Draw frame

 Drawframe is a machine in spinning line which comes
after blowroom and carding machine.
 The main operation which is followed by drawframe is
Drawing by which slivers are blended, doubled and
levelled.
 Drawframe is the definitive compensation point for
eliminating errors.
 High performance drawframes currently produce over 400
kg of sliver per hour at each delivery.

 Equalizing: One of the main tasks of drawframe is improving
evenness of the sliver by drafting and doubling.
 Parallelizing: To straighten the fibers and to make them parallel
to the central axis for obtaining an optimum value of yarn strength.
Every drafting step leads to straightening and parallelizing of the
fibers for better orientation.
 Blending: To blend raw materials of same hank perfectly.
 Dust removal: With removing irregularities from carded slivers,
It also removes dusts from slivers.
 Hook Removal: The card sliver contains more trailing hooks
than leading hooks. In drawframe, Trailing hooks are removed and
leading hooks are present in feed sliver.

CONVENTIONALDRAWFRAMEMODERNDRAWFRAME

 Drawframe consists of four
sections:
 Creel Section
 Drafting Section
 Sliver condensing section
 Coiler Section

 Sliver fed:6 – 8
 Draft: 5 – 8
 Drawn sliver can
capacity: 15-22 kg
 No. of heads:
Single/double
 Delivery Rate: 350-800
m/min
(Generally,Two production
heads are common and
Sliver may be fed in from
up to 8 cans per drawing
head)

 Elements of Drafting arrangement-
 Bottom Rollers : -made of steel (metal)
-mounted in roller strands/frame by means of
needles, rollers or ball bearings.
-positively driven from the main gear transmission.
-formed with flutes to improve the ability of
carrying fibers along.
 Top Rollers : -made of steel and covered with thick coating of
synthetic rubber.
-not positively driven.
-Soft rubbers coating can grip the fibre strand
more perfectly than that of hard one, but soft
one wears out more quickly.
 Top roller pressure: To clamp the fibers, the top rollers must be forced at
high pressure towards the bottom roller. The pressure can be generated
by dead weights, spring weighing e.t.c.

The reduction of weight/yard of sliver and increase in length is called
drafting. Or Attenuation of sliver without breaking is called draft.
If we consider a 3-over-3 roller drafting arrangement,then-
 The zone between back rollers and middle rollers is known as ‘Break
Draft zone’.
 The zone between middle rollers and front/delivery rollers is known as
‘Main Draft zone’.
 The Draft between the back rollers and middle rollers is known as Break
draft (usually 1.25-1.8) and the draft between middle rollers and delivery
rollers is known as Main draft.
 V1,V2,V3 are the surface speeds of back, middle and front rollers and
V1<V2<V3 . Here the rollers diameters are same so
delivery roller speed(rpm)
Draft= feed roller speed(rpm) , thus, Break draft= V2/V1 ,Main draft = V3 /V2
Total Draft of 3-over-3 drafting system = Break draft * main draft = V3 /V1

 Factors dependent upon
the fiber materials-
 mass of the fibers in the
strand cross section.
 degree of order of the fiber.
 length of the fiber.
 compactness of the fiber
strand.
 twists present in fibre strand
etc.
 Factors dependent upon the
drafting arrangement-
 diameters of the rollers.
 hardness of the top rollers.
 pressure exerted by top rollers.
 clamping distance.
 level of the draft.
 type and forms of fiber guiding
devices such as, pressure nods,
pin bars, condensers etc.

It is the force required to accelerate a bunch of fibers.Due to acceleration of
the fibers, attenuation is carried out from slower speed (back roller) to
greater speed(front roller).
It is heavily dependent upon :
 Fibre length
 Arrangement of fibres in the cross section ( parallel or crossed)
 Cohesion between fibers
 Nip setting
 Area of overlapping region (higher the area, more force is needed)
What is Ideal Drafting?
It is defined that the fibers should move with the speed of the back roller until
and unless it is gripped by the front roller nip.

 In a drafting system 6 or 8 slivers are fed together which is known as
number of doubling. So, if 8 slivers are fed to the drafting system, then the
number of doubling is 8.
 In Drawframe, the no. of doubling and the total draft is almost equal.
 As per requirement of sliver delivered, practically total draft is lesser or
higher than no. Of doubling.
- If our requirement is to get coarser sliver, here draft is reduced and the
value of draft is lesser than the no. of doubling.
- If our requirement is to get finer sliver, here draft is increased in such a
manner that the value of draft will be greater than the no. of doubling.
 So, in practice the total draft may be greater or equal to the no. Of doubling.

 It is expected that the thick places of one sliver will be
compensated by the thin places of neighbouring sliver or
vice-versa.
 So, the irregularity of delivered sliver is less than the
irregularity of feed sliver.
If, CVi is the co-efficient of variation of input sliver, CVo is
the co-efficient of variation of output sliver and n is the no.
of sliver fed( no of doubling),then-
 CVo = CVi /√n [ here added irregularities is
considered as 0]

 Generally two drawframes are used in industries in
random.
 The First drawframe is known as ‘Breaker Drawframe’. It
removes the card sliver irregularities.
 The second drawframe is known as ‘Finisher Drawframe’.
It removes the drawn sliver irregularities.
Problems of using higher no. of drawframes-
• Power and labour consumption
• Space requirement
• High initial investment

 Autoleveller is an additional device which is meant for
correcting the linear density variations in the delivered
sliver by changing either the main draft or break draft of
the drafting system, according to the feed variation.
 It maintains the consistent hank of sliver or count C.V% ,
hence the yarn will be suitable for dyeing evenly and
knitting.

There are two types of
Autolevelling systems. They
are-
-Open loop system
-closed loop system
 Most of the autolevellers which
are incorporated in the
Finisher Drawrframe are
open loop auto levellers.
 In open loop autolevellers,
sensing is done at the feeding
end and the correction is
done by changing either a
break draft or main draft of the
drafting system. In closed loop
system sensing is done at
delivery side.

 Condensing:-
Delivery roller converging tube(1) trumpet guide(2) calender roll
(passes the fiber(collects them)(condensing) (compressing and
web to 1) depositing to coiler)
 Coiling:
Calender rollers Coiler tube(fixed on Cans(rests on rotating plates)
(passes drawn sliver)  the coiler plates ) (coiler gears fixed on
coiler plates, helps to
rotate the coiler tube so
the sliver can be laid in
the cans in forms of coils)

 Automatic Can Changer:
For the efficiency the modern
drawframe is equipped with two
completely independent automatic liner
can changers. The empty can magazine
contains two cans per side. The cans
are transported through the machine
from the rear to the front.
 Efficient Suction system:
Additional succession position in the
sliver feed i.e before scanning of the
autolevelling ensures optional sliver
purity and less cleaning already at the
beginning of the drafting process.

NAME: SUBARNA DEY
STREAM: TEXTILE TECHNOLOGY
ROLL: 11101417009
SUBJECT: YARN FORMATION III ( TT-
601)
YEAR: 3rd YEAR
SEMESTER: 6th SEMESTER

Draw frame

Draw frame

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