Sunday, April 30, 2017

Yarn Count Numbering System and Conversions

Yarn count:
Yarn count is the physical thickness, coarseness or fineness of yarn which can be measured and defined as fine increasing in size to thick or course.

The size or thickness of the yarn relates to a unit of length and weight of the yarn and also influences the covering power of the yarn. Yarn of finer thickness requires a greater number of yarns to fill a square inch measured space of fabric. Yarns of coarse or greater thickness require less yarn to fill the same square-inch measured space. High covering power or good covering power translates to mean, fewer yarns are required. Low or poor covering power many yarn are required.

Yarn count or yarn thicknesses are measured by a direct and indirect system of measuring. The direct system is used to measure all filament yarns. The indirect or inverse proportion system is used to measure all spun yarns.

Types of yarn count:
Yarn count numbering system divided into two types. They are

  1. Direct system/Decitex system/Dtex – Tex, denier, Ibs/spindle.
  2. Indirect system/yarn count system – English, metric, worsted.
1. Direct yarn count system:
This system measures filament yarn only. The direct system is a direct reading where by the weight of the fiber is the same as the yarn count. Weight is measured in grams; the grams equal the denier count. The basic unit used for measuring is 9000meters or one gram.

As the number increase, the physical size of the yarn gets thicker. Fine or thin yarns will have a lower count than coarse, thick yarns. This system is generally used for synthetic fiber, jute, silk etc.

Let,


       W x l
N = --------------
          L


Where,

N = The yarn number or count
W = The weight of the sample
L = The length of the sample
l = The unit of length of the system

In the denier system, the weight unit is the gram and the unit of length is 9000 meters. The denier of a yarn is the weight in grams of 9000 meters.

If sample weight, W = 1.67 gm, sample length, L = 100 meters and unit length, l = 9000 meters

                                     W x l
Therefore Denier, N = --------------
                                       L


    1.67 x 9000
= -------------------------
         100

= 150.3 denier

2. Indirect system of yarn count:
This system measures spun yarn only. The yarn count number is inversely proportioned to the weight of the yarn. As the number increases, the physical size of the yarn gets finer and thinner. A fine, sheer yarn will have a higher count number than a coarse, thick yarn. Yarn count standards differ for each staple fiber classification. Yarn count standards represent the number of yards in one pound of a number one count of that specific yarn.

In an indirect system the yarn number or count is the number of units of length per unit of weight. There are various units of length and weight and numerous system.

Let,


       w x L
N = -----------
       W x l


Where,

W = The weight of the sample
w = the unit weight of the system
L = The length of the sample
l = The unit of length of the sample.

e.g. A length (120 yards) of cotton yarn weight 25 grain calculation its count in the cotton system. In this case the “Unit of length” is the hank 840 yards and the “Unit of weight is lbs. (1 lb =7000 grain)

Hence,

L = 120 yard. l = 840 yard.


          25
W = ----------- lbs.       w = 1 lb
        7000

(The small “s” after the count number is a convention used for expressing count)

Note: The values 7000 and 840 appear in all such cotton yarn calculations and may therefore be reduced to a constant fraction 100/12 i.e. 7000/840


                            Length in yards              100
i.e. Yarn count = ------------------------------- X -----------
                            Wt. in grains                   12

Further it is always tested, then


                               120 x 100
Cotton count = ------------------------------
                          Wt. in grains x 12


        1000
= ------------------------
   Wt. in grains

Tex system of yarn numbering (direct system):

This is a direct system of measuring. It is used to measure both filament and spun yarn of silk, regenerated cellulosic fiber and man-made fibers. As the numbers increase, the physical size of the yarn gets thicker. The tex system using fixed weights, states the weight of 1000m of a given yarn.

The yarn number or count in the Tex system is the weight in grams of 1 kilometer of yarn.

Millitex:
The weight in milligrams per kilometers is “millitex”. It is used to express fineness of fibers.

Kilotex:
The weight in kilograms per kilometer or what amount to the same things of grams per meter.

Units of Length and Weight in Counting Systems:

Conversion systems of count:
Conversion from one system to another is achieved by conversion factors and constants. Where a direct to a direct system or an indirect to an indirect system is connected, a multiplying conversion factor is used.

