Knitting Technology

About This Presentation

Title:

Knitting Technology

Description:

Knitting Technology Chapter 1 The Definition of knitting 1.1 The Fabric Forming Method There are 3 kinds of fabric forming method, the weaving, the knitting and the ... – PowerPoint PPT presentation

Number of Views:6812

Avg rating:3.0/5.0

Slides: 124

Provided by: You142

Category:

more less

Transcript and Presenter's Notes

Title: Knitting Technology

1
Knitting Technology
2
Chapter 1 The Definition of knitting

1.1 The Fabric Forming Method
There are 3 kinds of fabric forming method, the
weaving, the knitting and the non-woven.

3
The weaving

By interlacing two sets of yarns at right angles
into fabric
A conventional woven fabric is a textile
structure formed on a loom when two sets of yarns
are interlaced at right angles. The longitudinal
yarns are known as the warp and the widthwise as
the weft.

4
The Knitting

By intermeshing the loops of yarn into fabric
Normally, the knitted structure consists of one
set of yarn, weft or warp, and is divided into
weft knitted fabric and warp knitted fabric.

5
The Non-woven

By bonding fibers, filaments, yarns or
combinations of these into fabric

6
1.2 knitting classification

knitting may be divided into two types according
to the formation method
Warp knitting and weft knitting

Warp knitting

weft knitting

7
1.2.1 Weft knitting

The yarn is feed into the needle along the weft
direction and knitted into fabric.

8
1.2.2 Warp knitting

The yarn is feed into the needle along the warp
direction and knitted into fabric.

9
1.3 Knitted structure

Knitted structure are progressively built up by
converting newly fed yarn into new loops in the
needle hooks, the needles then draw these new
loop through the old loop.

10
1.3.1 Knitted loop structure

(1) Loop The simplest unit of knitted
structure. It consists of needle loop and sinker
loop. The needle loop include a head and two side
limbs.

11
(2) Knitted Stitch

The basic unit of intermeshing and usually
consists of three or more intermeshed loops, the
center loop having been drawn through the head of
the lower loop that had in turn been intermeshed
through its head by the loop which appears above
it.

12
(3) Face loop stitch

The side of the stitch shows the new loop coming
through towards the viewer as it passes over and
covers the head of the old loop. Face loop tend
to show the side limbs of the loops as a series
of intermeshing Vs.

13
(4) Reverse loop stitch

This is the opposite side of the stitch to the
face loop side and shows the sinker loops in weft
knitting and the underlaps in warp knitting.

14
(5) Course

A course is a predominantly horizontal row of
loops produced by adjacent needles during the
same knitting cycle.
In weft knitted fabrics a course is composed of
yarn from a single supply.

15
(6) Wale

A wale is a predominantly vertical column of
needle loops produced by the same needle knitting
at successive knitting cycles and thus
intermeshing each new loop through the previous
loop. In warp knitting a wale can be produced
from the same yarn.

16
(7) Stitch density

(a) Wale density
The wales in a centimeter or 5 centimeters or in
an inch along the course.
(b) Course density
The course in a centimeter or 5 centimeters or in
an inch along the course.

17
(8) Stitch length

The yarn length that form a loop.

18
1.3.2 Knitted Fabric

(1) Single faced fabric
Single faced fabric is produced in warp and weft
knitting by the needles operating as a single
set.
It shows the face loops in one side and the
reverse loops in another side.
(2) Double-faced fabric
Double-faced fabric is produced in warp and weft
knitting when two sets of independently
controlled needles are employed.
It shows the face loops or the reverse loops in
both side.

(3) Piece-goods
The fabric in a continuous uninterrupted length
of constant width
The fabric here need be made up into apparel
through cutting and sewing.

20
(4) Garment

the fabric in a certain length and width which
fit to the body-size and Sometimes with a certain
shape or fully fashion
The Garment here can be made up into a sweater
through sewing but the cutting is not necessary
or only a little cutting is necessary.

