knitting technology one lecture notes

1. WOLLO UNIVERSITY
KNITTING TECHNOLOGY I
3RD YEAR TEXTILE
ENGINEERING PROGRAM

2. 1. Introduction
1.1 The different types of textile products and
their processes
1. Woven fabrics: yarns cross each other at right
angles/interweave.

3. 2. Knitted fabric: yarn is made in to a series of
intermeshed loops

4. 3. Braided fabrics: yarns are intertwined, twisted
or knotted.

5. 4. Non-woven: fibers/filaments/yarns are bonded
together bonded together.

6. 1.2. Application
Apparel products

7. Technical textiles
7
Surgical mashes and membrane

8. 1.3. Development
Hand pin knitting: 1st recorded in religious painting in
1350/14th century in northern Italy
Christ’s garment was expected to be made by braiding
Stocking hand frame/ weft knitting: invented in 1589 by
William Lee
Many researchers made improvements/mechanized weft
knitting was introduced in 17th century
Warp knitting was invented in 1769 by Crane and Porter

9. Modernized knitting like
 Seamless garment,
Fully fashioned garments
are widely produced in Europe, Fareast,
middle east

10. 1.4. Yarn/filaments used for Knitting
Can be made from any filament or yarn but;
requires a relatively soft, fine, smooth, strong yarn
with good elastic recovery properties
Synthetic fibers are smooth and can be produced to
required fineness, but poor comfort properties
Texturing processes is introduced to increase
bulkiness of the fabric

11. IMPORTANT TERMS in KNITTING
1. knitting element
A generic term describing the loop forming parts of
a knitting machine and those parts used to control and
/ or select the loop forming instruments.
Example needles, sinkers, cylinder, cams etc.

12. 2. machine knitting
•It is the process of formation of intermeshed
loops for the formation of cohesive structure of
knitted fabrics.
3. knitting machine
•It is a machine for the productions of fabrics or
garments from yarns by warp knitting or weft
knitting.

13. 4. knitted loop
•The principal unit of a knitted fabric is known as the
loop.
5. knitted loop structure –
•The knitted loop structure may not always be
noticeable because of the effect of structural fineness,
fabric distortion, additional pattern thread, or the
masking effect of finishing processes.

15. 6. A course
•A course is a predominantly horizontal row of needle loops
produced by adjacent needles during the same knitting cycle.
6.1 A course length
In weft knitted fabrics a course of loops is composed of a single
length of yarn termed a course length.
6.2 A pattern row
A pattern row is a horizontal row of needle loops produced by
adjacent needles in one needle bed.

16. 7. A wale
A wale is a predominantly vertical column of intermeshed needle
loops generally produced by the same needle knitting at
successive knitting cycles.
• When loop transfer occurs it is possible to transfer a wale of
loops from one needle to another.
• Wales are connected together across the width of the fabric by
sinker loops (weft knitting) or underlaps (warp knitting).
• Wales show most clearly on the technical face and courses on
the technical back of single needle bed fabric.

17. 8. Stitch density
•Stitch density refers to the total number of loops in a measured
area of fabric and not to the length of yarn in a loop (stitch length).
•It is the total number of needle loops in a given area (such as a
square inch, or square centimetrs).
9. Technically upright
•A knitted fabric is technically upright when its courses run
horizontally and its wales run vertically, with the heads of the
needle loops facing towards the top of the fabric and the course
knitted first situated at the bottom of the fabric.

18. 10. The needle
•The needle is the principal knitting element of the
knitting machine.
•There are three types of needles used in knitting
Bearded needle
Latch needle and
Compound needle

20. 11. Fabric draw-off
•The fabric loops are always drawn from the needles on the
side remote from their hooks.
•When two sets of needles are employed, either arranged
vertically back-to-back or at some other angle to each other,
each set of hooks will face away from the other set and the
fabric will be produced and drawn away in the gap between the
two sets.

21. 12. KNITTING CAMS
The knitting cams are hardened steels and they are the
assembly of different cam plates so that a track for butt can be
arranged.
Each needle movement is obtained by means of cams acting
on the needle butts.
13. TEXTURE:
Courses per inch is said to be texture of the knitted fabric.
The course and Wales per unit space (inch or Cm) determine
the quality of fabric.

22. 14. SINGLE JERSEY FABRIC:
A weft knitted fabric made on one set of needle is
called as single jersey fabric.
15. DOUBLE JERSEY FABRIC
A fabric made on two sets of needles is called as
double jersey fabric, if fabric produced from this
will reduce the natural extensibility of the knitted
structure.

23. WEFT KNITTING MACHINES
The three main groups of weft knitting
machinery may broadly be classified as either
 straight bar frames,
 flats, or
 circulars,
according to their frame design and needle bed
arrangement.

