Ginning: Cotton Ginning, Process, Types, and Objectives

Ginning: Cotton Ginning, Process, Types, and Objectives

What is Ginning? To answer the question what is ginning? I would say, the process by which the fibers are separated from the seeds is called ginning. Human using cloth for the last seven thousand years. From the beginning, the cotton fiber is manually processed by hand until the 18th century. When automated cotton the processing machine was invented that time ginning process become so easy. Here we will discuss Ginning: Cotton Ginning, Process, Types, and Objectives.

It is one of the most important steps of the spinning process. After collecting seed cotton from the field, cotton moves to nearby gins for separation of lint, seed and any other foreign particles. The production of a typical gin is about 12 bale per hour (here 1 bale = 500 pounds). Earlier the ginning process is to be done by manually but right now for higher production, manufacturers use an automated machine with higher productivity. The machine is well known as a cotton ginning machine.

What is Ginning, Ginning, Ginning of Cotton

Simply to define ginning we can say that the process is used to get the cleaned cotton by separating or removing the seeds, dust or any other foreign particles. So that better cotton can be offered for the cotton spinning mills.

Objects of Ginning

  • To make the fiber-free from seeds without gin-cut fiber.
  • To ensure the best quality of cotton and get the fair price of cotton in the market.
  • To be confident that fiber does not contain excess and unexpected seeds or any other particles.
  • To make the spinning process easier and effective

Cotton Ginning Process

  1. At first, the cotton is made to go through dryers to reduce moisture content.
  2. Then the cotton is made to go through cleaning equipment to remove foreign particles or materials.
  3. The cotton is then sent to the air conveyed to gin stands where revolving circular saws pull the lint from the saw teeth by air blasts or by rotating brushes.
  4. The cotton is compressed into 500 pounds weigh contained bales.
  5. Then the bales of cotton are shipped to the textile spinning mill for further processes.
  6. To ensure better quality the overall process is monitored by a quality control team.
ginning process of cotton
Ginning of cotton

Modern Cotton Ginning Process

In an automatic modern ginning process of cotton, a modern machine is used. Before cotton arrives at the spinning mill to spin into thread and woven into the fabric, it makes the journey from field to bale. Cotton needs about five months to grow from a planted seed to a ready plant. The harvesting machine named cotton picker plucks fluffy seed cotton out of the plant’s boll and leave a trail of burrs and sticks behind. The machine empties the pulled cotton into a tractor-drawn buggy. The machine builds the seed cotton into a humongous rectangular block called a module. A truck transports the module to the processing plant, which is known as a cotton gin. Once the cotton arrives at the processing plant, sticks and burrs are removed as well as any lingering debris and seeds. A truck dumps the module into a feeder, which moves the packed seed cotton into a dispenser. The ground seed cotton falls onto a conveyor belt, which leads to the hot box, then the hotbox mixes the seed cotton with hot air, which allows the moisture to evaporate, making the seed cotton easier to clean. A machine called the Wad Buster breaks up the clumps of seed cotton by tossing it against a screen. Loose remains fall through the screen openings down a narrow chute. Then the seed cotton moves through a machine called the steady flow, which divides it equally between two processing lines. On each line, the seed cotton enters a Burr Machine, which grabs the seed cotton with a circular saw and swings it against metal bars.

The centrifugal force shakes off the heavier debris. The seed cotton passes the machine through one pipe and the debris through another. A large auger transfers the debris to a waste drop and out of the plant. Then the seed cotton is ready for the final step of processing. A network of pipes feeds a row of machines called Gin Stands. The gin stand separates the seed from the fluffy stuff, called the lint. Inside each stand are arranged horizontally, each separated by a steel rib. The saw teeth grab the seed cotton and pull the lint through the narrow gap between saw and rib. The seeds are too large to pass through, so it spins in front of the rib, then drops into a conveyor. The lint goes into a flue, which leads to the packaging area. And then use this cotton in the spinning mill to make the thread.

Types of Cotton Ginning

There are two basic types of Ginning you may find. These are:

Saw Ginning of Cotton

Rather than manual ginning, saw ginning is used which provides more clean cotton compared with manual or handheld separation process of seed from cotton.

