Bobbin | Structure of the Bobbin

Bobbin is a cylindrical or slightly tapered barrel, with or without flanges, for holding slubbings, rovings, or yarns.

The Structure of the Bobbin
The shape of the bobbin The tube is usually made of paperboard, plastics and has a conical shape similar to the spindle tip; the yarn is wound on the tube leaving a free space (10 ÷ 13 mm) at both ends. A full bobbin (Figure) consists of three different parts:

1.  The “H2” tapered base (kernel),
2.  The “H1”cylindrical part at the centre (yarn package or buildup),
3.  The “H” cone-shape upper end A bobbin is wound starting from the base to the tip by overlapping the various yarn layers frustrum-like; except for the kernel, this gives a conical shape to the material from the edge of the kernel to the tip of the bobbin. 

Each step of the bobbin formation consists essentially of the overlapping of a main yarn layer with a cross-wound tying layer. The main layer is wound during the slow upward travel of the ring rail; the yarn coils laid one next to the other provide the bobbin build-up. The cross layer, made of distant coils inclined downwards, is formed during the quick downward travel of the rail. This system keeps the main layers separated, in order to prevent them from being pressed one inside the other (thus resulting in a quite difficult or almost impossible unwinding of the yarn). 

Bobbin structure

The ratio between the number of yarn coils wound on the bobbin during the upward travel of the rail and the number of yarn coils wound during the downward travel usually range between 2:1 and 2.5:1 ; for this reason the rail must raise slowly (A) and lower quite quickly (B). When unwinding the bobbin at high speed (D) the simultaneous unwinding of many coils could lead to entanglements of the yarn (this does not occur in .C. case).

The yarn wound on the bobbin during each upward and downward travel of the ring rail is called run-out.; to facilitate successive unwinding, the length of the run-out ranges from 3 to 5 m and is smaller for coarse yarns and greater for finer ones. The travel of the rail is considered sufficient when it is 15÷18% larger than the 

ring spinning diameter.

The structure of the bobbin is the result of the continuous motion of the winding point of the yarn on the bobbin affected by the ring rail. The rail travels up and down along the vertical axis to form the main layers, and on the cross axis (with an upward progressive increment) to homogeneously distribute the yarn on the bobbin .

The increment value, i.e. the space between the two subsequent upward travels of the ring rail (winding cycles), determines the forming bobbin diameter with respect to two different parameters: the run-out and the yarn count.

To obtain bobbins of a given diameter it is necessary to consider that the increment is inversely proportional to the yarn count (Nm) and directly proportional to the length of the run-out; in other words, after establishing the diameter of the bobbin, with the same yarn count, when doubling the run-out length, the increment must also be doubled or, with the same run-out length, when doubling the yarn count (Nm) the increment value must be halved.

Ring Traveller | Features of a Ring Traveller | Types of Traveller |Factors for Ring Traveller Selection

Traveller

Traveller is a tiny element which is used in ring spinning system , acts as the main of twist imparter during yarn production. On the other word , it is also called the twisting element merely responsible for twist impartion.It is a C-shaped, metal clip that revolves around the ring on a ring spinning frame. It guides the yarn onto the bobbin as twist is inserted into the yarn.

Ring Traveller

The traveller allows the twisting and the correct delivery of the yarn on the bobbin. The take up speed of the yarn, which corresponds to the difference between the peripheral speed of the bobbin and the peripheral speed of the traveller, is equal to the peripheral speed of the delivery cylinders of the drafting unit. The difference between spindle rpm and the traveler rpm, within a specific unit of time, gives the number of coils deposited on the bobbin within a specific unit of time. Therefore, with the same spindle speed, the traveller rpm increases along with the bobbin diameter while the number of coils wound on the bobbin decreases.

