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Wrap spinning
This presentation discusses various methods of wrap spinning yarns. It describes the selfil, repco, hollow spindle, ring frame, differential twist, wrap rotor, woolen card, and parafil systems. The hollow spindle method is identified as the most important technique, involving drafting fibers through a hollow spindle while wrapping with a filament to produce wrap yarns in a single continuous process without true twisting. Other methods like the selfil and repco systems use self-twisting to wrap core fibers with filaments.
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Wrap spinning is a method for producing composite yarns featuring a core of fibres wrapped by filaments, leading to high-quality yarns.
Various methods include Selfil, Repco, and RDWCS systems, emphasizing efficiency in yarn production.
Discusses processes on ring frames and rotor spinning, enhancing yarn strength and versatility.
Details on hollow spindle and Parafil systems, highlighting their efficiency and strength in wrapped yarn production.
Wrap yarns categorized into flat, structured, and fancy types, each designed for specific functional and aesthetic outcomes.
An overview of materials for wrap yarns, emphasizing their characteristics such as uniformity, strength, and less hairiness.
Economic insights into wrap spinning reveal cost advantages over traditional spinning methods for certain yarn types.
Wrap spinning offers numerous advantages but also faces challenges related to visibility of filaments and market acceptance.
Wrap yarns are utilized in a variety of products such as knitted items, upholstery, shirts, and carpets.
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Wrap spinning
- 1. WRAP SPINNING In thispresentation wrap spinning Principles and developments will be explained
- 2. Presenters Ali Asher 12-NTU-0003 MuhammadNaeem 12-NTU-0020 Muhammad Samran 12-NTU-0023 Muhammad Sohail Anjum 12-NTU-0024 Muhammad ZubairTahir 12-NTU-0029 Muhammad Umar 12-NTU-0109
- 3. Introduction • A wrapyarn is a composite structure comprising a core of twisted or twist-less fibers bound by a yarn or continuous filament. • Wrap spinning, although not new, has become the subject of renewed interest in recent years. The process is claimed to provide the spinner with a highly efficient method of producing yarns of high quality for a wide range of applications. High production speeds are claimed and the resultant yarns possess many desirable qualities.
- 4. Introduction • Wrap yarnswere produced more than a century ago by the woven horsehair interlining trade. A horsehair core of virtually untwisted fibers having been wrapped first with a yarn in "S“ direction and then with one in “Z" direction or vice versa.This was then wound and used as weft in high quality interlining fabrics. • Wrap spun yarns are said to be as strong as, more regular and bulkier than conventional ring spun yarns, effecting good cover and a full handle when converted into fabric. Wrap yarns have been successfully employed in the production of a wide range of products including both woven and knitted goods, tufted carpets and velour fabrics.
- 5. Methods of wrapyarn production • Different types of wrap spinning is available to produce wrap yarns; 1) Selfil 2) Repco 3) Hollow spindle method 4) Wrap yarns produced on ring frame 5) Differential twist yarns 6) Wrap spun rotor yarns 7) Wrap yarns produced on woolen card 8) Parafil System
- 6. Selfil system • Amethod of yarn production whereby two continuous filaments are wrapped around a staple fiber core on a modified Repco self-twister has been described by Walls. • These yarns consisted of a core of staple fibers which is wrapped in alternating directions with a fine filament by a self-twist unit. A second self-twist unit repeated this action such that the point of low twist of the second filament coincided with the point of high twist of the first filament and vice versa. • The resultant yarns were called SELFIL wrapped yarns.
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- 8. Selfil Process • Aworsted roving is fed into the drafting system E to B and the drafted strand is fed through self- twist rollers at A, which, as well as rotating to move the strand forward, reciprocate longitudinally to impart alternating twist to the strand. • A monofilament converges with the strand at C and a second monofilament converges at D. The final yarn is wound at F.
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- 10. Repco system • Amethod of yarn manufacture which utilizes the self twist principle, has been developed at SAWTRI. These yarns are termed Repco Wrapped Core-Spun (RWCS) yarns and consist of a strand of staple fibers and filament core, self twisted with a single filament binder yarn. • The system was initially developed for the production of fine mohair yarns which were subsequently up-twisted and used for weaving. RWCS yarns have since been produced for knitting.
