Slub yarn and its measurement

SLUB YARN & ITS MEASUREMENT

A.MURALIKRISHNANLECTURER – TEXTILES

P.A.C.RAMASAMYRAJA POLYTECHNIC COLLGE,RAJAPALAYAM, TAMILNADU, INDIAEmail: [email protected]

Compiled by A.Muralikrishnan, PACR Polytechnic college, Rajapalayam, Tamilnadu

Definition of Slub

“Yarn that is spun intentionally to achieve an irregular shape, in

terms of length and diameter.”

Or

“Yarn that has been purposely spun with thicker sections

along the yarn”.

• It was before seen only as a defect but slub yarn is now

intentionally created to give fabric with more personality.

• However, slub yarn reduces the durability of the fabric as the

yarn inherently has weak spots.Compiled by A.Muralikrishnan, PACR Polytechnic college, Rajapalayam, Tamilnadu

Slub yarn appearance


FABRICS FROM SLUB YARN


Whether Slub measurement is necessary ?

• How many slubs per unit length are produced

• What is the slub distribution

• What is the size, their distance and the mass increase

• What is the relation between the settings of slub

device and the resulting yarn


Importance of slub measurement

• Slub yarns are used in textile for various applications

• An accurate determination of slub characteristics is also

required for negotiations and specifications between slub

yarn spinners and weavers, traders and retailers

• Uster / Premier developed software called Fancy yarn

profile (FYP) for slub measurement.

• FYP offers comprehensive analysis of slub types by means

of various values and graphs


Purpose of FYP measurement

• Daily quality control in order to compare the reproducibility and to compare machine settings

• To provide information for the spinner to create and develop new pattern


Types of slub


• Slub length bottom – Length measured at the bottom of trapezoid

• Slub length – Half of the height of trapezoid

• Mass Increase – From the base to the top of Trapezoid

• Ratio T/B – Top to bottom: Gives an indication about the steepness of ramps of yarn


• Slub distance: Half of trapezoid height between the end of previous slub to the start of subsequent slub.

• Slub populations: different size of slub is called populations.


• Mass decrease (left /Right)– Mass decrease before and after a slub can lead to severe weak places

in the yarn.

– Affects the performance of subsequent machine / Process

– Only mass decreases within a distance of 3cm on left and right side of slub are evaluated.

– A mass decrease counted, if mass drops below 30% of base yarn


Summary of slub specifications


Slub production

• Amsler system


Slub measurement in Uster

• Parallel plate capacitor is used for slub ( which is

similar to one used for yarn)

• Equipment must have Fancy Yarn profile option

• Recommended test length – 1000m at 400 m/min

• Slub manufacturer recommended speed – 50 m/min


Sample Numerical output from UT5


Sample Diagram – For slub yarn


Sample Diagram – Base yarn ( slub removed)


Sample Sequence diagram• Used to make a pattern in the sequence of slub


Sample Histogram for slub length

• Two kind of population in the slub yarn

• Population 1 – from 4 cm to 8 cm

• Population 2 – from 11cm to 23 cm


Sample Histogram for slub distance


Sample Histogram for mass increase• Mass increase is between 90% and 250%

based on a 0% reference level.


Sample Classification matrix

• It is a tool to quickly check the distribution of slub

• Mass increase divided into 5 classes

• Slub length is divided into 8 classes


Determination of Slub defects by Uster


Detection of missing slubs

• For a length of 40 meters , no slubs were produced.


Slubs are not produced correctly

• Fault : The mass increase is too low

• Causes: The drive of slub insertion device is not strong enough


Yarn mix up in Slub• Two different slub yarn mixed together


In correct repeat pattern• This will not be identified in mass diagram. Only represented in sequence

diagram

• There are always two slubs repeating after a short distance and the pattern repeats itself after a Longer distance again.


REFERENCES

• Measurement of slub yarns- Part 1 basics: Application report, www.uster.com

• Measurement of slub yarns – Part II: Application report, www.uster.com

• Measurement of slub yarn with Uster Tester 4 : Application report, www.uster.com

• Fabric simulation, slub and fancy yarn measurement, Premier tester iQ2 – Technical brochures, www.premier-1.com


http://www.uster.com/



http://www.premier-1.com/


Engineering

Slub yarn and its measurement