Advantage of Cotton Saw Ginning

  1. Saw ginned cotton is more uniform
  2. Cotton is more clean than usual.

The Disadvantage of Cotton Saw Ginning

  1. Possibility of fiber breakage due to draw up the fiber from the surface of the seed.
  2. Increase neps
  3. Increase short fiber content

Roller Ginning of Cotton

In the case of modern ginning, an automated roller is used in the ginning process of cotton. Nowadays this type of ginning technology is highly used for industrial purpose.

Advantage of Roller Ginning of Cotton

  1. Fiber quality is better compared with saw ginned cotton.
  2. High production because of the use of advanced technology in the ginning process.

The Disadvantage of Roller Ginning of Cotton

  1. The moisture of seed mixes up with fiber in processing which causes cake cotton fault.

Faults in Ginning Process of Cotton

  1. Gin-cut fiber
  2. Crushed seeds
  3. Neps formation
  4. Too much wastage

Written by
Engineer Sheikh Nurja, and
Md. Nahian Mahmud Shaikat

Process Flow Chart of Jute Spinning

As jute is a long staple fiber, it is produced by long staple spinning process. Naturally, jute is a long, soft, shiny vegetable fiber that can be spun into coarse strong threads. There many kinds of useful product made by jute yarn. Hope this process flow chart of jute spinning will help you to understand who jute spinning is done.

Process Flow Chart of Jute Spinning

The sequence flow of jute spinning is followed by a selection of batch=>piecing up=>Jute softening=>Piling or conditioning=>Breaker carding=>Finisher carding=>1st Drawing=>2nd Drawing=>3rd Drawing=>Spinning=>Winding (Spool or cop winding).

process flow chart of jute spinning

Process Flow Chart of Jute Spinning

Written by

A.M. Amirul Islam (Washim)

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E-mail: [email protected]

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Introduce with High Volume Instrument

Introduce with High Volume Instrument (HVI)

Advanced fiber testing system high volume instrument is used to determine fiber properties in bale management system. It is fiber classing system. HVI is used to determine fiber length, strength, maturity, micronaire and other properties of the cotton fiber. HVI test report helps to law down the same properties bale before mixing. Mixing is a very important process for spinning.

Introduce with High Volume Instrument

Tests by HVI

  1. Micronaire (Mic)
  2. UHML (Upper half Mean length)
  3. UI (Uniformity index)
  4. SFI (Short Fiber Index)
  5. Fiber strength in g/tex
  6. Elongation
  7. Moisture content
  8. Color (Reflectance Rd, Yellowness +b)
  9. Color grade(USDA upland, Pima or regional customized color chart)
  10. Trash (% Area, trash count) & trash Grade (USDA)
  11. SCI (Spinning consistency Index)

Micronaire (Mic)

The parameter is describing the cotton fiber fineness. Micronaire Ratings: below 3.0= very fine 3.1-3.9 =fine 4.0-4.9 =average 5.0-5.9 = course over 6.0 =very coarse
Upper Half Mean Length (UHML)
Upper Half Mean Length means length by weight of the longer 50% of fibers.

Uniformity Index (UI)

Uniformity Index= length uniformity of the fibers. Uniformity index= ML. 100/UHML Classification of the length uniformity: very low-> below 76 low->77-79 average-> 80-82 high->83-85 very high ->above 86

Strength

Breaking force of the fiber bundle divided by fiber fineness Assessment of the fiber strength in gram per tex <gf/tex> (without long staple) below 21= very low 22 to 24 = low 25 to 27= average 28 to 30=high over 30= very high

Short fiber index (SFI)

Short fiber index =percentage of fibers shorter than 1/2 inch or 12.7 mm

Spinning consistency index (SCI)

A coefficient is calculated by means of various quality characteristics by a multiple regression analysis. The SCI used is calculated with the original formula provided by USTER. The main benefit of the SCI is a simplified selection of bales for a predetermined blend of fibers as well as the long-term check of the say material blend.

Color

Reflectance (Rd) – reflectance of the fibers, higher Rd values mean a higher color grade. Yellowness (+b)-Yellowness of the fibers (Nickerson/Hunter scale)

Trash

Trash Area (Tr Area)
•    Area of the sample covered with trash particles.
•    Trash Cnt (Tr cnt)
•    A number of trash particles in a sample.

