What is CV percentage in yarn?
The coefficient of mass variation CV % is the ratio of standard deviation of mass variation divided by average mass variation. The higher the CV value is the more irregular the yarn. A modern instrument, such as the Uster Evenness Tester, can measure the U and CV values of a fiber assembly at a high speed.
How do you control yarn count on a CV?
So control of with in CV should be focus at (a) D/F U % (b) stretch at S/F Control of sliver U% , U% Check by 10 mm layer cut. Depending upon draft yarn spun is 40 mtrs- 160 mm. so directly affect CV within U % of 2nd passage D/F is 3-5% & first – 5-7% Less U% is 3 passage but hooks at R/F is not favourable.
How do you calculate yarn count?
The indirect system uses the formula: N = (L/w) / (W/l). In these formulas, N is the yarn count, W is the weight of a sample of yarn, l is the unit of length, L is the length of the sample, and w is the unit of weight.
How is yarn IPI calculated?
The imperfection index (IPI) is the sum of yarn thin places/ km (-50%), thick places/km (+50%) and neps/km (+200%) per kilometer of tested yarn for ring spun yarn [2, 59] .
What is yarn evenness?
YARN EVENNESS Yarn evenness is a measure of the level of variation in yarn diameter along its length. … A yarn with poor evenness will have thick and thin places along yarn length, while an even yarn will have little variation in mass or diameter along length.
What is RKM in yarn?
RKM is the short expression for “Reisskilometer” – “Breaking-kilometer”, which is an unit out of date. E.g.: a Cotton-yarn with 15 RKM means, it would break of its own weight, if you wind off 15 km of the yarn and hang it up in 15km.
What is limit irregularity?
For a particular fiber and count of yarn, there is a basic or limit irregularity which cannot be improved by the spinning machinery. The CV of the most regular/uniform strand of material in which the ﬁber ends are laid in a random order in the sliver, roving, or yarn is called limit irregularity.
How many types of yarn are there?
In this system, yarn count is defined as the number of hanks of 256 yards per pound. For example, woollen yarn count 30 means that there are 30 hanks (of 256 yards) per 1 lb or 1 pound of that yarn.
Systems of Yarn Count Measurement.
|Count System Name||Unit of length||Unit of mass|
|Worsted Count (NeK)||560 yards||lb|
|Woollen Count||256 yards||lb|
How can you tell the quality of yarn?
Skein strength or Lea strength: The skein breaking strength was the most widely used measure of yarn quality in the cotton textile industry. for determination of the linar density of the yarn as well.
- yarn twist.
- linear density.
- yarn strength.
- yarn elongation.
- yarn evenness.
- yarn hairiness etc.
What is yarn number?
Yarn number is a measure of the fineness or size of a yarn expressed either as mass per unit length or length per unit. Yarn Count and Yarn Size are synonymous with Yarn Number.