How Woven Fabrics Are Made: Looms, Process & Types

What is Woven Fabric?

Woven fabrics are among the most important groups of fabrics. Weaving is one of the oldest textile-forming arts, with archaeological evidence indicating prehistoric origins. It is the process of forming a fabric by interlacing two sets of yarns at right angles to each other on a weaving machine called a loom. Accordingly, a woven fabric consists of two sets of threads: warp and weft. To understand how woven fabrics are made, it is essential to begin with these two basic yarn systems. These are as follows:

Warp: Runs lengthwise through the fabric. An individual warp yarn is called an end.
Filling or weft: Runs across the fabric. An individual weft yarn is called a pick.

Warp and Weft: Key Differences

Warp yarns generally have the following characteristics:

Run lengthwise through the fabric
Are stronger
Are finer
Have lower hairiness
Contain more twist
Are present in greater numbers per unit width of fabric
Are subjected to abrasion and repeated stress and strain during preparation and weaving

Weft yarns generally have the following characteristics:

Run from side to side across the fabric
Must be wound properly on a suitable package for insertion
Are comparatively weaker
Are bulkier
Contain less twist
Are present in fewer numbers per unit length than warp yarns

How Woven Fabrics are Made?

Passing one set of yarns above or below another set at right angles is called interlacement. On the loom, the warp is arranged under tension and is raised and lowered by specific mechanisms to form a nearly rectangular network. This is the basic principle behind how woven fabrics are made. The first step in weaving is to prepare and stretch the warp, or longitudinal yarns, which must be sufficiently strong to withstand tension and abrasion. The weft then crosses the warp, and the fabric edges form the selvage. Once the warp has been stretched, the three essential operations are shedding, picking, and beating-up. Shedding is the raising of selected warp yarns, or groups of yarns, to create an opening for the weft. Picking is the insertion of the weft into the shed. Beating-up is the action of pushing the newly inserted weft into the fell of the cloth to compact the fabric. In early forms of weaving, these operations were performed by hand, as in the making of mats and baskets. Over time, frames for maintaining warp tension and devices for inserting the weft were developed, leading to increasingly efficient looms.

weaving principle — Figure 1: Weaving principle: (1) weavers beam, (2) warp yarn, (3) back-rest, (4) drop wires, (5) healds, (6) reed, (7) shuttle, (8) fabric fell, (9) take-up roller and (10) cloth roller.

The schematic diagram of how woven fabrics are made is shown in above Figure 1. The warp is usually present (2) and supplied for the formation of the fabric from a warpers beam (1). The warp yarn unwinds from the beam, run around the backrest (3), and then passes through tension bars to keep the warp in tension. The warp then passes through the eyelets in drop wires (4), followed by through the heald eyes in heald (5). The healds are designed for separating the warp yarns and then interlacing the weft yarns. The upward and downward movement of the healds divides the warp in two layers, creates free spaces, called shed. For better movement, the warp yarns individually pass through the dent of a set of combs, called the reed (6). The shuttle or the carrier (7) containing the weft passes through the shed. After insertion of the pick, the reed effects beating up the weft to the fabric fell (8). This is followed by closing the shed. In continuation, a new shed is formed, while the healds with the draw in warp change their position. This makes the weft to be fixed at the fell. A new weft is inserted into the newly formed shed, and then, it transferred to the fabric fell by beating. This process of cloth formation is repeated cylindrically, and the cloth thus formed is slowly wind up on cloth roller (10) by rotating take-up roller (9).

Weaving Motions

The process of cloth formation on a loom is continuous, although it consists of a series of interconnected cyclic and intermittent actions. The actions required to perform weaving are known as motions. Conventionally, three primary motions and two secondary motions are associated with the weaving cycle. These motions explain how woven fabrics are made efficiently on different types of looms.

Primary Motions in Weaving

For the formation of woven fabric on any loom, whether a handloom, power loom, or automatic loom, three primary motions are necessary: shedding, picking, and beating. These may be controlled manually on handlooms or mechanically or electronically on other looms.

Shedding: Shedding is the lifting and lowering of selected warp yarns, dividing the warp into two sheets. The opening formed is called the shed, into which the filling yarn is inserted. This movement is possible because each warp yarn passes through the eye of a heddle mounted on a harness or shaft. The shedding arrangement determines the weave or pattern produced on the loom.
Picking: Picking is the action of weft insertion. The weft yarn is inserted into the shed.
Beating: Beating, or beat-up, pushes the newly inserted pick into the fell of the cloth.

Secondary Motions in Weaving

In addition to the three primary motions, two secondary motions are required on most power and automatic looms: take-up and let-off. The take-up motion gradually draws the formed fabric away from the fell and winds it onto the cloth roller. The let-off motion releases warp yarn from the warp beam at the required rate while maintaining the tension necessary for stable weaving.

Types of Weaving Looms

The classification of the weaving machine is shown in Figure 2. Weaving machines, or looms, may be classified as single-phase or multiphase machines. In a single-phase machine, one weft thread is inserted across the full width of the warp sheet during each weaving cycle and is then beaten to the fell. The weft may be inserted either by means of a shuttle, as in shuttle looms, or without a shuttle, as in shuttleless looms. Shuttle looms may be manual, power-operated non-automatic, or automatic. In non-automatic power looms, the exhausted weft package in the shuttle must be replaced manually.

Figure 2: Classification of weaving machine

Shed Formation in Weaving: How It Works

The shed formation mechanism divides the warp into two groups for the insertion of the weft. One group is lifted while the other is lowered or held down, creating the open channel called the shed. Shed formation is the central element of weaving technology. Each warp end passes through a single heddle, which has a central eye for the warp and points of attachment above and below for connection to the shedding mechanism. The mechanism operates by raising or lowering the heddles and, therefore, the warp ends. There are two main methods of actuating the heddles:

Through heald shafts or harnesses, which hold many heddles and move them as a group
Through thin harness cords, which connect individual heddles to the shedding mechanism

On looms with only a few heald shafts or harnesses, the shedding motions are relatively simple. More elaborate woven designs require more complex shedding motions.

