Single Guide Bar & Double Guide
Bar Fabrics
Jimmy K.C. Lam
The Hong Kong Polytechnic University
Agenda
Factors that can affect the properties of warp knit
fabrics
 Single guide bar fabrics
 Double guide bar fabrics
 Part-set threading: eyelet fabrics

Factors affect warp knit fabric
properties

Yarn type
– This is exactly the same case as on weft knitted fabric. Yarn
and fibre properties like pilling, felting, elasticity,
electrostatics, handle and bulkiness will give great influence on
warp knit fabric..

Finishing
– The history of yarn and finish of fabric such as washing,
tentering and brushing will affect the fabric handle, density,
appearance and dimensional stability.

Fabric Structure
– This item included the lapping movement of guide bars, the
number of guide bar used, the threading of each bar and weft
insertion..
Single Guide Bar Fabrics
Characteristics
Warp knit fabrics produced by one guide bar alone have
the following drawback:
 Poor Dimensional Stability
– Like a loosely knitted single jersey in weft knitting.

Lower Patterning potential
– One of the main fabric design elements on warp knit is the
use of guide bars.
– The modern raschel machines have expanded from 48 guide
bars to 76 just for the purpose of increasing the pattern
potential.
Characteristics (II)

Poor Cover
– In knitting the regular structures, the number of yarns used to
form a loop is directly proportional to the number of guide
bar. For single bar fabrics, most loops are composed of one
yarn only and consequently the cover is not as good as 2 or 3
guide bar.

Loop distortion
– The loops of each course tend to deflect to the same direction
as the guide bar overlap. This problem is not so serious in
those two or more bar fabrics, simply because the guide bars
usually move in a direction opposite to each other.

Edge curling
– All single bar fabrics are made of unbalanced structures and
fabrics will curl to one side.
Examples

Pillar Stitches

Pillar stitch is a chain of loops
produced by a single needle.
For example, if a machine has
2000 needles, it will produce
2000 chains of loops instead of a
unique piece of fabric.
However, pillar stitches are used
as the ground structure for other


multi bar structures.
Pillar stitches with weft insertion


The only possible way
to make a fabric out of
single guide bar pillar
stitch is to add weft
yarn to link up the
chains.
Fabrics of this type are
used for decoration
purposes.
Half Tricot

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
Also known as 1 X 1 closed lap
The 1 X 1 lap is the basic formation of warp knit
fabric.
The guide bar feeds yarn on a needle in the first course,
and then it moves sideways to feed yarn on the
neighbouring needle in the second course and repeat
All the warp knit fabrics are formed in the similar
manner, except that there might be more guide bars
used, more courses per repeat, or different underlaps
and different direction of guide bar shogging.
Modification of Half Tricot
The difference between these three fabrics is the amount of guide
bar shogging for underlaps.
Fabric weight: 3x1 > 2x1 > 1x1
Finished Width: 3x1 < 2x1 < 1x1
Single Atlas


A typical single
guide bar fabric with
horizontal stripe
effect
The lapping
movement of guide
bar moves in one
direction for a
number of courses
and then return; this
changes the direction
of inclination of
loops.
Double Guide Bar Fabrics
Characteristics

Good Dimensional stability, reasonable cover
– Most of two bar fabrics are tightly knitted with their
underlaps in different directions, the fabrics have much
lower elasticity compared with weft knitted

Better loop shape and ladder resistance
– Each loop is composed by two individual loops stick
together. In most cases, the loops are formed by overlap in
opposite direction; therefore, the resultant loop is perfectly
balanced and show no distortion
Characteristics (II)

Reasonable weight
– The weight of two guide bar fabrics is not necessary equal to
double the weight of the single guide bar fabric.
» 28 gauge single bar fabric , 150 deniers
» 28 gauge two bar fabric, 75 deniers
» 28 gauge three bar fabric, 50 deniers
– The resultant count on each loop is similar, but the stitch density
and underlaps will influence the fabric wieght.with weft knitted

Better pattern scope
– Two guide bar machine can have the following pattern
»
»
»
»
vertical colour stripes; - colour check effects;
two different guide bars with individual overlap and underlap movements
two guide bars of different materials;
application of different warp tensions.
Examples : Full Tricot


