Unconventional or shuttleless weaving machines have gained high
popularity in the recent years. The yarn supply for weft is utilised
directly without need for conversion into pirn. There are four principles of
weft insertion on these machines. Each type has its own merits for different
types of production. A considerable amount of filling waste is made during
weaving on these machines.
Suitability of different machines
Projectile weaving machines
These machines are mainly used for spun yarns made of cotton, rayon,
polyester, etc and also their blends. It is also possible to effectively
weave filament yarns. The technical aspects relating to warp yarns remain
the same irrespective of whether it is shuttleless or shuttle looms. Some of
the recommended weft yarn counts are given in Table 1 below.
Table 1. Recommended weft counts
Range of yarn counts
6s - 36s Ne
2. Spun synthetic fibres
18 - 70s Ne
70 - 270 Denier
Popular types of projectile weaving machines (such as Sulzer Ruti)
incorporate the following special features so as to enable successful
weaving of filament yarns
a) Feeding of the warp yarns from the warp beams to temple without
b) Whip roll filament weaving machine is hard chromed and polished.
c) The drop wires are lesser in thickness so as to minimise friction, and
also the points of contact are hard chromed.
d) Three wheel types of temple, which only engage at the selvedge zone,
e) The tucking needle is redesigned so as to modify its motion during
selvedge formation. It remains stationary for a short duration after
gripping an end, till the healds are almost closed. Also the tuck in needles
are pointed at their edges and are highly polished and chromed. Straight
needle tucks the thread quite close to the edge of the fabric. Melt
selvedges are also available on these machines.
f) The gripping surface of the projectile is highly polished and slightly
curved at the ends, so that the individual fibrils are not ripped off. The
same is applied to projectile feeders.
g) All the eyelets in the thread tensioners and package creel are to be
replaced by fine ceramic, so as to prevent the damage to the threads due to
h) The closing of warp shed should be late, ie, 10 - 250 for ground
threads, and between 3250 - 3400 for the selvedge zone.
i) The whip roll and the warp detectors should be adjusted as
horizontally as possible, so that the top and the bottom shed are tensioned
as equally as possible.
j) Stoppage due to broken warp threads should take place about 3350 to
3400. If the normal setting of 3500 - 00 is selected, there will be a great
risk of starting marks.
Rapier weaving machines
These machines can satisfactorily weave sheeting, flannels, drills,
muslins, print cloths, etc and it can be extended to the weaving of carpets
from continuous filament yarns. Textured filaments made from Taslan,
untwisted filament and intermingled cotton and polyester covered core yarns
and elastomeric yarns can be effectively woven on these machines. Heavy
denier multifilament yarns can also be successfully used. PET with crepe
twist or reinforced Lurex are both woven as weft without problems.
Industrial fabrics, tyrecords, tents, screens, sail cloth tarpaulin, and
glass fabric can also be woven
Air-jet weaving machine
These machines have proved to be ideal for spun yarns. Recently it has
been possible to weave a wider range of fabrics in spun as well as filament
yarns and with up to six colours in weft or yarn counts. However, the yarn
quality restricts the machine speed. Modern spinning mills are able to give
better quality yarns. Modern warp preparation is crucial for today’s
Water-jet weaving machine
This system has proved very useful in the case of synthetic filament
yarns, which are hydrophobic. It is advantageous as compared with shuttle
looms for bulk production of fabrics made of polyamides and other
hydrophobic fibres. This machine is confined to only hydrophobic synthetic
filament yarns. This is due to the problems associated with sizing, wet
strength of hydrohphillic yarns and also the requirement of a perfectly
clear warp shed.
Thus the machine is restricted to filamental warp yarns that do not
require sizing and also do not lose strength on wetting. Normally weaves
such crepe, matt, and twill are used, with yarn counts ranging between 10 -
120 denier. The warp/weft thread sett or density ranges between 25/25 and
360/240 per square inch and the maximum achievable areal density of the
fabric is about 6oz/sq yd. Since the construction of the weaving machine,
specially, the sley, is light, heavier varieties of fabrics cannot be woven.
There is a possibility to increase the weft set to 300 picks/inch. However,
the maximum dents/inch in reed is only 76. If reeds of higher densities are
used, there is problem of water clogging, which can create difficulties in
shedding. The twist in warp yarns is minimum, about 7.5 tpi, as the yarn is
unsized. Fabrics such as lingerie, ladies dresses, shirting, tent canvas and
industrial fabrics can be successfully woven on these machines.
The overall quality of the fabric is below the expected level, which is
mainly due to the problems concerned with the water jet weft insertion.
These machines have the advantages of high speed and low noise. Also they
are well suited for weaving of super fine continuous filament yarns. The
effectiveness of the weft propulsion is mainly dependent on the wettability
of the weft. The drag on hydrophobic filament yarn is much lesser than that
on cotton yarns.
Generation of static charges is prevented due to the presence of water.
It is crucial that the weft yarns do not contact the warp yarns during their
insertion into the shed, as otherwise this could lead to fabric defects due
to entanglement. Effectiveness of weft insertion requires the fluid jet to
remain in contact with the weft and to move into the shed more quickly than
the yarn. A major problem with hydraulic picking is the presence of partial
of full double picks across the width of the fabric, which can arise due to
a number of reasons.
