TPI (twists per inch or turns per inch) is a term used in the textile industry. It measures how much twist a yarn has, [1] and can be calculated by counting the number of twists in an inch of yarn. [2]
TPI (twists per inch or turns per inch) is a term used in the textile industry. It measures how much twist a yarn has, [1] and can be calculated by counting the number of twists in an inch of yarn. [2]
Twist is needed in yarn to hold the fibres together, and is added in the spinning and plying processes. [2] The amount of twist varies depending on the fibre, thickness of yarn, preparation of fibre, manner of spinning, and the desired result. [2] Fine wool and silk generally use more twist than coarse wool, short staples more than long, thin more than thick, and short drawn more than long drawn.
The amount of twist in a yarn helps to define the style of yarn – a yarn with a lot of air such as a woollen-spun yarn will have much less twist than a yarn with little air such as a worsted-spun yarn. The amount of twist also affects the yarn in terms of stretchiness, strength, halo, and many other attributes. Filling or weft yarns usually have fewer twists per inch because strength is not as important as with warp yarns, and highly twisted yarns are, in general, stronger. Warp yarns have to be stronger so that they can withstand the tension of the loom. Filament fibers, such as silk, or many synthetics, need only be twisted slightly to create a yarn.
Handspinners use the number of twists per inch often. Because the amount of twist defines a lot about a yarn, the number of twists per inch is an important measure to recreate a yarn. As a spinner spins, they will often stop every few minutes to check to see that the number of twists per inch is the same throughout the yarn, as well as that the number of wraps per inch (the thickness of the yarn) is the same. Measuring the number of twists per inch while spinning singles also helps the spinner create a balanced yarn when plying. Yarns that have relatively few twists per inch tend to have a softer hand but are not as strong as yarns with more twists per inch, such as medium twist or hard twist yarns. Yarns that have a very hard twist, enough so that the yarn will double back onto itself when released from tension, are called crepe-twist yarns.
The number of twists per inch can, in plied yarns, be determined by counting the number of bumps in one inch, and dividing that number by the number of singles (the strands plied together to make the yarn). [2] If the adjacent picture, for example, was of an inch of two ply yarn, then the number of twists per inch would be 6 divided by 2, or three, as there are six bumps, and it is a two ply.
While this method works well with plied yarns, singles don't have bumps to count. One way to determine the tpi for a single is to add a contrasting color fibre when spinning it, and then count the number of times the contrasting fibre has wrapped around the yarn. Another method is to measure an inch of yarn and untwist it, counting how many full revolutions it takes until there is no twist left. This can be done by inserting two paper-clips into the yarn, at an inch apart, thus making it easier to count a full revolution. [2] A less precise method is to allow the single to ply against itself: the resulting two ply yarn is about half the number of twists per inch of the single. [2] Thus one can roughly find the number of twists per inch for the single, or one can use the doubled back yarn as a measure.
With a thick-and-thin yarn, it is best to count the twist over several inches and average the results. [2] This is because the number of twists per inch will tend to vary between the thin and thick sections.
In the industry the number of twists per inch is calculated as:
where is the Twist Multiplier, also known as or the Twist Factor. This Twist Multiplier is an empirical parameter that has been established by experiments and practice that the maximum strength of a yarn is obtained for a definite value of K. In the case of ring spun cotton yarns, for example, the following values of K have been found to give the best results.[ citation needed ]
Warp yarns, 35's and less 4.75 Warp yarns, 35's to 80's 4.50 Warp yarns, 80's to 110's 4.25 Filling yarns, medium numbers 3.50
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Crochet is a process of creating textiles by using a crochet hook to interlock loops of yarn, thread, or strands of other materials. The name is derived from the French term crochet, meaning 'hook'. Hooks can be made from a variety of materials, such as metal, wood, bamboo, or plastic. The key difference between crochet and knitting, beyond the implements used for their production, is that each stitch in crochet is completed before the next one is begun, while knitting keeps many stitches open at a time. Some variant forms of crochet, such as Tunisian crochet and broomstick lace, do keep multiple crochet stitches open at a time.
