The Rotor spinning & a comparison between ring and rotor spinning-yarn

Md. Nakib-Ul-HasanLecturer

Dept. of Textile EngineeringGreen University of Bangladesh

Rotor spinning

Rotor Spinning is a more recent method of yarn formation compared to Ring Spinning. The first functioning of rotor spinning, machine was presented at the ITMA in 1967. Yarn spinning according to the rotor spinning principle predominates for all non conventional spinning methods. It omits the step of forming a roving. After drafting, the sliver is fed into a rotary beater. This device ensures that the fibers are beaten into a thin supply which enters a duct and gets deposited on the sides of the disc(rotor).The transportation of the fibers is achieved through air currents.This is a form of open-end spinning where twist is introduced into the yarn without the need for package rotation Allowing for higher twisting speeds with a relatively low power cost. In rotor spinning a continuous supply of fibres is delivered from delivery rollers off a drafting system or from an opening unit.

Characteristics

• Higher Productivity• Large Sliver Can• Large Final Package• Less Power Consumption• Automation• Flexibility of spinning component• Handling count range

Feed roller

Feed trough

Opening roller

Naval

Feed tube

Rotor

Rotor groove

Withdrawal

roller

Important parts of a rotor spinning machine

Passage diagram of a Rotor machine

Tasks of the Rotor Spinning Machine

Opening almost to individual fibers (fiber separation)

Cleaning Homogenizing through back

doubling Combining i.e. forming a

coherent linear strand from individual fibers

Ordering (the fibers in the strand must have an orientation as far as possible in the longitudinal direction)

Improving evenness through back-doubling

Imparting strength by twisting Winding

OpeningCleaningHomogenizingCombiningOrderingBack-doublingTwisting

Technical Data of Rotor Spinning Machine:

• Number of spinning positions up to 220 per m/c• Count range 12- 125 Tex (5 – 50 Ne)• Draft 25- 400• Rotation speed of opening roller 6000- 11000 rpm• Rotation speed of rotor up to 120000 rpm• Rotor diameter 32 -65 mm• Delivery speed up to 200 m/ min• Package mass up to 5 kg• Angle of taper 2° - 4° 20’• Winding angle 29° – 45°

Rotor Spinning Machine

Input Material Processing Machine Output MaterialsBlow Room

Carding

Pre-Comb Drawing

Lap Former

Combing

Finisher Drawing

Simplex/ Speed Frame

Ring Frame

Winding

Lap / Chute

Card Sliver

Drawn Sliver

Lap

Comb Sliver

Drawing Sliver

Roving

Yarn

Large Yarn Package

Raw Cotton

Lap / Chute

Card Sliver

Drawn Sliver

Lap

Comb Sliver

Drawn Sliver

Roving

Yarn

Flow Chart of Conventional Comb Yarn

Blow Room

Carding

Breaker Drawing

Finisher Drawing

Rotor

Lap / Chute

Card Sliver

Drawn Sliver

Drawing Sliver

Rotor Yarn

Raw Cotton

Lap / Chute

Card Sliver

Drawn Sliver

Drawn Sliver

Input Material Processing Machines Output Materials

Flow Chart of Conventional Rotor Yarn

Ring Sp Ring Spinning Rotor Spin Rotor Spinning

Bobbin rotates constantly for insertion of twist

Spool does not need to be rotated to insert twist

Cannot handle spools of bigger size Much larger spools can be wound

Can spin finer yarns (up to 20m/min) 3-5 times faster than ring spinning (200m/min)

Uniform and strong yarn Uniform but flexible yarn with better dye ability

Combed yarns (finer) Carded yarns (coarser)

Yarns for varied applications Yarns for heavier fabrics such as denims, towels and poplins

Stronger 20% more twisted but 15-20% weaker as the yarn is coarser

Suitable for all staple fibres Not suitable for man-made staple fibre spinning except rayon as the fibre finish clogs the rotor

Ring Vs Rotor spinning system

Advantages over ring spun yarn • Better CV% of strength• Higher elongation at break• Better mass irregularity ( over short lengths)• Lower imperfection index• Greater volume• Higher abrasion resistance• Higher stiffness• Harder Handle• Less power consumption• Lower energy consumption with productivity

Rotor spun yarn Vs Ring spun yarn

Disadvantages over ring spun yarn• Breaking strength lower than ring spun Yarn• Less yarn count range• Possible yarn counts rotor Ne 3 – 60 and Ring Ne 6 – 200

Comparison between Ring and Rotor yarn [20 Ne]

Parameters Ring yarn (Card) Rotor yarnTenacity (cN/Tex) 17.5 15.1

CSP 2550 1830

Elongation % 3.75 4.35TPI 14.23 18.31

Uster U% 9.774 9.41CVm% [1cm] 12.412 11.872CVm% [3m] 2.882 2.91

Thin [-40%]/Km 20.687 36.56

Thick [+35%] 446.25 178.75Thick [+50%] 48.125 5Neps [+200%] 60.3125 26.25

Hairiness Index [H] 7.21 4.65

Note: This experimental data is an average test result out of 8-10 tests. The tests were done at The Delta Spinning mills Ltd.

Garments

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