knit 144 Textile Technology • • Applications • • •  Formats

Warp Sheet jacquard knittingwithindependently controlled guidebars. Coloured andpatterned fabrics are produced usingraschel spacer andopenwork textiles for avariety ofapplications. process. With this technology it is possible to make plain, tubular, the stitches are madesimultaneously, makingthisavery rapid In warpknitting,oneormore are fed to eachneedle and Footwear Apparel Spacer Tubular Plain

Layers • • • Technical Interior ) Openwork (net and

Block • • • Quality • •  Materials Dimensional stability Continuous Intermeshed structure less prone to ravel Natural andsynthetic Staple, filamentandnovelty yarn Composite

Shaped

Relief • •  Costs • • • Related Technologies Very rapid cycle time Low to moderate unitcost Weft lace Fancy loom weaving

Pattern lingerie andgloves.lingerie Jacquard knittingis sportswear, swimwear, underwear, capable of, plusseamlessandlightweight single bedsareto make that used all bannersandawnings.advertising conveyor belts, safety clothing,tarpaulin, reinforcing composite laminates, ends,fringed suchasscarves. produce sequential lengthsoffabric with to suited well knitting isparticularly mosquito netsandpackaging. Warp underwear, curtains, fishingnets, to makeLace andnetsare used garments, garments, andupholstery. underwear are usedflat,that into andsewn cut or to make fabrics plainandpatterned machinesareSingle needle-bed used Applic seamless sportswear. to make and such asused upholstery may beincorporated into asolidground, By combining different looppatterns, net of densities, fromto finelace. heavy cloth produced. canbemadeinarange Andit yarninserted may andopenstructures be separate yarn, arange ofinterlocked, knitted structure. yarnsneighbouring to produce acohesive guide barandsointermeshes with yarntracked is the to sideby from side machine . With eachstitch, the to 5,000up ends, the dependingon of may consist t-shirt So along-sleeved Each isfed needle withoneormore yarns. (courses),the caseinweft knitting. asis single yarnthe fabricthe widthof across lengthways (wales), to a asopposed between multipleyarns running 126). isformed loopedstructure The than weft knitting(page development Machine warp knittingisamore recent Introduc Double needle-bed machinesareDouble needle-bed Industrial applicationsinclude With eachstitchbeingformed bya ations tion

Yarn looped The sideways movement produces azigzag and backagain,produces anatlasstructure. direction for aspecificnumberof courses, guide bar. Lappingthestitches inthesame as ahalftricot, isproduced withasingle The basicwarpknit,whichisalsoknown are usedto make flatsheetsof textile. formed simultaneously. structure. Eachloop inthesamecourse is thus creating azigzagging intermeshed yarn ispassed from onecourse to thenext, around theneedle witheachcycle. Thewarp a warpguide.Theguidepasses theyarn loop formation are different. the loops andtherange ofpossibilities for like weft knitting.However, thestructure of Warp knittingforms courses andwales, just Technical description The Warp KnittingProcess around needle needle Single-bed machines, known astricot, Each needle is fed aseparate yarn via Warp guide Latch Single-bed warpknitting yarn length of Continuous away Textile pulled technical back Diamond net Course lock-knit, double atlas(thetwo guidebars Other typesoftwo-bar fabric include the loops, seeStitch Bonding, page196). with inlaidweft thatdoesnotpass around (for adetailed descriptionofwarpknitting which isoverlapped byasecond guidebar must beconnected by aninserted yarn, stitches thatform unconnected wales. They knitting onraschel jacquard. only balanced netsare possible, unless same barwillbethesame.Thismeansthat tandem, soeachstitch inacourse onthe knitting machines,theguidebars move in an openwork structure. Withconventional either direction isusually permitted. the tension ontheyarn, only oneoverlap in pattern down thelength ofthefabric. Dueto A pillarstitch ismadeupofchains Overlapping theyarns atintervals forms Basic (orhalftricot) technical back of knitting) Wale (direction Pillar stitch withyarn insertion Inlaid warp complex patterns are reproduced. is controlled independently. This ishow produced. With jacquard, eachyarn guide structures, suchasgloves andt-shirts,are at anypoint.Thisishow seamless tubular overlapped between bothsetsofneedles to back.Withthisset-up,yarns maybe machines (page134)withtheneedles back up inasimilarwayto V-bedweft-knitting bars for eachbed(sixintotal). They are set needle bedsmay have upto three guide needle beds. Machines equippedwithtwo may have upto four guidebars. into aknitted structure). Tricot machines floats are formed on the technical back,tied balanced fabric) andpile structures (long mirror eachother’s movements to create a technical back Raschel machineshave oneortwo Single atlasstructure technical back

