warp knitting machine

1. TEXTILE SCIENCE

2.  Warp knitting is a method of
fabric formation in which the
loops are made in a vertical way
along the length of the fabric
from each warp yarns.
 Thus, there will be a needle for each yarn. The knitted
stitches in warp knit fabrics have a crisscross diagonal
appearance which feels smoother than weft knits.
 Warp knitting differs from weft knitting, basically in that
each needle loops its own thread.

3.  The needle produce parallel rows of loops
simultaneously that are interlocked in a zigzag
pattern.
 The stitches on the face of the fabric appear
vertically, but at a slight angle and the back appear
horizontally as floats at a slight angle.
 These floats called laps, or underlaps are called
laps or underlaps are a distinguishing identification
of warp knits.

4.  It shows less elasticity than weft knitting.
 It becomes favorable over weft in properties like soft and
drapery, higher density, warm to wear.
 Through this process many different types of yarn can be
processed like combed, staple, carded and filament which
is not possible with weft knitting.
 It may be flat or tubular and can be produced in many
varieties of patterns.
 It can yield cloth with a dimensional stability almost
equal to that of woven fabrics.

5. Warp Knitted
Fabrics
Tricot Knits
Raschel
Knits
Milanese Knits

6. Warp Knitted Fabrics
Tricot
Knits
Bearded /
Compound Needle
Double
Needle
Bar
Gloves,
Lingerie
Single
Needle
Bar
Weft Insertion, Pile
Fabric, Curtain,
Lining
Raschel Knits
Double Needle Bar
Carpet,
Pile
Single Needle Bar
Standard (co
weave knit, weft
inlay)
Multiple
Guide Bars,
(Crochet,
Milanese)

7.  The word tricot comes from the
French word “Tricoter” which
means to knit.
 Each set of yarns from a warp
beam is fed to a row of needles arranged across the width of
the machine and is controlled by yarn guides set in a
guide bar that is also laid across the machine.

8.  Tricot fabrics have many good attributes.
 They are porous and permit passage of
water vapor and air for body comfort.
 They also offer bulk without undue weight.
 Tricot fabrics are soft, wrinkle resistant, and
have good drapability.

9.  They have controllable elasticity and they do
not run or fray.
 Tricot construction contributes to good
abrasion resistance and high bursting and
tearing strength.
 Other factors that contribute to the fabrics
strength are the fiber and yarn structure.

10.  Tricot knits are used for a wide variety of
fabric weights and designs.
 Typical uses of tricot fabrics are lingerie,
lounge wear, sleep wear, blouses, shirts,
dresses, slacks, uniforms for nurses and
waitresses, bonded fabric material, outer
wear and automobile upholstery. These
fabrics may be identified by type.

11.  In tricot warp knitting machine compound
needles are used.
 The warp yarns are feed to the needles through
guide bars using shogging and swinging
motion.
 Normally tricot warp knitting machine is used
for fashion fabrics, mesh fabrics.

12.  Modern tricot machines are constructed with
compound needles, while in the past tricot
machines were equipped with beard needles.
 Tricot machines are commonly equipped with
from two to four yarn guide bars and require the
same number of warps to be used.

13. Tricot warp knitting machine

14.  The raschel knit ranks in importance of production with
tricot, but it surpasses it in variety of products, which range
from veilings and laces to power nets for foundation
garments to such pile fabrics as carpets.
 The raschel knit is made with latched needles rather than
the bearded type used for tricot, Milanese and simplex.

15.  The raschel fabrics can usually be
distinguished from tricot fabrics
in that raschel constructions are made
with heavy yarns and usually have an
intricate, lacelike pattern, whereas tricot constructions are
made with fine yarns and are either flat or have a simple
geometric pattern.
Raschel

16.  Raschel machines are extremely versatile.
 They can knit every type of yarn made of any
kind of fiber, including metallic and glass,
and in any form, whether staple or filament,
standard or novelty.
 Knits can be lacy, highly patterned and even
piled.

