# Yarn Numbering System

## Yarn Numbering (Count) System

Md. Ahsan Ul Habib (Saikat)1 & Md. Amir Khasru2
B.Sc. in Textile Engineering1,2,
Department of Yarn Engineering, SARSTEC1,2
Email: santo.amirkhasru2002@gmail.com2

What is Yarn Count / Linear Density?
Count is the numerical expression which expresses fineness of yarn. A definition of Yarn count is given by the textile institute,

“Count a number of indicating the mass per unit length or the length per unit mass of Yarn”.

Types of Yarn Numbering (Count) System:
Basically two types of yarn counting system –

Direct system: Tex, Denier, lb/spindle

Indirect system: English, Metric, Worsted

Direct system:
The direct system of denoting linear density is based on measuring the weight per unit length of yarn. Hair higher the count course are there it is used for silk, jute etc.

Here, higher the count coarser the yarn.

It is used for silk, jute, etc.

Example: Tex, denier, lb/spindle.

Nd = (W×l)/(L×w)

Indirect system:
The indirect system is based upon the length per unit weight (mass) of yarn.

Here, higher the count finer the yarn.

It is used for cotton, woolen, worsted, linen etc.

Example: English, Metric, Worsted.

Nid = (L×w)/(W×l)

Where,

Nd = Yarn Count in direct system

Nid= Yarn Count in indirect system

W = mass of the sample.

l = Unit length of the system.

L = Sample length.

w = Unit mass of the system

Count in Different System:

Direct:

Tex = (Weight in gram)/(Length in 1000m or 1 km)

Denier = (Weight in gram)/(Length in 9000m or 9 km)

Pounds per spindle = (Weight in lb)/(Length in 14,400 yds)

Millitex = (Weight in milligram)/(1000m )

Kilotex = (Weight in kilogram)/(1000m )

Wollen = (Weight in grain)/(20 yds)

Indirect:

English system, Ne = (Length in Hanks of 840 yds)/(Weight in lbs)

Metric, Nm = (Length in Hanks of 1000m)/(Weight in kg)

Metric, Nm = (Length in 560 yds)/(1 pound )

Wollen = (Weight in grain)/(20 yds)

Conversion of Count System:

NR = Count of required system.

Nk = Count of Known system.

lk = Unit length of Known system.

lR = Unit length of required system.

Wk = Unit Weight of Known system.

WR = Unit Weight of required system.

Calculation of Conversion Factor:

English (Cotton count) to Denier:
From count conversion system,

Here,

Wk = Unit weight of known system = 1 pound = 453.6 gm

lk= Unit length of known system = 840 yds = 840×0.9144 m= 768.096m

WR= Unit weight of required system = 1 gram

lR = Unit length of required system = 9000 meter

Denier = 1/Ne × {(453.6 )/1}/{(768.096)/9000} = 1/Ne ×5315

Denier to English (Cotton count):

Here,

Wk=Unit weight of known system=1gm

lk = Unit length of known system = 9000 meter

WR = Unit weight of required system = 1 pound = 453.6 gm

lR = Unit length of required system = 840 yds = 840×0.9144 m = 768.096m

Ne= 1/D×5315

Denier to Tex:

Prove: denier = 9Tex

Here,

Wk = 1 gram

lk = 9000 meter

WR = 1 gram

lR = 1000 meter

NR = Nk×(1/1)/(9000/1000)

=> Tex = D×1/9

=> D = 9×Tex

English to Metric:

Here,

Wk = 1 pound =453.6 gm=453.6×10-3 kg

lk = 840 yds= 840×0.9144 m = 840×0.9144×10-3km

WR = 1 kg

lR = 1 km

Nm=Ne×(840×0.9144×10-3/1)/(453.6×10-3)/1)

Nm=Ne×1.69

Tex to English:

Here,

Wk = 1 gram = 1/(453.6)  lb or pound

lk = 1000 meter = 1000 × 1.09 yds

WR = 1 pound

lR = 840 yds

Ne = 1/Tex×{(1000×1.09)/840}/[{(1/453.6)}/1]

=> Ne=1/Tex×590.5

Relation between Yarn Dia & Count:
Pierce approached the problem from consideration of the apparent specific volume of yarns. By experiment an apparent specific volume of 1.1 for cotton yarns was obtained.

So, specific volume of yarn = 1.1 cm3/gm

The weight of 1.1 cm3 yarn = 1 gm

Let,

Yarn count = N tex.

∴ Wt of 1000m yarn is N gm

Length of N gm yarn is 1000m

∴ Length of 1 gm  yarn is (1000 m)/N or (1000×100 cm)/N

So, Length of 1.1 cm3 (Volume) yarn is 105/N cm

Since, The volume = Cross section ×Length

1.1 cm3 = π×(d/2)2×105/N  cm          (For Direct system)

1.1 cm3 = π×d2/4×105/N  cm

d2           =(1.1×4×N)/(π×105 )cm

[Where d = dia of yarn in cm]

d = √{(1.1×4×N)/(π×105 )}

d =  0.375/100 √(N ) cm

d∞√(Ne)

Converting cm to Inches and Tex to Cotton Count:

d (inch)  =0.375/100×√(590.5 )/√(Ne)×1/2.54          (For Indirect system)

d = 3.6/{100√(Ne )}

d = 1/{28√(Ne)}

∴ d ∞1/√(Ne)

Count Calculation for Double Yarn:

For Direct system
N = N1 + N2

For Indirect system
1/Nr  = 1/N1 + 1/N2

Where,

Nr = resultant count

N1 & N2 = component count

Measurement of Count:

1. Warp Reel and Balance Method:
3. Knowles balance
4. Beesley balance
5. Sliver, roving count by measuring drum
6. Count data system
7. Auto sorter by Uster

References:

1. Handbook of Textile Testing and Quality Control (PDF) – B. Grover, D. S. Hamby
2. https://textilelearner.net/yarn-count-numbering-system-and-conversions/
3. https://textilestudycenter.com/yarn-numbering-system/
4. Textile Testing by Angappan.
5. Principles of Textile Testing by Booth
6. Physical Testing of Textiles by Saville

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