TX230 Yarn Formation I

byDr. Umer Farooq

Contact Details:

Umer.farooq@umt.edu.pk

Room Ext: 330

Office hrs: M, T, W, Th: 9:30 to 10:30 am

Introducing myself… 2000 – 2004: PhD Textile Mechatronics,

University of Leeds, Leeds, UK 1999 – 2000: MSc Textile Engineering,

University of Leeds, Leeds, UK. 1992-1996: BSc Textile Engineering,

NCTE, Faisalabad. 2004-2005: Research Associate, Leeds

1997-1998: Advisor BTTM Program, ILM 1996-1997: ASM, JK Fibres, Faisalabad

Rules of Engagement… 6 Assignments (15%) / 6 Quizzes (15%) Absolutely no make-up quiz / late

assignment. One presentation of randomly selected topic

(5%) Mid-term – 60 min (30%) 5 min late – OUT OF THE CLASS A treat to the whole class if I am 5 min late!! 20% absent – CAN’T SIT IN THE EXAM

Course Description This course aims at imparting fundamental

knowledge about the manufacturing of yarns from fibres that can range up to 63.5 mm i.e. 2.5 inches in length – short staple yarns. Short staple spinning constitutes of multiple processing steps each of which has a number of critical control factors which must be known, measured and reacted to routinely if the highest quality yarns are to be spun. In the present course we will concentrate on each of the processing steps and their associated critical factors.

Recommended books MMT - Manual of Textile Technology – Short

Staple Spinning Series Vol:2, 3, and 4, (W. Klein 1987) The Textile Institute.

SSYM - Short Staple Yarn Manufacturing, (Mc. Creight, Feil, Booterbaugh, Backe, 1997), Carolina Academic Press.

FSYT - Fundamentals of Spun Yarn Technology, (Carl. A. Lawrence, 2003), CRC Press

Some Important Definitions / Concepts

Fibre Textile raw material generally characterized

by flexibility, fineness and a high ratio of length to thickness. (TI).

The fundamental unit used in the fabrication of textile yarns and fabrics.

A unit of matter characterized by having a length at least 100 times its diameter or width.

Natural fibres; Man-made fibres – regenerated fibres, synthetic fibres;

Staple-spun Yarn

A staple-spun yarn is a linear assembly of fibres, held together, usually by the insertion of twist, to form a continuous strand, small in cross-section but of any specified length: it is used for interlacing in processes such as knitting and weaving

Yarn Numbering SystemA yarn is always specified by a number which

is a relative indicator of its fineness or linear density.

There are different systems; which can broadly be catagorised into two groups:

Indirect or reciprocal yarn numbering systems where a higher number indicates a finer of lighter in weight yarn; and

Direct yarn numbering systems with a higher number meaning a coarser or heavier in weight yarn.

Indirect Yarn Numbering System

The yarn number signifies the number of units of standard length that are necessary to balance one unit of standard weight.

Spinning System Standard Length Standard Weight Common Name

Cotton 840 yards (Yd) 1 pound (lb) Cotton / English (Ne)

Woolen 1600 yards 1 pound (lb) Woolen Run

Woolen 300 yards 1 pound (lb) Woolen Cut

Worsted 560 yards 1 pound (lb) Worsted (Nw)

All 1000 meters (m) 1 Kilogram (kg) Metric (Nm)

Plied Yarn Representation in Indirect Yarn Numbering System

Yarn Numbering System

Count of Yarn to be twisted

Number of strands (plies) twisted together

Yarn Number

Cotton 20/1 or 20’s 2 20/2

15/1 or 15’s 3 15/3

15/3 2 15/3/2

Worsted 1/20 2 2/20

1/15 3 3/15

3/15 2 2/3/15

Direct Yarn Numbering System

The yarn number in direct yarn numbering system indicates the number of units of standard weight that are necessary to balance one unit of standard length.

Yarn Numbering System

Standard Weight Standard Length

Denier 1 gram (g) 9000 meters

Tex 1 gram (g) 1000 meters

Decitex (Grex) 1 gram (g) 10000 meters

Yarn Numbering cont …

1000 tex = 1kilotex (ktex)0.1 tex = 1decitex (dtex)0.001 tex = 1 millitex (mtex)100 tex yarn spun from 1detex fibres

will have aprx. 1000 fibres in CA.(dtex and denier are used to express

fibre fineness)

Brain Storming …..

1 Ne = ?? Tex 1 denier = ?? Tex 1 Metric = ?? Tex

Do you think the count of the yarn reflects its diameter i.e. bulkiness??

