Wrap Spinning techniques of spun yarn technology are briefly elaborated.........

1. WRAP SPINNING
In this presentation wrap spinning Principles and developments will be
explained

2. Presenters
Ali Asher 12-NTU-0003
Muhammad Naeem 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 wrap yarn 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 yarns were 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 wrap yarn 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
• A method 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.

7. Selfil system

8. Selfil Process
• A worsted 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.

9. Selfil wrapped yarns

10. Repco system
• A method 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.

11. Repco RWCS System

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.

13. Repco RDWCS
System

14. Wrap spun yarns produced on ring frame
Differential twist yarns &
Wrap rotor spun yarns
BY
Ali Asher

15. Wrapped yarns produced on 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.

16. Wrap yarn
produced on
ring frame

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 rotor yarns
• 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 rotor yarns

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 Hollow spindle 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 Hollow spindle 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 produced on 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 produced on 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
• In this 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 Parafil system
• 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 Parafil yarns
• 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 & Economic Inter
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 wrap spun yarns
BY
Muhammad Umar

35. Types of wrap yarns
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 yarns wrap 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 yarns wrap spinning
assembly

40. Fancy yarns
• Fancy yams 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 wrap spinning assembly

42. Fancy yarns basic structure

43. Raw material,
Properties,
Advantages & Disadvantages
BY
Muhammad Samran

44. Wrapping filaments
The most important 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:
Virtually all 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 of wrap 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 of wrap 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 wrap spinning
• 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 wrap spinning
• 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 wrap spinning
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 wrap spinning
• 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 wrap spinning
• 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 wrap spinning
• 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 of wrap yarns
BY
Muhammad Naeem

55. End uses of wrap yarns
Knitted ladies tides

56. End uses wrap yarns
Knitted ladies
shirts

57. End uses wrap yarns
Knitted fancy
cloths

58. End uses wrap yarns
Knitted
Upholstery

59. End uses of wrap yarns
Elastic fabrics

60. End uses of wrap yarns
Tufted carpets

61. End uses of wrap yarns
Male Shirting

62. End uses of wrap yarns
Velour fabrics