Direct system:


Indirect system:

System
Unit of length
Unit of mass
Asbestos (American)
100 yds. (cut)
Pound
Asbestos (British)
50 yds.
Pound
Cotton (British)
480 yds.(hank)
Pound
Glass
100 yds. Kilometer
Kilogram
Spun silk
840 Yds (hank)
Pound
Worsted
560 yds (hank)
Pound
e.g. Denier x 0.111 = Tex direct to direct.

Cotton count x 1.5 = Worsted count indirect to indirect

Where the conversion is from a direct to an indirect or vice verse, a constant is used into which the known count is divided to give the equivalent count in the other system.

e.g. the constant for cotton and denier is 5315 then 

                             5313
32 cotton count = ----------
                              32


= 166 denier


                            5315
and 100 denier = -------------
                             32


= 53.15 cotton count

Conversion from one system to another direct to direct:

Indirect to indirect:


Known yarn count in
Multiplying factor to give yarn count in
Cotton & spun silk
Linen (wet. Spun)
Woollen (York, skein)
Worsted
Cotton and spun silk
-----
2,800
3,281
1,500
Linen (wet. Spun)
0.3571
-----
1,172
0.5375
Woollen (York, skein)
0.3048
0.8533
-----
0.4571
Worsted
0.6667
1.867
2.188
-----





Direct to indirect & in direct to direct:

Known yarn count in
Constant into which the known yarn count is divided in order to obtain the equivalent yarn count in the other system.
Tex
Denier
Linen (dry-spun), hemp, jute and woollen
Cotton and spun silk
590.5
5315
17.14
Linen (wet. Spun)
1654
14,880
48.00
Woollen (York, skein)
1938
17,440
56.25
Worsted
885.8
7.972
25.71
There is a relationship between count or yarn number to twist of yarn. In s direct system:

TPI (Twist Per Inch) = Twist factor x √count

In a indirect system, 

                                         Twist factor
TPM (Twist per meter) = ---------------------
                                         √Tex count

Traditional system of conversion:


                    590.5
a. Tex = -------------------------
              Cotton count

b. Tex = Denier x 0.111

Measurement of yarn count:

  a. Wrap reel and analytical balance
  b. Wrap reel and knowledge balance
  c. Wrap reel and quadrant balance

Yarn diameter and count relationship:


                                                  1
Yarn diameter (in inches) = ---------------
                                           √28 count

Different yarn counting system:

English cotton count:
It is the number of hank of 840 yards in one pound yarn e.g. in English cotton count system 40” or 40 ne as it is expressed means one pound yarn contains 40 numbers of hanks, each of 840 yards length.

Tex:
Weight in gms per 1000 meter or 1 km of yarn e.g. if 1000 meter of a yarn weight 25 gm then the yarn count is 25 denier.

Denier:
Weight in gms per 9000 meter of yarn, e.g. if 9000 meter of a yarn weight 225 gm. them the yarn count is 225 denier.

Metric system:
It is the number of hanks of 1000 meter in one kg. of yarn. eg. If in one kg, of yarn there are 40 hanks each of 1000 meter length, then the count of the yarn is 40 Nm.

Jute count system:
Weight in pound per 14,000 yards (spindle) of yarn e.g. if 14,400 yards of a jute yarn weight 5 pound, then the count is 5 pound/ spindle.

Worsted system:

Number of hanks of 560 yards in one pound.

Conversion of yarn count from one system to another:
1. English cotton count to Tex & vice versa.


English cotton count x Tex = 590.5

i.e. If yarn count is known in one of the systems, other can be found by dividing 590.5 by that known count.

Example:

Convert 20 cotton into Tex?

We know,

20 x Tex = 590.5


                590.5
e.g. Tex = ----------
                 20

= 29.525

2. English cotton count to worsted count.

We know,

Worsted count = English cotton count x 1.5

e.g. 20 cotton yarn = 30 worsted

3. Metric count to tex and vice varsa.

We know,

Metric count x Tex =1000


                                  1000
e.g. Metric count = --------------------
                                  Tex

Or


              1000
Tex = ----------------
         Metric count

4. Worsted count to Tex & vice varsa

We know,

Worsted count x Tex = 855.8


                                  855.8
e.g. Worsted count = ---------------
                                   Tex

Or


                855.8
Tex = -----------------------
          Worsted count

You can also like:

  1. Yarn Count Measurement System
  2. Yarn Count Range for Different GSM
  3. How to Find Yarn Count from Fabric GSM