When the traveller rotates the high contact pressure between the ring and the traveller creates huge friction forces that generate heat; the traveller can reach temperatures exceeding 200 ÷ 300 °C since its small mass does not allow a quick transfer of the heat to the air or to the ring. For this reason, significant improvements in ring spinning can be hardly achieved with the materials currently available, since the speed of the traveller has apparently reached its maximum limit (approx. 33 ÷ 35 m/sec for steel travellers and 45 ÷ 47 m/s for nylon-glass fibre travellers). This is why the traveller used for producing a specific type of yarn must feature the most suitable shape, mass, material, finish and cross section. To reach the highest speeds, the shape of the traveller must correspond to the shape of the ring.

This creates a very large contact surface, which facilitates heat transfer; the surface must also be very smooth to grant a low barycentre. The flat profile must allow space enough for the yarn since the friction between the yarn and the ring could increase the yarn hairiness and consequently the formation of flying fibres.

The mass of the traveller determines the friction force between the ring and the traveller, the balloon size and consequently the take up tension of the yarn. If the mass of the traveller is very small, the balloon will be sufficiently large, the take up tension will be limited and the bobbin will be soft; on the contrary, a heavy traveller will determine an increase in the take up tension and a greater number of breaks. In a few words, the mass of the traveller must be strictly proportional to the yarn mass (count and resistance) and to the speed of the spindle. 

Features of a Traveller:

1. Generate less heat
2. Dissipate heat fastly
3. Have sufficient elasticity for easy insertion and to retain its original shape after insertion
4. Friction between ring and traveller should be minimal
5. It should have excellent wear resistance for longer life
6. Hardness of the traveller should be less than the ring

Types of Traveller:

Traveller are normally three types. They are:

1. OS -Type
2. C-Type
3. G-Type

Factors for Ring Traveller Selection :

1. Count of yarn to be spun
2. Fiber used in the yarn
3. Ring cup diameter
4. Spindle speed

What is Spinning? | Types of Spinning | Dry Spinning | Wet Spinning |Melt Spinning | Gel Spinning

Spinning is manufacturing process for creating polymer fibers. It is a specialized form of extrusion that uses a spinneret to form multiple continuous filaments. There are four types of spinning: wet, dry, melt, and gel spinning.

First, the polymer being spun must be converted into a fluid state. If the polymer is a thermoplastic then it is just melted, if not then it may be dissolved in a solvent or chemically treated to form soluble or thermoplastic derivatives. The fluid polymer is then forced through the spinneret, where the polymer cools to a rubbery state, and then a solidified state.

Types of Spinning
There are different types of spinning. Such as:

1.Dry Spinning
2.Wet Spinning
3.Melt Spinning
4.Gel Spinning

Now they are descrived below:

1.Dry Spinning
Dry spinning is also used for fiber-forming substances in solution. However, instead of precipitating the polymer by dilution or chemical reaction, solidification is achieved by evaporating the solvent in a stream of air or inert gas.

The filaments do not come in contact with a precipitating liquid, eliminating the need for drying and easing solvent recovery. This process may be used for the production of acetate, triacetate, acrylic, modacrylic, PBI, spandex, and vinyon.

2.Wet Spinning
Wet spinning is the oldest process. It is used for fiber-forming substances that have been dissolved in a solvent. The spinnerets are submerged in a chemical bath and as the filaments emerge they precipitate from solution and solidify.

Because the solution is extruded directly into the precipitating liquid, this process for making fibers is called wet spinning. Acrylic, rayon, aramid, modacrylic and spandex can be produced by this process.

3.Melt Spinning
In melt spinning, the fiber-forming substance is melted for extrusion through the spinneret and then directly solidified by cooling. Nylon, olefin, polyester, saran and sulfar are produced in this manner.

Melt spun fibers can be extruded from the spinneret in different cross-sectional shapes (round, trilobal, pentagonal, octagonal, and others). Trilobal-shaped fibers reflect more light and give an attractive sparkle to textiles.

Pentagonal-shaped and hollow fibers, when used in carpet, show less soil and dirt. Octagonal-shaped fibers offer glitter-free effects. Hollow fibers trap air, creating insulation and provide loft characteristics equal to, or better than, down.

