Fabric Manufacturing Engineering-

II Primary Motions

JAHID KHAN
LECTURER,

DEPATMENT OF TEXTILE ENGINEERING,

PORT CITY INTERNATIONAL UNIVERSITY.
Fabric
A manufactured assembly of fiber and/or
yarn produced by interlacing, interloping,
interbonding or intralooping having
substantial surface area which is
thousand times in relation to it’s thickness
and have sufficient cohesion to give the
assembly useful mechanical strength.
Types of
Fabric
 Woven Fabric (Produced by Interlacing)
 Plain Weave Fabric
 Twill Weave Fabric
 Satin/sateen Weave Fabric
 Knitted Fabric (Produced by Interlooping)
 Warp Knitted Fabric
 Raschel
 Tricot
 Chrochet
 Milanese
 Weft Knitted Fabric
 Single Jersey
 Rib
 Purl
 Interlock
 Non Woven Fabric (Produced by Interbonding)
 Braid Fabric (Produced by Intralooping/Intertwisting)
LOOM
:
 Loom is machine or device which is used to produce woven
fabric. It is the central point of whole process of cloth
production.

It is a device used to weave cloth. The basic purpose of any loom

is to hold the warp threads under tension to
facilitate the interweaving of
the weft threads. The precise shape of the loom and its mechanics
may vary, but the basic function is the
same.
Cross section of
loom
CHRONOLOGICAL/ HISTORICAL DEVELOPMENT OF
LOOM
1. Vertical loom: Damask, Tapestry.
2. Pit loom.
3. Frame loom.
4. Chittarangan/ Semi-automatic loom:Take up automatic but let off manually.
5. Hattersley loom.
6. Natural Source/ Ordinary power loom: a) Water wheel was until 195
b) Steam engine
c) Diesel engine

7. Electric power loom: 1st power loom 1784

1st weaving mill with power loom 1789
a) Large single motor
b) Large group motor
c) Individual motor in 1930
8. Modern loom:
a) Projectile
b) Rapier
c) Air Jet
d) Water Jet
e) Multiphase
PRIMITIVE OR VERTICAL
LOOM:
PIT
LOOM:
Weaving has a long tradition in Egypt going back as far
as 6,000BC during which time methods have changed
enormously. This simple pit loom is the kind that is
frequently found in farms and villages operated by men
and women who make carpets, chair covers, shawls,
blankets and bed covers

The weaver sits with his or her legs in the pit where there
are two pedals which open the warp threads allowing the
weft shuttle to pass through freely. This type of loom
leaves the weavers' hands free to pass the weft shuttle
through from side to side and to compress the weaving as
they go.
PIT
LOOM
FRAME
LOOM
 Simple and effective
- wonderful introduction to weaving
- very quick to warp and weave
- strong
- compact

Create wall hangings, cushions, tablemats and

coasters. The loom is ideal for students or any
weaver wanting a simple way to be creative. Made
from solid Silver Beech hard wood the frames are
strong and robust for a variety of warps and
tensions. Small and compact, the weaving frame is
ideal for taking on holiday. The finished piece can be
left in the frame and hung on the wall
FRAME
LOOM
 Loom motions: There are three types of
loom motions:-
1. Primary
2. Secondary
.
3. Tertiary.
Primary motions are: a) Shedding b) Picking c)
Beating.
Secondary motions are: a) Take- b) Let-off
up
Tertiary motions are: a) Warp stop b) Weft stop c)
stop. Reed

Drafting: The process of passing yarn through the drop wire

is called drafting.
Drawing: The process of passing yarn through the heald
eye
is called drawing.
Denting: The process of passing yarn through the reed is
 POWER DEVELOPMENT OF LOOM
DRIVE
1. Hand loom: Human power drive
2. Power loom:
1. Water wheel
2. Steam wheel
3. Diesel Wheel
4. Electric wheel
3. Large common motor (200loom/
motor)
4. Group motor ( 200 loom/ motor)
5. Individual motor invented at 1930
1. Direct drive
2. Indirect drive
6. Multiple motor : for each modern loom
Primary Motion Of
Weaving
 What is Primary
Motion..?
These are fundamental or essential mechanisms of loom.
Without these mechanisms, it is practically impossible to
produce a fabric. It is for this reason that these mechanisms
are called Primary mechanisms.
Types of
Primary
Motion….
Shedding

Pickin
g

Beat-up
SHEDDING
: Dividation of warp threads into two parts for
insertion of weft threads is called shed and
mechanism of shed is called shedding.it is
the first primary motion of weaving.
Types of shed:
 Bottom close shed
 Centre close shed
 Semi open shed
 Open shed
 Shedding
Mechanism
The shedding mechanism separates the warp threads into two layers or
divisions to form a tunnel known as shed. The shed provides room for
passage of the shuttle.

