Production Dpt

8/6/2019 Production Dpt

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2.2 PRODUCTION DEPARTMENT

This department deals with the production of yarn. The entire production and

process controls is directly under the control of production manager. The spin plan or the

counts to be manufactured will be decided well in advance according to the market demand

or the demands of the customer. Again it depends upon the raw material availability and

balancing of the process in each department. Production Manager in consultation with the

quality control manager has decided the process parameter for the counts to be produced.

This is the activity which converts raw materials into finished goods. The works manager will

make decisions on the form of production.

Job production - meeting the requirements of the individual customer.

Mass production - large scale production of a standard product.

Small batch production - large production of a good which is modified to meet demand.

PROCESS FLOWCHART

BLOW ROOM

CARDING

SIMPLEX

SPINNING

CONE WINDING

PACKING


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GINNING

The seed cotton goes in to a Cotton Gin. The cotton gin separates the seeds and

removes the "trash" (dirt, stems and leaves) from the fibre. In a saw gin, circular saw grabs

the fibre and pulls it through a grating that is too narrow for the seeds to pass. A roller gin is

used with longer staple cotton. Here a leather roller captures the cotton. A knife blade, set

close to the roller detaches the seed. By drawing them through teeth in circular saws and

revolving brushes which clean them away.

The ginned cotton fibre, known as lint, is then compressed into bales which are

about 1.5m tall and weigh almost 220 kg. Only 33% of the crop is usable lint. Commercial

cotton is priced by quality, and that broadly relates to the average length of the staple, and

the variety of the plant. Longer staple cotton (2 1/2 in to 1 1/4 in) is called Egyptian, medium

staple (1 1/4 in to 3/4 in) is called American upland and short staple (less than 3/4 in) is

called Indian.

The cotton seed is pressed into cooking oil. The husks and meal are processed into

animal feed, and the stems into paper.

BLOW ROOM

With all harvesting methods, however, the cotton seed, together with the

fibers, always gets into the ginning plant where it is broken up into trash and seed-coat

fragments. This means that ginned cotton is always contaminated with trash and dust

particles and that an intensive cleaning is only possible in the spinning mill.

Nep content increases drastically with mechanical harvesting, ginning and

subsequent cleaning process. The reduction of the trash content which is necessary

for improving cotton grade and apperance unfortunately results in a higher nep content

level.


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The basic purpose of Blow room is to supply

Small fibre tufts

clean fibre tufts

Homogeneously blended tufts if more than one variety of fibre is used to

carding machine without increasing fibre rupture, fibre neps, and broken seed

particles, without removing more good fibres.

The raw cotton arrives in the form of large bales. These are broken open and

a worker feeds the cotton into a machine called a "breaker" which gets rid of some of

the dirt. The cotton may not be consistent in quality from bale to bale and samples will

be taken. This machine cleans the cotton of the remaining dirt and separates the

fibres. The cotton emerges in the form of thin "blanket" called the "lap". An important

quantity is called the "tex"which basically measures the mass per metre. Ideally the

tex of the emerging lap should stay more or less the same. The final end product of the

mill, the yarn, needs to be of constant quality and character and this is achieved by

checking the cotton through all the preceding stages.

The above is achieved by the following processes in the blow room

1. Pre opening

2. pre cleaning

3. mixing or blending

4. fine opening

5. dedusting

Tex is the weight in grams of 1 km of yarn


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BLOW ROOM

CARDING

Historian of science Joseph Needham ascribes the invention of bow-

instruments used in textile technology to India. The earliest evidence for using bow-

instruments for carding comes from India (2nd century CE). These carding devices,

called kaman and dhunaki would loosen the texture of the fiber by the means of a

vibrating string.

Carding, process by which fibers are opened, cleaned, and straightened

in preparation for spinning. The fingers were first used, then a tool of wood or bone

shaped like a hand, then two flat pieces of wood (cards) covered with skin set with

thorns or teeth. Primitive cards are rubber-covered and toothed with bent wires, are

still employed by some countries. Modern carding dates from the use of revolving

cylinders patented in 1748 by Lewis Paul. A mechanical apron feed was devised in

1772, and Richard Arkwright added a funnel that contracted the carded fiber into a

continuous sliver. Cotton and wool are probably the most common fibers to be carded.


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MODERN CARDING MACHINE

In simple terms, Carding is the processing of brushing raw or washed

fibers to prepare them as textiles. Carding is used to take unordered fibers and

prepare them for spinning by either the worsted or woolen process or to produce webs

of fiber to go into nonwoven products depending on the mechanism at the output from

the card. It can also be used to create blends of different fibers or different colors. The

process of carding involves mixing up different fibers, thus creating a homogeneous

mix of the various types of fibers, at the same time as it orders them and gets rid of the

tangles. Machine cards for carding wool also have rollers and systems designed to

remove some vegetable contaminants from the wool.