(5) Selvedged Fabric
A selvedged fabric is one having a self-edge to
it and can only be produced on machines whose
yarn reciprocate backwards and forwards across
the needle bed so that a selvedge is formed as
the yarn rises up to the next course at the edge
of the fabric.
(6) Tubular Fabric
Produced mainly in double faced form or
single-faced structure on circular machines.

(7) Cut Edge Fabric
By slitting open a tube of fabric produced on a
circular machine.
A slit tube of fabric from a 30-inch (76cm)
diameter machine will have an open width of 94
inches (2.38m) at knitting before relaxation.

23
1.4 Knitting Machine classification

1.4.1 Weft Knitting Machine
(1) Circular weft knitting machine
(a)Bearded needle machine
sinker wheel knitting machine
loop wheel knitting machine

24
(b)Latch needle machine

circular single jersey machine
rib machine
interlock machine
terry machine
3-thread fleecy machine
jacquard weft knitting machine
hosiery machine

(2) Flat knitting machine (latch needle)
hand flat machine
computerized flat machine
glove machine

(3) Straight bar frame (bearded needle)
(Cotton machine)

27
1.4.2 Warp Knitting Machine

(1) Raschel warp knitting machine

(2) Tricot warp knitting machine

29
1.5 Machine Gauge

(1) The machine gauge is determined as the
number of needles in one inch of needle bed
i.e.2.54 cm.
(2) Machine gauge influences choice of yarn
and count, and affects fabric properties such as
appearance and weight.

30
1.6 Needle

1.6.1 Bearded needle
There are six main parts of the bearded needle
1-stem
2-head
3-beard
4-eye or groove
5-shank
6-tip

31
1.6.2 Latch needle

The latch needle has five main features
1-stem
2-hook
3-latch
4-rivet
5-butt

32
1.6.3 Compound needle

it include two separately parts1-the needle
2-the tongue (close member)

33
1.7 The Basic knitting Action
34
1.7.1 Knitting Action of the Bearded Needle

(1)ClearingThe old loop is cleared from the hook
to the stem below the tip of the beard.
(2) Feeding A new piece of yarn is fed onto the
stem and bringed into hook by the sinker wheel.
(3) Closing The presser presses the beard and
the tip of beard enter the eye cut in stem. The
new yarn therefore is enclosed by beard.

(4) Landing The old loop moves upwards and is
located on the outside of the beard as soon as
the beard is closed.
(5) Knocking-over and loop length formation
As the old loop continues upwards the old loop
slide off the needle and the yarn is drawn
through it forming a new loop.

36
1.7.2 Knitting Action of the Latch Needle
37
sinker top circular latch needle machine
38
(1)Clearing

As the needle move upwards along the clearing
cam, the old loop slide inside the hook and is
cleared from the hook and latch spoon on to the
stem. At this point the feeder guide plate acts
as a guard to prevent the latch from closing the
empty hook.

39
(2) Yarn feeding and latch closing

The needle starts to descent the stitch cam so
that its latch is below the verge with the old
loop moving under it. At this time the new yarn
is fed through a hole in the feeder guide to the
descending needle hook. The old loop contacts the
underside of the latch causing it to close on to
the hook.

40
(3) Closing and landing

As the needle continues downwards the latch is
forced to close under the influence of the old
loop. The old loop is located on the outside of
the closed latch.

41
(4) Knocking-over and loop length formation

As the head of the needle descends below the top
of the trick the old loop slides off the needle
head draws the loop length, which is
approximately twice the distance the head of the
needle descends below the surface of the sinker
or trick-plate supporting the sinker
loop.

42
1.8 Knitting Notations

A knitting notation is a simple, easily
understood symbolic representation of a knitting
repeat sequence and its resultant fabric
structure which eliminates the need for time
consuming and possibly confusing sketches and
written descriptions.

43
1.8.1 Sketches of stitch
44
1.8.2 Pattern grid

In a squared paper, each square represents a
needle or a stitch and the different symbol in a
square represents a different type stitch. For
example, an X symbol in a square can represent
a face loop, an O is a back loop. The means of
a symbol can be defined by you self according to
the stitch what is knitted. The X can also is a
tuck loop or a loop knitted with a certain color
yarn etc.