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- 12. Repco RDWCS System •A further method has been developed, primarily for the production of wrapped core-spun cotton yarns on a self-twist spinner, which could be used readily without the necessity of up-twisting. • These yarns have been termed Repco Double Wrapped Core-Spun (RDWCS) yarns and employ two wrapping filaments. • It was stated that with the exception of yarn tenacity, the RDWCS system produced yarns as good as up-twisted RWCS yarns.
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- 14. Wrap spun yarnsproduced on ring frame Differential twist yarns & Wrap rotor spun yarns BY Ali Asher
- 15. Wrapped yarns producedon Ring frame • A continuous filament, drawn off a bobbin situated behind the drafting mechanism of the spinning frame is threaded through the delivery rollers so that it will emerge at the front of these rollers alongside the drafted dubbing. • Correct positioning of the filament is achieved by means of a guide at the back of and close to the delivery rollers. Both filament and dubbing are then twisted into a yam consisting of a core of staple fibers wrapped with filament at the balloon zone. • his method has been used both for the production of waste yams and cotton yams which need not be sized.
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- 17. Differential twist yarns •A further method of wrap spinning is that of passing a core of staple fibers through a hollow spindle, wrapping the fibers with filament and subsequently ring spinning the yams in one continuous process. • This system is used both for the production of fancy yarns and for the production of straight yams.
- 18. Differential twist yarns •These yarns consisted of a strand of staple fiber which had been first wrapped with filament and subsequently twisted together with the same filament, the outstanding character being that the twist of the staple fiber was lower than that of the filament.
- 19. Differential twist yarns •The direction of twist inserted by the ring spindle was the same as that of the 'wrapping' twist. In this manner the strand of staple fiber was given twist and the final twist of the filament in the spun yam was the sum of the 'wrapping' twist and 'spinning' twist. • Tensile properties, spinability and regularity, of Differential Twist Yarns is invariably better than conventional ring spun yarns.
- 20. Wrap spun rotoryarns • A method of producing Wrap-Spun Rotor yams bas been developed in Czeckoslovakia. The process which was termed 'ROTONA" made its first international appearance at ATME '82. • Fundamentally, the system is a modification of the rotor spinning process which makes it possible in one operation to spin a single rotor yarn and to wrap it around another continuous textile product such as a staple core or filament yarn, while it is practically still in the rotor. • ROTONA yarns were designed primarily to replace traditional ply yarns in a broad range of textile products.
- 21. Wrap spun rotoryarns
- 22. Hollow spindle method& Prafil system BY Muhammad Zubair
- 23. Hollow Spindle method •The hollow spindle system of wrap yarn production, in which no real twist is inserted during the actual spinning process, has become generally accepted as the most important method of wrap yam production.
- 24. Hollow spindle method •The hollow spindle method of wrap yam production involves the drafting of a sliver produced either on the worsted, semi-worsted or cotton system of manufacture into a roving of parallel fibers which is then passed together with a fine filament, through a hollow spindle onto which the filament package is mounted. • By rotating the spindle, the core is helically wrapped with filament. The filament exerts radial pressure on the fiber core resulting in frictional forces acting between the individual components, which, together with the wrapping filament, are responsible for yam strength.
- 25. Principle of Hollowspindle method • A roving or sliver feedstock (1) is drafted in a three-, four- or five-roller drafting arrangement. • The fiber strand delivered runs through a hollow spindle (3) without receiving true twist. • In order to impart strength to the strand before it falls apart, a continuous-filament thread (4) is wound around the strand as it emerges from the drafting arrangement.
- 26. Principle of Hollowspindle method • The continuous-filament thread comes from a small, rapidly rotating bobbin (5) mounted on the hollow spindle. • Take-off rollers lead the resulting wrap yarn to a winding device.
- 27. Wrap yarns producedon aWoolen card • A system whereby wrap yams can be produced directly on the condenser of a woolen carding machine. • Hollow spindles were fitted between the rubbing apron and the condenser surface drum of a woolen carding machine, thus producing a wrap yam from staple fibers in one continuous process. • An additional method is described whereby the rubbing aprons are bypassed so that yarn is produced from fiber ribbons as presented by the condenser tapes, thus eliminating the rubbing aprons and eccentric motion of the condenser.