4.Gel Spinning
Gel spinning is a special process used to obtain high strength or other special fiber properties. The polymer is not in a true liquid state during extrusion. Not completely separated, as they would be in a true solution, the polymer chains are bound together at various points in liquid crystal form.

This produces strong inter-chain forces in the resulting filaments that can significantly increase the tensile strength of the fibers. In addition, the liquid crystals are aligned along the fiber axis by the shear forces during extrusion. The filaments emerge with an unusually high degree of orientation relative to each other, further enhancing strength. The process can also be described as dry-wet spinning, since the filaments first pass through air and then are cooled further in a liquid bath. Some high-strength polyethylene and aramid fibers are produced by gel spinning.

Step Cleaner/Ultra Cleaner/Super Cleaner | Object of Step/ Ultra/ SuperCleaner Machine

Step cleaner machine is an inportant machine in ring spinning for cleaning and opening impurities from cotton. This machine is set normally after porcupine opener machine.

Object of Step/ ultra/Super Cleaner Machine
i. To open & clear the cotton by combinations of opposite spike action & the beating action.
ii. To remove the impurities such as leaves, stalk, motes & sand without damage the fiber.

Main Parts :
i. Motor.
ii. Motor pulley.
iii. Beaters.
iv. Baffle plate.
v. Grid.

Step Cleaner

Main Setting Point :
Set to do the require amount as cleaning close grid bars, setting gives good opening & large grid bar setting gives poor opening, other setting points are, Beater to Grid bar = 1“ & beater to beater = 8“.

Specification :

i. Motor r.p.m = 695

ii. Dia of the beater = 18.6“

iii. Dia of two pulley = 21.2“

iv. Dia of one pulley = 16“

v. No. of striker = 26

Calculation :

          Beater r.p.m = 695*(16“/21.2“)

                                   = 524.5

          Beater per min. = 524.5*26

                               = 13637

Conclusion :
This is the second m/c of blow room line. It works step by step & for this it is called step cleaner. It is a good instrument of opening & cleaning of cotton by the action of beater. It also removes ascertain a out of leaves, stalk & other impurities. It is suitable for process of low grade cotton.

Carding Machine | Carding Process | Object/Task of the Carding | Actionin Carding Machine

The card is the machine which is used for carding. In the card we put lap from blow room and after carding we get carded sliver. This is second stage machine operation in conventional spinning line. Carding may be defined as the reduction of an entangled ways of fibers to a filmy web by working between surfaces clothed with shirp wire point.

The proverbs of the experts ” The card is the heart of the spinning mill and well carded is half spun demonstrate the immense significance of carding for the final result of spinning operation.” The importance of carding is still greater where new spinning system are concerned.

 Object or Task of the card:

Opening to individual fibres:  
The blow room only opens the raw material to flocks where as the card opens it to the stage of individual fibres. This enables the eliminations of impurities and good performance of the other operation.

Elimination of impurities: 
Impurities are mostly eliminated in taker in and a small portion of it is eliminated by flat stripping. Modern card removes 80 – 90% impurities from lap and sliver contain only 0.05 – 0.3% foreign matter.

Elimination of dust:  
Card is good dust removing machine. I t removes free dust as well micro particles by significant friction.

Disentangling of neps:  
Blow room increase neps from machine to machine, but card reduce it to a small friction. The card does not remove neps but disentangles it by opening them. Closer spacing between the clothing, sharper clothings optional speed of taker in, low doffer speed etc. Can improre the disentangling process of neps.

Fibre blending:  
The card scarcely improve long term blending as the residence time of the material in the machine is to short. The card improves traverse blending and fibre with fibre mixing.

Action in Carding Machine: 

The following 4 actions take place in a carding machine:

1. Combing action;

2. Carding action;

3. Stripping action;

4. Doffing action.

1. Combing action:  
Combing action takes place feed roller and taker in. Here the pin direction of the two surfaces are the same. Combing is the straightening and paralleling of fibre and the removal of short fibres and impurities by using a comb or combs which is assisted by roller and brushed.