The two main ways to card fibers are by

Hand

Machine


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HAND CARDING

To card by hand, the person carding holds a carder in each hand. The carder

in their non-dominant hand rests on their leg. They place a small amount of fiber on

this card and pull the other carder through, while taking care to catch some of the

fibers. By catching some fibers on the moving card, the fibers are separated, which

allows vegetable matter to fall out, and they are aligned. Once all the wool has been

transferred, the person carding repeats this process until all the fibers are aligned and

the fiber is satisfactorily clean of debris. They then roll up their carded wool into a neat

rolag.

HANDCARDS
http://en.wikipedia.org/wiki/File:Rolag.jpg


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MACHINE CARDING

Machine carding is done on a device called a drum carder. These devices

vary in size from small to large. Depending on the size of the carder, the number of

rollers varies. In Kitchen type carders, they have two drums, or rollers. One is small,

and used to catch the fibers and feed them in. The other drum takes the fibers from the

first drum, and, in the process of transferring them from one drum to another, the fibers

are straightened out and made more orderly.

SMALL DRUM CARDER

In Carding the fibres are separated and then assembled into a loose strand

called sliver or tow. The carders line up the fibres nicely to make them easier to spin.

The cotton leaves the carding machine in the form of a sliver; a large rope of fibres.

Carding can refer to these four processes:

Willowing - loosening the fibres

Lapping - removing the dust to create a flat sheet or lap of cotton

Combing - the tangled lap is made into a thick rope of 1/2 inch in diameter, a

sliver.
http://en.wikipedia.org/wiki/File:Carding_llama_hair.jpg


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Combing is optional, but is used to remove the shorter fibres, creating a stronger yarn.

Drawing - a drawing frame combines 4 slivers into one- repeated for

increased quality.

COMBING MACHINE

Several slivers are combined. Each sliver will have thin and thick spots, and

by combining several slivers together a more consistent size can be reached. Since

combining several slivers produces a very thick rope of cotton fibres, directly after

being combined the slivers are separated into rovings. These rovings (or slubbings)

are then what are used in the spinning process.

SIMPLEX

In this process the output of drawing is drafted, twisted to make roving bobbin

form.

SPINNING

The spinning machines take the roving thins it and twists it, creating yarn which it

winds onto a bobbin. The term "spinning" is sometimes used to denote this final

process in the production of the yarn. This involves attenuating (stretching) the yarn to
http://en.wikipedia.org/wiki/File:Catalonia_Terrassa_mNATEC_Pentinadora.jpg


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the required tex. There by giving the thread strength by adding twist and winding it on

to a bobbin.

There are two main methods

Mule spinning

Ring spinning

MULE SPINNING

The MULE was originally developed by Samuel Crompton from the "jenny". In

mule spinning the roving is pulled off a bobbin and fed through some rollers, which are

feeding at several different speeds. This thins the roving at a consistent rate. If the

roving was not a consistent size, then this step could cause a break in the yarn, or

could jam the machine. The yarn is twisted through the spinning of the bobbin as the

carriage moves out, and is rolled onto a cop as the carriage returns. Mule spinning

produces a finer thread than the less skilled ring spinning. The mule operated in two

stages. In one stage the whole 'front' of the machine is moved away from the back part

stretching and twisting the thread as it did so. It would move several feet (say 5 feet).

In stage two the front carriage moved back and at the same time wound the stretched

yarn on to a bobbin (orcop).

Mules would be placed in lines so that the front of one faced the front of

the next. As the carriages moved forward, towards each other, only a narrow gap


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would be left between them for the spinner to walk between. The mules were tended

by spinners, piecers, doffers.

Piecers would mend broken threads and

doffers would remove the full cops

Doffing is a separate process. The attendant winds down the ring rails to the

bottom. The machine stops. The thread guides are hinged up. Removing the bobbin

coils thread around the spindle, and placing the new bobbin on the spindle firmly traps

the thread between it and the cup in the wharf of the spindle. This done, the thread

guides are lowered and the machine restarted.

MULE SPINNING

RING SPINNING
http://upload.wikimedia.org/wikipedia/commons/b/b8/Textile-Spinning_room.jpg


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Ring spinning is a method of spinning fibres, such as cotton, flax or wool, to

make a yarn. The ring frame developed from the throstle frame. Ring spinning is a

continuous process, unlike mule spinning which uses an intermittent action. In ring spinning,

the roving is first attenuated by using drawing rollers, then spun and wound around a

rotating spindle which in its turn is contained within an independently rotating ring flyer.

Traditionally ring frames could only be used for the coarser counts- but they could be

attended by semi-skilled labour.

