MULTIPHASE LOOMS
INTRODUCTION
In multiphase looms,a series of sheds are formed
successively,either in the warp direction or in the weft
direction.
These machines are classified depending upon the type
shed formed.
They have simultaneous weft insertions in the series of
sheds formed by several weft carriers.
This gives a very high rate of weft insertion to the
extent of 2000 to 3000 mph.
In these looms, the weft is unwound continuos from the
supply package and laid into the shed at a uniform
speed.
CLASSIFICATION
Depending upon the direction in which the
series of sheds are formed,the multiphase
looms are classified as ,
+ Flat multiphase looms including
+ Drum type multiphase looms.
RECTANGULAR / FLAT MULTIPHASE LOOMS
There is no large scale commercial installation of flat weft-
way multiphase weaving machines.
Nevertheless,it can be predicted safely that any massive
increase in weft insertion rate of shuttle-less weaving
machines can only come from a multiphase weaving
machine.
The flat multiphase machine consists of a number of weft
carriers which traverse simultaneously, one behind the other
with constant phase difference, across the reed space.
Each carrier moves in an individual shed, the shed advancing
simultaneously along with the carrier.
The number of carriers vary between four and sixteen.
Continued….
A weft insertion rate of about 2000mpm is attainable
with the carrier velocity of 100mpm.
Weft is continuously drawn from the weft package
and
transferred to the carrier one pick length at a time
i.e,
each carrier will have a store of one pick.
The movement of the series of sheds form,give an
impression of a wave motion travelling from the
weft
insertion side to the opposite side.
Because of this phenomena it is also known as wave
shed
loom.
DRUM TYPE MULTIPHASE LOOMS.
In the drum type of multiphase looms multiple sheds are formed
and
each shed extends across the full width of the loom. The sheds are
formed in the warp way direction.
The weft can be inserted from a stationary supply package outside
the
shed either by Rapier or Air-jet.
The number of supply packages and weft insertion devices depend
upon
the number of sheds formed.
The Sulzer multiphase weaving machine is a drum type of machine
in
The drum is provided with combs which form the shed as well
as
form the channel for weft passage.
There are warp positioners which displays the warp threads in
the
weft direction to position them for shed forming,so that the
threads are either located on the shoulders of the shed forming
elements or in between them.
The rotating movement of the drum lifts the threads of the
shoulders and lays them over the weft channels , while
remaining
threads come to rest below the channel.
Once a shed is formed completely , weft is inserted by means
of
Air-jets.
After the insertion of weft , it is clamped and cut on the feed
side.
There after the weft yarn in beaten-up by the special beat-up
Some of the important features of the Sulzer
M8300 multiphase machine are,
Weft insertion rate of about 5000 mpm.
Weaving width of about 190cms.
Weave is plain.
Yarn count range is 15-60 Tex.
Leno selvedge.
SULZER MULTIPHASE LOOM
MODEL : M 8300
WEFT CARRIER DRIVE
On the multiphase weaving
machines,the weft carriers are embraced by
the warp ends,and can not there fore be
projected across the shed, but must be driven
by a constant mechanical or electromagnetic
force. Multiphase - M8300_insertion.mpg
The following are some weft carrier
drives,
Travelling roller drive.
Leverage drive.
TRAVELLING ROLLER DRIVE.
The weft carrier is guided by the side way and
stationary reed.
Moving the reed, is a chain with driving roller
which
is provided with pressing roller acting on the
roller
which is fitted on the weft carrier.
The warp ends in the upper part of the shed must
pass between the moving rollers, and are
therefore
excessively stressed.
It is recommended to provide at least one of the
rollers with a rubber covering.
TRAVELLING ROLLER DRIVE
Chain with
driving link
Stationary reed
Roller on
chain
Weft
carrier
Slide Way
for weft
carrier
warp Roller
on weft
carrier
THE LEVERAGE DRIVE
In this type of weft carrier drive , levers act
on the surface of the weft carrier as shown
in the figure.
The levers are rotatably mounted above the
warp
and perform a reciprocating motion due to
the
circular shape of the active part of the driving
levers, the stressing of the warp threads is
minimal.
LEVERAGE DRIVE FOR
WEFT CARRIER
lever
Active part of
surface
Weft carrier
SHEDDING MECHANISMS
Several types of shedding motions are
available for flat multiphase weaving
machines. A few important ones are given
below:Multiphase - M8300_sheding.mpg
# Finger shedding motion.
# Cam shedding motion.
FINGER SHEDDING MOTION
4 Fingers made up of an elastic material are used to control
the warp threads.