This structure is actually
knitting two “half tricot”
together with two bars moving
in opposite direction.
This is a balanced structure,
the two set of warp yarns are
doing their overlap in opposite
direction. This result in
perfect upright loops in the
fabric surface.
Locknit
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Most two guide bar structures
are not balanced.
Although all structures have
their overlap and underlaps in
the opposite direction, but the
underlap displacements of the
two bars are different.
Locknit is one of the
examples.
The FGB makes a longer
undrlap than BGB, and the
result is the fabric will give
lower sideway elasticity than
tricot.
Satin
Satin is a locknit base structure. It contains even
longer underlap in the FGB. I.e 3 to 4 needles
underlap and the BGB will remain 1x1 closed
lap.
 The excessive length of underlap at the back of
the fabric will give very good light reflection
when the FGB yarns are flat acetate.
 E.g FGB= 1-0/3-4 and BGB=1-2/1-0

Reverse locknit and Sharkskin

They are very similar to locknit. The only difference is
the swapping of the chain notations between FGB and
BGB.
– Reverse locknit: FGB=1-0/1-2; BGB=2-3/1-0
– Sharkskin : FGB=1-0/1-2; BGB=4-5/1-0


The reverse locknit and locknit fabrics if knitted under
the same condition show different appearance and
properties.
The reverse locknit is more rigid fabric because the
BGB long underlaps are trapped by the shorter FGB
underlap.
Reversed Locknit and Sharkskin
FGB: 1-0/1-2
BGB: 2-3/1-0
FGB: 1-0/1-2
BGB:4-5/1-0
Sharkskin
The Sharkskin which has a longer underlap
4-5/1-0 on the BGB, will be even heavier in weight
Queen’s Cord



Queen’s cord is a very
stable structure.
The pillar stitches act as
warp yarns and the long
underlaps act as weft
yarns in the fabric.
Therefore, its
dimensional stability
should be near to the
woven fabrics.
Double Atlas

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Combination of two pieces
of single atlas knitting
together with opposite
lapping direction.
The two guide bar (double
atlas) will give a solid
vertical wales and is more
stable than single atlas.
Normally double atlas is
knitted with colour
patterns.
Marquisette Curtain Net
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This is a two bar inlay fabric with FGB making the pillar
stitch and the BGB making the inlay.
It is common to make on raschel machine because of coarser
gauge and the underlaps can shog for longer distance.
The inlay yarns, which will never form into loops in the
fabric, is usually thicker, and sometimes, fancy yarns are
used.
In warp knitting, the FGB is always used for knitting ground
structure, and the guide bars for inlay are always at the back.
– For example: A 6 bar raschel will have to used the first 2 bars for the
ground structure and the No. 3, 4, 5, and 6 guide bars for inlay yarn
as pattern bars
Marquisette Curtain Net
The 2 bar Marqiosette os a see through net fabric composed
of square cells, is used for low cost curtain net.
FGB:1-0/0-1
BGB:0-0/1-1/0-0/3-3/2-2/3-3
Raschel Lace Ground Structure
The modern raschel laces are knitted with up to
48 guide bar, and normally the first 2 or 3 bars
are used for ground structure, and the rest are
called the pattern bars.
 The most popular ground structure for raschel is
a two bar structure called TULLE
 FGB: 2-0/0-2/2-0/2-4/4-4/2-4
 BGB:0-0/2-2/0-0/4-4/2-2/4-4

Raschel Lace
Part-Set Threading
Two guide bar fabrics with part set
threading

The term part set
threading means that
the guide bar is party
threaded with warp
yarn, and the pattern of
threading could be:
– 1 in 1 out
– 2 in 1 out;
– 2 in 2 out; or any fancy
setout
Eyelet formation

The formation of
holes or eyelets on
warp knit fabrics
is purely a kind of
miss connection
between the wales
on a particular
spot for a certain
courses.
Eyelet formation (II)
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Fig A: both guide bars are fully threaded, a normal
warp knit fabric can be produced
Fig B: both guide bars are half set ( 1 in 1 out) and the
relative position of the bars are shown in the diagram.
No fabric can be formed because of the lack of
connection between wales.
Fig C: both guide bars are half set, but the relative
position of the bars are off set. No fabric can be formed
because the loops will press off at the “X” needles.
Eyelet Formation (III)
Vertical dotted lines = location of holes
FGB=2-3/2-1/1-0/1-2
BGB=1-0/1-2/2-3/2-1