Loom:

A loom is a device used to weave cloth and tapestry. The basic purpose of any loom is to hold the warp threads under tension to facilitate the interweaving of the weft threads. The precise shape of the loom and its mechanics may vary, but the basic function is the same.

Weaving:

Weaving is done by intersecting the longitudinal threads, the warp, i.e. "that which is thrown across", with the transverse threads, the weft, i.e. "that which is woven".

The major components of the loom are the warp beam, heddles, harnesses or shafts (as few as two, four is common, sixteen not unheard of), shuttle, reed and take up roll. In the loom, yarn processing includes shedding, picking, battening and taking-up operations. These are the principal motions.

· Shedding: Shedding is the raising of part of the warp yarn to form a shed (the vertical space between the raised and unraised warp yarns), through which the filling yarn, carried by the shuttle, can be inserted, forming the weft. On the modern loom, simple and intricate shedding operations are performed automatically by the heddle or heald frame, also known as a harness. This is a rectangular frame to which a series of wires, called heddles or healds, are attached. The yarns are passed through the eye holes of the heddles, which hang vertically from the harnesses. The weave pattern determines which harness controls which warp yarns, and the number of harnesses used depends on the complexity of the weave. Two common methods of controlling the heddles are dobbies and a Jacquard Head.

· Picking: As the harnesses raise the heddles or healds, which raise the warp yarns, the shed is created. The filling yarn is inserted through the shed by a small carrier device called a shuttle. The shuttle is normally pointed at each end to allow passage through the shed. In a traditional shuttle loom, the filling yarn is wound onto a quill, which in turn is mounted in the shuttle. The filling yarn emerges through a hole in the shuttle as it moves across the loom. A single crossing of the shuttle from one side of the loom to the other is known as a pick. As the shuttle moves back and forth across the shed, it weaves an edge, or selvage, on each side of the fabric to prevent the fabric from raveling.

· Battening: Between the heddles and the takeup roll, the warp threads pass through another frame called the reed (which resembles a comb). The portion of the fabric that has already been formed but not yet rolled up on the takeup roll is called the fell. After the shuttle moves across the loom laying down the fill yarn, the weaver uses the reed to press (or batten) each filling yarn against the fell. Conventional shuttle looms can operate at speeds of about 150 to 160 picks per minute.

There are two secondary motions, because with each weaving operation the newly constructed fabric must be wound on a cloth beam. This process is called taking up. At the same time, the warp yarns must be let off or released from the warp beams. To become fully automatic, a loom needs a tertiary motion, the filling stop motion. This will brake the loom if the weft thread breaks. An automatic loom requires 0.125 hp to 0.5 hp to operate.

Operation:

Operation of weaving in a textile mill is undertaken by a specially trained operator known as a weaver. Weavers are expected to uphold high industry standards and are tasked with monitoring anywhere from ten, to as many as thirty separate looms at any one time. During their operating shift, weavers will first utilize a wax pencil or crayon to sign their initials onto the cloth to mark a shift change, and then walk along the cloth side (front) of the looms they tend, gently touching the fabric as it comes from the reed. This is done to feel for any broken "picks" or filler thread. Should broken picks be detected, the weaver will disable the machine and undertake to correct the error, typically by replacing the bobbin of filler thread in as little time as possible. They are trained that, ideally, no machine should stop working for more than one minute, with faster turn around times being preferred.

Once the weaver has made their circuit of the front of the machines, they will then circle around to the back. At this point they will gently stroke their hand over the raised metal "tells" on the back of the machine. These tells, located over a special metal circuit, are held up by the tension of the thread coming from the warp. Should the warp thread be broken, the tells will drop and cause the machine to stop working. However, it is possible for them to become stuck in the upward position, and by doing so create problems in the weaving. By gently touching the tells, then, it is possible for the weaver to find tells which have become stuck in the up position, and correct the error. As with pick breaks, the weavers are trained to keep the machines running as much as possible; with speedy knot tying and correction being stressed. In this situation, they are expected to take less than a minute, with the mean ideal being ten to thirty seconds, to correct a break. The weaver also watches for warps that are about to run out, or problems in the warp itself which were not detected in the slashing process. Typically, weavers can expect to make several dozen circuits of their machines a night, with most of their time spent ensuring the quality of the cloth and the company standards of production.