Lab Report # 09
Submitted By:
Esha Nazir 2021-TXE-04
Aqib Shabbir 2021-TXE-05
Bilal Ikhlaq 2021-TXE-06
Subject Name & Code:
Weaving Mechanisms and Advancements (TEX-302L)
Submission Date:
22/11/2023
Submitted Date:
Dr. Usama Bin Humayoun
Department of Textile Engineering
University of Engineering and Technology Lahore
Faisalabad Campus
Table of Contents
Abstract..........................................................................................................................................................3
Introduction:...................................................................................................................................................3
Nature of weft break..................................................................................................................................4
Experimental..................................................................................................................................................4
Material......................................................................................................................................................4
Procedure...................................................................................................................................................5
Result and discussion.....................................................................................................................................5
Conclusion.....................................................................................................................................................5
References......................................................................................................................................................6
Title:
Observation and understanding setting of weft insertion on Air jet loom
Abstract:
In this lab weft insertion on an air-jet loom was seen and its process understood. To examine the effects
of yarn characteristics on yarn velocity, several yarns were tested under the same laboratory
conditions.. Relationships between total insertion time, yarn velocity, air velocity, and distance were
found for each yarn.
Introduction:
The control for predicted weft insertion. The essence of the new design is based on the idea that a
particular nozzle should only continue to function when the weft tip of that nozzle is passing through its
active sector. To do this, it is first required to determine the weft tip's transient position during the
insertion cycle. [1]
Sensor of Yarn Position The weft tip position during the insertion cycle can be found using a variety of
techniques. Fixing optical sensors along the insertion path is one method. Since the entire unit is moving
during the insertion and beat up, this method produces exact results but is costly and challenging to apply.
Other options involve measuring the weft yarn's velocity as it exits the feeder and then numerically
integrating the outcome. Since the yarn's elongation also affects the length of the weft root that exits the
feeder, this approach clearly contains an inherent inaccuracy. [2]
Nevertheless, three different kinds of sensors were examined in this area because of how easily they could
be implemented. The first relied on the correlation between two signals that were collected using laser
sensors. At weft yarn acceleration, which may reach 2000 G, this principle was unable to produce
consistent results. An electrostatic sensor that was conveniently positioned at the feeder output was the
subject of the second principle, which dealt with spatial frequency filtering. However, a variety of yarns
that are difficult to charge electrically caused this sensor to perform inaccurately. The installation of nine
optical sensors on a disk at the feeder output produced the greatest results. Every time the weft yarn
breaks a laser beam, these sensors send out a pulse.
Figure 1:Operating principle of Air jet loom
Nature of weft break
Broken Pick: Broken pick is measure problem or the measure fault in the textile industries. It completely
affects the production of the company products. It is necessary to avoid this problem or the fault in
machine. So By using the standard air pressure it may reduce or minimizes the fault.
Bend Pick: Bend Pick is the fault which arising due the air pressure where the yarn is distract. It may
create the problem yarn is its original position and it not goes to its destination due to that air pressure. So
it is entanglement of shed. That’s why use of the proper pressure of the main nozzle and relay nozzle.
Short Pick: Though the prewinder is used, slippage in the friction of the drag rollers could cause a
problem. Cleanliness of the stopper is another reason for a short pick. Any observation in the passage of
weft would cause a short pick.
Loose pick: In this case loom will not be stop but woven cloth will be defective as weft yarns will be
shown in
Left hand side.
1. Low air pressure on main or sub nozzle.
2. Delay beating time, short lead angle of main nozzle.
3. Discrepancy in weft yarn, thickness or other defect may be present in yarn.
4. Air jetting time of main nozzle either more or less.
Experimental
Material
Air jet loom
Weft yarn
Procedure
The profile reeds with sub-nozzle systems are the most beneficial for the weft insertion mechanisms of air
jet looms because they enhance high speed weaving and enable greater cloth width. In this method, the
flying state of the yarn at weft insertion is directly related to not only the airflow from the main nozzle
and sub-nozzles but also the airflow in the weft tube. The best weaving conditions must be established in
order to use air jet looms to produce high-quality fabrics. Depending on the kind of well yarn, these
criteria include the supply air pressure and air injection timing for the main nozzle and sub-nozzles.
Figure 2:Airjet loom feed filling mechanism
As shown in Figure 1, the filling is fed by the air jet loom. One loom rotation is used to determine the
filling length based on the fabric's breadth. It enters the air guide of the reed after being accelerated by the
main nozzle at a precise moment. Sub-nozzle clusters can be seen all the way across the breadth.
Compressed air is blasted from each group in a precise order to feed the filling tip to the fabric's right end.
The compressor provides the compressed air, which is then stored in the appropriate tank after its pressure
is adjusted by the regulators for the main nozzle and the sub-nozzles.
Result and discussion
Weft Breakage Study for Cotton Yarn: For 40Ne cotton yarn, lowering the main nozzle's air pressure
results in a 40% decrease in CMPX filling. This is followed by bringing the main and relay nozzles' air
pressures into sync. Because coarser yarns are more hairy than finer yarns, they require lower air pressure
values to propel the weft during insertion.
Additionally, adjusting the shed crossing timing for finer yarns (80Ne and 100 Ne) as weft results in a
modest decrease in the filling CMPX value. This is due to the fact that closing the shed too soon will
cause the weft yarn in the warp yarn in the shed's upper layer to arrest.
Conclusion
When air jet picking, compressed air is used to propel the weft yarn. To make it easier to remove any
leftover weft yarn, the machine stops if the weft yarn is not entered all the way. Weft transfer failure
during picking may be impacted by air pressure, nozzle settings, and shed opening timings. Therefore, it
is crucial to optimize these parameters in order to control filling breakages when it comes to polyester and
cotton weft yarns.
References
[1] a. a. muhammad, "Analysis of Air Flow in Air-Jet Filling Insertion,," pp. 257-265, 2005.
[2] adanur, " Analysis of Air Flow in Single Nozzle Air-Jet Filling Insertion," vol. 2, pp. 401-406, 1998.