Yarn Diameter

If the specific volume of a fibre is given derive an equation to find the diameter of the yarn??

Yarn ClassificationGroup Sub-group Example

Continuous filament yarn Untextured (flat) TwistedInterlacedTape

Textured False twisted Stuffer box crimpedBi-componentAir-jet

Staple Spun Yarn Non-effect / Plain (Conventional)

Carded Ring SpunCombed Ring SpunWorsted Semi-worsted Woolen

Non-effect / Plain(Unconventional)

Rotor SpunCompact-ring spunAir-jet spunFriction spunHollow spindle warp spunRepco

Fibre Blends Blend of two or more fibres

Effect / Fancy Fancy twistedHollow spindle fancy yarnSpun effects

Composite yarns Filament core / Staple core Core spun (filament or staple fibres forming the core) and staple fibres as the sheath of a noneffect staple yarn

Folded / plied / doubled Filament / Staple Two or more yarns twisted together

Coarse Yarns(>40 tex / <14.76Ne )

Medium to fine Yarns (40 - 16 tex / 14 - 36 Ne)

Fine Yarns(16-7.5 tex /36-79 Ne)

Supper fineyarns (7.5-2tex /79-295 Ne

Furnishing fabricsTerry goods, DenimCarpet yarns

Leisure and sports

Home textile and woven goods

Nightwear and underwear

Shirts/Blouses

Workwea rTicking / Poplin

Sewing

Staple Spun Yarns

Filament YarnsIndustrial Yarns: Tire Cords,Safty Belts, Airbags, Conveyor Belts, Ropes

Hosiery

Clothing: shirts,blouses, leisure &sportswear

UpholsteryCarpetYarns Semi-industrial yarns:

Bags, Sports Articles etc.

Count Range of product areas for Filament and staple spun yarn

Short Staple Yarn Manufacturing

Spinning System Millimeters (mm) Inches

Cotton Up to 64 Up to 2.5

Woolen 51 – 102 2.0 to 4.0

Worsted 76 – 203 3.0 to 8.0

This course will cover the fundamentals of manufacturing yarns from fibres that can range up to 63.5 mm i.e. 2.5 inches in length – short staple yarns. These are produced on sequence of machines collectively called as the cotton spinning system.

Fibre Length (nearest mm)

Principle of short staple yarn manufacturing

Raw material – entangled and impurities (NF)

Opening and Cleaning – The BR

Fibre Disentangling and Cleaning – Carding

Fibre Straightening and Parallelisation - Drawing

Short fibre removal + additional cleaning - Combing

Combed yarn

Fibre straightening parallelisation, attenuation – Roving Production

Final attenuation and twist insertion – yarn formation – Ring Frame

Some Important Points in Cotton Spinning wrt Pakistan

Cotton Bale is about 165-170 Kg (363 lbs – 375 lbs). Bale density 32 lbs/c.ft

Cotton rates are quoted per ‘Maund’ where 1 Maund = 82.6 lbs

Weight of standard cotton / PC yarn bag is 100 lbs

Two yarn ‘cone’ (package) sizes: 2.5 lbs cone (small) – 40 cones in a bag and 4.16 lbs (big) – 24 cones in a bag

Some Important Points in Cotton Spinning wrt Pakistan …

Yarn Prices are quoted per 10 lbs Cotton prices fluctuates a lot Ranging

from Rs. 1800 to 2500 per Maund http://www.aptma.org.pk/ - to get

latest info on Pakistan’s textile ind.

Blowroom Contributes only 5-10% of production

cost. MAIN FACTOR – loss of raw material and

possible deterioration of fibre properties BR machines must eliminate foreign

matter but they can only do so at the expense of good fibres.

Good fibres can make up to 50% of the eliminated waste!

20,000 sp.; 3000 tons of cotton per yr. @ 40 US cents / lbs; waste elimination increases unnecessarily by 0.5%. LOSS??

Blowroom …

Stressing of fibres – negative influence on fibre characteristics: fibre strength; elasticity; fibre length

Proportion of short fibres increases by 10% if BR has one extra cleaning m/c

BR eliminates only about 50% of the incoming waste.

Basic Operations in the BR

Bale storage, management and laydown

Opening Cleaning Dust Removal Blending Even feed of material to the card

Bale storage, management and laydown

Suppose a mill produces 150,000 lbs of cotton yarn per week; total waste eliminated is 7.1%. Find the number of bales needed per day?