Knitting is a method by which yarn is manipulated to create a textile, or fabric. It is used to create many types of garments. Knitting may be done by hand or by machine.
Spinning is a twisting technique to form yarn from fibers. The fiber intended is drawn out, twisted, and wound onto a bobbin. A few popular fibers that are spun into yarn other than cotton, which is the most popular, are viscose, and synthetic polyester. Originally done by hand using a spindle whorl, starting in the 500s AD the spinning wheel became the predominant spinning tool across Asia and Europe. The spinning jenny and spinning mule, invented in the late 1700s, made mechanical spinning far more efficient than spinning by hand, and especially made cotton manufacturing one of the most important industries of the Industrial Revolution.
Yarn is a long continuous length of interlocked fibres, used in sewing, crocheting, knitting, weaving, embroidery, ropemaking, and the production of textiles. Thread is a type of yarn intended for sewing by hand or machine. Modern manufactured sewing threads may be finished with wax or other lubricants to withstand the stresses involved in sewing. Embroidery threads are yarns specifically designed for needlework. Yarn can be made of a number of natural or synthetic materials, and comes in a variety of colors and thicknesses. Although yarn may be dyed different colours, most yarns are solid coloured with a uniform hue.
Worsted is a high-quality type of wool yarn, the fabric made from this yarn, and a yarn weight category. The name derives from Worstead, a village in the English county of Norfolk. That village, together with North Walsham and Aylsham, formed a manufacturing centre for yarn and cloth in the 12th century, when pasture enclosure and liming rendered the East Anglian soil too rich for the older agrarian sheep breeds. In the same period, many weavers from the County of Flanders moved to Norfolk. "Worsted" yarns/fabrics are distinct from woollens : the former is considered stronger, finer, smoother, and harder than the latter.
Carding is a mechanical process that disentangles, cleans and intermixes fibres to produce a continuous web or sliver suitable for subsequent processing. This is achieved by passing the fibres between differentially moving surfaces covered with "card clothing", a firm flexible material embedded with metal pins. It breaks up locks and unorganised clumps of fibre and then aligns the individual fibres to be parallel with each other. In preparing wool fibre for spinning, carding is the step that comes after teasing.
Woolen or woollen is a type of yarn made from carded wool. Woolen yarn is soft, light, stretchy, and full of air. It is thus a good insulator, and makes a good knitting yarn. Woolen yarn is in contrast to worsted yarn, in which the fibers are combed to lie parallel rather than carded, producing a hard, strong yarn.
In the textile arts, plying is a process of twisting one or more strings of yarn together to create a stronger yarn. Strands are twisted together in the direction opposite that in which they were spun. Plied yarns will not unravel, break, or degrade as easily as unplied yarns. When enough twist is added to the plies to counter the initial twist of each strand, the resulting yarn is "balanced", having no tendency to twist upon itself.
A spindle is a straight spike usually made from wood used for spinning, twisting fibers such as wool, flax, hemp, cotton into yarn. It is often weighted at either the bottom, middle, or top, commonly by a disc or spherical object called a whorl; many spindles, however, are weighted simply by thickening their shape towards the bottom, e.g. Orenburg and French spindles. The spindle may also have a hook, groove, or notch at the top to guide the yarn. Spindles come in many different sizes and weights depending on the thickness of the yarn one desires to spin.
Textile Manufacturing or Textile Engineering is a major industry. It is largely based on the conversion of fibre into yarn, then yarn into fabric. These are then dyed or printed, fabricated into cloth which is then converted into useful goods such as clothing, household items, upholstery and various industrial products. Overall, many things can be made with cotton, not just clothing.