45
1.8.2 Weft knitting thread path notation
46
1.8.3 Warp Knitting Lapping Diagram
47
Chapter 2 The Four Primary Base Structure of
Weft Knitted Fabric
48

There are four primary base structures
plain, rib, interlock and purl, from which all
weft-knitted fabrics are derived.
Each is composed of a different combination of
face and reverse meshed stitches knitted on a
particular arrangement of needle beds.
Each primary structure may exist alone, in a
modified form, with stitches other than normal
cleared loops, or in combination with another
primary structure in a garment length sequence.

49
2.1 Plain Fabric (single jersey)

2.1.1 The StructurePlain is produced by the
needles knitting as a single set, drawing the
loops away from the technical back and towards
the technical face side of the fabric.
It is the base structure of ladies hosiery,
fully fashioned knitwear and single jersey
fabrics.
Plain is composed entirely of face loops (or
entirely of back loops).
Its basic structure unit is only one face loop
(or one back loop).

50
2.1.2 The characteristics

(1) The appearance of the face and back
differThe technical face is smooth, with the
side limbs of the needle loops having the
appearance of columns of Vs In the wales.
The technical back has an appearance of columns
of semi-circles formed by the heads of the needle
loops and the bases of the sinker loops.

(2) Extensibility widthwise is approximately
twice that of the length direction. it normally
has a potential recovery of 40 per cent in width
after stretching.

(3) The edges of the fabric tend to curl or roll

(4) A run (collapse of a wale) will occur if a
cut or exposed loop is stressed. The direction of
collapse can be either from top to bottom or vice
versa
(5) The fabric can be unraveled, course by
course from the course knitted last or from the
course knitted first

(6) The fabric thickness is approximately 2
times the diameter of the yarn used.
(7) Plain is the simplest and most economical
weft knitted structure to produce and has the
maximum covering power.

55
2.1.3 The knitting

(1) Producing by loop wheel or sinker wheel
bearded needle knitting machine
(2) Producing by sinker top (or open top)
circular latch needle machine
(3) Produced by flat knitting machine
(4) Produced by straight bar frame (Cotton
machine)

56
2.2 Rib Fabric

2.2.1 The Structure
(1) Rib requires two sets of needles operating in
between each other so that wales of face stitches
and wales of reverse stitches are knitted on each
side of the fabric.
The simplest rib fabric is 11 rib. It consists
of alternate face and back wales, where a face
wale is composed entirely of face loops and a
back wale is composed entirely of back loops.

(2) There is a range of rib set-outs apart from
11 rib, the fist figure in the designation
indicates the number of adjacent plain wales and
the second figure, the number of adjacent rib
wales.
Single or simple ribs have more than one plain
wale but only one rib wale, such as 21,31,etc.
Broad rib has a number of adjacent rib as well as
plain wales, such as 63 Derby Rib.

58
2.2.2 The characteristics of 11rib

(1) The appearance of the face and back are
identical (11rib, 22rib)
(2) The extensibility of the fabric widthwise
is approximately twice that of single jersey. The
lengthwise extensibility is essentially the same
as in single jersey.
(3) The fabric does not curl at the edges.

59
2.2.2 The characteristics of 11rib

(4) A run will develop in the fabric if an
exposed loop is cut, as is the case for single
knits, except that the direction of collapse will
be from top to bottom only.
(5) The fabric can be unraveled course by
course but only from the end last knitted.

60
2.2.2 The characteristics of 11rib

(6) The relaxed fabric is theoretically twice
as thick and half the width of an equivalent
single jersey fabric.
(7) Particularly suitable for the extremities
of articles such as tops of socks, the cuffs of
sleeves, rib borders for garments, and strapping
for cardigans.

61
2.2.3 Knitting

(1) Producing by body-size circular rib machine
(2) Producing by double jacquard weft knitting
machine
(5) Produced by V-bed flat knitting machine
(6) Produced by double cylinder hosiery machine

62
2.2.4 Knitting action

(1) Clearing. The cylinder and dial needles
move out to clear the plain and rib loops formed
in the previous cycle.