Pillar stitch

warp knitting warp 145 warp knitting 147 Technical back Technical Atlas Polyester Material: Laminating Application: produces back and forth The lapping movement Notes: the fabric. down a zigzag pattern Textile Spacer PP Material: Upholstery Application: is held diamond net structure A double-faced Notes: a cushioning fabric. produce to yarns by spacer together face Technical Inlay with Textured Pillar Stitch Ramie and nylon Material: Bath cloth Application: with inlaid warp to combined are Pillar stitches Notes: a wavy structure. creates yarn a grid. The textured form rinted Net Printed and elastane Polyester Material: Hosiery Application: reproduced are patterns and intricate Complex Notes: printing. by transfer Technical back Technical titch Mesh Pillar Stitch Polyester Material: apparel Technical Application: stretch underlapping reduces Horizontal Notes: structures. in openwork particularly Tricot Polyester Material: Sports shoe Application: with good cover, has a smooth face tricot Full Notes: printing. for making it an ideal fabric Net Colour Two- and elastane nylon Polyester, Material: Hosiery Application: different to react yarn types of different The two Notes: knitting. after be coloured types, so can dye Diamond Net PE Material: packaging Fruit Application: strong form to together is knitted strip Plastic Notes: fruit and vegetables. packaging for and lightweight Technical face Technical cs abri itted f arp-kn Technical back Technical back Technical back Technical arn ovelty Y Novelty and elastane nylon Wool, Material: Hosiery Application: in the knitted incorporated are yarns Novelty Notes: and feel. a unique look create to structure olour Raschel Jacquard Colour Two- and elastane nylon Polyester, Material: Sportswear Application: and plated knitted jacquard are types of yarn Two Notes: or hide it inside. the front, to either bring the colour to ary: w l Gloss Visua Half Tricot Polyester Material: lining Apparel Application: with a produced is a sheer fabric Half tricot Notes: lapping motions. guide bar making repeated single oneycomb Mesh Honeycomb polyester Titanium-coated Material: lining Apparel Application: used for meshes are Nanometal-coated Notes: lining. such as heat retention applications, technical Technical face Technical face Technical face Technical

Spacer Spacer textile made up of is face two inserted visual are provide to Yarns it is insertionWith the yarn technique, is there knitting, to weft Compared is fabrics of warp-knitted The surface in one of is applied ways: three Colour industrial linings and geotextiles.linings and industrial which connected yarn, by spacer fabrics is perpendicular fabrics. to face the outer and resistance density to The thickness, determined by stitch and are compression selection. yarn or performance-enhancing properties weft, stitch bonding with inlaid (see also have fabrics Weft-insertion page 201). and warp- laid in across the wales, yarn laid in-line yarns insertion knits have many are There with the vertical chains. such benefits of using these techniques, that yarns otherwise as introducing to knitwould be impractical (too delicate, or reducing too coarse too fine) and and recovery, stretch or increasing Combined or weight. surface handle, and yarns different with jacquard, colour, used are to provide configurations bulk and so on. stretch, graphics, pattern, bi- and multiaxial possible uni-, to make high-performance such as for textiles, sets One or more laminates. composite be inserted may into the secure of yarns knitted structure. applied during less stress to the yarn knitting is warp Therefore, production. relatively used from to construct fabrics aramid such as glass, yarns, less-flexible and carbon. techniques, conventional finished with Pile (page 220). such as calendering or with is made using inserted yarns, which are tied into floating stitches, secure structure the ground to form Cut pile be made by cutting may loops. splitting double-faced or by looped pile, These fabrics. two cut-pile to make fabric velour velvet, used techniques are to make fur. and fake piece dyeing yarn, knitting coloured or printing (page 240) the knitted item, (pages 256–79). up warp-knitting Setting because process, machines is a lengthy each for ends are threaded one or more to it efficient is more Therefore, needle. and dye the yarn knit plain-coloured By mixing twofinished garment. types

