T.NANDINI DEVI

MVM 15025

The major steps necessary to process wool

from the sheep to the fabric are:

shearing,

cleaning and scouring,

grading and sorting,

carding,

spinning,

weaving, and

finishing.

Shearing

Sheep are sheared once a year.

The fleece recovered from a sheep can weigh between

6 and 18 pounds (2.7 and 8.1 kilograms).

While most sheep are still sheared by hand, new

technologies have been developed that use computers

and sensitive, robot-controlled arms to do the clipping.

Australian scientists created a chemical method of

shearing called "bio-clip."

Injected with recombinant epidermal growth

factor (EGF), that causes the wool follicle to break

and the fleece to drop off on its own.

This causes natural disruption of hair growth,

allowing the wool to be slid, glove like, from the

sheep 4 weeks after the injection.

Scientists have developed a shearing table so

the shearer doesn't have to hold the sheep.

They have also developed a "robot" for

shearing.

Cleaning and scouring

Wool taken directly from the sheep is called "raw" or

"grease wool."

It contains sand, dirt, grease, and dried sweat (called

suint).

Weight of contaminants 30 to 70 percent of the

fleece's total weight.

To remove these contaminants, the wool is scoured in a

series of alkaline baths containing water, soap, and

soda ash or a similar alkali.

Scouring is washing the wool in hot soapy water to

remove dirt, grease and dry plant matter from the

fleece.

The preferred water temperature for washing wool

is 140⁰F.

Use a mild soap.

Commercial processors may use a slight alkaline

solution (by adding sodium carbonate) to aid in the

scouring process.

The key is to keep the water temperature and the

volume of soap used as low as possible while still

being able to wash out the grease and dirt.

Wool that is very greasy will require hotter and

stronger solutions to remove the grease.

In the scouring process the wool undergoes several

soaks and rinses until the wash water remains

clean.

Let wool soak and avoid agitation.

Between each wash the wool is pressed or

squeezed to remove excess water.

When washing wool, consideration must be given

to the quality of the water.

Skirting a fleece:

The wool from the back end of the sheep, their

legs and sometimes their belly is too full of

manure to use. These are referred to as "tags”

These are removed first before washing the fleece;

this process is called skirting

Lanolin, a kind of grease, is the by-product of this

process and it is purified for use in the manufacture of

cosmetics, soap and other household products.

used as a moisturizer to treat or prevent dry, rough,

scaly, itchy skin and minor skin irritations.

Lanolin oil is used as a stabilizer, as an emulsifier in

ointments, and in medications such as zinc oxide.

Lanolin oil benefits industries as an anticorrosive or a

lubricant and is often used in the leather industry.

Grading and sorting

Grading is the breaking up of the fleece based on

overall quality.

In sorting, the wool is broken up into sections of

different quality fibers, from different parts of the

body.

The best quality of wool comes from the shoulders

and sides of the sheep and is used for clothing; the

lesser quality comes from the lower legs and is

used to make rugs.

Wool Grading by the American Blood

Count System:

Fine Wool 2 1/2 inches in staple lengthVery fine crimp (close

together)

1/2 Blood Wool 3 inches in staple length Medium fine crimp

3/8ths Blood Wool 3 1/2 inches in staple length Medium crimp

1/4 Blood Wool 4 inches in staple length Medium coarse crimp

Low 1/4 Wool 4 1/2 inches in staple length Coarse crimp (large waves)

Common 5 inches in staple length Very coarse

Braid 6 inches in staple length The most coarse

SPINNING COUNT:

It is defined as the number of hanks of yarn

that can be spun from a pound of wool.

A hank of wool is 560 yards long (560 yd/lb =

1.129 km/kg).

"A hank of wool is a length of wool pulled into

a coiled form. A hank of wool is used in heavier

textiles and for some furniture.”

A hank of linen is 300 yards or approx 270 metres

A hank of cotton or silk is 840 yards or approx

768 metres.

