There are three different systems used in wool processing;
Woollen, where the fibres
are spun after carding
Semi-worsted, where the fibres are gilled after carding, then spun
Worsted is the process used at AusTop for most wools.
The following covers the worsted process which is the most common treatment
of Australian wool.
Blending
Blending is a very important aspect of the Topmaking process at AusTop because
when greasy wool is received in bales to be processed, it is the product of
many different growing conditions, microns, lengths, strengths, types and cleanliness.
To process the wool fibre, avoid significant variations in the Top quality and
reduce the need to vary machine settings blending is needed.
The blending of wool begins from the time the bales are unloaded from the truck. It is further blended in the Wool Opening machine and again as the wool is removed from the Greasy wool bin prior to scouring. Further blending occurs as the wool is taken out of the Card wool bins prior to the carding process. The wool blending system at AusTop is very efficient in minimising the variation within a batch and ensures a quality Top is produced.
Scouring
Scouring involves washing the wool to remove dirt, Lanolin/wax and other impurities.
Some of the vegetable matter is also removed when the wool is "opened".
The AusTop scour is based on a development by CSIRO called Siroscour. The advantages of this system involve being able to produce a longer cleaner Top and using considerably less water.
Carding
Carding is the process where the washed scoured wool which is in an entangled
state, is put through a series of rollers with metal teeth. This process gradually
teases the wool into a parallel form.
The main aim of carding is to;
open the wool
and to lay the fibres parallel
remove impurities remaining after scouring (particularly vegetable matter)
dispose the fibres in an even veil which will be condensed in a band called
"card sliver". This is the first step in producing a yarn.
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Gilling
After the carding process a "web" of fibres is formed. The fibres
are mostly parallel, however, the sliver has to undergo a further series of
straightening processes called "gilling" until the fibres are parallel
enough to be passed through the comb. Hooks that are formed in carding are straightened
to ensure an effective combing process.
The gilling process
is performed at two stages: preparation for combing; and finishing after combing.
The purpose of the Preparer gills is to reduce the number of hooks and thus
the amount of fibre breakage in the comb which ultimately reduces the noil content.
The purpose of the Finisher gills is to "finish" the final product
by blending and evenly distributing the fibres.
Combing
After three passages of gilling, straightening the tails (hooks) and making
the fibres parallel, the sliver is ready to be finally straightened in the combing
process to form "Tops". This produces a product that can be spun and
then made into a saleable yarn. All remaining impurities are removed including
vegetable matter (forms part of noil).
The purpose of combing is to divide the mass of fibres into three parts of different importance;
the "Top"
comprising the clean fibres over a given length
the first "Noil" which are the shorter fibres and the "Neps".
(The Neps are an entanglement of short fibre from carding and gilling).
the second Noil or "fly" which is accumulated with the first noil.
Pressing and Packing
The finished product is packaged, depending on customer requirements, into Bumps,
Bobbins, or open Tops. All are then pressed with a 500 tonne press and wrapped
in polythene, polypropylene or nylon ready for shipment to the customer. The
500 kg bales are packed into shipping containers and freighted to the destination
required by the customer. Much of the product goes overseas to spinning mills.