Ambient conditions

The standard temperate atmosphere for textile testing according to ISO 139
•    Temperature: -20+_(plus minus) 2 degree C -68+_ 4 degree F
•    Relative Humidity(RH):65+_4%

Written by

A.M. Amirul Islam (Washim)

Facebook: Amirul Islam Washim
E-mail: [email protected]

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Flow Chart of Bale Management

Bale management is the first step of spinning. 40% yarn quality come from bale management. Good bale management give good result in yarn manufacturing. Good mixing depends on good bale management.

Flow chart of Bale management

Raw cotton => Bale-Moisture % test => Collect sample (Every bale) => Sample testing => Classify bale => Bale law down => Mixing

flow chart of bale management

Flow Chart of Bale Management

*Ideal Moisture percentage for cotton fibre 7.5% to 8.0%.
*There three testing of bale sample. HVI, AFIS and trash content

Some properties to determine of cotton bale:

  • Length
  • Strength
  • Fineness
  • Maturity
  • Uniformity
  • Rd (Reflectance/Brightness/Whiteness) + b (Yellowness)
  • Trash content
    *According to test result same properties of bale should lay down for mixing.

Written by

A.M. Amirul Islam (Washim)

Facebook: Amirul Islam Washim
E-mail: [email protected]

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Basic Operation in Blow Room

Blow Room: There are some methods of opening the mass of fibers into small tufts before further processing. This process of opening & clean is known as blow room process. Blow room consists of a number of m/c degree 40% to 70% trash is removed in this section.

basic operation in blow room

Blow Room

Objects of Blow Room Process

  1. To open the compressed layer of a bale of cotton or any staple fibers with minimum damage to the fibers.
  2. To remove the impurities like sand, seed, bits, neps & short fibers present in the cotton with minimum loss of lint by opening & blending.
  3. To effect a through blending with minimum neps formation.
  4. To convert the mass of cotton fibers into a uniform thick sheet of cotton both longitudinally & transversely &fed as it in the case of chute feed system or wound in the form of a compactly built lap with minimum lap rejection.
  5. Intensive de-dusting of cotton fibers to extract micro-dust in order to improve the working of opened spinning m/c.
  6. Fiber recovery from the waste produced by the various processes the conversion of fiber to yarn in order to reduce the consumption of raw material.

Basic Operation in Blow Room

Opening

  • The opening is the first operation required carried out to the stage of flocks in the blow room & to the stage individual fibers in the card flock weight can be reduced to about 0.1mg in the room.

Cleaning

  • The blow room cannot eliminate all or even almost all of the foreign matter in the raw material.
  • A blow room installation removes approximately 40% to 70% of the impurities.
  • The result is dependent on raw material on the m/c s & on the environment.

Dust Removal

  • Dust removal is not easy operation since the dust particles are completely enclosed in the flocks & hence are back during suction.
  • The suction units remove dust 64 dust removal will more intensive the smaller the flocks.

Blending

  • Fibers can be blending at various stages of the process. These possibilities should always be exploited.
  • The start of the process is one of the most important stages for blending.
  • Intensive blending in a suitable blending m/c must be carried out after separate flock extraction from individual bales of the layout.
  • This blending operation must collect the sequentially arriving bunches of fibers from individual bales & mixes them thoroughly.

Even feed of material of the card

  • Finally, the blow room 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 flock feeding installations are increasingly being used.
  • While in the introductory phase such installations were subject to a problem regarding evenness of flock deliver, today they generally operate well or at least adequately.

Written by

Engineer Sheikh Nurja

B.Sc engineer of textile

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Blending in Spinning Mill

Blending may be defined as a condition in which every fibre characteristic is found in the same proportion as in the original blending within every unit cross section of the yarn .Fibre blending has been practiced since the beginning of the cotton textile industry due to the variation in the physical properties of cotton fibres like scrapple length, fineness, strength & cleanliness.

Blending in Spinning Mill

blending in spinning millObjects of blending

  • To achieve uniform quality of product for a longer duration.
  • To improve processing performance, increase yarn strength.
  • To reduce & control cost of production.
  • To facilitate the cotton for regaining its moisture content lost during baling.