24. 1. Straight bar frame machines
 Have a vertical bar of bearded needles
 The needle movement is controlled by circular
engineering cams
 The length of the machine is divided into a
number of knitting heads (‘sections’)
 Each head is capable of knitting a separate
fashion-shaped garment

25. 2.Circular Knitting Machines
5/11/2022
 In circular knitting machines needles are fixed on a
cylinder or dial in a circular shape.
 There are more than one feeders to feed yarn to needles
at different places.
 In most of the cases needle bed (cylinder or dial) moves
while feeders remain stationary.
 Diameter of cylinder and dial is fixed but in case of sock
knitting machines it is changeable due to structure of
socks

27. 3. FLAT KNITTING MACHINES
5/11/2022
• In flat knitting machines needles are fixed on
a straight plate.
• On this machine needle bed remains
stationary while yarn feeding system called
carriage moves from one end to other end
• This machine is used to knit collars, arm
bands and sweaters

29. Weft Knitting
m/cs
Bearded needle
machines
Latch needle
machines
Straight bar
Circular
Flat bar
Circular
- 1 needle bed
- Sinker wheel or
loop wheel
- produce fabric
- 1 needle bed or
- 2 needle bed
V-bed/flat for purl
- produce knit wear
- 1 needle bed
for plain
- 2 needle bed
for rib, interlock
- double cylinder
for purl
-Produce garment
or fabric
- 1or 2 needle bed
- Fully fashioned
- produce
shaped knit wear

30. Comparison of Weft and Warp Knitting
1. Weft knitting
•Weft knitting is the more diverse, widely spread and
larger of the two sectors, and
•accounts for approximately one quarter of the total
yardage of apparel fabric compared with about one
sixth for warp knitting.

31. •Weft knitting machines, particularly of the garment-
length type, are attractive to small manufacturers because
 their versatility,
 relatively low total capital costs,
 small floor space requirements,
 quick pattern and machine changing facilities, and
 the potential for short production runs and low stock-
holding requirements of yarn and fabric.

32. 2. Warp knitting
•Warp knitted fabric is knitted at a constant continuous
width, although it is possible to knit a large number of
narrow width fabrics within a needle bed width, usually
separating them after finishing.
•There is considerable potential for changing fabric
properties during the finishing process, as well as during
knitting.

33. Warp knitting is the process of making a fabric
in which the loops form in a vertical or warp
wise direction; the yarn is prepared as warp on
beams with one or more yarns for each needle.
The fabric has a flatter, closer, less elastic knit
than weft knit and is very often run resistant.
Weft knitting is the most common type of
knitting, it is the process of making a fabric by
forming a series of connected loops in a
horizontal or filling-wise direction.
Warp
Weft
Warp and weft knitting definitions

34. Weft Warp
 The loops are formed across the width
of the fabric
 The loops are formed vertically down to
the length of the fabric
 Possible to knit with ONE thread  Warp beam is used
 Staple and filament yarns can be used
successfully
 Filament yarns can be worked
successfully
 Latch needle is used mostly  Latch, bearded or compound needles
are used
 Less dimensional stability  More dimensional stability
 Speed reduce with design change in
cams
 Change in pattern does not affect the
speed of m/c
 Fabric quality is not consistent  Fabric quality is consistent
 Loops are not uniform  Loops are uniform
 Stretch in both direction  Stretch in widthwise direction
Comparison of Weft and Warp knitting

35. KNITTING VS WEAVING
Defined
Knitting may be defined as
“Inter-looping / Inter-meshing / hook-up / Inter-lock of single
or set of yarn moving only in one direction either lengthwise
(warp knitting) or cross-wise (weft knitting).
Weaving may be defined as:
Interlacement of two sets of yarn at right angle (90o).

36. Principle
The inter-lopping is carried out by needles (may be
Latch or beard or compound needle etc), the needles are
equipped on a cylinder and Needle butt moves between
the grooves of cams to accomplish knitting cycle and
producing the fabric.
The shape of the needle cam grooves depends on the
required knitting pattern.

37.  Weaving is carried out by inter-lacing warp
thread with filling thread.
The warp yarns from a beam pass through the
heddles and reed, and the filling is shot through
the “shed” of warp threads by means of a shuttle
or other device and is settled in place by the reed
and lay.

38. Construction
Both knit and weaved fabric comes in huge variety of construction
and design, but the basic and simplest is illustrated in the figure
given below
Schematic of Knit fabric Schematic of weave fabric

39. Woven
• Produce by interlacing of
yarns
• Set of yarn is required for
warp and weft
• Elasticity and stretch ability
is poor
• Dimensionally stable
• More durable
• Less moisture absorption
Knitted
• Produce by interloping of
yarn
• Minimum one yarn is
required
• Good elasticity and stretch
ability
• Dimensionally not stable
• Less durable
• Wicking and moisture
property is better
Woven vs knitted

40. • Poor drape property
• Good crease resistant and
no need of ironing
• Excellent air permeability
• Fabric is comparatively
strong
•Good drape property
• Less crease resistant
property
• Air permeability property is
poor
• Tensile and Tear strength
are fair.
Woven vs knitted

41. Common Knitting terms
•Stitch Length :- the length of the yarn in
the knitted loop.
• Stitch density :- total number of needles
loop in a given area.
• Wales :- is a vertical column of loops
produced by the same needle
• Courses : are rows of loops across the
width of the fabric produced by adjacent
needles.

42. Problems of knitted fabrics
 loosely knitted fabric tend to stretch out of the
shape and /or sag /snag on sharp articles.
Due to loop breakage a hole informed which start
to run (laddering).
Considerable shrinkage may occur unless a
special technique for shrink-proof is made.