training personnel, inculcating the importance of material handling, housekeeping, quality to workmen, etc.

Jobbers Development Programme

At the request of a member mill in Rajasthan, SITRA conducted a 4 day training programme for 25 jobbers in August 2015. The programme covered various technical topics involved in spinning mills like the present textile scenario, type of trainers, right work methods in mills, absenteeism control, material handling, housekeeping, etc.

Pre-employment training and retraining programmes for textile workers

Two out-station mills availed SITRA's training services for their workers. 130 operatives in Ring spinning, autowinder and TFO departments were trained in 6 batches. The training programmes were conducted in Kannada and Hindi.

YARN PROPERTIES DEVELOPMENTS WITH DIAGONALLY SLOTTED ROLLER ON RING SPINNING MACHINEAli Akbar Merati, Aliasghar Alamdar Yazdi & Alireza FarokhniaIndian Journal of Fibre & Textile Research, Vol. 39, Setember 2014, pp .289-295

In this article, the authors have discussed the development of a new ring spinning process with the installation of diagonally slotted rollers

0 0 0(DSR) of various angles (15 , 30 & 45 ) below and parallel to the top front rollers of a ring spinning frame. A schematic of slots on the surface of DSR rollers is shown in Figure 1.

0 0Figure 1 Schematic of slots on the surface of DSR rollers (a) 15 , (b) 30 0and (c) 45

The method of installation of DSR rollers on the drafting zone of ring spinning frame is shown in Fig 2.

22 SITRA News

July - Aug. 2015

Figure 2 Method of installation of DSR rollers on the drafting zone of ring spinning frame [(a) A Schematic of side view, (b) a photograph of front view]

SITRA News 23

July - Aug. 2015

Yarn samples of 20 tex were produced in conventional ring spinning as well as in the newly developed DSR spinning. In ring spinning process, the escaped fibre ends from the strand surface in the spinning triangle do not entangle with other fibres when the yarn is twisted and therefore they make the yarn hairy. In DSR rollers, the slot walls provide a condition to prevent escaping of fibre ends from the strand and keep the fibre ends on the strand surface in the twisting process. The experimental results show that the

0yarns produced with DSR roller of 30 slot angle (DSR30) have less S3 value of hairiness and a cleaner appearance than conventional ring-spun yarns.

The DSR spinning process also helps to produce yarns with higher tenacity & elongation in comparison with conventional ring spinning process.

CHARACTERISTICS OF DRAW TEXTURED AND AIR-JET TEXTURED YARNSM.Y. Gudiyawar & Rahul Gadkari, Department of Textiles, D.K.T.E.S. Textile & Engineering Institute Journal of the Textile Association, Jan-Feb 2015, pp.337-340

Texturing is increasingly gaining importance in textile production, not only in yarns for weaving and knitting fashion products, but also for carpets, furnishing fabrics and a variety of technical textiles. False twist and Air-Jet texturing methods are the most common processes. Textured yarns impart higher bulk, excellent dimensional stability and softer handle to the fabric. In the draw texturing process, crimps are introduced into the filaments by twisting, heating and untwisting. In the air texturing process, one or more ends of multifilament yarns are passed through a jet in which air turbulence is maintained. Multifilament yarn or yarns are fed into the jet at a higher rate and withdrawn at a lower rate. The air flow causes the filaments to be blown apart and getting curled into loops.

In this research work, the authors have used polyester POY of 126 / 34 denier for conducting trials. The polyester draw textured yarn was manufactured using Himson HDS-CX2 draw texturing machine at a delivery

0speed of 300mpm, primary heater temperature of 1800 c, secondary heater temperature of 160C, draw ratio of 1.7, D/Y of 2, stabilizing overfeed of 4% and take-up overfeed of 6%. The polyester POY, which was used for manufacturing draw textured yarn, was also used for preparing air-jet textured yarn on Himson HJT-1000 air-jet texturising machine at a delivery

2speed of 300 mpm, 8 kg /cm air pressure, 1 litre /jet /hr water, 30% overfeed 0to jet and at a stabilizing heater temperature of 180 C. Various

- V.VijayajothiSpinning Division

characteristics of both draw textured and air-jet textured yarns were analysed and compared.

The authors report that the structure of draw textured yarn has wavy filaments and the air-jet textured yarn has loops on the surface and these loops are held in their position by the entanglement of filaments and this entanglement makes the core of air-jet textured yarns. The tenacity and breaking elongation of draw textured yarns are higher than air-jet textured yarn which may be attributed to the difference in the structures of these yarns. The lower tenacity and lower breaking elongation of air-jet textured yarns, firstly, is due to the higher filaments entanglement in the yarn core formed by texturising and secondly, due the obliquity effect and the lower number of filaments sharing the axial load. The authors also report that the higher strength of draw textured yarn is due to the crimpy parallel filaments without entanglement. The boiling shrinkage of draw textured yarn is lower than air-jet textured yarn. It means that the draw textured yarn has higher dimensional stability as compared to air-jet textured yarn. The moisture management in terms of drop absorbency and wicking rate of air-jet textured yarn is lower than draw textured yarns. A more open structure of the draw textured yarn had resulted in higher wetting.

The authors have concluded that the filament arrangement is different in draw and air-jet textured yarns. The draw textured yarn structure is more open with crimpy parallel filaments and air-jet textured yarn has compact structure with surface loops. Air-jet textured yarn has higher balk, lower strength and lower extensibility. Dimensional stability, moisture absorption and transportation characteristics of draw textured yarn are better than air-jet textured yarn.

- S. Kowsalya and S. Sivakumar Textile Chemistry Division

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