1 hank = 20 feet = 6.096 metres

American

Blood Grade

Spinning

Count

Range for Average

Fiber Diameter (µm)

Maximum

Standard

Deviation

Fine Finer than 80s

80s

70s

64s

under 17.70

17.70-19.14

9.15-20.59

20.60-22.04

3059

4.09

4.59

5.19

1/2 Blood 62s

60s

22.05-23.49

23.50-24.94

5.89

6.49

3/8 Blood 58s

56s

24.95-26.39

26.40-27.84

7.09

7.59

1/4 Blood 54s

50s

27.85-29.29

29.30-30.99

8.19

8.69

Low 1/4 Blood 48s

46s

31.00-32.69

32.70-34.39

9.09

9.59

Common 44s

40s

34.40-36.19

36.20-38.09

10.09

10.69

Braid 36s

Coarser than 36s

38.10-40.20

more than 40.20

11.19

The English (Bradford) Spinning Count System

or MICRON SYSTEM:

This originated in the 19th century (along with

mechanized spinning equipment).

It is the number of hanks of yarn, each 560 yards in

length, that it is possible to spin from one pound of

clean wool.

Finer the wool fiber, the more hanks (greater length,

thinner yarn) that can be obtained from one pound.

For this you need a microscope and a background slide

with micron crosshairs for comparison

Fine Wool 64 to 70 to 80 Hanks Less than 22.04 Microns

1/2 Blood 60 to 62 Hanks 22.05 to 24.94 Microns

3/8 Blood 56 to 58 Hanks 24.95 to 27.84 Microns

1/4 Blood 50 to 54 Hanks 27.85 to 30.99 Microns

Low 1/4 46 to 48 Hanks 31.00 to 34.39 Microns

Common 44 to 40 Hanks 34.40 to 36.19 Microns

Braid 40 to 36 Hanks 36.20 to 40.20 Microns

Delaine Merino 18 to 22 Microns

Rambouillet 19 to 25 Microns

New Zealand Merino 20 to 25 Microns

Targhee & Romeldale 22 to 26 Microns

Corriedale & Columbia 22 to 34 Microns

Southdown 24 to 31 Microns

Blue Leicester 24 to 28 Microns

Shropshire, Suffolk, Dorset Horn,

Montadale25 to 31 Microns

Finish Landrace (Finns) & Cheviot 25 to 32 Microns

Oxford 29 to 34 Microns

Romney 31 to 36 Microns

Border Leicester 33 to 38 Microns

Lincoln & Cotswold 37 to 40 Microns

Breed Range of

Average Fiber

Diameter (µm)

Range of

Grease Fleece

Weight (lb)

Range of Clean

Wool Yield (%)

Border Leicester 38-30 8-12 60-70

Cheviot 33-27 5-8 50-65

Columbia 30-23 9-14 45-60

Cormo 22-19 10-14 60-70

Corriedale 31-24 9-14 45-60

Debouillet 23-18 9-14 45-55

Delaine-Merino 22-17 9-14 40-50

Dorset 32-26 5-8 50-65

Finnsheep 31-24 4-8 50-70

Hampshire 33-25 6-10 50-60

Lincoln 41-34 10-14 55-70

Merino (superfine) <18 6-9 60-70

Merino (fine) 19-20 6-11 60-70

Merino (medium) 21-22 9-13 65-75

Merino (strong) 23-26 11-15 65-75

Montadale 30-25 7-11 50-60

Oxford 34-28 7-10 50-60

Rambouillet 23-19 9-14 45-60

Romney 39-32 8-12 55-70

Shropshire 33-25 6-10 50-60

Southdown 29-24 5-8 40-55

Suffolk 33-26 4-8 50-60

Targhee 25-21 9-14 45-60

Texel 33-28 7-10 60-70

*Primary source: Sheep Production Handbook. 1996. American Sheep Industry Association Inc. Production,

Education, and Research Council.

The clean wool now to be further processed before

being spun into woollen or worsted yarn.

Woollen yarn more bulky, hairy and irregular

than worsted yarn and today is used for items such

as carpets or knitwear.