Blending procedure

Stages in Blending operation, Blending is carried our three stages:

  • Metering determination & precise establishment of quantities of the individual components.
  • Mixing that is bringing together of the metered quantities.
  • Intermingling distributing the components evenly in the body of fibres.

Types of blending operation

Blending type     

Process stage

Bale Mixing Before the blow room
Flock blending Within the blow room
Lap blending By using scatters
Web blending At the ribbon-lap m/c or the blending
Sliver blending At the D/F,the sliver-lap m/c the comber
Fibre blending At the card or the OE- spinning m/c
Roving blending At the Ring Spinning m/c

Blending Techniques

To achieve homogeneous blend the following techniques were adopted.

  • Lap Blending
  • Card Blending.
  • Bin Blending.
  • Hand-stock Blending.
  • D/F Blending.
  • Massive Blending.

Here detailing about some common technique of blending

Lap blending

The blending technique is still used successfully to permit the blending of cotton of contrasting fiber properties to produce a variety of end users. A doubling scutcher is requires, this has a conveyor lattice in feed on which from four to six laps could be laid. The lap sheets from these laps passed doubled through a beater position followed by pair of cages &lap winding device.

Advantage of Lap blending

Procedure very good transverse blends & also a good longitudinal blend.

  • It is very easy process.

Disadvantages of Lap blending

  • Blend proportions are limited.
  • Need for control of lap wt.

Card Blending

Blending by doubling with laps at the card is sometimes used in high production cards. The procedure involves use of a double lap roll attachment whose feed rolls are positively driven by a link chain by the regular lap roll gear.

Advantages of Card Blending

  • Most intimate blend is obtained.
  • This method is used to randomly mix two laps differing in color.

Disadvantages of Card Blending

  • It can’t be obtained from wide range.
  • Controlled metered blending can’t be carried out.
  • Only make a previously proceeded blend more intimate.

D/F Blending

With D/F blending the card slivers are doubled at the drawing process in a predetermined fashion. The percentage of the blending depends on the number of slivers processed. In processing of cotton this method is not used for blending purposes, but it is the most popular method for blending man-made fiber fiber with cotton.

Advantage of D/F Blending

  • Suitable for blending two different cotton qualities.
  • Provide best blend in the longitudinal direction.
  • Working procedure is not complex.

Disadvantage of D/F Blending

  • Require additional blending passage.
  • Stripiness may be produce in the finished product.
  • Poor transverse blending in the product.
  • Fiber heterogeneity produced.

Written by

Engineer Sheikh Nurja

B.Sc engineer of textile

Merchandiser at buying house

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Mixing in the Spinning Mill

Mixing is the first and important process in the spinning process. Mixing is a process by which different grade of the same fiber is kept together.

Types of Mixing

  • Volume mixing.
  • Bin mixing.
  • Card mixing.
  • Weight mixing.
  • Automatic mixing.
  • Hand stock mixing.
  • Lap mixing.
  • Sliver mixing.
  • Mixing by hopper.

Mixing in the Spinning Mill

mixing in the spinning mill Mixing in a Spinning Mill

Factors to be Considered Before Doing Mixing

Length of cotton

The length of the fibers should be equal otherwise various types of problem will create. Fibers having different length causes the problem in drafting zone &also in simplex or ring frame.

Micronaire of cotton

The second considerable factor for mixing is the micronaire value of fiber, the higher, the micronaire value, the fibers are regarded coarser.

Color of cotton

Color is also a very important factor in mixing. In the case of cotton, it is measured by the brightness of cotton and the presence of yellow color in cotton.

Micronaire CV % of mixing bales

The micronaire CV % of mixing bales should be 5%.

Micronaire deviation

The micronaire deviation of cotton fibers should be (+-0.1) or (+-0.05). Otherwise mixing quality cannot be classified as good quality.

Length deviation

Length deviation should not exceed 10% deviation from mixing to mixing for the same lot.

Color deviation

in mixing, two lot of adjacent color can be mixed, such as white and light spotted or light spotted and can be mixed. But white and spotted cannot be mixed.

Lay down

Every cross section of the laydown plant should be the same. Which means average micronaire value should be controlled in every cross section.

Written by

Engineer Sheikh Nurja

B.Sc Engineer of Textile

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