The textile art in which two distinct sets of
yarns or threads, called the warp and the
filling or weft (older woof), are interlaced
with each other to form a fabric or cloth.
The warp threads run lengthways of the
piece of cloth, and the weft runs across
from side to side.
Yarn Preparation For Weaving Process
Basic Mechanism of Warp & Cloth Control
Woven Fabric Analysis
The warping process transfers the yarn from
multiple packages to a section beam.
To produce a quality beam suitable for weaving, the
following must be accomplished:
no lint, fly, wild yarn
no high or low selvage
maintain warper speed
maintain braking systems
no crossed or loose ends
uniform tension across beam
uniform tension beam to beam
smooth section beams, rollers
Application of sizing chemical to yarns
The purposes of sizing process are :
1) To reduce the yarn hairiness that would interfere with the
2) To protect the yarn from various yarn-to-yarn and
3) To increase the strength of the yarn
Tying-in the new warp ends to the depleted warp is done when a new
pattern is not required.
Weaving means to make cloth
and other objects. Threads or
strands of material are passed
under and over each other.
In order to interlace warp and weft threads to produce fabric on any
type of weaving machine, three operations are necessary :
Separating the warp threads, which run down the fabric into two
layers to form a tunnel known as the shed
Passing the weft thread, which traverses across the fabric, through
Pushing the newly inserted length of weft, known as the pick, into
the already woven fabric at a point known as the fell
A. Shedding occurs here…
Shedding is the lifting of
some of the warp yarns, so
that the warp is divided into
2 sheets. This creates an
opening (a shed) between
them for the weft carrier to
The weft yarn taken from
one side of the warp
through the shed.
The inserted pick is
consolidated or ‘beaten-up’
into the fabric when the
new pick is pushed into the
cloth-fell by the reed.
Basic Mechanism of Warp & Weft Control
Cloth control (or take-up)
This motion withdraws
fabric from the
weaving area at the
constant rate that will
give the required pickspacing and then
winds it onto a roller
Warp control (or let-off)
This motion delivers warp to the weaving area
at the required rate and at a suitable constant
tension by unwinding it from a flanged tube
known as the weaver’s beam
Auxiliary Functions :
Temples – hold the cloth firm at the fell to assist in the formation of a uniform fabric
A drop wire assembly, one wire for each warp yarn, to stop the loom when a warp
end is slack or broken
A tension sensing and compensating whip roll assembly to maintain tension in the
A mechanism to stop the loom when a filling yarn breaks
Filling feeders to control tension on each pick
Pick mixers to blend alternate picks from two or more packages (up to eight)
Filling selection mechanism for feeding multi-type filling patterns
Filling selvage devices such as trimmers, tuckers, holders and special weave
harnesses for selvage warp ends
Methods of weft insertion :
single or multiple grippers or projectiles
fluid jet, water jet, or air jet
various other method
The simplest of the weaves and the most common
Consists of interlacing warp and filling yarns in a pattern of over
one and under one.
Woven Fabric Analysis
There are several analysis that can be done to the woven fabric.
Number of warp ends per unit length of fabric – spacing between warp threads.
Units: ends per cm (e.p.c) or ends per inch (e.p.i)
Number of picks per unit length of fabric – spacing between weft threads.
Unit: picks per cm (p.p.c) or picks per inch (p.p.i)
Count of cloth
The closeness or looseness of the weave.
Determined by the number of picks and ends (filling and warps) to the square inch.
Fabric weight is expressed in grams per square meter (W/m2) or in grams per meter of
the fabric with full width (W/m)
Crimp (waviness of yarns)
%c = [(ly – lfab) / lfab] x 100
Fabric Take up
% Take up, %t = [(ly – lfab) / ly] x 100