Types of Shedding Mechanism :

1.Tappet Shedding Mechanism:
a. Positive tappet shedding
b. Negative tappet shedding
2.Dobby shedding Mechanism:
a. Positive dobby shedding
b.Negative dobby shedding
3.Jacquard Shedding Mechanism:
a. Single lift and single
cylinder (SLSC)
b. Double lift and single
cylinder (DLSC)
c.Double lift and double
cylinder (DLDC)
BOTTOM CLOSE
SHED
This type of
shedding is produced
B
by giving motion
C
only to threads that
are to form the upper
line.under this condition, A
the warp is level in the
bottom line. Hence in A Bottom line of warp
order to form a top shed B Rising and falling line
it is necessary to move C An arrow showing the
some threads through a space
space equal to twice passed through
the depth of a shed.
ADVANTAGE:
 Used in hand loom
 Alternate tightening and slacking the warp
threads produce a covered cloth

DISADVANTAGE:
 More stress or tension on top warp line
 Different tension on the warp threads
 Low speed
 Not possible to produce compact fabric
 Poor quality fabric
 More chance of breakage on top warp line
 More power consumption
CENTRE CLOSE
SHED
 This type of shed is produced by imparting an upward
movement to those threads which are to form the top line
and a downward movement to the threads which are to form
the bottom line. Then after inserting pick both trhe lines
meet at the centre between the highest and lowest lines of a
divided warp
B

D
 A Closed warp line
 B, C Upper and lower lines of
a divided warp A A
E
 D Arrow showing the half
distance of a shed in an C
upward direction
E Arrow showing the half distancen
of a shed in a downward directio
ADVANTAGE:
 Equal tension on top and bottom warp
line
 Less time required, so high production
 Less wear of the machine
 Less power consumption
 Less tear of the threads

DISADVANTAGE:
 Beat up takes place in the closed shed
 Compact fabric can not be produced
 Chance of weft being moved backward
SEMI OPEN
SHED
 In this shed, the stationary bottom is retained but threads
for the top line either passes to bottom at one movement
and again carried to the top mid way and again carried to
top. In this shed close and open shed occurred
simultaneously. In it the stationary bottom line is retained,
but threads for the top line either pass to the bottom at
one movement, or are arrested midway and again carried
to the top. Such a shed can be formed as expeditiously as
an open shed, for the upward movement begins and
ends with the downward through movement, and the
arrested downward movement is converted into an
upward movement immediately the falling threads are in
the same plane as the rising ones. They all reach the top
together but the strain upon them is not equally distribut
SEMI-OPEN
SHED:
A STATIONARY BOTTOM LINE
B TOP POINT
C THE POINT WHERE DOWNWARD MOVEMENT CEASES IN
THREADS D, E SHOWING THE MOVEMENT OF THROUGH HEALDS
F ARROW SHOWING THE THREADS WHICH ARE TO LIFT FOR THE
NEXT PICK
F

C E D

A
SEMI-OPEN
SHED:
ADVANTAGE:
 Equal tension on the top and bottom warp line
 Beat up takes place in the close shed
 Speed faster
 For fency fabric
 Less power need
 Less tear of threads
 Possible to produce compact fabric

Disadvantage:
unusual movement
OPEN
SHED:
 In open shed, the warp threads form two stationary lines,
the top line and the bottom line and changes are made by
carrying the threads from one fixed line to the other without
any interval.
 A, B Stationary warp line
C, D Arrows which show the movement of rising and
falling warp to equal the distance between A & B
B

C D

A
OPEN
SHED
ADVANTAGE:
 Beat up takes place in cross shed condition
 Equal tension top and bottom warp threads
 Faster speed
 Extensively used in tappet shedding mechanism
 Basic fabric (twill, sateen, plain) can be produced
 Less power consumption
 Less wear of loom
DISADVANTAGE:
 High breakage rate
 If higher no of heald shafts are used then warp in back
healds are more stained than the front ones
BASIC SHEDDING
MECHANISMS:
1. Paddle/ treadle loom: hand loom
2. Tappet shedding mechanism
3. Dobby shedding mechanism
4. Jacquard shedding mechanism
5. Combined shedding
TAPPET
SHEDDING
A type of cam which transforms a rotary motion into
a reciprocating motion in rods and levers by sliding
contact is tappet.
When the receives a series of lifts, with intervals of
rest and thus forms a shed called tappet

Scope of tappet shedding:

 Maximum capacity 14 heald shafts
 Normally produce square design
 Only the basic weave and small design are
produced
CONSTRUCTION OF TAPPET
SHEDDING:
 The figure shows a negative tappet shedding mechanism. A pair
of tappets A and B are fixed to the bottom shaft C at 180
degrees to each other. Two treadle levers D and E are
connected to the loom back-rail by a bracket F.
The bracket acts as a fulcrum for the levers. The two treadles
have teeth to carry the lamb rods G and H respectively. Two heald
shafts J and K are connected to the lamb rods. A top reversing
roller shaft Q carries two rollers of different diameters. The roller
of small diameter N is connected to a leather strap L to which
the front heald shaft J is connected. The roller P of large
diameter is connected to a leather strap M to which the back
heald shaft K is connected. The tappets A and B touch the anti-
friction bowls or followers R and S respectively, which are fixed to
the treadle levers. The heald shafts have heald eyes T and U
through which the war p threads pass X is the war p sheet and Y
is the cloth. The odd ends are passed through one heald shaft
while the even ends are passed through the other heald shaft.
WORKING PRINCIPLE OF
TAPPET:
 When the bottom shaft is rotate as shown in the figure, the
tappets also rotate. The tappet will depress the anti-friction
bowl and the treadle. Being fulcrumed at one end, the front
portion of the treadle moves down. This action is transferred to
the lamb rod, the heald shaft and the leather strap. So one
heald shaft is lowered and the threads connected to this heald
shaft are lowered and form the bottom layer of the shed.
 The leather straps attached to the reversing rollers are
connected in opposite directions, i.e. when leather strap is pulled
down, it is unwound from its roller. The shaft therefore rotates in
the clockwise direction and the other leather strap is wound on to
its roller. The heald shaft is raised and therefore the lamb rod
and treadle lever are also raised. The threads connected to the
heald shaft are also raised and form the top layer of the shed.
 For the next shed, the other tappet works with the other set of
bowl, treadle, lamb rod, heald shaft, strap and roller and the
other heald shaft is lowered.
TYPES OF
TAPPET:
 Negative tappet: in a tappet shedding
mechanism if the tappet controls only one
movement either an upward or downward
movement of heald shaft, then the shedding
is known as negative tappet shedding.
 Positive tappet: : in a tappet shedding
mechanism if the tappet controls both the
upward and downward movement of heald
shaft,then the shedding is known as positive
tappet shedding.
ADVANTAGES OF TAPPET
SHEDDING:
 Simplest
 Cheapest
 If properly used, it gives the best results within
its capasity
 Action is certain
 It is capable of lifting heavy weights with less
wear and tear than other shedding mechanisms
 Less wear and tear
 Consumes less power and give greater output
DEFECTS OF TAPPET
SHEDDING:
 Over shedding strains and breaks the warp
threads
 Under shedding does not permit the space to
pass the shuttle through the shed.
 Sometimes unequal shedding by lifting one end
of the shaft more than the other
 Missed shedding
 May impart jerky motion
 Capacity is only 14 heald shaft
 Pickin
•
g the weft through the shed from one
Picking: Picking is the second primary motion in the weaving. It is
the action of filling insertion
edge of fabric to the other edge.
• The object of picking is to insert the weft yarn through the warp sheet
during
weaving.
• Types of picking:
1. Conventional picking mechanism or negative picking
mechanism
2. Unconventional picking mechanism or positive picking
mechanism
• Conventional Picking mechanism – types
1. Overpick mechanism – Cone overpick mechanism
2. Underpick mechanism
a) Side- lever underpick mechanism
b) Side- shaft underpick mechanism
c) Cone underpick mechanism
Over Pick: When picking arm position is situated above the shuttle box then it is
called over pick.
Under Pick: When picking arm position is situated under the shuttle box then it
is called under pick.

Difference between over pick and under pick:

Over Pick Under Pick

1. Arm position is above the shuttle box. 1. Arm position is below the shuttle box.

2. Higher loom speed. 2. Lower loom speed.

3. Less power required. 3. More power required.
4. Works more smoothly. 4. Works less smoothly.
5. Less clean mechanism. 5. More clean mechanism.

6. Less direct action. 6. More direct action.

7. Comparatively gentle in 7. Comparatively harsh in picking action.
picking action.
8. Less wear and tear. 8. More wear and tear.
Cone overpick
.
mechanism
Working flowchart of tappet cone over picking mechanism:

With the rotation of loom/bottom shaft, picking tappet or cam

rotates
↓
In revolving, picking tappet nose strikes the cone shaped
antifriction roller on the stud and partly rotates the picking shaft
and the picking lever/stitch
↓
The picking arm/lever moves from right side to left side of the
loom. It will give angular movement which causes the picker to
move inward with sufficient velocity to drive the shuttle across the
loom
↓
When the picker strikes the shuttle, the shuttle moves into the
open shed through race board
↓
Picking is done
↓
The spring causes the picking arm and picker to move back after
the delivery of a pick.
Cone overpick
mechanism

