This document summarizes information about an autoleveller, stop motion, and defects in a draw frame. It discusses that an autoleveller helps correct linear density variations in sliver by changing the main or break draft to achieve consistent count CV%. It then describes open and closed loop autolevellers. Stop motions are designed to immediately stop the machine if a mechanism fails. Common defects in draw frames include thin or thick sliver, irregular drafting, roller lapping, and excessive breaks.

1. YARN MANUFACTURING-II ASSIGNMENT
BRANCH-T.T SEMESTER-IV SESSION:2018-19
TOPIC- AUTOLEVELLER , STOP MOTION AND DEFECTS IN DRAW FRAME
SUBMITTED BY- SUBMITTED TO –
 TANISHQ AWASTHI , UDAY BHAN VERMA MR. SHUBHAM JOSHI SIR
 VAIBHAV SINGH PANWAR , VIKASH SHARMA
 VIVEK SHANKHWAR , GOURI DUBEY
 DEEKSHA MALHOTRA , PRIYANSHI GUPTA

2. AUTOLEVELLER
 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 is an online monitoring device in spinning
process.
 It helps in achieving consistent count CV%.
 The high performance draw frame is the only one
equipped with autoleveller and fully digital
electronic draft system.

4. Object of Auto leveling:
Theobject of an autoleveller is to measure
thesliver thicknessvariations&
thencontinuouslyto afterthedraft
accordinglyso thatmore draftis applied to
thickplaces & less to thinplaces withthe
resultthatthe sliver delivered is less irregular
thanit,otherwisewould havebeen. Besides
animprovement in production appearance,
autolevelling canalso contributeto better
productive efficiency, fewer end-breakages
in subsequentprocess, less waste& constant
process conditions.

5. There are two types of
autoleveller-
 Open loop autoleveller.
 Closed loop autoleveller.

6. The open loop control principle, which can be used for the
correction of fairly short term variations, where the solid
lines indicate the flow of fibres through the m/c & the broken lines
represent to flow of information in the autoleveller unit. The control
unit compares the measurement signal with the reference signal
which in this case represents the mean output reqd. The control
unit accordingly increases, leaves unaltered, or decreases the
output of the regulatory which in turn provides a variable speed to
the back of front rollers of the process to give the reqd draft when
the measured mtl has reached the point at which draft is applied.
The magnitude & direction of each change in draft is determined by
the magnitude of the change of count previously indicated by the
measuring unit. Most of the drawframe autolevellers are open loop
auto levellers.

7. The closed loop principle is used for the correction of long
term & medium term variations. Again the measurement
signal is compared with the reference signal by the control
unit which then determines the output of the regulator
which provides the variable speed to the process to give
the reqd draft. It is immediately apparent that the control
unit contunually cheeks the results of its own actions
because measurement is taken from the product of the
process. Because the flow of fibres in the process forms
part of the control loop, this means that the amount of
control which can be applied is restricted not only by the
limitations of the control unit itself, but the characteristics
of the process.

8. ADVANTAGES OF AUTOLEVELLER
 All variations are corrected.
 Count c.v.% will be consistent & good, hence the yarn will be suitable
for knitting.
 Ring frame breaks will come down, hence pneumfil waste will be low.
 Fluff in the department will be less, therefore uster cuts will be less.
 Fabric quality will be good because of lower number of fluff in the
yarn.
 Labour productivity will be more.
 Machine productivity will be more.
 Idle spindles will be less.
 RKM c.v.% will be low, because of low number of thin places.
 Workability in warping & weaving will be good, because of less no. of
thin places & lower end breaks in spgn & winding.
 Low sliver U%, hence yarn U% will be good.
 Production will be more accurate in autoleveller draw frame
compared to non autoleveller draw frame.
 Variation in Blend percentage will be very less, if both the
components are autolevelled before blending, hence fabric
appearance after dyeing will be excellent.

9. HIGH SPEED DRAWFRAME WITH AN
AUTOLEVELLER

10.  The basic function of any
stop motion is to stop the
machine when any of its
important mechanish
fails.
 Generally it is a device
which provides to ensure
the machine to be
stopped immediately
when any of its basic
mechanism fails.

11.  The sliver runs out of the creel can.
 Sliver breaks in the creel.
 Lap up on drafting rollers.
 If sliver is choked in sliver collecting plate
and funnel.
 If sliver chocked between calendering and
trumpet.
 If delivery can filled with sliver.

12.  Considerable damage may cause to machine.
 The output sliver may be thick or thin.
 Lapping up on drafting and calendering
roller.
 Irregular drafting.
 Excess of full can.
 Too much waste production.
 Yarn or roving strength may vary.

13. There are many defects in drawframe, from which some are
described below-
Fine sliver or end missing: any sliver may break when doubling is 5 to 6;this
is known as fine sliver or end missing. The causes of this fault may be
1- faulty stop motion device.
2- operators carelesness.
Irregular sliver: for two reason the sliver may be irregular, these are-
1- roller slip.
2- defective drafting system.
Long fibre in the waste
Roller lapping: The causes of roller lapping are-
1- improper cleaning of the roller.
2- improper temperature and relative humidity.
Excessive sliver breaks: causes are feed zone, draft zone, delievery zone

14.  Improper stock filling.
 Thick and thin places.
 Uneven web.
 Bad coiling.

15.  https://textilelearner.blogspot.com
 https://nptel.ac.in
 https://www.definetextile.com
 A book by W. Klein.
Thank you!