1.0 Preamble

Blowroomis the first operation of yarn production in spinning mill. The saying “Wellbegun is half done” signifies the importance of first operation. Basicobjectives of the blow room operation are as under:

Opening of the fibre tufts

Cleaning of thefibre

Blending of the different fibre

Even materialfeed for next operation i.e. Carding

ImproperBlowroom action can seriously affects the spinning performance and finalquality of yarn in terms of higherimperfections, blend variation and associated dyeing concerns in the downstreamprocesses. The parameters like conditioning time, number of beating points, fanspeed, grid bar setting, lap weight and CV% significantly affect the quality ofblow room operation. The feed to carding machine can be in batch form like lapfeed or in continuous form like chute feed system. In any case even feeding isutmost required for good carding action, spinning performance and yarn quality.

2.0 Introduction about current Paper

As Blow room operationis very important, a more intricateunderstanding is requireddue to

Presence of different blow room machines

Availability of different types of fibres

Newer fibre blends formingfashion statements and

Exceptional innovations in fibre technology

Itis justified to appreciate that different fibres or blends require differentset of process conditions for utilizing the strong characteristics andshielding the weak traits. Regenerated cellulosic fibres have made their presencestrongly felt in providing functionaland aesthetic characteristics to the appareland home textiles. Three generations of regenerated cellulosic fibres namelyViscose, Modal and Lyocellare jewels in today’s worldand are increasingly being processed independently or in blends with naturalas well as synthetic fibre

Thepresent paper is an attempt to provide information on processing of regeneratedcellulosic fibre in Blowroom. As lapfeed requires needs greater care, focus of this paper is on the factors for lap feed operation.

3.0 CurrentScenario

SinceBlowroom machines have to fulfill various functions, they vary in concept anddesign. Basically following types of machine constitute Blowroom:

Opening machineswhose main functionis to open the biggertufts into smallerones

Mixingmachines whose main function is to mix different fibre so as to produceconstant blend

Fine Cleaningmachines whose main functionis cleaning of the fibres fromdirt, dust etc

Dust removingmachines whose main functionis removal of dust from fibre assembly

Basedon the fibre blend, number of machines can be selected accordingly. Like forprocessing 100% Cotton fibre more intense opening and cleaning action isrequired in comparison to processing man made fibres like regenerated celluloseand synthetic fibres like Polyester, Acrylic fibres etc as they contain lesseror almost zero impurities. Man made fibres require only require gentle openingat the Blowroom. In general, Cotton fibre requires 3 to 4 beating pointsdepending on the origin and trash content while manmade fibres requires 1 to 2beating points only.

Differentgeneration of machines are available in all the above four categories. Over theyears regenerated cellulosic fibres (Viscose/Modal/Excel) have established thatthey can be run successfully at any generation machines.

4.0 TechnicalSpecifications

Asregenerated cellulosic fibres are also cellulosic, it is commonly understoodthat parameters suitable for processing Cotton fibre shall also work well forregenerated cellulosic fibres. In comparison to Cotton fibres, regeneratedcellulosic fibres are more even in length and have very low short fibre content.

Effective Blowroomoperation is mainlydependent on followingparameters:

Secondary finishapplication and conditioning of the fibres

Viscoseis manufactured through a wet process. In view of this it is difficult toachieve equal level of moisture across the bale. Forte calibration systemprovides composite level of moisture in the entire bale but chances of somelumps having higher/lower moisture at some place cannot be ruled outcompletely. Thus conditioning of fibre sample after opening is very muchessential for achieving the uniformity. Following measuresshould be taken for achievingthe best results:

Largest possiblemixing size shouldbe taken for maximum possiblehomogeneity

Open the bale wrapperfor acclimatizing at higher RH (70 to 75%) for 8 to 12Hrs.

Process the regenerated cellulosic fibre at to get small tuff size of 30 to 40 mg

Wider settingsbetween Inclined lattice and evener Roller is preferred

Over- sprayby anti-static and water as per requirement (Preferable water ≤ 1% )

Conditioning for maximumpossible time (24 to 40 hours) at65% RH. This will lead to naturalseparation of fibres.

Toppling of fibres at least2 to 3 times by hand for better and even distribution

Beater and Fan Speed of fine cleaner

Themost suitable beater for providing mild but excellent opening is Kirschnerbeater or any of its modern variants.The beater has three or more arms fitted with a large number of hardened andpointed steel pins arranged in staggered pattern across the whole width. Due tolarge number of pins the material is well opened and gets deposited as a uniformlayer on the cages to produce asmooth and uniform lap that is essential for good carding.

5.0Conclusions

Mixingand Blowroom operation are very important as they set the tone for the highquality yarn spinning. Care should be taken in selecting the finish,conditioning time, beating points, type of beaters and different settings. Onceall these factors are taken into consideration it is ensured that feed tocarding will be uniform for lap as well as chute feed.