Cone over picking mechanism

Working Flow Chart of Cone Under Picking:
The tappet is driven by the bottom shaft
↓
When the picking tappet strikes the picking cone, it displaced and the side shaft is
turned
↓
The turning action of side shaft pulls the picking stick which is connected to side shaft
by picking strap
↓
The lower end of picking stick is pivoted. So that is pulled with the pulling of side shaft
↓
Then the picker connected to picking arm strikes the shuttle and causes it to pass
through the warp shed
↓
Picking is done

Cone under picking mechanism:

 Loom Timing
diagram
• All events on the loom are to be properly synchronised which can be demonstrated
on a loom timing diagram.
• However, all the basic motions of a loom have to be completed in 360°
• The shuttle starts moving at around 80° following the beatup.
• The contact between the shuttle and the picker lasts around 30° which corresponds
to approximately 20 cm.
• At this position, the shuttle reaches a speed of around 15 m/sec, the picker stops
pushing the shuttle and the shuttle flies across the loom by itself.
• Once at the other side of the loom, the shuttle is brought to a stop by
thechecking mechanism which is similar to picking.
• Insertion with shuttle is an inefficient process in the sense, that the shuttle weighs
0.5 kg while the weight of the inserted weft is less than 1/1000 of the shuttle
weight
Loom timing
diagram
 PICKING MECHANISM AS A
SIMPLE ELASTIC
• MATERIAL
If the picking mechanism behaves as a simple elastic system, it can be
represented by a mass in series with a spring. In fig, the mass M, which
rests on a smooth, horizontal surface, represents the shuttle, and the
spring represents the elasticity of the picking mechanism.

An elastic model of the picking

mechanism
Beat – up
mechanism
 Beat-up
• Beating up is the third and final primary motion in weaving; it performs driving
the last pick of weft to the fell of the cloth.
• The object of the beatup mechanism is to push the last laid weft thread into
the fell of the cloth by means of a reed.

Types of Beating Up:

1.According to number of beat-up:
1. Single beat-up.
2. Double beat-up.
2. According to beat-up
mechanism:
1. Conventional beat-up.
2.Cam beat-up.
3. According to movement
of reed:
1. Real beat-up.
2. False beat-up.
4. According to Fell of the cloth:
1.Fixed fell beat-up.
2.Moving fell beat-up.
Beat –up
Mechanism
 Single beat
mechanism
The lower end of sley sword is pivoted to the rocking shaft and the sley race
is connected to the sley-sword and reed.
The connecting rod or crank arm is connected to the back of sley-race by a
pin called sword pin and its other end fastens round the bend in the crank
shaft, known as cranks.

Working principle: For beating up process, the sley sword must reciprocate;
the sley sword is connected to the rocking shaft for this purpose.
When the crank of the crank shaft rotates and comes in forward position (at
90°), then it pushes the crank arm forward. Thus crank arm gives to purpose.
and fro movement.
As the crank arm is connected to the sley race and reed is situated above
the, reed race, reed also moves for vard as the crank arm move forwards. The
reed pushes the weft in the fell of the cloth. In this mechanism, one beat up
is done for every picking.
Single beat
mechanism
Double beat up
sley:
Construction: Construction by a sley sword, a crank, a connecting arm, two
arms one of them is hinged to the framing & other is attached to sley by
usual connecting pin.

Working principle: In one drawing the arms E & F are straight but when the
crank moves to the top centre it is pushed up & E,F are bent.
When the crank moves & there comes a stage when the arm become s
traight & a beat-up is done by the system. When the crank again moves up,
the knuckle joint moves up & again the arms become straight & cause
beat- up. Hence the two beat up is done for a pick.
The time, that elapses between the first & second straightening, can be
increased either by moving the crank centre up or by lengthening the crank
arm
Lowering the crank or shortening connecting arm can reduce time
Lengthening the size of the crank the force of beat up may also be
increased
Double beat up
sley:
Motion of
sley
The sley is wooden frame accommodating two shutte boxes, a
sley race, a reed, a reed cap and two sley- swords. It swings
forward and backward. At its forward and two sley- motion, the
last pick of weft is beaten up to the fell of the cloth and at its
backward motion the shuttle is allowed to pass over the sley-
race through the open shed. So its forward centre position is
known as beating up position and the back centre position is
called shedding and picking position
The sley gets motion from the rotation of crank via a erank
arm. When the crank shaft rotates it pushes and pulls the sley
with the help of it pushes and pulls the sley with the help of the
crank arm in forward and backward direction.
Motion of
sley
 Beating
mechanism
•