The ring was a descendant of the Arkwright water Frame 1769. It was a

continuous process; the yard was coarser, had a greater twist and was stronger so

was suited to be warp. Ring spinning is slow due to the distance the thread must pass

around the ring, other methods have been introduced. These are collectively known as

Break or Open-end spinning.

MODERN RING SPINNING ERAME

1 Draughting

rollers

2 Spindle

3 Attenuated

roving

4 Thread

guides

5 Anti-ballooning

ring

6 Traveller

7 Rings

8 Thread on


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A ring frame was constructed from cast iron, and later pressed steel. On each

side of the frame are the spindles, above them are the draughting (drafting) rollers and

on top is a creel loaded with bobbins of roving. The roving (unspun thread) passed

downwards from the bobbins to the draughting rollers. Here the back roller steadied the

incoming thread, while the front roller which was moving much faster pulled thread out

(attenuated) forcing the fibres to mesh together. The rollers are individually adjustable,

originally by mean of levers and weights. The attenuated roving now passes through a

thread guide that is adjusted to be exactly above the spindle. Thread guides are on a

thread rail which allows them to be hinged out of the way for doffing or piecing a broken

thread. The attenuated roving passes down to the spindle assembly, where it is threaded

though a small ring called the traveller. It is this that gives the ring frame its name. From here

it is attached to the existing thread on the spindle.

Like the hour and minute hands on a mechanical clock, the traveller, and the

spindle share the same axis but travel at different speeds. The spindle travels faster. The

bobbin is fixed on the spindle. In a ring a frame, the different speed was achieved by drag

caused by air resistance and friction. The spindles rotate at 7000 to 8000 rpm, this spins the

yarn. The traveller, winds the yarn on the bobbin. The ring on the traveller is fixed on a lifting

ring rail which guides the thread onto the bobbin in the shape required: ie a cop. The

lifting must be adjusted for different cotton counts.

CONE WINDING

The yarn which emerges from the spinning process cannot usually be woven

directly and needs some preparation. Winding is the process of transferring the yarn to

larger bobbins or cones. The idea is to get a long continuous length. Weft-winding

involves winding on to smaller bobbins that will go into a shuttle. Racks of bobbins are

set up to hold the thread while it is rolled onto the warp bar of a loom. Because the

thread is fine, often three of these would be combined to get the desired thread count.


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Spinned yarn is brought into this process to make into cone yarn at the

required weight (say 1.275/ cone). The cone yarn of 1.275 weights is then transferred

to packing and bundling department.

BEAMING

The beam is a long cylinder with flanges and perhaps 600 threads are wound

on to it side-by-side. The machine is watched over by a "beamer". The full beam is

very heavy. In early days beaming was often done in the weaving mill but then tended

to be transferred to the spinning mill which would send the full beams to the weavers.

Note that this is more specifically called a "warper's beam"

SIZING

The yarn is a little fragile for the rough treatment imposed by the weaving

process and a "size" is applied to make it more robust. A number of warper's beams

(as above) are placed at the back of the sizing machine and the yarn is drawn through

and wound on to a "weaver's beam". If the machine is fed by 8 warper's beams of 500

threads each then the weaver's beam will have 4000 parallel threads. Generally the

set of warper's beams will produce up to 20 weaver's beams each of 1000 yards or

more. The operative is called a "tape sizer" or a "taper". This was a skilled job to get

the right degree of dryness.


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UNITS IN TEXTILE MEASUREMENT

Cotton Counts: The number of pieces of thread, 840 yards long needed to

make up 1 lb weight. 10 count cotton means that 10x840 yds weighs 1lb.

Hank: A length of 7 leas or 840 yards

Thread: A length of 54 in (the circumference of a warp beam)

Bundle: Usually 10 lbs

Lea: A length of 80 threads or 120 yards

Denier: this is an alternative method. It is defined as a number that is

equivalent to the weight in grams of 9000m of a single yarn.15 denier is finer than 30

denier.

Tex: is the weight in grams of 1 km of yarn.

The Worsted hank is only 560yd.

PACKING AND BUNDLING

Yarn Twist

The amount of twist is an important factor in finished consumers goods. It

determines the appearance as well as the durability and serviceability of a fabric.

Fine yarns require more twist than coarse yarns. Warp yarns, which are used for the

lengthwise threads in woven fabrics, are given more twist than are filling yarns,

which are used for the crosswise threads.


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Here the cone yarn produced is measured to confirm its weight and the cone

yarn is individually covered with poly pack and its packed to form a bundle weighing

51 kgs per bag or bundle. On the average 85 bags are produced per day, but this has

been drastically reduced to 55 bags per day due to the recent power-cut in Tamilnadu.

1 bundle = 50 cones

20 bundles = one bale

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