Knitting with two sets of yarn requires requires Knitting with two sets of yarn knitting is the most versatile Warp Warp-knitted fabrics are less likely less likely are fabrics Warp-knitted common are knits warp Lightweight or more courses. courses. or more provides which guide bars, two or more As in weft design freedom. greater the knitting, settwo needle beds are up in this raschel, Known as V configuration. a double- of producing technique is capable tubular and openwork structures. faced, (independent And by adding jacquard and intricate complex guide bars), into the patterns be introduced may this jacquard, raschel Termed structure. butis of knitting, the most form versatile itbecause of of movement the complexity challenging is very to design for. They can range nets. making for process to wide open, semi-breakthrough from other Like depending on the structure. resistant they are structures, warp-knitted Therefore, and runs. ravelling to slipping, used many types of they are to produce packaging, including lightweight net, Design are known as also tricot, Basic fabrics, and knitted with a single set of yarns a stitch is Because single guide bar. on each needle simultaneously, formed the machine can run at high speed very Tricot per minute. courses – up to 2,000 fancy of producing capable machines are up over yarns five to by floating fabrics satin soft textiles are example, For wales. pile by breaking is made with high lustre; the floats during finishing (see napping, constructed by and nets are page 216); one knitting pillars for without overlap on the back. on the back. stretch and little or no crosswise stretch stretch crosswise or no and little stretch across more stretch fabrics (weft-knit And certain constructions, their width). (page nonwovens such as stitch-bonded virtually have may weft, 196) and inlaid in either direction. stretch zero types, and run than weft-knitted to ravel because structurethe loop formed is in a intermeshed yarns multiple from formation. zigzag and because soft they are in sleepwear, are The simplest fabrics good drape. have on by vertical ribs (wales) characterized ribs (courses) and horizontal the face The amount of stretch depends on The amount of stretch the Warp knitting is used to make double- knitting is used to make Warp Warp knitting is faster than weaving than weaving knitting is faster Warp Both weft and warp knitting are knitting are and warp Both weft stitch and the yarn. Warp-knitted fabrics fabrics Warp-knitted stitch and the yarn. of lengthwise amounts varying have Thanks to the different number of needle Thanks to the different a wide beds and guide bar arrangements, be achieved, can qualities of fabric variety dense stable to high stretch; from ranging and single- to smooth to lofty; to open; double-faced. Quality faced and spacer textiles, similar to fancy similar to fancy and spacer textiles, faced Both technologies are (page 84). weaving constructions such as used in composite laminating and thermoplastic molding (page 446). and capable of producing larger widths, widths, larger of producing and capable regard With it economical. making more of design is a wider range there to lace, owing to the different opportunities, Machines fitted with loop structures. bars guide controlled independently (jacquard) very of producing capable are patterns similar and intricate complex to lace (page 108). Leavers capable of producing seamless garments seamless garments of producing capable A significant in a single operation. knitting is of warp the design advantage opportunities of openwork structures. garments lightweight example, For support and stretch, with localized in a single produced are breathability In addition multiple yarns. from operation openwork structures in a solid to creating the in a be combined two may ground, layer single sheet a honeycomb to create known semi- as on top of the ground, breakthrough. Warp knitting is not as straightforward not knitting is as straightforward Warp and so knitting, as weft to design for used Processes used. less widely remains finished garments, to join panels into only are 386), such as linking (page loop with compatible the weft-knitted fabrics warp-knitted although structure, by lock stitching (page 355). be joined may ies ed technolog relat used to make nets and lace employed nets and used to make from of applications, manner in all sportswearand lingerie uppers, to shoe upholstery. and products medical

knit 146 Case Study w Warping

In preparation for warp knitting, filament yarn is wound onto cones. From a creel, 256 ends are gathered together with a fine comb image( 1). The yarn is coated with a layer of synthetic oil (natural yarns are coated with paraffin wax) as it passes over a roll (image 2). The coating reduces friction between the yarns and so improves knitting efficiency. It takes roughly an hour to fill a beam (image 3). The northern Italian company Cifra uses machines with 3 m (9.8 ft) beds. Six beams are required to cover the length of the bed (image 4). The double- warp knitting bed machines use up to three beams on either side, so 36 in total. Each end is carefully threaded through K nit the machine and into the guide bar (image 5). It is a delicate process and can take several operators half a day or 148 149 more to replace the yarns on a machine

(image 6). Therefore, Cifra warp knits all 1 of its garments in plain white and dyes 4 the finished items if colour is required. Using two different types of yarn, such as polyester and nylon, means that two different colours can be achieved with dyeing (page 240).

