1. Blow room is the first step of yarn
production in the spinning mills.
Basic operations in the blow-room:
opening
cleaning
mixing or blending
micro-dust removal
uniform feed to the carding machine
Blow room
2. Blow room installations consist of a sequence of different
machines to carry out the above operations.
Moreover, since the tuft size of cotton becomes smaller
and smaller,
The required degree of processing necessitates different
machine configuration.
Cont.….
Opening separates the compressed masses of staple into loose
tufts and removes the heavier impurities.
Opening
3. Cont..
The working hypothesis of opening
is illustrated by calculation of the
theoretical tuft weight curve starting
from the bale, up to the cylinder of
carding.
How?
5. It is necessary to open more & more surfaces by opening devices
Then remove the impurities from the newly created surfaces.
Various types of grid bards are used for this purpose.
In addition, air flow is also used to separate the trash from fibers.
Suction devices are also used for separation of trash and dust.
Various types of cleaning devices are:
Cleaning by Grid
Cleaning by Air
Cleaning
7. Some Technological points connected to opening and cleaning
The larger the dirt particle, the better they can be removed.
Higher the degree of opening results in higher the degree of
cleaning.
Higher roller speeds give a better cleaning effect, but also more
stress on the fiber.
The degree of cleaning is strongly dependent on the TRASH %.
It is also affected by the size of the particle & stickiness of cotton.
Therefore cleaning is always an important basic operation in
modern blow-room.
8. opening device
fiber alignment
speed of the opening device
degree of penetration thickness of the feed web
density of the feed web
size of the flocks in the feed
area of the grid surface and grid settings
ambient R.H.% and ambient temperature etc.
General factors which affect the type of degree
of opening , cleaning and fiber loss are:
9. Amount of trash in raw cotton – Trash in lap
D.C = …………………………………………… * 100
Amount of trash in raw cotton
Degree of cleaning(D.C) of the machine is the ratio of the trash
removed by the machine to that of total trash fed to the
machine, expressed as percentage.
Degree of cleaning
Mixing or Blending
Blending:
When different fibers of same/
different grades are kept together,
then it is called blending.
Mixing:
If different grade of same
fibers are kept together, then it
is called mixing.
10. Almost all manufacturers of blow room machinery now offer
dust-removing machines or equipment
In addition to opening and cleaning machines.
The dust is mainly removed, due to high fiber to metal friction
or high fiber to fiber friction.
Micro-dust removal
Uniform feed to the carding machine
Finally, the blow room must ensure that raw material is
uniform deliver to the carding.
11. Magnetic extractors: This is used in order to remove ferrous
metals mixed with material.
Fire eliminators: This consist spark detector & eliminating device.
Foreign matter detectors: It would intercept or prevent foreign
matter in the opening and cleaning line, beginning of the spinning
process in order to prevent fibrous contaminants.
Associated equipment
12. Some general recommended process conditions in blow-room
It is advisable to run the fans at optimum speeds and reduce the
number of fans in the line
All blow-room machines should work with maximum efficiency.
Number of cleaning points are decided based on type of ginning.
Machinery selection should be based on the type of cotton and
production requirement.
Grid bars should be inspected periodically, damaged grid bars
should be replaced.
Fiber rupture should be checked for each opening point
13. Carding
In the yarn manufacturing process, carding comes after opening
and cleaning of fibers at blow room.
Carding process is considered, so important that carding is often
called “the heart of spinning”.
Individualization of fibers
Elimination of impurities
Elimination of dust
Reduction in neps
Fibre mixing/blending & Sliver forming
Objectives of Carding
14. Individualization of fibers
Carding is done primarily to individualize fibers.
Blow-room machines open fibers in the form of flocks and
A card will be a finishing operation of opening by individualizing
them.
Elimination of impurities
The degree of cleaning of card is achieved up to 80-90 % in the
modern carding machine.
The over-all degree of cleaning achieved by the blow room and the
carding together is as high as 95-99 %.
But, card sliver still contains 0.05-0.3 % of trash and other foreign
matters.
15. Reduction in Neps
Number of neps in fibres increases in the blow-room.
In carding, neps are drastically reduced.
This can be attributed largely to the un-entanglement of
neps rather than removal of neps during carding action.
Elimination of Dust
Dust removal requires significant fiber/metal and
fiber/fiber friction; since, both are available in carding.
Fiber Blending
There is a repeated rotation of fibres in the card cylinder before
it is removed by the doffer, the time spent is very small.
So, there is not much longitudinal blending in carding.
However, sufficient transverse blending takes place when web
is condensed in to a sliver.