4 One end of these thing is fixed to the machine frame i.e,
fulcrummed,while the other end has warp threads resting
on them.
4 As many number of warp ends, so many fingers across
the width of the loom.
4 Each finger has got a projection which rests against the
contour of a cam.
4 the cams are positioned in between separating discs, and
are fast on the shedding shaft along with the separator
discs.
4 A movement of the shedding cams will lift the
corresponding finger and the warp end leading to the
formation of a shed.
4 Series of sheds can be formed,as each and every end can
be lifted and lowered individually.
FINGER SHEDDING MOTION
Warp ends
finger
cam
Finger
extension
s
cam
CAM SHEDDING MOTION
In this type of shedding motion, the fingers are
absent.
Here the warp threads directly rest against the cam
contours.
A series of cams are fast on the shedding shaft, their
number depending upon the density of warp
threads.
Each cam is placed in between separator discs
which
are also called as distant discs.
CAM SHEDDING MOTION
cam
Distant disc
warp
Distant disc
cams
BEAT UP MECHANISM
The following are the different methods of
beat up,
ª Beat up by weft carrier
ª Beat up by rotating reed
ª Beat up by brush rollers
BEAT UP WEFT CARRIER
The weft carrier is provide with a spur,which
extends into the next shed wave of the next
weft carrier.
The spur is crossed by the warp and the weft
thread is pushed to the fabric fell.
But the weft carrier is exposed to the effect of
the pitching moment and guided by the reed.
The disadvantage is the high resistance of the
warp to the passage of the weft carrier.
BEAT UP BY WEFT CARRIER
SPUR
Following weft carrier
reed
Weft
carrier weft
spur
BEAT UP BY ROTATING REED
The weft thread is beaten up by a rotating reed.
The reed is composed of individual blades
separated by rings.
The blades are mounted on the rotating shaft so
that their grooves form a helix.
The reed rotation and the groove helix are
synchronized with the progress of the weft
carrier.
The weft carrier is inserted in the groove.
When the shed is closed, the weft thread is
slipped out of the groove.
Due to the effect of the reed rotation and pushed
to the fell of the fabric.
BEAT UP BY ROTARY REED
D
A
B
A – BLADE
B – ROTATING SHAFT
C – GROOVE
D – WARP
- WEFT
Selvages (Selvedges):
As the shuttle moves back and forth
across the width of the shed, it weaves a
self edge called a selvedge on each side
of the fabric. The selvedge prevent the
fabric from raveling. It is usually made
more compact and stronger than the rest
of the fabric by using more or heavier
warp yarns or by using a stronger weave.
The kind of selvedge depends upon the
economy of production and the
expected use of the fabric.
CONTINUE..
Plain selvages:
simple plain weave, same size yarns,threads
more compactly packed. Fairly durable and firm.
Tape selvages:
basket weave for flatter edges, made of heavier
yarns or ply yarns for greater strength.
Split selvages:
made by weaving narrow width fabrics twiceits
ordinary width with two selvages in the center.
CONTINUE…
Fused selvages:
for fabrics of thermoplastic fibers. The fabric is fused to
seal at the edges. This technique is sometimes used to
split wider fabrics in to narrow width fabrics.
Leno selvage:
used on shuttle less looms. Uses a narrow leno weave
at the edges which locks the cut ends along the edges.
Tucked selvage:
used on shuttle less looms. A special device is used to
tuck and hold the cut ends in to the fabric weave.
Tuck-in
Selvedge
Formation
Leno selvedge
Leno Selvedge
Formation
Weft
Accumulator
Weft Accumulator
• The weft yarn is drawn off the package and wound onto
measuring bands 2 by the rotating motion of thread guiding
tube 1.
• The pick length depends on the fabric width. The pick length
is set by adjusting the measuring bands and the number of
coils.
• The electromagnetically controlled stopper pin 3 releases the
weft yarn at the machine angle set.
• A sensor 4 controls the number of coils to be unwound.
• As soon as the parametrized number of coils has been
withdrawn from the drum feeder, the stopper pin blocks the
following coils.
• The pick length is fine-tuned by adjusting the measuring
bands on the drum feeder.