Worsted yarn more tightly spun, smoother

looking than woollen yarn and stronger

Woolens Worsted

Spun from short wool fibers

(1-3 inches long)

Spun from long wool fibers

(more than 3")

Spun from medium or coarse

diameter wool fibers

Spun from fine diameter wool

fibers

Fibers are washed, scoured and

carded

Fibers are washed, scoured,

carded, combed and drawn

lower tensile strength than

worsteds

higher tensile strength than

woolens

low to medium twist tighter twist

Bulky, uneven yarn Fine, smooth yarn

Soft, fuzzy appearance crisp, smooth appearance

heavier weight lighter weight

not as durable as worsteds More durable than woolens

does not hold crease well holds crease well

Woolen Processing Worsted Processing

Spun from wool fibres of:

Length : spun from short fibres of 1-3”

Diameter: medium or coarse

The fibres are washed, scoured and carded.

Spun from wool fibres of:

Length : longer than 3”

Diameter: fine diameter

Fibres are washed, scoured, carded,

combed and drawn

Yarn

Bulky

Uneven

Low to medium slack twist

Tensile strength lower than worsted

Yarn

Fine

Smooth and Even

Tighter twist

Higher tensile strength

Fabric Appearance

Soft, Fuzzy, Heavier weight

Fabric Appearance

Crisp, Smooth,Lighter weight

Characteristics

Insulator due to trapped air

Does not hold a crease well

Less durable than worsted

Characteristics

Less insulator

Holds creases and shape

More durable than woollens

Uses

Sweater,Carpets,Tweeds

Uses

Suits, Dresses, Gabardines,Crepes

Carding

The fibers are passed through a series of metal teeth

that straighten and blend them into slivers.

Carding also removes residual dirt and other matter left

in the fibers.

Carded wool intended for worsted yarn is put through

combing, a procedure that remove short fibers and

place the longer fibers parallel to each other.

Carded wool to be used for woolen yarn is sent directly

for spinning.

Combing

Combing takes out the shorter fibres, also called

noils, and lines the longer fibres up parallel with

one another in a 'sliver‘ [A sliver is a long bundle

of fiber that is generally used to spin yarn].

Spinning

The craft of spinning is thousands of years old.

During the spinning process the fibres are twisted into

a long, continuous thread, or yarn. This used to be done

with ‘spindle whorls’

The invention of the spinning wheel greatly increased

the speed at which yarn could be spun.

Today, spinning can be done on a variety of machines,

depending on whether the yarn is destined to become

woollen or worsted cloth.

Weaving

The wool yarn is woven into fabric.

Wool manufacturers use two basic weaves: the

plain weave and the twill.

Woolen yarns are made into fabric using a plain

weave (rarely a twill), which produces a fabric of a

somewhat looser weave and a soft surface (due to

napping) with little or no luster.

Worsted yarns can create fine fabrics with

exquisite patterns using a twill weave.

The result is a more tightly woven, smooth fabric.

Better constructed, worsteds are more durable than

woolens and therefore more costly.

Finishing

After weaving, both worsteds and woolens

undergo a series of finishing procedures including:

• Fulling (immersing the fabric in water to make the

fibers interlock); and stretching.

• crabbing (permanently setting the interlock) and

decatsing (shrink-proofing);

• occasionally, dyeing.

Fulling

Use of heat, moisture and extreme agitation to

make a wool fabric shrink and therefore become

stronger and warmer

Fulling can reduce the size of a piece of cloth by

up to a third.

The cloth was then treated by being beaten with

large hammers called ‘stocks’.

Stretching

Fulling processes are followed by stretching the

cloth on great frames known as tenters, to which it

is attached by tenterhooks.

The area where the tenters were erected was

known as a tenterground.

Crabbing:

The process ensures that the fabric is stretched

or loosened as necessary and evens out the thickness of

the fabric.

Crabbing prevents the formation of creases or uneven

shrinkage.

DYEING:

As wool readily accepts dye colors, dyeing can

occur at almost any stage of the wool processing.

The two common stages for wool dyeing is right

after washing or after spinning wool into skeins of

yarn.

If the dyeing occurs after the wool is washed then

it is referred to as stock dyed wool.

If the wool is dyed after it is spun into yarn then it

is referred to as yarn dyed.