16. Sliver Formation
Card forms a bulky sliver of overlapping and partially aligned
fibres.
The linear density of card sliver has hank from 3 ktex (new
spinning processes) to 6 ktex.
General, the hank lies b/n 4 and 5.5ktex in the spinning mills.
Functional Zone of carding
Generally there are four
functional zone of carding
Feeding zone - feed roller
Cleaning zone- licker-in
Carding zone- cylinder & flat
Sliver formation zone-doffer
17. Draw frame
Draw frames are used after carding in yarn manufacturing process.
In the case of combed yarn manufacturing, draw frames are used
before as well as after combing.
Objectives
Improvement in material
evenness
Parallelizing fibers
Blending
Dust removal
Improving Evenness
It is done in two stages; at breaker
and at finisher draw frames.
Therefore, two passages of drawing
with eight ends (sometimes six) each
time would produce a single sliver
consisting.
18. Parallelization
To achieve an optimal value for the strength of yarn, fibers must
be arranged parallel to each other & along the axis of yarn.
Draw frame fulfills this task by way of the drafting rollers.
Mixing and Blending
Drawing is the final stage of quality improvement in a spinning
plant before yarn is spun.
This is by providing the degree of compensation of raw material
variation by blending.
This result is exploited in particular, in the production of blended
yarns consist of cotton/synthetic blends.
19. Dust removal
Draw frame is a machine where a very high degree of fiber/fiber
friction takes place in the drafting zone; so it lead separating dust.
Many modern draw frames have appropriate suction removal
systems; more than 80% of the incoming dust can be extracted.
Elements of the draw frame
Creel (sliver feed)
The drafting system
Delivery and coiling
20. Combing
Elimination of a precisely pre-determined quantity of short fibers.
Elimination of remaining impurities after blow-room and carding.
Elimination of large proportion (not all) of the neps in the fiber
To straighten the fibers
Formation of a sliver having maximum possible evenness.
21. Roving frame
Objective
Attenuation: drafting the sliver into roving.
The drafting arrangement in the roving frame attenuates the slivers
with a draft between 5-20.
Twisting: Twist of 30-65 per meter is usually provided in the roving
frame.
Winding: the twisted roving on a bobbin.
22. In cotton yarn production there are two main spinning systems
which are used for the production:
Ring spinning system,
OE rotor spinning system
Apart from these systems, there are new yarn spinning systems
Friction spinning systems
Air jet spinning systems
Spinning
The final stage of producing yarn.
23. Functions of Ring frame
The ring spinning machine is designed to :
To attenuate the roving until the required
fineness is achieved.
To imparting strength to the fiber strand by
inserting twist.
To wind up the resulting yarn in a suitable for
storage, transportation and further processing.
The main spinning arrangements are:
1- Drafting arrangement
2- Spindle
3- Ring and traveler
24. OE rotor spinning
Tasks of rotor spinning machine
Opening almost to individual fibers (fiber separation)
Cleaning
Combining (forming a coherent linear strand from individual
fibers)
Ordering (the fibers in the strand must have an orientation as far as
possible in the longitudinal direction)
Homogenizing to improve evenness
Imparting strength by twisting and
Winding to a cylindrical(weaving) or conical(knitting)cross-wound
packages
26. Post-spinning processes
Winding
Bobbins from a ring frame contain too little yarn to be useful in
modern fabric making equipment and,
It is necessary to rewind the yarn onto larger packages.
It is very important that the yarn which is to be sold or used in a
subsequent process should be ‘put up’ into the correct sort of
package–usually cones, cheeses, or occasionally, hanks.
The transfer of yarn from the ring tube to the cheese or cone
provides an opportunity to remove yarn faults.
27. Winding is carried out for the following purposes:
To change the type of wind.
To change the package density.
To remove yarn faults.
To create a package which is not influenced to damage.
Plying
For sewing threads, as well as certain speciality and industrial
yarns, it is necessary to ply (i.e. to double or fold) the yarns to
give them a smoother and less hairy character.
Doubling improves the evenness; plying balances torque if
carried out correctly and binds some of the hairs on the
component yarns.
28. When, smooth cotton yarns are required, as in sewing thread,
they are sometime singeing (or ‘gassed’) to remove the hairs.
Such yarns are often two-ply; long-staple cottons are frequently
used to give maximum strength and resistance to abrasion.
Singeing
Waxing
It is applied in some machine specially winding in order to
reduce the effect of friction on yarns, Ex Candle.
Oil is applied through a device located on spindle head and
comprising/consist a tank and a bush that, by capillary action,
allows the oil to rise, reaching the yarn contact zone.
