The document discusses warp and weft knitting machines, highlighting two main types of warp knitting machines: tricot and raschel. Tricot machines typically use bearded or compound needles and have a specific structure allowing for high-speed fabric production, while raschel machines utilize latch needles and have distinct production characteristics. It also contrasts warp and weft knitting methods, noting the differences in thread direction, elasticity, and the loops produced in each technique.

2. Types of warp knitting m/c:
Two major classes of warp knitting m/cs:-
1. Tricot warp knitting m/c
2. Raschel warp knitting m/c.
Features Tricot warp knitting m/c:
• In the past, tricot m/cs mainly employed bearded
needles with a pressure bar
• Tricot m/cs have a gauge expressed in needle per
inch and chain link numbering 0, 1, 2, 3, 4 etc.
generally with three links per course
• Their sinkers, which are joined to each other at the
front and back, never move clear of the needles as
they combine the functions of holding down, knocking
over and supporting the fabric
• The fabric is drawn-away towards the batching roller
almost at right angles to the needles bar.

3. • The warp beams are accommodated in an
inclined arc towards the back of the m/c with the
top beam supplying the front guide bar and the
bottom beam supplying the back guide bar
• The warp sheets pass over the top of the guide
bar rocker shaft to their tension rails situated at
the front of the m/c
• Mechanical attention to the knitting elements is
carried out at the front of the m/c, as the beams
prevent across to the back.
• As all the warp sheets are drawn over the rocker
shaft to the m/c, it is easier to thread up the guide
bars commencing with the needle bar.
• The guide bars are therefore numbered from the
back towards the front of the m/c because of
threading sequence.

5. FeatureRachel warp knitting m/c:
1. Rachel m/cs used latch needles together with a wire or
blade
2. It has a gauge expressed in needles per 2inches
(5cm) so that for example a 36 gauge Rachel m/c will
have 18npi
3. Their chain links are usually numbered in even numbers
0, 2, 4, ….etc generally with 2 links/course
4. Rachel sinkers only performs the function of holding
down the loops whilst the needles rise
5. Rachel sinkers are not joined together by a lead across
their ends nearest to the needle bars so they can move
away clear of the needles towards the back of the m/c
for the rest of the knitting cycle
6. The fabric is drawn downwards from the needles,
almost parallel to the needle bar at an angle of 120°-
160° by a series of take-down rollers.

6. 7. The warp beams are arranged above the needle bar,
centered over the rocker shaft, so that the warp
sheets pass down to the guide bars on either side of it
8. The beams are placed above the m/cs so that it is
accessible at the front for the fabric inspection
9. At least four 32″ diameter beams or large numbers of
small diameter pattern bars
10. The guide bars are threaded, connecting with the
middle bars and working outwards from the eitherside
of the rockershaft
11. The guide bars are numbered from the front of the
m/c
12. The needle trick plate acts as a fabric support ledge
and knockover surface.

8. Difference between Tricot & Rachel warp knitting m/c:
Tricot Raschel
1. In the past, bearded needle was
used but now a days compound
needle used
2. M/C gauge expressed in needle per
inch
3. Chain link numbering 0, 1, 2, 3,
….etc
4. Function of sinker is holding down,
knocking and supporting the fabric
5. The fabric is drawn away towards
the batching roller almost at right
angles to the needle bar
6. The warp beams are
accommodated in an inclined
towards the back of the m/c there
the top
7. The warp sheets pass over the top
of the guide bar rockershaft to their
tension
8. Mechanical attention is carried out
at the front of the m/c
9. The guide bars are numbered from
the back towards the front of the
m/c
10. High speed production
1. Rachel m/c used latch needle
together with a wire or blade
2. M/C gauge expressed in
needle/2inch
3. Chain link numbered in even
numbers 0, 2, 4, ….etc
4. Sinker performs the function of
holding down the loops whilst the
needle rise
5. The fabric is drawn downwards from
the needles almost parallel to the bar
at an angle of 120°-160°
6. The warp beams are arranged
above the needle bar centered over
the rocker shaft
7. The warp sheets pass down the
guide bar
8. Mechanical attention is carried out at
the back of the m/c
9. The guide bars are numbered from
front of the m/c
10.Low speed production

9. Tricot warp knitting M/C Rashel Warp knitting M/C

10. WEFT KNITTING
Types of weft knitting m/c:
According to the end product, the weft knitting m/c
may be broadly classified as either:
– Fabric m/cs
– Garment length m/cs
According to their frame design and needle bed
arrangement, the weft knitting m/c may be
broadly classified as either:
– Straight bar frame m/cs
– Flat knitting m/cs
– Circular knitting m/cs

