When you get interested in fabrics, you will inevitably be fascinated by how the threads interlace together in woven fabrics to form their basic structure. And warp and weft yarns form the basis for the fabric structure.
The weaving process involves two distinct elements: warp and weft yarns. Understanding these integral components of fabric production can help us better appreciate the making of fabrics.
Warp and weft threads are the components that make up a woven fabric. A woven fabric is made by weaving the weft and warp thread in various patterns. Different types of fabrics with different textures and patterns are made by varying the interlacing of the same set or different sets of warp and weft yarn.
Warp threads are the lengthwise thread, and the weft threads are the crosswise threads. The warp yarns are positioned on the fabric’s straight grain and run parallel down the fabric roll. Another name for warp yarn is End.
Weft yarns run crosswise in the opposite direction along the crosswise grain of the material. To make it clearer, weft is the yarn running from selvage to selvage. The weft yarns are also called filling threads. The alternate name for weft yarn is Pick.
Warp vs Weft
The most common fabrics fall under these weaves – 1/1 plain weave, 1/2 twill weave, 3/1 twill weave, 2/2 twill weave, 2/2 rib weave, basket weave, and satin weave. And in all of them, the warp thread lies parallel to the selvage and weft yarn lies crosswise to the selvage.
In any given fabric, the warp and weft thread can vary in texture, counts, picks, the twist of the yarn, and even their origin.
If you take a lot of fabrics, you will find that warp yarns are thicker and stronger. The weft yarns will be thinner and a lot less strong. The warp threads are stronger for a reason – they are stretched and held on the beams of the weaving loom.
Features of warp and weft
The colors used in the warp and weft threads can decide the color of the fabric. If color used in the weft thread is different from the color of the warp thread there is a two tone effect. Textured yarns or yarns with greater twists are usually introduced in the weft direction.
The type of yarn used in the warp and weft can make all the difference to the characteristic nature of the fabric. For e.g., when thin breakable fibers like rayon are used, there is a chance of contraction when the weaving is finished.
The yarn tension of either of the yarns, either warp or weft, has a butterfly effect on other aspects of the fabric like shrinkage. When shrinkable fibers like cotton and linen are used, there is a possibility of shrinkage in one direction and puckering.
Other variables like yarn tension on the loom, the count of both warp and weft yarns, and the weave structure, decide the final fabric you get in weaving. The importance of warp and weft can be seen in the appearance, texture, strength, and drape of the fabric.
Weft and warp yarns of common fabrics
A 100% cotton fabric will have cotton weft and warp yarns. A polycotton blend fabric may have polyester yarns in the weft.
A poplin fabric has characteristic ribs in the weft direction. Stretch woven fabrics usually have spandex fibers as weft yarns.
Warp and weft in knitting
In knitting, warp refers to a type of knitting in which yarns are laid out lengthwise /warp direction; a set of parallel yarns is used to create a fabric. It is the most basic form of knitting and produces durable and stable warp-knit fabrics.
In Weft knitting, the weft yarns are held in the width-wise or weft direction, and the knitting is done by going in and out with the yarns creating the necessary loops and stitches to form the fabric. The weft knits are more elastic and drapey than warp knits.