(2) Yarn Feeding. The needle are withdrawn into
their tricks so that the old loops are covered by
the open latches and the new yarn is fed into the
open hooks.

(3) Knocking-over. The needles are withdrawn
into their tricks so that the old loops are cast
off and the new loops are drawn through them.

65
Rib knitting action
66
2.2.4 Needle Timing

Needle timing is the relationship between the
loop-forming positions of the dial and cylinder
needles measured as a distance in needles between
the two stitch cam knock-over points. There are
three kind of timing
(1)Synchronized timing
(2)Delayed, rib, or interlock timing
(3)Advanced timing

67
2.3 Interlock Fabric

2.3.1 the structure
Interlock is composed of two 11 rib fabrics
locked together. It has the technical face of
plain fabric on both sides but its smooth surface
cannot be stretched out to reveal the reverse
loop wales.

68
2.3.2 the characteristics

(1) the appearance of the face and back is the
same
(2) Extensibility widthwise and lengthwise are
approximately the same as single jersey
(3) The fabric does not curl at edges
(4) A run will develop in the fabric the
direction of which will be from the end last
knitted. An interlock fabric will run less freely
than single jersey or rib structure
(5) The fabric can be unraveled from the end
last knitted. Two yarns must be removed to
unravel a complete knitted course
(6) The thickness of the fabric is
approximately twice that of single jersey
(7) Interlock relaxes by about 30-40 percent

69
2.3.2 Knitting

(1) Interlock gating. The needles in two beds
must be exactly opposite to each other so only
one of the two can knit at any feeder
(2) Two separate cam systems in each bed, each
controlling half the needles in an alternate
sequence, one cam system controls knitting at one
feeder and the other at the next feeder
(3) The needles are set out alternately one
controlled from one cam system the next from the
other, diagonal and not opposite needles in each
bed knit together
(4) The the conventional interlock machine has
needles of two different lengths, long needles
knit in one cam-track and short needles knit in a
track nearer to the needle heads.

70
2.4 Purl Fabric

2.4.1 the Structure
Purl structures have one or more wales which
contain both face and reverse loops. The
semi-circles of the needle and sinker loops
produced by the reverse loop intermeshing tend to
be prominent on both sides of the structure.

71
2.4.2 the Characteristics of 11Purl fabric

(1) Same appearance,face and back (similar to
the back of single jersey).
(2) Highly extensible in all directions.
Approximately twice as extensible as single
jersey in the length direction.
(3) The fabric does not curl at the edges.
(4) The fabric will run in the wale direction
starting from either end.
(5) The fabric may be unraveled course by
course starting from either end.
(6) The fabric tends to be two or three times
thicker than single jersey.

72
2.4.3 the knitting

(1) With double ended latch needles in some
double cylinder garment length circular machine
or half-hose machine or plat purl machine
(2) By rib loop transfer in V-bed flat machine

73
Chapter 3 Fancy Stitch in Weft Knitting

3.1 the Float Stitch
3.1.1 the StructureA float stitch is composed of
a held loop, one or more float loops and knitted
loop.
The float or welt stitch shows the missed yarn
floating freely on the reverse side of the held
loop which is the technical back of single jersey
structures, but is the inside of rib and
interlock structure.

Missing is useful for hiding an unwanted colored
yarn behind the face loop of a yarn of a selected
color when producing jacquard designs in face
loops of differed colors.

Float Jacquard Fabric
Rib Jacquard Fabric
75
3.1.2 the Characteristics of Float Stitch

(1) Structures incorporating float stitches
tend to exhibit faint horizontal lines
(2) They are narrower because the wales are
drawn closer together
(3) The width-wise elasticity is reduced
(4) The stability of the fabric tend to be
better

76
3.1.3 Knitting

(1) The Knitting Action
A float loop is produced if the needle neither
clears nor is fed a new yarn, i.e., the needle
remains at the run position. Thus while adjacent
needles form a new loop, the needle making the
float loop merely retains the held loop.

