Blowroom&Carding

Bahirdar UniversityEthiopian Institute of Textile and Fashion Technology

by Biruk Fentahun Dec. 2015

Seminar on process control in blow room and carding

1. Introduction-spinning During spinning process, it is necessary to think and work on

the following points- in process control point of view

1. Raw Material Selection fibre lengthmicronaire range and averagecolor range and averagematurity coefficient range and averagehomogeneous mixingLevel of moisture

2. Process Control in Blow Room• cleaning and waste• performance of blow room • neps• Fiber brakages

3. Process Control in Carding •average level of waste and variation between individual cards•correct type of wire suited to a given quality•Settings•Neps

4. Process Control in Draw Frame & Fly Frame

• high tension draft • improper pinion changes • improper roller settings. • sliver break5. Process Control in Ring Spinning

•end breaks •yarn evenness and imperfections•improper pinion changes •improper roller settings. •high tension draft •twist

6. Process Control in Rotor Spinning•Unevenness •Periodic variation•Tensile property

2. Blow room

Basic Functions Of Blow Room

1. Opening & Cleaning-1st

2.Mixing or Blending3.Micro dust removal4.Uniform feed to the Carding5.Recycling of waste

yarn quality characteristics that are influenced by blow room operations

• Evenness • Imperfections • Neps• Hairiness • Count consistency

basic parameters to be considered in Blow room

speed of beatersetting between feed roller and beaterproduction rate of individual machinethickness and density of the feed websize of flocks in the feedpoint density of clothingair flow through the gridTypes of fiber and amount of trash in itType of opening and cleaning deviceType, Angle & setting of grid bardegree of penetrationAtmospheric conditions

crucial things to be controlled in blow room

1. the waste generated -contains mainly unwanted

foreign matter and spinnable fibers

2. generation of short fibres -by avoiding rupture as far

as possible

3. Fibre damage

4. generation of neps.

Neps in the Blow room

avoid rough and blunt beater edges, pins Avoid damaged and rusty grid bars Maintain beater clearance setting Maintain optimum cleaning efficiency the maximum cleaning efficiency of a blow room cannot be

more than 70% . Above this cleaning efficiency will result in unnecessary

nep generation.

Fiber breakage in the blow room

attempting to achieve a higher cleaning efficiency will result in unnecessary loss of fibres, fibre breakage .

Higher roller speeds give a better cleaning effect but also more stress on the fibre.i.e. fiber loss

cleaning and Waste in the blow room

If cotton is opened well in the opening process, cleaning becomes easier because opened cotton has more surface area, therefore cleaning is more efficient.

it is necessary to measure the amount of the waste removed and its composition.

It depends on trash%, machine performance factor and cotton properties factor.

factors that cause variation in the blow room material, and hence inconsistent final yarn quality

insufficient opening of cotton and variation in tuft sizeineffective functioning of the evener motionvariation in cotton level in the blended reserveuneven mixing of waste and cottonsfaulty air currentsuneven or worn fluted rolls and calendar rollsdirty screens or screens with rough surfacesincorrectly set or chocked damperstoo large a draft between calendar section and lap windertypes and speeds of beaters unsuitable for the quality of cotton

3. Carding

The carding is a very important process because unless the fibres are separated into individuals, they can not be spun into smooth and uniform yarns neither can they be blended properly with other fibres.

It contributes a lot to the yarn quality

FunctionsIndividualization of fibersparallelizationto remove impuritiesDisentangling of nepsto reduce the blend to a web of fibers andto divide it up into roving's of the required count,

suitable for feeding to the spinning machines.

Important carding parameters

Licker-in clothingCylinder clothingDoffer clothingFlat clothing

Process parameters

Machine parameters

1. SpeedsLicker in speedCylinder speedFlat speedDoffer speed

2. SettingsLicker-in to feed, cylinderCylinder to flat, dofferMote knife to licker-in

3. MaterialsThickness of lap/eed weightSliver countdraft between feed

roller and doffer

process parameters and specifications are to be selected properly to produce a good quality yarn with a lower manufacturing cost.

Influence of cylinder speed

cylinder speed depends upon the production rate

Higher cylinder speed increases the space for the fibre

leading higher production.

The higher the cylinder speed is, higher centrifugal force

on fibers and trash particles-more libration of trash, short

fibers, increase transfer efficiency

Intensive opening action between cylinder and flat -

Individualization, stress exerted on fibers, libration of trash

particles, seed coat and short fibers

Cylider wire The following characteristics of cylinder wire should be considered. wire angle tooth depth wire population rib thickness tooth profile tooth pitch tooth point overall wire height

Wire front angle depends on mainly cylinder speed and coefficient of friction of raw material.

Higher the cylinder speed, lower the angle for a given fibre. It is the wire that keeps the fibre under its influence during carding operation.

Therefore the space within the wire should also be more for higher production.

Cont… Higher the cylinder speed, higher the centrifugal force created by the

cylinder, this tries to eject fibre from the cylinder, along with trash. It is cylinder wire's front angle which overcomes the effect of this force. Low front angle with too low cylinder speed and with high frictional

force will result in bad quality, because the fibre transfer from cylinder to doffer will be less. Hence recycling of fibres will take place, which result in more neps and entanglements.

movement of the fibres towards the tip of the tooth coupled with centrifugal action demands an acute front angle to hold the fibre in place during carding.

Lack of stiffness associated with fine and/or long fibres necessitates more control during the carding process. This control is obtained by selecting the tooth pitch, which gives the correct ratio of the number of teeth to the fibre length. Tooth pitch reduction is therefore required for exceptionally short fibres and those lack stiffness.

Number of points across carding is decided by the rib width. Finer the fibre, finer the rib width. The trend is to finer rib width for higher production.

sliver U%

Worn gear wheels

narrow setting of the undercasing

large waste particles reaching to

doffer

uneven or worn doffer & feed roller

bearings

draft at excessively high tension

jerky motion of calendar roller

incorrect setting of the coiler base

incorrectly sized coiler trumpet

not suitable to the hank feed

poor functioning of roller weighting

uneven feed to nose of the feed plate

worn and improper clothing settings

uneven heights in the wire clothing

excessive humidity

poor feed roller grip, caused by failure

of feed roll weighing

bent feed roller and feed plate

High card sliver U% can be caused by a number of factors

Causes of excessive wastage in carding

Wider winch angle (deflector blade) setting. Incorrect delivery speed. Gauge in changeable points. Amount of trash removed in Blow room section. Incorrect setting in mote knives.

Neps in carding

Avoid damaged wires Waxy covering on the wires Double carding reduce neps by over 50%

THANK U !!