Woven fabrics are made by interlacing two sets of yarns at right angles to each other. The lengthwise yarns are known as warp yarns or ends, while the widthwise yarns are known as filling yarns or picks. The lengthwise edges of the fabric are the selvages. The selvage is usually easily distinguishable from the rest of the material.
Warp yarns and filling yarns
One way to better understand the characteristics of woven fabric is to know the differences between the warp yarns and the filling yarns. Since swatch is mounted with the warp yarns vertically, it must be determined which set of yarns is the warp so the mountings will be correct. Also, clothes are usually cut with the warp yarns running the length of the garment, so the lengthwise drapability of the fabric must be checked by the garment designer to be sure that it meets the garment requirements.
Yarn differentiation is necessary. A textile technician making a complete analysis of a cloth must be able to identify both the warp and filling yarns in order to report such information as their size, twist per inch and fiber content.
There are three basic weaves. They are plain weave, twill weave and satin weave. All other weaves are a variation or a combination of these weaves.
The plain weave is the simplest and the most used weave. It is found in a wide range of fabrics, from the sheerest to the heaviest. There is only one plain weave, but there are many different twill and satin weaves. Fabrics with a plain weave are reversible unless one side is made the face by finishing or printing.
Twill weaves produce diagonal lines on the cloth. In a right hand twill, the diagonals run upward to the right. In a left hand twill, the lines run upward to the left. A herringbone weave has vertical stripes of both right and left hand twills. The direction of the twill on the back of the cloth is opposite to what it is on the face.
In a true satin weave, there is only one interlacing for each warp yarn, and only one interlacing for each filling yarn in each repeat of the weave.
Also, no two interlacings ever touch or are adjacent. Thus, the satin weave fabrics have relatively long floats.
The machine used for weaving fabric is a loom. The following is a simplified explanation of the weaving process using a conventional shuttle loom.
Looms are divided into various categories. The two major ones are based upon the method of filling insertion. Looms that use shuttles are called conventional shuttle or fly shuttle looms. Looms that use other devices to bring the filling yarn through the shed are called shuttleless looms. The source of yarn for shuttleless looms is cones placed at the sides of the loom. Once the filling yarn is inserted completely (through the shed) the yarn is cut, leaving a little fringe at the edge of the fabric.
The selvage is the lengthwise edge of a fabric. It is usually about 1/4 to 1/2 inch wide and exists on both sides of the cloth. It is actually a self-edge, but the term selvage is now used.
The main purpose of this area is to insure that the edge of the fabric will not tear when the cloth is undergoing the stresses and strains of the finishing process.
Various techniques are used to make the selvage area stronger than the body, including: (a) heavier warp yarns; (b) more warp yarns per inch; (c) plied warp yarns; (d) greater twist, if spun warp yarns; and (e) use of different weave. Since the selvage is usually constructed differently than the body, it is usually easy to identify.
Warp yarns and filling yarns
One way to better understand the characteristics of woven fabric is to know the differences between the warp yarns and the filling yarns. Since swatch are mounted with the warp yarns vertically, it must be determined which set of yarns is the warp so the mountings will be correct. Also, clothes are usually cut with the warp yarns running the length of the garment, so the lengthwise drapsbility of the fabric must be checked by the garment designer to be sure that it meets the garment requirements.
Comparison of basic weaves
Fabric performance and characteristics
A woven textile fabric is described citing its average width, length, number of yarns per inch in warp and filling, yarn size, and weight in ounces per square or linear yard. This information is important to product manufacturers who are billed for the fabric. If fiber content is known and constant, it provides a basis for price comparison and for determination of suitable end uses.
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