77
(2) The knitting Machine

(a) Mini-jacquard circular knitting machine
(mechanical selecting)
(b) Electronic Jacquard circular knitting
machine
(c) Computerized flat knitting machine
(d) Jacquard hosiery machine

78
3.2 The Tuck stitch

3.2.1 the Structure
A tuck stitch is composed of a held loop one or
more tuck loops and knitted loops.
Its side limbs are not restricted at their feet
by the head of an old loop and assume an inverted
V or U-shaped configuration.

79
3.2.2 the Characteristics of Tuck Stitch

(1) Tuck loops reduce fabric length and
length-wise elasticity because the higher yarn
tension on the tuck and held loops causes them to
rob yarn from adjacent knitted loops making them
smaller
(2) Providing greater stability and sharp
retention
(3) The fabric width is increased because the
tuck loops pull the held loops downwards causing
them to spread outwards and making extra yarn
available for width-wise elasticity

(4) Fabric distortion and three-dimensional
relief is caused by tuck stitch accumulation
(5) Tuck stitches are employed in accordion
fabrics to tie in the long floats produced on the
back of single-jersey knit-miss jacquard
(6) Producing openwork effects, improving the
surface texture
(7) Joining the two piece of plain structures
together to produce a double-face fabrics

81
3.2.3 Knitting

(1) In latch needle machine, when a needle
holding its loop also receives the new loop
(2) In bearded needle machine, when its beard
is miss-pressed so that the old loop is not
cast-off and remains as a held loop inside the
beard with the newly fed tuck loop

82
(3) The machine that can knit tuck stitch

(a) Loop wheel or sinker wheel frame
(b) Four or more than 4 track single or double
circular knitting machine with latch needle
(c) The jacquard circular knitting machine with
3-way selecting technique
(d) Flat knitting machine
(e) Some hosiery machine

83
3.3 Plating Fabric

3.3.1 the structure
A plated structure contains loops composed of two
(or more) yarns, often with differing physical
properties, each having been separately supplied
through its own guide or guide hole to the needle
hook in order to influence its respective
position relative to the surface (technical face)
of the fabric.
Plating can be all-over effect or on selected
stitches and may be used to produce surface
interest, colored pattern, openwork lace or to
modify the wearing properties of the structure.

84
3.3.2 the Knitting Principle

(1) The perfect plating so that the underneath
yarn dose not show or flash onto the surface is
difficult. The mainly controlling points are the
yarn tension, angle of feed and the
already-formed loops
(2) The yarn positioned nearest to the needle
head shows on the reverse side of the needle loop
and therefore shows on the surface of reverse
stitches

85
3.4 the Fleecy (laying-in) Fabric

3.4.1 the Structure and Characteristics
A in-lay yarn is bind to the back of plain jersey
or plating fabric using tuck stitches so that
this yarn never knits.
This is achieved using a combination of floating
and tucking.

Plating fleecy is named as three-thread fleecy as
there are three ends of yarn is needed.Since the
laid-in yarn never knits, it is possible to use a
wide variety of yarns for this purpose,
particularly very thick soft and relatively week
yarns.
An inlay yarn may have count which is 6-8 times
heavier than the optimum count for that machine
type and gauge under normal knitting conditions.
The in-laid yarn can be napped into a pile in the
finishing process and the fabric can been used to
make sportswear and sweatshirts.

87
3.4.2 the Knitting Machine

(1) producing by three thread fleecy knitting
machine (latch needle)
(2) producing by the multi-track circular
knitting machine (latch needle)
(3) producing by the loop wheel or sinker wheel
frame (bearded needle)

88
3.5 the Plush fabric

3.5.1 the Structure
The plush structure consists of the plain loop
and elongated plush sinker loops which show as a
pile between the wales on the technical back as a
result of having been formed over a different
surface to that of the normal length ground
sinker loops with which they are plated.
Henkelplush or velour is achieved during
finishing by cropping or shearing the loops in
both directions, to leave the individual fibers
exposed as a soft velvety surface whilst the
ground loops remain intact.