11. Features of fabric m/cs:
• Large diameter, circular, latch needle m/cs (also known
as yarn goods or piece goods) knit fabric, at high
speed.
• The fabric is manually cut away from the m/c usually in
roll form after a convenient length has been knitted.
• Most fabric is knitted on circular m/cs either single-
cylinder (single jersey) or cylinder and dial (double
jersey) of the revolving needle cylinder type, because
of their high speed and productive efficiency
• Sinker wheel and loop wheel frames could knit high
quality specialty fabrics with bearded needles although
circular m/cs employing bearded needles are now
absolute, the production rates of these m/cs were
uncompetitive

12. • Unless used in tubular body-width, the
fabric tube requires splitting into open-
width
• The fabric is finished on continuous
finishing equipment and is cut-and-sewn
into garments or it is used for household
and technical fabrics
• The productivity and patterning facilities of
fabric m/cs vary considerably.
• Generally; cam settings and needle set-
outs are not altered during the knitting of
the fabric

13. Flat knitting m/c: Feature:
• 2 stationary needle bed in flat knitting m/c arranged in an
inverted V formation
• Latch needle is used
• Angular cam of a bi-directional cam system used
• There is a separate cam system for each needle bed
• The two cam systems linked together by a bridge, which
passes across from one needle bed to the other
• Carriage with determined yarn carrier issued
• Cam system is attached to bottom side of carriage
• The flat m/c is the most versatile of the weft knitting m/c
• Fabric produce with finer to coarser yarn
• The operation and supervision of the m/c is simple
• The stitch length range is wide and possibly of changing the
m/c gauge
• Trimmings, edging, collars, to shaped panels and integrally
knitted complex garments and other articles

14. Classification of circular knitting m/c:
1. Circular bearded needle single-jersey fabric machine
2. Revolving cylinder latch needle machine
3. Circular garment length machine
1. Circular bearded needle single jersey fabric machine:
Types of machines are divided into two types:-
a) Sinker wheel machine or French/Terrot type m/c
b) Loop wheel frame or English type m/c
Both of them have the following common features:-
 Needles are fixed in a revolving circle on needle bed
 Knitting action is entirely achieved by ancillary elements moving yarn
and loops along the needle stem
 Here tubular fabric is knitted with its technical back facing outward
 Low productivity but has an ability to produce unusual and super-
quality knitted structures
2. Revolving cylinder latch needle machine:
There ate two main types of revolving cylinder latch needle machine,
namely-
 Open top or sinker top or single jersey m/c
 Cylinder & dial m/c or double-jersey mc/

15. 11/23/15
Md.Ahashan Habib
B.Sc in Textile Engineering(DU)
Knitted Loop
1. Knit Loop
2. Tuck Loop
3. Miss Loop

16. Tuck stitch:
• A tuck stitch is composed of a held loop, one or more
tuck loops and knitted loops.
• It is produced when a needle holding its loop also
receives the new loop which becomes a tuck loop,
because it is not intermeshed through the old loop.
Miss/Float stitch:
• A float stitch is composed of a held loop, one or more
float loops and knitted loops. It is produced when a
needle holding its old loop fails to receive the new yarn
that passes, as a float loop, to the back of the needle
and to the reveres side of the resultant stitch.
• The miss stitch can occur accidentally as a fault due to
incorrectly set yarn feeders.

17. Methods to obtain Tuck/Held loops:
1. Without casting off operation in loop forming cycle , i.e.
Tucking of the latch
2. Without clearing operation in loop forming cycle, i.e.
Tucking in the hook
3. With switching a needle out of action from loop forming
cycle
Tucking on the latch:
– When tuck stitch formation is performed without casting-off and
sinking are excluded from the loop formation cycle. In this case,
the needles 4 and 7 knit the loops 3 and 6, while the needle 5
performs all the operations up to joining and stops. Then a new
yarn 2 is fed in its hook and this will be the tuck loop, the old
loop 1 remains on the closed latch and this will be the held loop.
– After the needle 5 is lifted for clearing, in the following loop
formation cycle it receives a new yarn and knits a loop from it,
casting-off upon it old held loop 1 and the tuck loop 2
– Step of forming held loop in 5 needle:

20. Difference between Warp knitting & Weft knitting.
Warp Knitting Weft Knitting
• The loops are produced
to the length of fabric
• The threads runs in the
vertical direction
• Each loop in the
horizontal direction is
made from a different
thread
• It is elastic to the length
• It’s elasticity is less
• Yarns are supplied from
beam
• At least one yarn is
needed for each needle
• Less shrinkage
• The loops are produced
to the width of the fabric
• The threads runs in the
horizontal direction
• A horizontal row of loops
can be made by using
on thread
• It is elastic to the width
• Higher elasticity
• From cone
• Any number of needle
are required for on e
yarn
• More/Higher shrinkage