2 3

of yarn that are affected by different Costs Environmental impacts types of dye, multicoloured patterns Warp knitting is a very rapid process, Like weft knitting, this is an efficient can be achieved. able to produce hundreds of courses per process and generates very little waste. minute. It is possible to produce wide Producing garments in a single operation Materials lengths of fabric or several narrow strips. removes pattern cutting and sewing, Man-made filament yarns (page 50) are In this way, a single machine may be further reducing or even eliminating the most commonly utilized, owing to capable of producing several garments waste completely. Warp-knitted spacer 5 the high consistency required, although at once, further reducing cycle time. fabrics are used in place of polymer 6 staple and are also used. The high consistency of yarn required foams, such as polyurethane (PU) in Frequently used filament yarns include increases costs slightly. cushioning applications. silk, nylon, polyester, polypropylene (PP), Setting up the machine takes longer The source of yarn is important; polyethylene (PE), viscose and elastane. than weft knitting if the yarns need to natural yarns should be from sustainable Technical yarns are warp knitted for be changed, because each needle is sources and processed with consideration high-performance applications, such as fed with a separate end. Knitting a for people and the environment. The Featured Company composite-laminated structures. These single colour and piece dyeing finished amount of recycled content in synthetic Cifra S.p.A. include carbon, aramid and glass. garments saves time and cost by reducing yarns varies according to the type of www.cifra-spa.net machine downtime. plastic and the supplier. Case Study w Seamless Warp Knitting

Seamless garments are produced on raschel behind (image 4). The needle is pulled jacquard machines. The fabric is made up of downwards, catching the yarns placed in pillar stitches, underlapped and overlapped front and forming a stitch (image 5). The with inserted yarn. With this technique, second bed of needles rises up and the openwork structures are seamlessly sequence is repeated in reverse. combined with plain fabric to make fitted The process is very rapid: up to 600 garments (image 1). courses are completed every minute and Plain white yarn, in this case polyester, the knitted item is drawn downwards is fed from the beams into the guide bars under tension (image 6). The finished (image 2). These are fine-gauge machines garment emerges from the machine and with 24 needles per 25.4 mm (1 in.). The more is ready to be dyed (image 7). needles per inch, the lower the diameter of Garments are checked to make sure

yarn that can be knitted and the higher the the knitting process is running without 1 7 8 9 density of fabric that can be produced. errors (image 8). A long-sleeved t-shirt warp knitting Each guide bar moves through three like this comprises around 1,322,000 actions with each stitch. When the needle stitches and a single one out of place Case Study has cleared the previous loop the guide bars will show up on the finished product. It K nit move forwards (image 3). Each guide bar is made oversize to allow for shrinkage w Warp Knitting with Novelty Yarn is independently computer-guided. They during dyeing and finishing. The outline

move sideways and pass the yarn around is knitted into the garment and the waste Yarns are inserted for decorative and 150 151 a designated needle, either in front or is removed (image 9). functional reasons. In this case, a gold- 2 metallized yarn is being inserted into jacquard-knitted hosiery (image 1). The yarn would be too fragile to knit as part of the loop structure and so is inserted into the loops as an additional warp. The fancy yarn is introduced from the front on both sides of the machine (image 2). It is knitted into the fabric and the finished item is drawn away

3 4 5 under tension (image 3). The areas that 1 2 will be open are visible as long slots. This is how they are knitted: a needle is missed out for a given number of courses and so a window is formed. Once the fabric has relaxed the openwork structure is revealed. On this narrow-bed knitting machine eight pairs of stockings are knitted

simultaneously (image 4). 4

Featured Company Featured Company

Cifra S.p.A. Cifra S.p.A. www.cifra-spa.net www.cifra-spa.net 6 3