Yarn count system and test methods
Contents
Yarn count introduction
What is yarn count?
Yarn count is a number which indicates the mass per unit length or the length per unit mass of yarn.
Classification
Generally, there are four representation ways of yarn count: Tex, Denier, Ne and Nm. Tex and denier belongs to the mass per unit length system, and Ne and Nm belong to per unit mass of length system.
Calculating methods of yarn count
Tex: The yarn count in the Tex system is the weight in grams of 1000m of yarn. Tex is usually used to express the count of natural material yarn. It is decimal and employs metric units.
Ttex=(m/L)*1000
Where,
m = The weight of the sample, g
L = The length of the sample, m
Denier: The count of yarn in the denier system is the weight in grams of 9000m of yarn. Denier is usually used to express the count of chemical fibers and filament.
Td=(m/L)*9000
Where,
m = The weight of the sample, g
L = The length of the sample, m
In the mass per unit length system, the yarn count is the number of “units of weight” per “unit of length” of yarn. This means the higher the yarn count, the thicker the yarn. It is based on the fixed length system.
Ne: Ne is the number of hanks (840yarns) of pound weight yarn. Ne is usually used to express the count of cotton type yarn in SI system.
N e=L/(840m)
Where,
m = The weight of the sample, lb
L = The length of the sample, yd
Nm: Nm is the length of per gram yarn, and it is usually used to express the count of wool yarn, linen yarn and natural fibers.
N m=L/m
Where,
L = The length of the sample, m
m = The weight of the sample, g
Conversion relationships between Tex, Denier, Ne and Nm
Ne=590.5/Ttex
Ne=0.5905Nm or Nm=1.6931 Ne
Ttex=1000/Nm
Ttex=Td/9
Yarn count test methods
There are 2 methods usually used to test the yarn count: Skein method and single yarn method
Skein Method
This test method covers the determination of the linear density of all types of yarn in package form.
Principle:
The linear density is calculated from the length and mass of suitable specimens. Specimens of suitable length are prepared by reeling test skeins for yarn numbering under specified conditions from samples that have been adequately conditioned after suitable preconditioning in skein form.
Apparatus needed:
Reel: YG086 Series Electric Wrap Reel is designed to produce up to 6 skeins of yarn of a pre-determined length and number of turns for count or strength testing. Complete with yarn package stand and pre-tension device, fitted with pre-determined counter.
YG086D (1000m) and YG086E (54in.) have the innovative design concept, which makes the instrument structure more compact than conventional models; Microcomputer control, LCD display. The number of winding turns can be set and the set number of turns can be accurately reeled. DC servo motor is adopted, which runs smoothly and reliably without noise.
ZK200C ELECTRONIC YARN COUNT SYSTEM:
ZK200C Electronic System consists of professional software and a multi-functional electronic balance which contains weighting balance, fabric yield package and count system. It is a professional balance for textile with a capacity of 200g×0.001g.
Zk200c has the professional software and high accuracy balance, it can calculate the yarn count and fabric yield automatically, and you can choose different unit according to different standard requirements.
Its function including of mass, linear density and fabric yield.
When measure mass, g, Oz and lb can be converted; When measure linear density, tex, Denier, Nm and Ne can be converted; When measure fabric yield, GSM and Oz/yd 2 can be converted; Completely display test results, can be saved in text format and printout.
Procedures of testing yarn count using skein method:
- Make lea yarn by YG086.
- Put the lea yarn on the scale pan of ZK200c
- ZK200C software will show the yarn count and average values automatically, and you can also select proper unit according to your requirement.
- ZK200C will make your tests of yarn count more convenient, you just need warp the yarn, and then put the yarn on its scale pan , input the length, the software will give you the test report.
Single yarn method:
This test Method is used to test the yarn count that Based on Short-Length Specimens.
Principle:
Specimens are cut from a conditioned sample, or removed from a rectangular strip of fabric under prescribed tension, and weighed. The yarn count is calculated from the mass and the measured total length of the specimens.
For the analysis of fabrics, this test method is adequate for estimating the approximate yarn number of the yarn used to weave or knit the fabric, but the results obtained by this test method may not agree with the nominal yarn number of the yarns actually used to make the fabric because of the changes in the yarn number produced by the weaving or knitting operations, the finishing treatments, and the dissecting operations. This test method is suitable for the evaluation of yarns as they occur in the finished fabric, when that information is needed.
Apparatus needed
Yarn straightening and length Measuring Device: FY111 DIGITAL CRIMP TESTER
FY111 is used to determine the straightened length and percentage crimp of a yarn removed from fabric under specified tension conditions.
Colorful touch screen display and operation, easy to operate;
Automatic stretching of right yarn clamp, stretching speed can be adjusted;
Automatic positioning of initial length, automatic extended length measurement;
High precision tension sensor, fast response speed, high measurement accuracy;
Precision stepper motor drive, imported synchronous belt, precision linear slider drive.
Balance: HZT-A+ SERIES ELECTRONIC BALANCE
Capacity (g): 100/200/300, buyer can specify according to different purposes
Readability: 0.001g
Scale pan size: Ø80mm
Sensor type: Strain sensor
Calibration method: External calibration
Structural material: Solid metal base + high strength ABS material
Display mode: LCD backlight display
Procedures of test yarn count using single yarn method:
- Take specimens:
- For packages specimen, such as cones, spools, or bobbins, take one specimen per package.
- For beams specimen, take ten ends at random from each half of the beam sheet.
- For fabrics, remove the first ten yarns from each strip and determine their straightened lengths. Then remove at least forty more yarns from each strip.
- Pre-condition the specimens according to corresponding standard requirement.
- Weigh all the measured length specimens together.
- Calculation:
Ttex=(m/L)*1000
Where,
m = The weight of the yarns taken from the fabric, expressed in g;
L = The total length of the specimens, expressed in m.
Calculate the total length of specimens L from the following formula
L=l*n
Where,
l = the mean straightened length, expressed in m;
L = the number of specimens weighed.