89
3.5.2 Knitting

(1) In sinker top latch needle machine, the
ground yarn is fed into the sinker throat and the
plush yarn fed at higher level is drawn over the
sinker nib.
(2) In sinkerwheel machine, sinkers with two
throats are employed, the shallow throat draws a
long sinker loop with the plush yarn whilst the
deeply cut throat draws a normal length sinker
loop with the ground yarn

90
3.6 Sliver or High-Pile fabric

Sliver or high-pile fabric is consists of ground
yarn and sliver. The ground yarn forms a normal
loop and the sliver forms only a partly loop.
The ends of sliver stand out the surface of the
fabric giving a high pile effect.
The high-pile machine is a special single-jersey
circular machine which has sliver feeds where the
slivers are drawn from cans and fed to the needle
through the wires of the doffer roller.
The end-use of this fabric is man-made furs,
linings, gloves, cushions, industrial polishers
and paint roller.

91
3.7 loop transfer stitch

3.7.1 Needle loop transfer
(1) Plain loop transfer stitches produced by
transference from one needle to another in the
same bed.
(2) Rib loop transfer stitch produced by
transference a loop from one needle bed to the
other.
(3) Needle loop transfer can be produced by hand
in hand flat knitting machine or with the
transfer needle in computerized flat machine
automatically.

92
3.7.2 Sinker loop transfer stitch (Pelerine or
Eyelet)

The apertures of eyelet are formed at courses
where adjacent plain wales move outwards, as a
result of the absence of connecting sinker loops.

93
Chapter 4 Pattern and Selection Devices

For producing a fancy fabric, normally the
pattern and selection devices must be employed.
There are several types of these devices
different lengths of butt
different butt position
pattern wheel
multi-step select butt and electronic select etc.

94
4.1 the different butt position

In single or double-jersey multi-cam-track
(raceway) machines needle butts may be positioned
in one of between two and five tracks which at
every feed position have fixed but exchangeable
knitting, tucking or missing cams.
In some machines a common top butt is controlled
by a stitch cam-track.

95
4.2 multi-step butt set-outs
96
4.3 The Pattern wheel

The pattern wheel is a cheap, simple device
occupying little space and is unique in employing
separate raising cams in the form of pattern bits
to select and move individual elements, if
necessary to three different positions in their
tricks.

97
4.4 Electronic needle selection

Electro-magnetic needle selection has now been
introduced onto a number of types of knitting
machines.
The electronic impulse which energizes an
electro-magnet is usually assisted by the field
of a permanent magnet and the minute selection
movement is then magnified by mechanical
movements.

98
Chapter 5 Weft Knitting Fabric Production

The rate of fabric production is usually
calculated in terms of linear yards (or meters)
per unit time.
Fabric production(Courses per unit time/Course
density)?
Course density is a fabric parameter and is
measured in the courses per inch (cpi) or course
per centimeter (cpcm).
The number of courses produced per unit time is a
function of the fabric structure, the number of
feeders on machine and the machine speed in terms
of revolutions per minute (rpm) or traverses per
minute (tpm).
The efficiency (?) is calculated by obtaining
data concerning machine running time and downtime.

99
Example

A single jersey fabric is produced on a 28 cpi
machine having 32 feeders and a rotational speed
of 20 rpm.
Calculating the production (yards) over a 4-hour
period if the machine is usually stationary for 3
minutes each hour.
Solution
Courses/revolution Feeders per machine
revolution/Feeder per knitted course
32/132 courses/revolution
Courses/ 4 hours Courses/rev.rpmmin/hr4hr

3220604 153,600 courses/4 hours
Efficiency (?) 57/60 0.95
Production 153,6000.95/28 5,211.4
inches/4hours 144.76 Yards/4hours

100
Chapter 5 Basic Warp Knitting Principles
101
5.1 The Warp knitting machine Classification
102
5.1.1 Tricot machine

A tricot machine is a warp knitting machine which
uses a single set of bearded or compound needles.
The fabric is removed from the needles at
approximately 90 degrees.
The tricot machine tends to have fine gauge
(28-32npi) and fewer guide bars (2,3 or 4),
produce simple and fine structure.