Weaving with multifilament yarns
Multifilament yarns are used in the manufacture of apparels so as to get
an excellent hand, drape, appearance, wrinkle resistance and easy care
properties. The yarn are either used as single, or plied together with or
without twist. The yarns are denoted as denier/number of constituent
filaments/twist. Generally higher the number of filaments of equal denier,
more fuller is the fabric. The yarns can be woven successfully on any of the
following types of machines (Table 2) but certain modifications on looms are
required for satisfactory weaving. It is desirable to weave the filament
warp beams on better and sophisticated looms.
Table 2. Suitability of weaving machines for filamental yarns
Type of weaving
a) Fancy multicolour fabrics coarser than
30dtex, both flat and texturised
b) High twisted fabrics
Fabric with single colour weft for mass production
3. High speed automatic
Fancy monocolour fabrics
b) High twist fabrics
All type of synthetic fabrics
Some of the suggested modifications on the weaving machine are as
a) Chrome plated iron or highly polished wooden back rollers should be
Extended backrest should be preferred.
b) The number of heald shafts and the number of rows of drop pins should
not have a common factor. Thus, for a plain weave on four shafts, three or
five rows of drop pins should be used according to the number of ends in the
warp. This procedure ensures that the ends from any given heald shaft are
distributed over all rows of pins.
Sizes of drop wires
Suitable dimensions of drop wires are to be used (Table 3). Heald frames
made of metal and having flat heald wires (with rectangular eyes) are
recommended. The rectangular eyes of the heald wires have large area of
contact, which reduces the pressure on length of yarn during shedding.
Shuttles made of laminated wood and having consistent size and weight are
to be used. The eye of the shuttle should be padded and have ceramic pins.
Low and uniform yarn tension are necessary for weft yarn during weaving.
This can be achieved by using shuttle lined with fur or nylon loop strip.
The distance between the pirn tip to the eye should be 12 - 30 mm.
Sizes of heald wires
The dimensions of flat heald wires are given in Table 4.
Table 3. Dimensions of flat healds
Warp count Cross section
of Size of eyes
Maximum heald wire per cm
mm x mm
5.0 x 1.0
5.5 x 1.2
a) Reed made of metal with 60% air space and 10 cm depth is preferable
b) Box front should be smooth and preferably lined with fur
c) Sley should be covered with corduroy fabrics, or velvet to reduce the
damage that may take place due to frictional contact between the moving
shuttles and the sley race board.
d) Warp tension should be enough just to get a clear shed
e) Photoelectric weft stop motion should be used
f) Tipless shuttles should be used for high-speed looms
g) For filament weaving, it is important that the cloth take-up roller
should hold the cloth firmly without slippage, but without causing any
abrasion of the filaments. Emery roll should be covered with rubber fillet.
h) The direct take-up motion where the cloth is wound on the take-up
roller directly is ideal as it ensures better control and avoids slippage of
i) Circular disc or sun temples are ideal. Roller temples with rubber
sleeves can be used. Ring temples with 2 or 3 rings are also used.
j) Part of the hammers coming in contact with the yarn should be lined
with fur to prevent damage to filament.
The following recommendations are made for weaving of texturised as well
as flat continuous filament yarns:
a) Back rest should be levelled with the breast beam or front rest and
drop wire stand is aligned to give an even shedding.
b) Tension in the top and bottom levels of shed should be equalised as
far as possible. Low warp tension, enough to get a clear shed opening, is
c) Weft tension should be set to minimum level enough, to prevent weft
snarl or loopy selvedge (approximately 0.10 - 0.15 gpd). The difference in
tension between the full and the empty pirn should not exceed 15g.
d) Late shedding by 150 or more for filament warp and normal for spun
warps with filament weft-flat or texturised is recommended.
e) Selvedge should be about 15 mm wide for dress material and 20 mm wide
Weaving of monofilament fabrics
Monofilaments are normally used both as warp and weft. However, in
special applications, such as parachutes, conveyor belt linings,
ski-anoraks, etc monofilaments are used in combination with multifilament
yarns. There is no restriction in the warp yarn with regard to the thread
density (sett) and yarn linear density. However, in the case of weft yarn
the yarn linear density and cloth width are to be considered, since other
conditions prevail for the monofilaments (10 - 1000 dtex) as, for coarse
monofilament wires (D 1 - 0.85 mm) in weft insertion, which are influenced
by the stiffness of the monofilament itself. Depending on the final use
polyester, polyamide, polypropylene, carbon fibres or PVC monofilaments or
wires are used. Some of the applications of monofilament fabrics are bolting
cloth, geo-textiles, filter fabrics, etc.
Weaving with synthetic filament yarns has now become possible on all
types of shuttleless weaving machines with suitable modifications. It has
become possible to weave wider denier range of yarns. Rapier weaving
machines can effectively weave industrial fabrics, tyrecords, tents,
screens, sailcloth tarpaulin, and glass fabrics. In the case of air-jet
weaving machines, it has been possible to weave a wider range of fabrics in
spun as well as filament yarns and with up to six colours in weft or yarn
counts. However, the yarn quality restricts the machine speed. Modern
spinning mills are able to give better quality yarns. Modern warp
preparation is crucial for today’s weaving machines. Multifilament yarns
of varying denier can also be woven on projectile, rapier and air-jet
weaving machines with certain modifications.
Note: For detailed version of this article please refer the print version
of The Indian Textile Journal May 2008 issue.
Department of Textile Technology,
Kumaraguru College of Technology,
Coimbatore 641 006.