weaving
The process of
producing a fabric by interlacing warp and weft threads is weaving. The machine
used for weaving is. Known as weaving machine or looms. Weaving is an art that
has been practiced for thousands, of years. The earliest application of weaving
dates back to the egyptian civilization. Over the years, both The process as
well as the machine have undergone phenomenal changes. As of today there is a
wide range of looms being used. right from the simplest handloom to the most
sophisticated loon.
In this range,
the most widely prevalent loom, especially with reference to India. is the
ubiquitous "plain power loom". In this and in the chapters
that follow, the various mechanisms associated with the plain power loom are
discussed in elaborate detail
Basic Mechanisms in a Plain Power Loom
In order to
interlace warp and weft threads to produce a fabric. The following mechanisms
are necessary on any type of loom:
1. Primary
mechanisms
2-Secondary
mechanisms
13-Auxilliary
mechanisms
1. Primary Mechanisms
These are
fundamental or essential mechanisms. Without these mechanisms, it is practically
impossible to produce a fabric. It is for this reason that these mechanisms are
called primary mechanisms. The primary mechanisms are three in number.
(i) Shedding mechanism
(i) Shedding mechanism
(ii) Picking
mechanism
(iii) Beat-up
mechanism
(iv) Shedding
mechanism
Shedding mechanism
The shedding mechanism
separates the warp threads into two layers or divisions from a tunnel known as shed.
Picking mechanism
The picking
mechanism passes weft thread from one selvedge of the fabric to the other
through the shed by means of a shuttle. A projectile, a rapier, a needle,
an air jet or a water-jet, The inserted a weft thread is known as pick.
Beat-up mechanism
The Beats -up mechanism beat or pushes
the newly inserted length of weft thread: (pick) into the already woven fabric
at a point known as fell of the cloth" These three mechanisms namely
shedding. picking and then beat-up are done in sequence.
2. Secondary Mechanisms
These mechanists
are next in importance to the primary mechanisms. If weaving, is to be continuous
these mechanisms is essential. So they are called the secondary. they are
a. Take-up
motion
b. Let-off
motion
these
mechanisms are essential. est oth the b-Let-off motion. a. Take-up motion The
Take-up motion
Take-up motion withdraws the cloth from the weaving-area
at a constant rate so as to give the required pick spacing (in picks inch or
pick s/cm) and then winds it onto a cloth roller.
b. Let-off
motion
The let-off
motion delivers the warp to the weaving area at the required rate and at
constant tension by unwinding it from the weaver's beam. The secondary motions
are carried out simultaneously
3. Auxiliary Mechanisms
To get high productivity
and good quality of fabric additional mechanisms, called auxiliary mechanisms,
are added to a plain power loom. The auxiliary mechanisms are useful but not
absolutely essential. This is why they are called the auxiliary mechanisms.
These are listed below.
a. Warp
protector mechanism
b. Weft stop
motion.
c. Temples
d. Brake
e. Warp stop
motion (Predominantly found in automatic looms)
a. Warp
protector mechanism
The warp
protector mechanism will stop the loom if the shuttle gets trapped between e
top and bottom layers of the shed. It thus prevents excessive damage to the
warp threads, reed wires and shuttle.
b. Weft stop motion
b. Weft stop motion
The object of
the weft stop motion is to stop the loom when a weft thread breaks or gets
exhausted. This motion helps to avoid cracks in a fabric
.
c. Temples
The function
of the temples to grip, the cloth and holt it at the same width warp
in the reed, before it is taken up
d. Brake
The object of
the warp stop motion is to stop the loom immediately when a warp thread breaks
during the weaving process
