Woven Fabrics

woven fabrics

Woven fabrics are made by interlacing two sets of yarns at right angles to each other. The length wise yarns are called WARP or ENDS. The width wise yarns are called FILLINGS or PICKS.

The term ON GRAIN is used if the fabric has been cut parallel to either warp or filling. If not it is called OFF GRAIN or BIAS.

Woven fabrics elongate most in a direction that is 45° to both sets of yarns. They have best drape in a bias direction (to obtain max drapability some garments are cut on the bias).

BIAS BINDINGS are narrow stripes of fabric cut in a bias direction used to finish the edges of seams in sewn products.

Ends help to stabilize, that is why usually there are more ends than picks. When weaving tension is created and ends are, for this reason, usually more in number than the picks. It is also more cost effective.

LOOM

WARM BEAM: it is a large roller on which all the warp yarns are wound parallel to each other.

HARNESS: it looks like a picture frame that hold many thin vertical wires called HEDDLES.

SHED: it is the V like opening that is formed when a harness is raised.

REED: it is a comb-like device that pushes the filling yarn in the shed into the body of the cloth.

WEAVE: the weave of the fabric is determined by the sequence in which harness is raised or lowered.

CLOTH ROLL: it is the roller that keep the woven fabric produced.

TYPES OF LOOM

PRODUCTION LOOMS

For early looms the insertion of the filling was done by hand. Later, a "shuttle" was inserted. A shuttle is a wooden device with a bobbin placed inside the filling yarn wound around it. It is projected across the loom. Later on, power was added increasing the rate of production. Most looms are shuttless, the yarn comes directly from cones placed at the side of the loom. They have the highesr rate of production. The speed of the loom and its productivity is designated by "number of picks per minute" PPM.

PROJECTILE LOOMS

They use a projectile to insert the filling yarn. It is a small, light gripper device propelled across the loom.

RAPIER LOOMS

uses a rapier steel tape to pull the filling yarn across the loom.

JET LOOM

they take the filling yarn across the loom by using a high speed jet of either