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


weaving of plain power loom

 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
(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
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


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