Processing
There are two distinct types of yarn production, the Worsted processing system, which is how the majority of Australian wool is transformed into yarn and the Woollen processing system.
The Worsted System
- Uses longer length wools (greater than 65mm staple length)
- Wool is made into tops before spinning into yarn
- 80% of Australia's wool is processd this way
The Woollen System
- Uses much shorter wool such as locks, crutchings, bellies and lamb's wool
- All carbonised wool and a substantial amount of scoured wool is processed this way
- Produces a bulkier yarn that is used in knitting and some weaving
The six major processes of worsted yarn are:
- Scouring - a washing process that removes dust, suint (sweat) and wool wax.
- Carding - rollers covered with teeth tease apart the staples of wool, laying the fibres nearly parallel to form a soft rope called a 'sliver'.
- Combing - the comb separates short from long fibres, ensuring that the long fibres are laid parallel to produce a combed sliver called a 'top'.
- Drawing - several tops are drawn out into the thickness of one, to thoroughly blend the wool and ensure evenness or regularity of the resulting 'roving'.
- Finisher drawing - reduces the roving thickness to suit the spinning operation and further improve evenness.
- Spinning - insertion of twist into yarn to give strength to the finished yarn
Worsted versus woollen fabrics
- Worsted fabrics are often more expensive than wool spun products due to the longer raw material to resultant yarn processing route used.
- Worsted fabric is stronger and wears better than a woollen spun fabric of equivalent weave construction and fabric weight.
- Worsted fabrics are preferred for trousers, suitings, other garments and upholstery fabrics where a smooth finish is required.
- Woollen spun fabrics are used for jackets, coats, skirts, upholstery fabrics, rugs and blankets where bulk and textured finishes are desirable.
Processing variations
The woollen processing system can be varied to meet various market requirements. Variance in processing methods occurs either chemically or physically.
Chemical processing variances include:
- Shrink proofing;
- Fire proofing; and
- Moth proofing.
Physical processing variances include:
- Blending exotic fibres, such as cashmere or silk; and
- Blending man-made fibres.
Source: Australian Wool Innovation