2. Carding action:
Carding action takes place between flat and cylindex.

In carding action:

•  Direction of wire in two surfaces are opposite.
• The moving direction of roller are also opposite.
•  One roller is slower and other is fast.

So carding action is known as point against point action.

3. Stripping action:  
Stripping action takes place between a. Taker in & Cylinder and b. Doffer & Stripper.

In stripping action:

• Wire direction will be the same.
•  Roller moving direction will be the same.
•  One roller will be faster than another.

So stripping action is known as “Point back point” action.

4. Doffing action:  
This action take place between cylinder and doffer. In this place fibre is transferred from cylinder to doffer. Low speed doffer is called fibre from high speed cylinder and make a condensed web for formation of sliver.

Basic Operations in the Blowroom | Actions in the Blowroom Section

Blow Room:

The section where the supplied compressed bale is turnt into a uniform lap of particular length by opening, cleaning, blending or mixing is called blow room section.It is the first steps of spinning.

Operations in the Blowroom

1. Opening
2. Cleaning
3. Dust Removal
4. Blending
5. Even feed of material to the card

Opening

The first operation required in the blowroom line is opening, carried out to the stage of tufts – in contrast to the  cards, where it is performed to the stage of individual fibers. Tuft weight can be reduced to about 0,1 mg in the blowroom. The small improvements by each of the subsequent machines are obtained only by considerable additional effort, stressing of the material, unnecessary fiber loss and a striking increase in neppiness. If necessary the card is able to assume rather more of the overall task.

Cleaning

It has to be kept in mind that impurities can only be eliminated from surfaces of tufts. Within a progressive line of machines it is therefore necessary to create new surfaces continuously by opening the material. And even then the best blowroom line is not able to eliminate all, or even almost all, of the foreign matter in the raw material. A blowroom installation removes approximately 40 - 70% of the impurities. The result is dependent on the raw material, the machines and the environmental conditions.

It is clear from this diagram that the cleaning effect cannot and should not be the same for all impurity levels, since it is easier to remove a high percentage of dirt from a highly contaminated material than from a less contaminated one. Looking at the machine, the cleaning effect is a matter of adjustment. Increasing the degree of cleaning also increases the negative effect on cotton when trying to improve cleaning by intensifying the operation, and this occurs mostly exponentially. Therefore each machine in the line has an optimum range of treatment. It is essential to know this range and to operate within it. 

In an investigation saw that the quantity of waste eliminated on a cleaning machine by modifying settings and speeds was raised from 0.6% to 1.2%: while the quantity of foreign matter eliminated increased by only 41%, the quantity of fibers eliminated increased by 240%. Normally, fibers represent about 40 - 60% of blowroom waste. Thus, in order to clean, it is necessary to eliminate about as much fibers as foreign material. Since the proportion of fibers in waste differs from one machine to another, and can be strongly influenced, the fiber loss at each machine should be known. It can be expressed as a percentage of good fiber loss in relation to total material eliminated, i.e. in cleaning efficiency (CE): 

AT = total waste (%); AF = good fibers eliminated (%). 

For example, if AT = 2.1% and AF = 0.65%: 

Dust Removal

Almost all manufacturers of blowroom machinery now offer dust-removing machines or equipment in addition to opening and cleaning machines. However, dust removal is not an easy operation, since the dust particles are completely enclosed within the flocks and hence are held back during suction (because the surrounding fibers act as a filter). Since, as shown  it is mainly the suction units that remove dust (in this example 64%), dust removal will be more intensive the smaller the tufts. 

It follows that dust elimination takes place at all stages of the spinning process.

Blending

Blending of fiber material is an essential preliminary in the production of a yarn. Fibers can be blended at various stages of the process. These possibilities should always be fully exploited, for example byTransverse doubling transverse doubling. However, the start of the process is one of the most important stages for blending, since the individual components are still separately available and therefore can be metered exactly and without dependence upon random effects. A well-assembled bale layout and even (and as far as possible simultaneous) extraction of fibers from all bales is therefore of the utmost importance. Simultaneous extraction from all bales, which used to be normal in conventional blending batteries, is now no longer possible (automatic bale openers). Accordingly, intensive blending in a suitable blending machine must be carried out after separate tuft extraction from individual bales of the layout. This blending operation must collect the bunches of fibers arriving sequentially from individual bales and mix them thorough.