The spinning mule is a machine used to spin cotton and other fibres. They were used extensively from the late 18th to the early 20th century in the mills of Lancashire and elsewhere. Mules were worked in pairs by a minder, with the help of two boys: the little piecer and the big or side piecer. The carriage carried up to 1,320 spindles and could be 150 feet (46 m) long, and would move forward and back a distance of 5 feet (1.5 m) four times a minute. It was invented between 1775 and 1779 by Samuel Crompton. The self-acting (automatic) mule was patented by Richard Roberts in 1825. At its peak there were 50,000,000 mule spindles in Lancashire alone. Modern versions are still in niche production and are used to spin woollen yarns from noble fibres such as cashmere, ultra-fine merino and alpaca for the knitware market.
The Orenburg shawl is a Russian knitted lace textile using goat down and stands as one of the classic symbols of Russian handicraft, along with Tula samovars, the Matrioshka doll, Khokhloma painting, Gzhel ceramics, the Palekh miniature, Vologda lace, Dymkovo toys, Rostov finift (enamel), and Ural malachite.
Spinning is an ancient textile art in which plant, animal or synthetic fibres are drawn out and twisted together to form yarn. For thousands of years, fibre was spun by hand using simple tools, the spindle and distaff. It was only with the invention of the spinning wheel in the Islamic world circa 1030, and its subsequent introduction to China, India and Europe in the High Middle Ages, that the output of individual spinners dramatically increased. Mass production later arose in the 18th century with the beginnings of the Industrial Revolution. Hand-spinning remains a popular handicraft.
The manufacture of textiles is one of the oldest of human technologies. To make textiles, the first requirement is a source of fiber from which a yarn can be made, primarily by spinning. The yarn is processed by knitting or weaving, which turns yarn into cloth. The machine used for weaving is the loom. For decoration, the process of colouring yarn or the finished material is dyeing. For more information of the various steps, see textile manufacturing.
Textile fibers, threads, yarns and fabrics are measured in a multiplicity of units.
A staple fiber is a textile fiber of discrete length. The opposite is a filament fiber, which comes in continuous lengths. Staple length is a characteristic fiber length of a sample of staple fibers. It is an essential criterion in yarn spinning aids in cohesion and twisting. Compared to synthetic fibers, natural fibers tend to have different and shorter lengths. The quality of natural fibers like cotton is categorized on staple length such as short, medium, long-staple and, extra long. Gossypium barbadense, one of several cotton species, produces extra-long staple fibers. The staple fibers may be obtained from natural and synthetic sources. In the case of synthetics and blends, the filament yarns are cut to a predetermined length.
Novelty yarns include a wide variety of yarns made with unusual features, structure or fiber composition such as slubs, inclusions, metallic or synthetic fibers, laddering and varying thickness introduced during production. Some linens, wools to be woven into tweed, and the uneven filaments of some types of silk are allowed to retain their normal irregularities, producing the characteristic uneven surface of the finished fabric. Man-made fibres, which can be modified during production, are especially adaptable for special effects such as crimping and texturizing.
Textile manufacturing is one of the oldest human activities. The oldest known textiles date back to about 5000 B.C. In order to make textiles, the first requirement is a source of fibre from which a yarn can be made, primarily by spinning. The yarn is processed by knitting or weaving to create cloth. The machine used for weaving is the loom. Cloth is finished by what are described as wet process to become fabric. The fabric may be dyed, printed or decorated by embroidering with coloured yarns.
Bradford Industrial Museum, established 1974 in Moorside Mills, Eccleshill, Bradford, United Kingdom, specializes in relics of local industry, especially printing and textile machinery, kept in working condition for regular demonstrations to the public. There is a Horse Emporium in the old canteen block plus a shop in the mill, and entry is free of charge.
Doubling is a textile industry term synonymous with combining. It can be used for various processes during spinning. During the carding stage, several sources of roving are doubled together and drawn, to remove variations in thickness. After spinning, yarn is doubled for many reasons. Yarn may be doubled to produce warp for weaving, to make cotton for lace, crochet and knitting. It is used for embroidery threads and sewing threads, for example: sewing thread is usually 6-cable thread. Two threads of spun 60s cotton are twisted together, and three of these double threads are twisted into a cable, of what is now 5s yarn. This is mercerised, gassed and wound onto a bobbin.