17.  It includes a fabric which can be dense or compact,
open or lofty, stable or stretchy, single faced or
reversible.
 It can be identified by their intricate designs.
 The use can be in almost any garment due to high
customization of the raschel machine from
lightweight lace to heavy chenille.
 The machines can produce both flat and tubular
warp knit fabrics.

18.  Made from heavier yarns, Raschel knits are used for
manufacturing versatile and flexible fabrics.
 These are more textured and can be used for a wide range
of technical textile applications.
 Such as- automotive textiles, home textiles, lingerie,
mosquito nets, lightweight coating substrates,
sportswear/swimwear, lining fabrics, outerwear, etc.
 Different types of single and double needle bar Raschel
machines are built today for the production of a wide variety
of products ranging from sacks to artificial blood vessels.

19.  Such as- automotive textiles, home textiles, lingerie,
mosquito nets, lightweight coating substrates,
sportswear/swimwear, lining fabrics, outerwear, etc.
 Different types of single and double needle bar Raschel
machines are built today for the production of a wide variety
of products ranging from sacks to artificial blood vessels.
 Seamless tubular fabrics, pile fabrics and many other special
fabrics can easily be produced in double needle bar machine
by using 4 to 6 guide bars.

20.  But by using more number of guide bars (16 and
above), production of branching tubular fabrics such as
artificial blood vessels, patterned panty-hose etc. and
shaped innerwear is no more a problem.
 Warp knitted spacer fabric (WKSF) is a three-
dimensional textile which is also made by a double-
needle bar Raschel machine.

21.  Raschel warp knitting machine may be made
with either single needle bar or double needle
bar.
 In Raschel, yarns coming from the beam as
parallel sheet are converted into fabric by loop
formation before being wound in open width
form on the cloth roller.

22.  Nowadays Raschel machines are available with
weft insertion facility.
 Raschel Warp Knitting Machine is used for
lace fabric and trimming.
 It is also used to produce in outdoors and
military fabrics for products such as backpacks.

23. Raschel Warp Knitting Machine

24.  Milanese knit is made of two sets of yarns knitted
diagonally.
 The face side has fine vertical rib and the reverse has a
diagonal structure.
 The Milanese stitch, though accomplished by a different
technique, produces a fabric very similar in appearance
to tricot.
 It can be identified by the fine rib on the face and a
diagonal pattern on the back.

25.  Milanese is knitted on the
flat bed machine with spring
beard needles and on the
circular machine with latch needles.
 It is usually knitted from filament yarn into fine light
weight fabrics.
Milanese

26.  It is lightweight, drapery, smooth and is
mostly used for gloves.
 Milanese fabric are superior to tricot in
smoothness, elasticity, regularity of
structure and split and tear resistance.

28. Tricot Knit Raschel Knit
In the past, bearded needle was used
but now a days compound needle used
Rachel m/c used latch needle together
with a wire or blade
M/C gauge expressed in needle per
inch
M/C gauge expressed in needle/inch
Chain link numbering 0, 1, 2, 3, ….etc
Chain link numbered in even numbers
0, 2, 4, ….etc
Three links per course 2 links per course
Function of sinker is holding down,
knocking and supporting the fabric
Sinker performs the function of holding
down the loops whilst the needle rise
The sinker are joined to each other at
the front and back
The sinker are not joined together by a
lead across their ends nearest to the
needle bar

29. Tricot Knit Raschel Knit
The sinker never move clear of needles
They can move clear of the needles
towards the back of the m/c for the rest
of the knitting cycle
The fabric is drawn away towards the
batching roller almost at right angles to
the needle bar
The fabric is drawn downwards from
the needles almost parallel to the bar at
an angle of 120°-160°
The warp beams are accommodated in
an inclined arc towards the back of the
m/c there the top
The warp beams are arranged above
the needle bar centered over the rocker
shaft
The warp sheets pass over the top of
the guide bar rocker shaft to their
tension
The warp sheets pass down the guide
bar

30. Tricot Knit Raschel Knit
Mechanical attention is carried out at
the front of the m/c
Mechanical attention is carried out at
the back of the m/c
The guide bars are numbered from the
back towards the front of the m/c
The guide bars are numbered from
front of the m/c
High speed production Low speed production