Even Feed of Material to the Card

Finally, the blowroom must ensure that raw material is evenly delivered to the  cards. Previously, this was carried out by means of precisely weighed laps from the  scutcher, but automatic tuft feeding installations are used nowadays. While in the introductory phase such installations were subject to problems regarding evenness of tuft delivery, today they generally operate well.

Card Clothing | Flexible Card Clothing | Semi-rigid Card Clothing |Advantage of Flexible Card Clothing | Disadvantage of Flexible CardClothing | Advantage of Semi-rigid Card Clothing

Card Clothing:  
The inclined wire set in base material which are covered around the surface of taker in. Cylinder, doffer and flat in the carding machine is called card clothing.

Card clothing is used on the surface of

• Taker in;
•  Cylinder;
•  Doffer;
•  Flat.

Flexible Clothing: 
These clothing have hook of round or oval wire which are set into elastic, multiple – ply cloth backings. Each hook is bent to a U-shape and is formed with a knee that flexes under bending load and return its original position when the load is removed.

Advantage of Flexible Card Clothing:

i. Point density being high, carding action is good.
ii. Wire point flexible so fibre damage is less.
iii. Fibre, yarn can produced.

Disadvantage of Flexible Card Clothing:

i. Carding angle cannot be choosen.

ii. Grinding action should be regular.

iii. Foundation material are required.

Semi Rigid Clothing:
In case semi-rigid clothing the sharp pointed wire are set in more rigid backings. This backing is made of multiple plies and the no of plies are more in number than that in flexible clothing. The wires have no knee & are deeply set inside the plies. The wire are much less capable yielding than flexible clothing.

Use: 
Semi-rigid clothing is found only in the flats.

Advantage of Semi-rigid Card Clothing:

• No need of sharpening after short use.
•  No dirt and dust in stored.
•  No need to of frequent grinding.
•  Grinding: It is process of retaining the original position of cloth wire after using for a long time.

Crighton Opener Machine/Verticle Opener Machine/Twine Opener Machine |Main Parts of Crighton Opener M/C

Crighton Opener

Crighton opener

Crighton opener machine is used to open cotton tuft in blowroom line. It is also called Verticle Opener Machine or Twine Opener Machine

Object Crighton Opener:
i. To strike the cotton while it is being carried by the air current.
ii. To open the cotton in to small fault.
iii. To use low quality cotton (i.e. cotton of short staple & more impurities).



Main Parts of Crighton Opener M/C :
i. Motor.
ii. Motor pulley
iii. Discs with strikes.
iv. Inclines Grid bar.

Adjustment of Different Parts :

1. Grid bar to grid bar :
Wider setting: High fiber loss, poor opening & cleaning, high speed, high productions.
Closer setting: Good opening, low speed gives lower fiber loss & low production.

2. Blade to grid bar :
Wider Setting: No fiber damage, high production, poor opening & cleaning.
Closer setting: Fiber damage, low production, lower removal of impurities, good opening.

Specification Crighton Opener M/C  :

i. Motor r.p.m = 1440
ii. Motor pulley dia = 14“
iii. M/C pulley dia = 32“
iv. No. of striker = 6

Calculation :
Beater r.p.m = 1440*(14“/32“) = 630
Beats per min = 630*6 = 3780

Conclusion :
This is the third m/c of the blowroom line. It stands on a vertical shaft & hence it is called vertical opener. This m/c is a major cleaning point of blow room line. There is a by pass system. So from step cleaner cotton can be difficulty pass to the hopper feeder without vertical opener. It can be used in case of low grade cotton. For beater opening & cleaning close setting of striker is done. But there is a rise of more fiber damage. Hence moderate setting is done.