- 28. Wrap yarns producedon aWoolen card
- 29. Parafil System • Three,four, or five roller drafting arrangements are used, depending upon the raw material to be processed. • The hollow spindle permits rotation speeds of up to 35 000 rpm and is designed as a false-twist assembly. • The fiber strand does not pass directly through the spindle vertically; instead, shortly after entering the spindle, the strand is led out again and back around the spindle, with a wrap of about one- quarter of the spindle periphery.
- 30. Parafil System • Inthis way, as the spindle rotates, the strand is provided with twist between the drafting arrangement and the head of the hollow spindle. • These turns of twist are canceled out again in the spindle head in accordance with the false-twist principle. This false twist prevents the strand from falling apart in the length prior to wrapping with filament.
- 31. Features of Parafilsystem • Slivers are used as feedstock, the roving frame is eliminated. • Parafil yarn (called Parallel yarn by Suessen) is usually more even than ring-spun yarn. • Its strength is also better because of the filament and because of the high degree of parallel orientation of the fibers. • Covering power is high and hairiness low.
- 32. Use of Parafilyarns • The yarns are used primarily for: • Machine-knitting yarn • Velours (home and automobile upholstery materials) • Woven goods (men‘s and ladies‘ wear) • Carpet yarns (mainly for tufted carpets). • At present, the process is more suited to the long-staple than the short-staple field, i.e. for fiber lengths above 60 mm. • In ParafiL yarns, the filament makes up 2 - 5% of the yarn.
- 33. Technological & EconomicInter relationships • High percentage of filament always has a disturbing effect. • More often in the coarse-yarn sector, and to some extent in the coarse-to- medium- yarn range. • The high price of filament relative to staple fibers exerts a strong influence on costs. • Economic production of fine yarns using the wrap-spinning process is therefore not possible, due to higher raw material costs. • Fine filaments in the 20 - 110 dTex count range are usually used. • Most common are polyamide fiber, polyester fiber, and viscose.
- 34. Types of wrapspun yarns BY Muhammad Umar
- 35. Types of wrapyarns Wrap yarns can be categorized into three groups; 1) Flat parallel yarns 2) Structured parallel yarns 3) Fancy yarns
- 36. Flat parallel yarns •These yarns are also referred to as straight regular or smooth yarns, and consist of a core of parallel, untwisted fibers helically wrapped with a fine filament yarn. • In addition, wrap yams of this type, which have been produced on the "LEESONA" range of wrap spinning machinery, have been termed "Core Spun" yarns. • In contrast to ring spun yarn, the fiber structure is held together not by twist, but by the wrapping thread.
- 37. Flat parallel yarnswrap spinning assembly
- 38. Structured parallel yarns •Structured or engineered yams can be created to give the finished product improved performance, enhanced aesthetics, softer handle, lower unit mass, greater bulk and cover etc. • An example of such a process is to use a filament yam which contracts when the wrap yam is dyed or steamed. The contracting filament exerts pressure on the staple fiber core, thus squeezing the staple fibers in a bow out of the yam axis. • A spiral appearance is therefore generated, which grows to a string of pearls pattern as volume builds up to a maximum.
- 39. Structured parallel yarnswrap spinning assembly
- 40. Fancy yarns • Fancyyams can be produced by feeding an effect yam together with the drafted sliver through the hollow spindle so that both the sliver and the effect yarn are wrapped by the filament. Fancy yams are also produced by employing overfeeding and intermittent feeding of the effect yarn or drafted sliver. • The fibers are drafted either with or without aprons. The core yarn is brought through a groove in the front draft roller and therefore runs at the speed of the delivery roller, permitting overfeeding at the front roller. The materials then pass through the hollow spindle, where they are wrapped with the binder.