103
5.1.2 Raschel machine

A Raschel machine is a warp knitting machine
which uses a single set of vertically mounted
latch or compound needles.
The fabric is removed from the needles at
approximately 150 degrees.
The Raschel machine tends to have coarse gauge
(16-18npi) and more guide bars (6,8,12-48),
produce normally coarse and complex structure.

104
5.13 Two needle bar Raschel machine

The two needle bars Raschel machine is a warp
knitting machine equipped with two sets of
vertically mounted latch needles.
The fabric is removed from the needles vertically
downwards between the two needle bars.

105
5.2 The Warp knitting machine elements

5.2.1 Warp Beams
Yarn is supplied to the needles in the form of
warp sheets.
Each individual warp sheet is usually supplied
from its own beam, which may consist of several
section beams.
The number of beams used on a machine is normally
equal to the number of guide bars.
To ensure uniform conditions of warp feed and
tension, the ends are supplied from flanged beams
attached to shafts which turn to unwind the warp
sheet in parallel formation.

106

For convenience of handling, a number of beams
may be attached to a beam shaft to achieve the
full width of warp sheet, for example, a warp
sheet 84 inches (213cm) which might be supplied
from a full width beam, two beam each 42 inches
(106 cm) wide, or four beams each 21 inches
(53cm) wide.

107
5.2.2 Guide bars

The guide bars extend across the complete width
of the machine and their function is to wrap yarn
around the needle (i.e. feed).
Each guide in the guide bar is usually provided
with a single end of yarn. Warp knitting machines
are usually equipped with two or more guide bars.
Each guide bar is normally supplied with a warp
sheet from its own beam shaft to suit its
requirements of threading and rate of warp feed
for its particular lapping movement.

108

Occasionally, two partly threaded guide bars may
be supplied from the same full-threaded beam
provided they make lapping movements of the same
extent to each other whilst moving in opposite
directions.
The minimum number of guide bars and warp sheets
for commercially acceptable structures is usually
two.

109
5.2.3 Needle Bar

Needles, either mounted individually or in leads,
are clamped to the needle bar which extends
across the complete machine width.

110
5.2.4 Sinker Bar

Sinkers are positioned between each pair of
needles in the needle bar and provide for fabric
control during loop formation.

111
Warp knitting Action
112
5.3 Construction of warp knitted fabric

5.3.1 Single guide Bar Fabric
Warp knitted fabrics, in which all the yarn
follows exactly the same lapping movement, are
normally made with a single guide bar controlling
the yarns.
These fabrics have little commercial importance
because of their low cover and lack of stability.

113
5.3.2 Two guide Bar Fabric

The use of two guide bars gives a wider scope for
patterning than is available with single guide
bar fabrics, and these fabrics form the basis of
the commercial trade, using continuous filament
materials in most cases.

114
5.3.3 Part-Threaded Fabric

The guide eyes of one or more guide bar are not
all threaded yarn, only a part of them are
threaded.
The part-threaded fabric can produce some
interest surface appearance, such as relief or
openwork structure.
The guide bar threading for one width repeat is
usually shown in its correct relative position
between the needle spaces at the first link of
the design with representing a threaded guide
and representing a empty guide.
Wales will be draw together where underlaps pass
across between them and will separate at points
where no underlaps cross producing net pillars in
former and net opening in the latter. If a
full-threaded guide bar which knits at every
course is also used, the effect will still occur
in the form of a cord or relief instead of a net.

115
Part-Threaded Fabric
116
Part-Threaded Fabric
117
5.3.4 Double needle-bar fabrics

As with weft knitting, the warp knitting can also
work with two sets of needle and produce double
needle-bar fabrics.
The most popular double needle-bar fabric is the
pile or velvet effect produced by splitting the
space fabric into two pieces.
The un-split space fabric can also be used as a
technical fabric such as a substitute of the
foam.It can produce the tubular form of fabric
for technique use such as vascular tubes,
bandages etc.

118
Circular weft knitting machine
119
loop wheel knitting machine
120
rib machine
121
interlock machine
122
computerized flat machine
123
jacquard weft knitting machine

Write a Comment

User Comments (0)