Introduction of Blowroom Section | Objects of Blow-room | BasicOperations in the Blowroom

Blowroom: 

Blowroom consists a number of machines used on succession to open and clean the cotton fibre. Since the tuft size of cotton becomes smaller and smaller, the required intensities of processing necessitates different machine configuration.

Blowroom

Objects of Blow Room: 

1. Opening:

a) To open the compressed bales of fibres.

b) To make the cotton tuft as small as far as possible.

2. Cleaning:

To remove dirt, dust, broken seeds, broken leaves, and other foreign materials from the fibre.

3. Mixing & Blending:

To make good value of yarn and to decrease production cost mixing and blending is done.

4. Lap or flocks formation:

To transfer opened and cleaned fibre into sheet form of definite width and length which is called lap or in modern system directly feed to the carding machine into flocks form.

Basic Operations in the Blowroom:

• opening 
• cleaning 
• mixing or blending 
• microdust removal 
• uniform feed to the carding machine 
• Recycling the waste 

Blow room installations consists of a sequence of different machines to carry out the above said  operations.Moreover Since the tuft size of cotton becomes smaller and smaller, the required intensities of processing necessitates different machine configuration. 

Technological Points in Blowroom 

Opening in blowroom means opening into small flocks.Technological operation of opening means the volume of the flock is increased while the number of fibres remains constant. i.e. the specific density of the material is reduced 

The larger the dirt particle , the better they can be removed . Since almost every blowroom machine can shatter particles, as far as possible a lot of impurities should be eliminated at the start of the process.Opening should be followed immediately by cleaning, if possible in the same machine. 

The higher the degree of opening, the higher the degree of cleaning. A very high cleaning effect is almost always purchased at the cost of a high fibre loss. Higher roller speeds give a better cleaning effect but also more stress on the fibre. 

Cleaning is made more difficult if the impurities of dirty cotton are distributed through a larger quantity of material by mxing with clean cotton.The cleaning efficiency is strongly dependent on the TRASH %. It is also affected by the size of the particle and stickyness of cotton. Therefore cleaning efficiency can be different for different cottons with the same trash %. There is a new concept called CLEANING RESISTANCE. Different cottons have different cleaning resistance.

If cotton is opened well in the opening process, cleaning becomes easier because opened cotton  has more surface area, therefore cleaning is more efficient . If automatic bale opener is used, the tuft size should be as small as possible and the machine stop time should be reduced to the minimum level possible .

If Manual Bale openers are used, the tuft size fed to the feed lattice should be as small as possible .Due to machine harvesting , cotton contains more and more impurities, which furthermore are shattered by hard ginning. Therefore cleaning is always an important basic operation. 

In cleaning, it is necessary to release the adhesion of the impurities to the fibres and to give hte particles an opportunity to separate from the stock. The former is achieved mostly by picking of flocks, the latter is achieved by leading the flocks over a grid. 

Using Inclined spiked lattice for opening cotton in the intial stages is always a better way of opening the cotton with minimum damages. Ofcourse the production is less with such type of machines. 

But one should bear in mind that if material is recyled more in the lattice, neps may increase. Traditional methods use more number of machines to open and clean natural fibres. Mechanical action on fibres causes some deterioration on yarn quality, particularly in terms of neps . Moreover it is true that the staple length of cotton can be significantly shortened . Intensive opening in the initial machines like Bale breaker and blending machines means that shorter overall cleaning lines are adequate. 

In a beating operation, the flocks are subjected to a sudden strong blow. The inertia of the impurities accelerated to a high speed, is substantially greater than that of the opened flocks due to the low air resistance of the impurities. The latter are hurled against the grid and because of their small size, pass between the grid bars into the waste box, while the flocks continue around the periphery of the rotating beater. By using a much shorter machine sequence, fibres with better elastic properties and improved spinnability can be produced. 

