WOOL PROCESSING


THE TWO WAYS THAT WOOL IS PROCESSED

WORSTED SYSTEM

Uses fine, long wool fibres with low vegetable matter contamination to make products with a smooth finish such as suitings and fashion fabrics. The processes that are used in the Worsted system are:
WOOLLEN SVSTEM

Uses coarser, shorter wool fibres with high levels of vegetable matter contamination to produce heavier, fuzzier products such as bulky knitware,
blankets & upholstery. The processes that are used in the Woollen system are:



PROCESSES

At the wool processing mills, there are steps involved when converting fibre to yarn and the better the workmanship at each stage, the better the resulting cloth.

SCOURING

Scouring or washing is the first mechanical process that raw wool goes through and its purpose is to remove the dirt, grease and other impurities from the fibres.

The wool passes through troughs containing various solutions before entering a drying chamber from which it emerges in a dry and open condition, weighing 30% less than its original weight!

The grease or lanolin obtained from the raw wool in scouring is purified and used in the manufacture of cosmetics. Basically, scouring removes dirt and impurities from the wool.

CARBONISING

If the wool is highly contaminated, containing burrs, seeds and other vegetable matter, it must go through the carbonising process. The wool is treated with sulphuric acid and heat which converts the disintegrated material into carbon.

In simple terms, carbonising breaks down any remaining impurities in the wool with the use of heat and a mild acid solution.

CARDING

This is where the worsted and woollen systems begin to differ. The scoured yarn is now ready for the carding process where rollers covered with fine wire teeth tease apart the wool fibres which have become tangled during scouring and carbonising.

The purpose of carding in the worsted system is to lay the fibres parallel to each other until an even web of fibres, or a sliver, is produced.

If entering the woollen system, however, the sliver is then divided into strips which are rubbed together to form slubbings which are wound onto bobbins ready for spinning.

Carding disentangles the wool and reorganises the fibres.




COMBING

This is the key operation in the production of worsted yarn involving the removal of any short and broken fibres (noils) from the sliver as well as any remaining vegetable impurities. The long fibres are left straight and parallel to produce a combed sliver which is wound into balls called "tops".

In summary, combing ensures that the wool fibres are straight, parallel and uniform in length, before passing onto the next stage.

DRAWING

Drawing involves passing the top through rollers and reducing slivers to a suitable thickness ready for spinning. The process is repeated several times to ensure regularity or evenness in the finishing, the final stage of the drawing process.

A small amount of twist is also added to the sliver at this stage to increase its strength. This reduced sliver is called a 'roving". Drawing simply blends and reduces the wool to a suitable thickness for spinning.

SPINNING

This is an extension of the drawing process and involves the roving being further reduced and given more twist so that the yarn has the necessary strength for manufacturing. Spinning twists the yarn to make it stronger.

WEAVING

In the process of weaving, two sets of yarn are interlaced at right angles to form a fabric. Flannel and tweed are both good examples of woven fabrics.

KNITTING

Knitting is the construction of fabric by forming loops of yarn with needles, then drawing new loops through those formed.

DYEING

Before lowering the wool into boiling dye for 1-2 hours, it needs to be bleached to ensure an even shade is produced all over. Wool can be dyed very easily and the range of colours that can be achieved is limitless.

FINISHING

All that remains now is for the fabric to be "finished' and given its final appearance and feel. Woollen fabrics are brushed so that the fibre ends are raised into a "nap".

This is either left to give a soft texture or shaved off to give a close finish.

Worsted cloth is placed into warm, soapy water through which process it shrinks slightly and the size of the weave is reduced. It is then passed through a brush roller to remove any loose threads before being pressed with steam and rolled onto a flat board, ready to leave the mill.
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