- 41. Fancy yarns wrapspinning assembly
- 42. Fancy yarns basicstructure
- 43. Raw material, Properties, Advantages &Disadvantages BY Muhammad Samran
- 44. Wrapping filaments The mostimportant filaments used in wrap spinning are; Filament Linear density (dTex) Nylon 17 – 228 Polyester 17 – 167 Polypropylene 78 – 330 Acrylic 78 Acetate 220 – 330 Water soluble 62 Glass 110 – 440 Silk 33 – 88 Elastomeric 22 – 156 Staple yarns 50 – 2000
- 45. Core fibers Fiber types: Virtuallyall textile raw materials can be successfully converted into wrap yarns including asbestos and glass. The system is considered suitable for both the long staple, and short staple sectors of the industry. It is said that any fibers that can be drafted can be wrap spun. Range of yarn linear density: Yams of a very wide range of linear densities can be spun on the hollow spindle system and it is said that restrictions on linear density range are economical rather than mechanical.
- 46. Physical properties ofwrap yarns • Yarn uniformity is found to be equal to or better than that of conventional ring spun yarns. • The wrap yarns are also being smoother and less hairy. • Wrap yarns were found to be very voluminous and therefore effect a better cover in fabrics. • Yam tenacity is reported to be higher than that of conventional yarn. The reason for this is stated to be as a consequence of the higher level of inter-fiber friction due to the better contact between the parallel staple fibers bound and compressed by the wrapping filament.
- 47. Physical properties ofwrap yarns • Elongation at break is higher in the case of wrap spun yams than in the case of conventional ring spun yarns. • A further important property possessed by wrap spun yarns is a lack of torsion. The zero twist of wrap spun yams reduces problems of spirality.
- 48. Economics of wrapspinning • The costs of package doffing during wrap spinning are lower than in ring spinning due to the longer running lengths in the former case. • Due to the lower yam tension and the even distribution of the wrapping twist, the yam breakages during wrap spinning are lower than for ring spinning by a factor of 2 to 3. • During wrap spinning, patrolling and supervision is more conveniently carried out due to the lower number of spindles employed. It is therefore, reasonable to assume that wage costs will be lower for wrap spinning.
- 49. Economics of wrapspinning • In the production of yams of a high linear density, the ratio of spindle price to production are more favorable in the case of wrap spinning. • In conclusion it Is stated that, when producing yams of a relatively high linear density, wrap spinning can compete with ring spinning economically. However, this does not necessarily follow in the case of fine yams.
- 50. Advantages of wrapspinning Many advantages are claimed for wrap-spun yams when compared to conventional ring spun yarns the most important of which are the f0llowing: • Greater bulk • Improved cover in pile fabrics • Softer handle • Higher absorbency • Greater strength • Higher elasticity • Less hairy • Simplicity of operation • Higher efficiency
- 51. Advantages of wrapspinning • Ability to "engineer" specific requirements • Requires fewer fibers per cross-section, therefore, coarse fibers can be spun into finer linear densities. • Increased production • Favorable costs per unit of production • Lower energy costs • Lower overall investments • Less floor space required • Greater scope and versatility • Less spinning waste
- 52. Disadvantages of wrapspinning • It seems clear that wrap spinning has much to offer in many areas, and has been receiving much attention in recent years. • However, not all reports have been positive. There are two purely textile facts limiting the filament yam spinning technology for articles made of flat yams. • In the first place it is noted that the filament share of a flat fabric surface becomes visible to available extent and leads to glazing effects which are considered unpleasant. • This weakness could be compensated for by using fancy yams, but they are very dependent on fashion.
- 53. Disadvantages of wrapspinning • Secondly it is stated, that according to certain textile labelling acts the type and content of the filament has to be stated, which is a psychological hindrance with the result that technically superior fabrics fail to be accepted by the consumer. • This can be overcome, however, if for example wool or even more precious fibers are combined with silk as filament yarn, or by employing a water soluble filament wrapper.
- 54. End uses ofwrap yarns BY Muhammad Naeem
- 55. End uses ofwrap yarns Knitted ladies tides
- 56. End uses wrapyarns Knitted ladies shirts
- 57. End uses wrapyarns Knitted fancy cloths
- 58. End uses wrapyarns Knitted Upholstery
- 59. End uses ofwrap yarns Elastic fabrics
- 60. End uses ofwrap yarns Tufted carpets
- 61. End uses ofwrap yarns Male Shirting
- 62. End uses ofwrap yarns Velour fabrics