By M. Naveed Akhtar

Short-staple SpinningBLOWROOM CARDING COMBING PREPARATION

Carded Yarn PathDRAWING

Combed Yarn Path

COMBING

ROVING FRAME

RING FRAME

A Ring Spinning Frame

Brief Historyy The ring spinning machine was invented in year 1828

by the American Thorp. y In 1830, another American, Jenk contributed the traveler rotating on the ring. y Since then a lot of modifications have been made but the basic principle remains the same.

Advantages over other Systemsy It is universally applicable, i.e. any material can be

spun y Suitable for a wide range of counts y It delivers a yarn with optimal characteristics (regarding structure and properties) y It is uncomplicated and easy to master,

Cost Structure of Spinning ProcessBlowroom, 11% Carding, 13%

Drawing, 4%

Roving, 12% Ring Spinning, 60%

Ring Spinning Roving Drawing Carding Blowroom

Objectives of Ring Spinningy To convert roving into very fine strand called yarn y To impart strength to the strand by twisting y To collect twisted strand called yarn onto a handy and

transportable package called cop or ring bobbin

Basic Principles of Ring Spinningy Drafting mechanism y To attenuate the roving until required fineness is achieved y Consolidation (strengthen) mechanism y To impart strength to the fibre strand by twisting it y Winding and package forming mechanism y To wind up the resulting yarn in a package suitable for storage, transportation and further processing

Ring Spinning Processy Roving bobbins are creeled in appropriate holders y Guide rods lead the roving into the drafting

arrangement y Drafting arrangement attenuate the roving to final count y The drafting arrangement is inclined at an angle of 45 to 60 y Upon leaving the front rollers the fibre strand is twisted to impart strength

Ring Spinning Process (contd.)y Each rotation of spindle imparts one twist to the

strand y The twist is generated by the spindle which is rotating at high speed y The direction of twist is either S or Z y This completes the spinning of the yarn

Direction of twist

S - Twist

Z - Twist

Yarn Winding Processy To wind yarn on to a bobbin tube carried by the y y y y y

spindle the tube must cooperate with the spindle The traveler moves on a guide rail (the ring) encircling the spindle The yarn is threaded through the traveler The traveler rotates as it is carried along the yarn being wound on to the bobbin The speed of the traveler is a bit less than that of the spindle The difference in speed between the spindle and traveler results in yarn being wound on to the bobbin

The Ring Spinning (contd.)y The amount of twist inserted in the yarn is controlled

by the front roll (or delivery) speed and traveler rotational speed

y In practice, spindle speed (nspindle) is used instead of

traveler speed in the above equation; the spindle speed is slightly higher than traveler speed

The Ring Spinning (contd.)y Yarn winding is performed simultaneously with

twistingy The difference in the speed between spindle and

traveler causes the yarn to wind on the packagey The size of the yarn package (bobbin) is limited by the

ring diameter, which has to be small to increase the spindle rotation at the same traveler speed

Draft, twist and winding speedy The draft is the ratio between delivery speed (Vdelivery)

and the speed (Vfeed)y Twist is the ratio between the spindle speed (nspindle)

and the delivery speed (Vdelivery)y Winding speed is directly proportional to the delivery

speedy Contraction occurs in yarn by increasing twist

Roving

Traveler speed/ Linear speed Relationshipy The twist is given by:

y The traveler speed can be approximated to spindle

speed (nspindle) in the above equationy Increase in productivity will be through an

increase in traveler speed

Steps of Ring Spinningy Ring Spinning Process y Drafting y Twisting y Yarn Winding Process

The Ring Spinning

Main Spinning Arrangementy The main spinning arrangements are: y The drafting arrangement y Spindle y Ring and traveler

Drafting Arrangementy It is the most important part of the machine y It influences mainly evenness and strength y All modern ring spinning machines are fitted with 3/3

double-apron drafting arrangements

The Drafting Arrangement

Drafting Arrangement

Drafting Arrangementy Drive is applied to the lower fluted steel rollers y Top rollers are carried in pivoted weighting arms y Top rollers are arranged over fluted rollers and pressed

against them y As the drafted strand contains few fibres in the main drafting field, aprons are used to guide the fibres

Draft limitsy Draft limits for ring spinning: y For carded cotton = up to 35 y For carded blend = up to 40 y For combed cotton and blended yarnsy y

Medium fineness = up to 40 Fine yarns = up to 45

y For synthetic fibres = up to 45 - 50

The SpindleThe Spindle 1. tread guide 2. balloon control ring 3. ring 4. spindle 5. bear 6. ring rail 7. bolster 8. nut

The Spindley Mechanically, the spindle is capable of speeds up to

28000 rev/min y This maximum speed cannot be exploited commercially because the traveller speed is limited y The centring of the spindles relative to the rings should be as accurate as possible

The SpindleSpindle Drive Basically, two groups of spindle drives can be distinguished: y Tape drives, y Tangential belt drives,

Spindle Tape drive

Tangential belt drive

The ringThe Form Of The Ring: Basic Forms are classified intoy Lubricated rings (in woollen and worsted spinning), y Unlubricated rings (in short staple spinning)

The ringy The standard ring of the short staple spinning mill is

the unlubricated type y It can be of two typesy Single sided rings y Double sided rings

The ringy For rings used in the shorty the internal diameter y the flange width

staple spinning mill two dimensions are of prime importance

Ring flange

Ring, traveller and yarn

Materials for ring and travellery Required properties for the ring materials y The ring should always be tough and hard on its exterior y The traveler hardness should be lower so that wear occurs mainly on the travelers, which is easier to replace and cheaper y Surface smoothness is also important.

The travellery The traveler imparts twist to the yarn y It enables winding of the yarn on the cop y Its speed is somewhat less than that of the spindle y The traveler does not have a drive of its own but is

dragged along behind the spindle

The traveller

The traveller massy The traveller mass determines the winding and the

balloon tension y If the traveller is too small, the balloon will be too big and the cop too soft; material take-up in the cop will be low y An unduly high traveller mass leads to high yarn tension and many end breaks

Traveler types

C

M

Elliptical