Process Control in Cotton Mixing

Process Control in Cotton Mixing

These two lectures answer the following questions:

1. How can I decide about cotton mixing for denim.

2. How can I decide about cotton mixing for making knitted fabric.

3. What is information required for an optimum cotton mixing.

4. What is an ideal cotton mix.

5. What are the steps to create an optimum cotton mix.

6. What are the four components of yarn quality. How each of these is affected by fiber quality.

7. What values of yarn quality parameters can be obtained from a cotton mix of particular fiber attribute.

8. For some pre specified values of yarn characteristics, what are the average values of fibre attributes that we should in cotton mix.

9. What are the various problems due to cotton mixing vairations, case study of fabric barre.

The answers to the above questions will be found here.

FAQ in cotton spinning-4

FAQs in Cotton Spinning
Q. Discuss about the feed rolls used in opening machine with given headings.
(i) Definition, (ii) Construction, (iii) Fundamental, and, (iv) Types of feeding
Q. Define the beater in opening machine.
Q. What are the objects of beater?
Q. Express the drafts and their calculation. What is the difference between the actual draft and mechanical draft?
Q. What are the objects of carding? How are these objects fulfilled
Q. What is meant by card clothing? With a neat sketch show the parts of a card clothing.
Q. What is meant by neps in carding?
Q. Mention and briefly explain the factors in judging the quality of carding.
Q. What are the effects of doubling
Q. Explain about the function of drawing rolls used in drawing frame.
Q. What is meant by cotton combing?
Q. What are the objects of combing? Explain briefly how these objects are fulfilled.
Q. List the various yarn characteristics improved by combing.

Please see the answers to these questions here

FAQ in cotton Spinning-3

FAQ in cotton spinning-3

Q: What are condensers, what is their role ?
Answer: These are perforated cage rollers. They supply a current of air at a high velocity, convey the cotton uniformly from stage to stage and incidently, perform a bit of cleaning by carrying away the floating dust, impurities and short fibres to a separate collection centre.

Q. What is difference between the conventional and the modern blow room lines.
Answer: Modern blowroom lines have more opening points and fewer beating points.

Q. What is the object of carding.
Answer: The objects of carding are three:
1. To open out thoroughly the tiny lumps so that every fibre becomes individualised and the cotton is no more in an entangled state.
2. To remove all impurities, neps, short fibres etc. which have escaped the blowroom action.
3. To prepare the well cleaned material into a compact sliver form and lay into containers for subsequent processes.

Q. Name the three major regions where cleaning takes place.
Answer: Taker-in and flats.

Q. What are the constituents of flat strips.
Answer: The flat strips are mostly short fibres with some of the impurities like kitty leaf bits etc.

Q. Why speed of licker-in is kept less for longer staples.
Answer: Longer fibres are held for longer time by the bite of the feed roller after the licker-in starts working on them. As a result more teeth act on the fringe of the fibres and there is every chance of fibres getting damaged.

Q. What is back plate. What is its function.
Answer: This ia a curved plate covering the cylinder just above the licker-in and its main function is to keep the fibre bunches delivered by licker-in, remain on the cylinder wire till they are taken by the flats. This also helps to prevent the development of undesirable air currents.

Q. What is front plate. What are its purposes. Why it is called percentage plate.
Answer: This is a plate similar to back plate and is fitted at the front just above the front door. This has a three fold purpose namely:
1. To keep the cylinder surface covered in order to prevent the fibres from flying off.
2. To keep all other material away from cylinder.
3. To provide the opening for stripping and grinding the cylinder.

It is known in America as 'percentage plate' as its adjustment helps to regulate the quantity of flat strips.

FAQs in cotton Spinning-2

FAQs in Cotton Spinning

Question: What are the causes of Cotton Fibre degradation

Light in the presence of moisture has a degrading effect on cotton fibres. Heat also affects strength, stretch and life of cotton.

Q: What are neps. How they are formed

Neps are fine specks in the form of tiny balls of entangled fibres. They are formed due to bad mechanical processing conditions. Longer and immature cottons are more prone to neppiness.

Q: What are naps. Hw they are different from neps


Naps contain fibres whcih are entangled together, but much more loosly than those in neps. A nap can open out while it is not possible to open out a nep.

Q. What is the necessity of a blowroom.

Textile mills are generally located far away from the fields where cotton is grown. Therefore, compressing loose cotton into a compact bale form is unavoidable for economic transportation. This cotton has to be opened in the blowroom.

Also during picking and ginning quite a number of impurities get associated with such cotton, to remove all such impurities from the cotton, blowroom sequence of machines is quite necessary.

Q. Why there are so many machines in the blowroom sequence

The real work of opening, cleaning and blending is done by the blowroom machines. The action of opening and cleaning should be gradual. Therefore, a number of machines are required which gradually open and clean the cotton. The machines in the beginning of the line are mostly expected to reduce the lump size, and the latter machines are expected to open out or still reduce the size of fringes or tufts.

Q. What are lattices in blow room line, what is their purpose

Lattices are made up of wooden legs which are either plain or spiked. Horizontally arranged lattices are mostly plain while spiked ones are meant for lifting purposes. They help to move the cotton ahead in regular and uniform quantities.

Q. What is the purpose of beaters.

The object of beating is to shake out the impurities and force them through specially arranged gridbars and perforated sheets.

Q. Why a three bladed beater is better than a two bladed beater

It is heavier in weight and each blow is more forcible than a two bladed beater. Besides, it gives 50% more beats, which means that this can be run at a lower speed than a two bladed beater and incidently reduces vibrations, wear and tear in the machine.