Tappet, Dobby, and Jacquard Looms: A Comparison

Depending on the design requirement, displacement of the warp on power looms may be controlled by tappets or cams, by dobby mechanisms, or by Jacquard mechanisms. Tappet and dobby mechanisms control warp ends in groups, whereas the Jacquard mechanism can control individual warp ends or very small groups. The main loom types, categorized by their shedding motion, are as follows:

Crank or cam shedding—used mainly for plain weave and other simple structures
Cam looms—commonly used with a limited number of heald shafts, often up to about eight, for plain, simple twill, and simple satin weaves
Dobby looms—used for designs requiring a larger number of shafts, typically about 8 to 32, and suitable for more complex twills, satins, small geometric figures, spot weaves, and pattern stripes
Jacquard looms—used when individual warp ends must be controlled to produce figured or highly intricate designs

Simple fabrics with simple designs can be produced on tappet looms. On such looms, it is difficult and uneconomical to produce large pattern repeats. Dobby mechanisms are more suitable when a greater number of heald shafts is required for design development. Because many shaft combinations are possible, decorative weaves and more complex patterns with larger warp and weft repeats can be produced on dobby looms, where the warp yarns form the shed collectively under shaft control. The dobby controls shaft movement by mechanical or electronic means and is relatively easy to maintain and operate. It also allows comparatively quick style changes. Even so, the design is limited because the warp can be divided only into a finite number of independently controlled groups.

Jacquard Weaving: Features and Applications

Complicated or figured designs require a much larger number of independently controlled warp ends, ranging from many hundreds to many thousands. This is achieved by the Jacquard shedding mechanism. In this system, the number of controlled elements increases dramatically, while the number of warp ends assigned to each control point may be reduced to one. Because each control point is associated with an individual heddle, a conventional shaft frame is not required. Instead, each hook in the Jacquard mechanism is connected by a harness cord to its corresponding heddle. Each warp end passes through its own heddle and lies adjacent to only a few neighbouring heddles, allowing much higher heddle density and patterning freedom. The Jacquard mechanism may be mounted on a handloom or a power loom and controls a large number of warp threads to produce the widest possible variety of sheds for figured and ornamental fabrics.

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Jacquard machines are used to produce large-pattern fabrics with substantial warp and weft repeats. The lifting of the warp threads is operated independently according to the design, which is essential for fabrics in which each warp yarn must participate in shed formation on its own. Historically, individual pattern cards were used, with one control step corresponding to each pick in the weft direction. In modern electronic Jacquard systems, the pattern is stored digitally, allowing very large repeats without the practical limitations of physical cards.

Jacquard shedding is especially suitable for producing intricate ornamental designs in form and colour when a large number of warp threads must be controlled individually. Its scope includes the following:

Production of large or figured designs that cannot be produced economically by tappet or dobby mechanisms
Individual and independent control of warp threads, rather than grouped control as in tappet or dobby shedding
Replacement of shaft-based heald control by an individual harness system
The ability to lift thousands of yarns in a single weaving cycle, depending on the machine and harness arrangement

Modern Weaving Technology

In automatic shuttle looms, the weft supply to the shed is maintained continuously by shuttle changing or cop changing immediately after the weft package in the shuttle is exhausted. In shuttleless looms, the weft is inserted by lighter carriers such as rapiers or projectiles, or by a fluid medium as in air-jet or water-jet weaving. In these machines, air or water propels the weft through the shed without the use of a shuttle. Shuttleless looms generally eliminate the need for pirn winding.

In multiphase weaving machines, several phases of the weaving cycle occur simultaneously, so several picks can be at different stages of insertion at the same time. These machines are commonly classified according to their shed formation. In wave-shed machines, different parts of the warp sheet are at different stages of the weaving cycle at any given moment, making it possible for a series of shuttles or weft carriers to move successively through the shed. In parallel-shed machines, several sheds are formed simultaneously, each extending across the full width of the warp, and the sheds move in the warp direction. In some specialized machines, shuttles or carriers travel around a continuous path; this principle is used in circular weaving machines.

Yarn Requirements for Weaving

Warp yarns are subjected to repeated extension during shedding and beating-up, as well as bending stress and frictional forces. Therefore, warp yarns must possess considerable strength, flexibility, elasticity, and resistance to abrasion. They must also be sufficiently smooth and uniform. Weft yarns are less affected by these forces. As a result, weft yarns may be lower in strength than warp yarns, but they should still have adequate flexibility and elasticity for efficient insertion and stable fabric formation.

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Triaxial Weaving

A different type of modern weaving is called triaxial weaving. It uses three yarn systems, rather than two orthogonal systems, with the yarns arranged at approximately 60-degree angles to one another. This configuration can provide more balanced strength in multiple directions, and fabrics made by this method show high resistance to tearing and distortion. Triaxial weaving is used in technical textiles such as sailcloth, filter fabrics, and certain composite and furnishing applications.

Conclusion

Woven fabric is formed through the systematic interlacement of warp and weft yarns on a loom. Its structure, properties, and design possibilities depend on the characteristics of the yarns, the sequence of weaving motions, and the type of shedding and weft insertion system used. Overall, understanding how woven fabrics are made helps explain the development of fabrics from simple constructions to advanced technical and decorative textiles. From simple handlooms to advanced shuttleless, multiphase, and Jacquard-controlled machines, weaving technology has evolved to produce fabrics ranging from basic constructions to highly intricate technical and decorative textiles.