The variation of the yarn count (CV count) is the variation from one bobbin to the other. … In general the lower the C.V.% the better is the measured value of the yarn.
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.
What is CV in spinning?
The Coefficient of Variation (CV) is the standard Deviation (SD) expressed as a percentage of the mean CV % = (SD ÷ mean) x 100 • Each process in a spinning mill contributes a part to the evenness. … Fig shows a comparison between two fabrics with a low (CV = 11.48%) and a high coefficient of variation (CV = 17.76%).
How do you calculate CV%?
The formula for the coefficient of variation is: Coefficient of Variation = (Standard Deviation / Mean) * 100.
How do you control CV count in spinning?
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.
What is CV% of count?
1.1 Definition of the relative count – Count C.V. The relative count gives the mass deviation in % of the whole test length of each test sample as compared to the average mass of all samples. This value is an indication of relative count deviation (CV). The lower the value the better.
What is yarn irregularity?
The irregularity or unevenness of a yarn is commonly deﬁned as the variation in ﬁneness along its length and more appropriately as the variation in mass per unit length along the yam’. It is expressed as U% or CV%.
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 is spinning draft calculated?
Draft = 12.597. Draft in front zone = 6.69.
- RPM of the motor =1440.
- Dia of the motor pulley = 5”
- Dia of the tin cylinder pulley = 10.5”
- Dia of the tin cylinder = 10”
- Dia of the wharve = 1.125”
- No of teeth of fibre wheel = 42T.
- No of teeth of front roller driving wheel = 98T.
- Dia of the front roller = 1”
What is cotton mixing?
Mixing and blending of different varities of cotton:
In mixing process, Two or more different varieties of cotton are mixed together. Some times two or more types of fibres such as cotton and polyester are mixed together in this process.
What is a good CV value?
Basically CV<10 is very good, 10-20 is good, 20-30 is acceptable, and CV>30 is not acceptable.
How do I calculate mean?
The mean is the average of the numbers. It is easy to calculate: add up all the numbers, then divide by how many numbers there are. In other words it is the sum divided by the count.
What is CV in statistics?
The coefficient of variation (CV) is the ratio of the standard deviation to the mean. The higher the coefficient of variation, the greater the level of dispersion around the mean. It is generally expressed as a percentage. … The lower the value of the coefficient of variation, the more precise the estimate.
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 RKM in textile?
RKM is abbreviation of Resistance per kilometer. It is an important yarn quality parameter without measurement units. It is calculated from the data of single yarn strength tests performed on manual or automatic single yarn testing installations, for example Uster Tensorapid 3 or Tensojet.
How do you calculate yarn realization?
For example, for t = 3%, Wk = 7% and Wh = 0.5%, the expected yarn realisation is 87%. In the above case, if the mill produces combed yarn with a noil extraction of 18%, then the expected yarn realisation will be 70.8%.