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Winding

Limitations of Spinning Technology

Progress in spinning automation and productivity

Despite of progress, it is still not possible to produce a

fault-free yarn

Depending on the raw material and state of the

machinery park, there are about 20 to 100 events over

a length of 1000 km yarn

Yarn exhibits a yarn faults every 1 to 5 km.

Yarn faults too thin, too thick, foreign fibre and dirty

places

Spinning process leads to formation of disturbing

faults

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1. Machine parts - worn out or out of tolerance

2. Contamination

trash, dust, seed coat fragments3. Foreign material

These yarn faults cause disruptions in subsequent

processes productivity and quality

Hence spinner has to fulfill the demand of fault free

yarn by two measures

1. Prevent origin of yarn faults by adequate measure

- Choice of raw material, m/c maintenance and cleanliness in

mill

2. Remove yarn faults by the aid of yarn clearers

- Winding process

Reasons for Disturbing Yarn Faults

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Winding Machine

Objects of Winding:

1. Extraction of disturbing yarn faults2. Conversion of smaller package to bigger

package

3. Waxing of the yarn during winding process4. Clearing foreign fibres

5. Clearing of Polypropylene

6. Detection of off-standard bobbins7. Monitoring frequent yarn faults

8. Monitoring & documentation of quality data

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Passage of Yarn through Winding Machine

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Yarn Faults

Textile industry is dividing the yarn faults in

1. Frequently occurring faults

- Tested on Evenness Tester

- Expressed per 1000 m of yarn

2. Seldom occurring defects

- detected & eliminated during winding

- expressed per 1,00,000 m of yarn Difference between Frequent faults & Seldom occurring

defects is mainly larger mass or diameter deviation and size

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Classification of Yarn Faults

1. Neps

Faults that are less than 1cm and having a massincrease of more than 100% are called Neps

They are basically produced due to immature

fibres / seed coat fragments in the raw material,

very short entanglements of fibres and yarns.2. Short Thick Places

Faults with a length of 1 cm to 8 cm and having

a mass increase of more than 100%

These faults are basically produced due to short

fibres, improper draft control, bad piecing, flies

in spinning

Neps

Short Thick

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3. Long Thick Places

Faults with a length of more than 8 cm and

having a mass increase of more than 45% arecalled Long Thick places.

These faults are basically produced due to

thick places in sliver, roving etc.

4. Thin Places

Faults with a length of more than 8 cm and

having a mass decrease of more than 30% are

called Thin places

These faults are basically produced due to

missing sliver in drawing, stretches in sliver

and roving etc.

Long Thick

Long Thin

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5. Count variations

Faults with a length of several meters and

having a mass increase / decrease of more

than 5% are called count variations

6. Foreign matters

Faults with a length of more than 1 mm and

visibility level of more than 5% are called

foreign matters

They are primarily produced due to mix up

of colour fibres, jute, hair, seed particles etc.

Count

Foreign

Fibres

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Yarn Fault Classification Matrix

Fault length in (cm)

Faults

ize(%)

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Spectrum of Yarn Faults

Fault Length (cm)-100%

0

+100%

+200%

+300%

+400%+500%+600%

0.1 21 4 8 16 32 64 . . . . . . . .

Unevenness

Imperfections

Short

Thick

Places

Long Thick Places

Long Thin Places

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Basic setting of N S L T

For an easy setting of clearing limits Thickplaces are divided in to

NSLclasses andThinplace expressed as T

N channel - Less than 1 cm (to clear nep faults)

S channel 1.0 to 8.0 cm (to clear short thick place faults)

L - channel up to 200 cm (to clear long thick place faults)T - channel up to 200 cm (to clear thin place faults)

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Class Clearing Curve

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Electronic Yarn Clearing

Yarn Faults Removing Principle 1.Yarn faults monitored by anelectronic device

2.As soon as yarn clearer detects a

yarn fault, the yarn will be

separated by the cutter

interrupting winding

3.Yarn fault removed by the suction

of the winding machine

4.Yarn splicing or knotting

5.Winding process continues up to

next fault

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Yarn Fault Measuring Principle

Thickness of the yarn monitored and converted into a

proportional electrical voltage signal

Sensor monitors a yarn running up to 120 km/hr and , the

yarn is measured every 2 mm

Signal conversion is carried by

Capacitive measuring principle or

Optical measuring principle

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1. Electrical measuring

condenser

2. Two electrodes

3. Electrical alternating

voltage

4. Yarn

5. Electrical signal

Capacitive Measuring Principle

Electrical signal corresponds to the yarn cross-section yarn mass

Changes of the yarn mass cause a proportional change of signal

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1. Infrared light source

2. Diffuser

3. Photocell

4. Yarn

5. Electrical signal

Optical Measuring Principle

Electrical signal corresponds to the diameter of the usually round

yarn

Changes in yarn diameter cause a proportional change of signal

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Cotton can be contaminated the cotton field to the spinning mill

Human and animal hair, feathers, strings, packing material,

stems, leaves and oil stains

Foreign fibers cause fabric defect, lower the efficiency of the

following processes

Foreign Fiber Clearing

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Detection of Foreign and Polypropylene Fibers

Optical measuring system

Comparison between the reflection of the foreignfiber and the normal yarn color

Classification Matrix - Uster

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Classification Matrix - Loepfe