This document discusses slub yarn, its measurement, and defects. Slub yarn is intentionally spun with irregular thickness to give fabric personality, though it reduces durability. Uster/Premier software measures slub length, distance, mass increase, and distributions. Proper slub measurement is important for quality control, specifications, and developing new patterns. The software can detect defects like missing slubs, low mass increase, mixed yarns, and incorrect repeat patterns.

1. SLUB YARN &
ITS MEASUREMENT
A.MURALIKRISHNAN
LECTURER – TEXTILES
P.A.C.RAMASAMYRAJA POLYTECHNIC COLLGE,
RAJAPALAYAM, TAMILNADU, INDIA
Email: muralikct@rediffmail.com
Compiled by A.Muralikrishnan, PACR Polytechnic college, Rajapalayam, Tamilnadu

2. 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

3. Slub yarn appearance
Compiled by A.Muralikrishnan, PACR Polytechnic college, Rajapalayam, Tamilnadu

4. FABRICS FROM SLUB YARN
Compiled by A.Muralikrishnan, PACR Polytechnic college, Rajapalayam, Tamilnadu

5. 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
Compiled by A.Muralikrishnan, PACR Polytechnic college, Rajapalayam, Tamilnadu

6. 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
Compiled by A.Muralikrishnan, PACR Polytechnic college, Rajapalayam, Tamilnadu

7. 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
Compiled by A.Muralikrishnan, PACR Polytechnic college, Rajapalayam, Tamilnadu

8. Types of slub
Compiled by A.Muralikrishnan, PACR Polytechnic college, Rajapalayam, Tamilnadu

9. • 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
Compiled by A.Muralikrishnan, PACR Polytechnic college, Rajapalayam, Tamilnadu

10. • 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.
Compiled by A.Muralikrishnan, PACR Polytechnic college, Rajapalayam, Tamilnadu

11. • 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
Compiled by A.Muralikrishnan, PACR Polytechnic college, Rajapalayam, Tamilnadu

12. Summary of slub specifications
Compiled by A.Muralikrishnan, PACR Polytechnic college, Rajapalayam, Tamilnadu

13. Slub production
• Amsler system
Compiled by A.Muralikrishnan, PACR Polytechnic college, Rajapalayam, Tamilnadu

14. 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
Compiled by A.Muralikrishnan, PACR Polytechnic college, Rajapalayam, Tamilnadu

15. Sample Numerical output from UT5
Compiled by A.Muralikrishnan, PACR Polytechnic college, Rajapalayam, Tamilnadu

16. Sample Diagram – For slub yarn
Compiled by A.Muralikrishnan, PACR Polytechnic college, Rajapalayam, Tamilnadu

17. Sample Diagram – Base yarn
( slub removed)
Compiled by A.Muralikrishnan, PACR Polytechnic college, Rajapalayam, Tamilnadu

18. Sample Sequence diagram
• Used to make a pattern in the sequence of slub
Compiled by A.Muralikrishnan, PACR Polytechnic college, Rajapalayam, Tamilnadu

19. 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
Compiled by A.Muralikrishnan, PACR Polytechnic college, Rajapalayam, Tamilnadu

20. Sample Histogram for slub distance
Compiled by A.Muralikrishnan, PACR Polytechnic college, Rajapalayam, Tamilnadu

21. Sample Histogram for mass increase
• Mass increase is between 90% and 250%
based on a 0% reference level.
Compiled by A.Muralikrishnan, PACR Polytechnic college, Rajapalayam, Tamilnadu

22. 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
Compiled by A.Muralikrishnan, PACR Polytechnic college, Rajapalayam, Tamilnadu

23. Determination of
Slub defects by Uster
Compiled by A.Muralikrishnan, PACR Polytechnic college, Rajapalayam, Tamilnadu

24. Detection of missing slubs
• For a length of 40 meters , no slubs were produced.
Compiled by A.Muralikrishnan, PACR Polytechnic college, Rajapalayam, Tamilnadu

25. Slubs are not produced correctly
• Fault : The mass increase is too low
• Causes: The drive of slub insertion device is
not strong enough
Compiled by A.Muralikrishnan, PACR Polytechnic college, Rajapalayam, Tamilnadu

26. Yarn mix up in Slub
• Two different slub yarn mixed together
Compiled by A.Muralikrishnan, PACR Polytechnic college, Rajapalayam, Tamilnadu

27. 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.
Compiled by A.Muralikrishnan, PACR Polytechnic college, Rajapalayam, Tamilnadu

28. 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
Compiled by A.Muralikrishnan, PACR Polytechnic college, Rajapalayam, Tamilnadu

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