WEAVING
Weaving is producing fabric by interlacing of warp and weft thread at right angle to each other.
The warp threads are placed along the length of the fabric and the weft threads are placed
along the width of the fabric.
Flow Chart of Weaving
Basic mechanism of weaving
1. The warp yarn unwound from the warp beam passes over the back rest and comes to
the heald frames (harnesses),which are responsible for separating the warp sheet to
form shed.
2. Meanwhile the shed is formed making the way for inserting the filling yarn and the weft
yarn is inserted through the shed in order to interlace with the warp yarn for
manufacturing woven fabric.
3. The warp yarn passing through the heal frames pass through the reed which holds the
threads at uniform spacing and is also responsible for beating up the last inserted pick.
4. All the threads unite again in the fabric at the point of cloth fell.
5. The cloth then passes over the front rest and is wound onto the cloth roller.
6. A drop wire signals the loom to stop immediately after a warp end breaks off.
7. In conclusion, the warp from the beam is converted into fabric which is taken-up on a
cloth roll.
Type of Weft Insertions in weaving loom.mp4
Properties of Woven Fabric:
It is produced by using two sets of yarn.
Elastic properties is less.
Higher labor cost than knit fabric manufacturing.
It is less comfortable than knit fabric.
It has lower extensibility characteristics.
Dimensional stability is high.
Finishing is not advantageous.
It is easy to sew on and feed through a sewing machine.
Hold a crease well.
Requires seam finishing, like serging, to prevent ravel.
Edges are prone to ravel.
Loom motion:
1. Primary Motion
In order to interlace warp and weft thread to produce fabric on any type of weaving machine 3
primary motion is necessary:
Shedding:
It is the process of separating the warp thread into two layers to form a tunnel called shed
(through which shuttle carrying weft passes) is known as shedding. During shedding some yarns
are raised up and some are depressed down create a tunnel.
Picking:
The method of passing the weft threads which traverse across the fabric through shed is called
picking. The inserted weft is called a pick.
Beat up:
It is the process of pushing the pick into the already woven fabric at a point known as fell of the
cloth .By pressure of wraith to jointed feed side of the cloth is called beat up.
2. Secondary Motion
Take up motion:
The motion which with draw (wound up) fabric from the weaving area at a constant rate and
thus give required pick spacings and winds the fabric on to a roller is called cloth control or Take
up motion. Positive Take up motions is mechanically driven. Negative Take up motions is spring
drive.
Let off motion:
The motion which deliver warp to the weaving at the required rate and at a suitable constant
tension by unwinding it from a flanged known as weavers beam is called let off motion.
3. Tertiary Motion
Tertiary motion is not must for fabric production but it is used for higher production.
Warp Stop Motion: Machine will be stopped electrically or mechanically.
Weft stop motion: It may be two types- ( a) Side weft motion & (b) Centre weft motion.
Reed stop motion: Two types( a) Fast reed motion. ( b) Loose reed motion.