Air streams are often used in the latest machine sequence, to separate fibres from trash particles by buoyancy differences rather than beating the material against a series of grid bars. There are three types of feeding apparatus in the blowroom opening machines two feed rollers( clamped) feed roller and a feed table a feed roller and pedals 

Two feed roller arrangements gives the best forwarding motion, but unfortunately results in greatest clamping distance between the cylinders and the beating element feed roller and pedal arrangement gives secure clamping throughout the width and a small clamping distance, which is very critical for an opening machine In a feed roller and table arrangement, the clamping distance can be made very small. This gives intensive opening, but clamping over the whole width is poor, because the roller presses only on the highest points of the web. 

Thin places in the web can be dragged out of hte web as a clump by the beaters Honeydew(sugar) or stickiness in cotton affect the process very badly. Beacause of that production and quality is affected. Particles stick to metal surfaces, and it gets aggreavated with heat and pressure. These deposits change the surface characteristics which directly affects the quality and running behavior.

There are chemicals which can be sprayed to split up the sugar drops to achieve better distribution.But this system should use water solutions which is not recommended due to various reasons. It is better to control the climate inside the department when sticky cotton is used. Low temperature ( around 22 degree Celsius) and low humidity (45% RH). This requires an expensive air conditioning set up. 

The easiest way to process sticky cotton is to mix with good cotton and to process through two blending machines with 6 and 8 doublings and to install machines which will seggregate a heavier particles by buoyancy differences.

General factors which affect the degree of opening , cleaning and fibre loss are, 

• thickness of the feed web 
• density of the feed web 
• fibre coherence 
• fibre alignment 
• size of the flocks in the feed (flock size may be same but density is different) 
• the type of opening device 
• speed of the opening device 
• degree of penetration 
• type of feed (loose or clamped) 
• distance between feed and opening device 
• type of opening device 
• type of clothing 
• point density of clothing 
• arrangement of pins, needles, teeth 
• speeds of the opening devices 
• throughput speed of material 
• type of grid bars 
• area of the grid surface 
• grid settings 
• airflow through the grid 
• condition of pre-opening 
• quantity of material processed, 
• position of the machine in the machine sequence 
• feeding quantity variation to the beater 
• ambient R.H.% 
• ambient teperature 

Cotton contains very little dust before ginning. Dust is therefore caused by working of the material on the machine. New dust is being created through shattering of impurities and smashing and rubbing of fibres.  However removal of dust is not simple. Dust particles are very light and therefore float with the cotton in the transport stream.Furthermore the particles adhere quite strongly to the fibres. If they are to be eliminated they are to be rubbed off.The main elimination points for adhering dust therefore, are those points in the process at which high fibre/metal friction or high fibre/fibre friction is produced. 

Removal of finest particles of contaminants and fibre fragments can be accomplished by releasing the dust into the air, like by turning the material over, and then removing the dust-contaminated air. Release of dust into the air occurs whereever the raw material is rolled, beaten or thrown about. Accordingly the air at such positions is sucked away. Perforated drums, stationary perforated drums, stationary combs etc. are some instruments used to remove dust.

Calculation of Draft, Draft Constant of Ring Frame

Name of the experiment: Calculation of draft, draft constant and draft in each zone of the ring frame.

Objects:
1) To find out draft, draft constant of the ring frame.
2) To find out draft of each zone of the ring frame.

M/C specifications:

• RPM of the motor =1440 
• Dia of the motor pulley = 5”
• Dia of the tin cylinder pulley = 10.5”
• Dia of the tin cylinder = 10”
• Dia of the wharve = 1.125”
• No of teeth of fibre wheel = 42T
• No of teeth of front roller driving wheel = 98T
• Dia of the front roller = 1”

Gearing diagram:

Figure :- Gearing Diagram of Drafting Zone of Speed Frame Machine

Calculation of draft, draft constant and draft of each zone of the ring frame:

 

Conclusion:
Ring frame is the final and very important machine for build the yarn onto bobbin in a form suitable for storage, transportation and processing. It is used to twist the drafted strand to form yarn of required count and strength.