Weft yarn picking process in loom

1. Group members:
Md. Al Amin
Bsc in textile engineering
Daffodil International University
Welcome
To
Our Presentation
Topic: Picking & its Classification

2.  Pick:
Pick is a single weft thread in fabric as
woven.
 Picking:
The process of passing through warp shed
during weaving is called picking. It is the 2nd
primary motion in weaving.

3. Objective of picking:
To insert the weft through
the shed.
The shuttle must travel in
the correct flight path.
To maintain pick spacing/PPI

4.  Negative picking
 Positive picking
1. over picking
2. Under picking
 Over pick mechanism - Cone over pick mechanism
 Under pick mechanisms –
a) Side-lever under pick mechanism
b) Side-shaft under pick mechanism
c) Cone under pick mechanism.

5. In this mechanism, a carrier known as shuttle
carries the weft yarn in a package called the
“pirn”.

6. A picking tappet, driven by the
bottom shaft and carrying a nose
bit, hits a cone, which in turn
drives a vertical shaft. From
here, the motion is transmitted
to the picker through a picking
stick and picker. The picker
pushes the shuttle into the shed.
Overpick mechanism

7. bottom shaft
↓
picking lever
↓
The picking arm
↓
shuttle moves
↓
Picking is done
↓
move back after the
delivery of a pick.

8. In this mechanism, a circular disc carrying a bowl is
driven by the bottom shaft. The bowl hits a shoe, which
in turn depresses a side lever, and the picking stick is
driven. So the picker is pushed and the shuttle is pushed
out of its box into the shed.
Under pick mechanisms

9. A disc carrying a bowl is driven by the bottom shaft. The
bowl hits a shoe, which in turn drives the picking stick
though a side-shaft lever and connecting lever. The picker
is pushed and the shuttle is shot out of the shuttle box into
the shed.
Under pick mechanisms

10. The nose of a picking tappet, driven by the bottom
shaft, hits a cone, which in turn drives a side shaft.
This in turn pulls a lug strap and picking stick. The
picker, connected to the picking stick, is pushed and
so the shuttle emerges from the shuttle box and
traverses the shed.
Under pick mechanisms

11. In throw shuttle process weft yarn is pas one
side to another side completely by hand

13.  In this mechanism, the weft yarn is inserted
through the warp shed directly or positively
by air, water, a projectile, a rapier or a
needle

14.  a small depth of shed
 Low Warp thread breakage.
 Pirns are not required.
 saving in floor space and labour.
 Produce high quality fabric

15. 
1. increasing motor seed.
2. increasing the nose shape of picking
tappet.
3. decreasing the length of picking arm.

16. 1) PROJECTILE(GRIPPER):-
The picking action is accomplished by a small Bullet like
Gripper(Projectile), which grips the weft yarn & carries it
through the shed.
Several gripper are normally used in the loom , while one is
crossing the loom with the weft yarn, the others are return to
the starting position. The return by conveyer chain.

17.  Low power consumption
 Reduced waste of filling
 Quick warp and change style
 Easy operation ,
 maintenance and low spare parts requirements
 Energy saving
 Different designs and color sequences can be
woven.
17

18. DRAW BACK OF PROJECTILE:-
The dragging of the weft yarn across a loom
creates strain on the yarn so projectile loom are
not suitable for weak yarn.

19. 2)RAPIER:-
A Rapier loom use a Rapier to pull the weft yarn across the loom.
For a single Rapier a long rapier device is
required to extend across the full width of
warp.
Two rapier enter the shed from opposite side of
loom & transfer the weft yarn from one rapier to
another rapier near centre of loom. Double
Rapier further divided into two categories 1)
Flexible Rapier & 2) Rigid Rapier

21. 3) AIR JET ;-
A loom in which the weft yarn is propelled through the shed by
means of a jet of air. Nozzle are used to insert the weft yarn into
the shed. The Fabric width of Air Jet loom is normally narrower
than Rapier or Projectile loom.
DRAW BACK;-
Air jet loom cannot produce great variety of fabrics.

22.  Multiphase loom continually inserts weft
yarns from yarn carriers.

23. 4) WATER JET LOOM:-
In this water is shoot under high force & with it a weft yarn.
The force of water as it propelled across the shed cross the yarn to
opposite side ..
In water jet unit use vacuum suction & heat to remove
water from the fabrics.
Only use for Hydrophobic fibres.

25.  High Efficiency
 Low Maintenance
 Smooth and Quiet
 Total Safety