Knitting
The technique by which yarn is manipulated
to create a textile or fabric is called knitting.
It is used for many types of garment making. Knitting may be done manually or by machine. Knitted fabric consists of a number of consecutive rows of connected
loops that intermesh with the next and previous rows.
What is knitting?
Knitting
is a process of forming fabric from a single strand of yarn, using two needles. The applied fabric has to pay more than the woven fabric. In other words, knitting is a
common term that refers to the mechanics of using a pair of needles & yarn for making fabric. When you look closely at the knitted fabric it is made up
of rows of loops that interlock with neighboring rows that is what gives the
fabric its stretch. This technique allows the fabric to be shaped for the intended
purpose, unlike woven fabric which is flat and needs to be cut to shape. Of
course, there are advanced techniques that use multiple needles, or a pair of
needles attached by a cord, that allow tubes to be knitted, or textural and multicolored
effects can be created by using multiple strands of yarn.
Knitting History
The
original origins of knitting are unknown, the earliest examples
are found in Egyptian pyramids being cotton socks. The first commercial sewing
guilds appeared in Western Europe in the early fifteenth century. With the
invention of the stocking frame, the people of the country became a craftsman
with an early form of the knitting machine, hand-knitted, with easy access to
fiber. Similar to quilting, spinning, and needlepoints, hand knitting became a
leisure activity for the wealthy. Richard Rutt, an English Roman Catholic
priest, and former Anglican bishop wrote a History of the Art of Hand Knitting.
His collection of books on knitting is now housed at the Winchester School of
Art.
Characteristics or properties of Knitted fabrics
1.
Loop length is the key factor to determine and maintain the quality of knitted fabrics.
2.
The loop length of knitting is generally measured in millimeters or inches,
which is the length of the yarn in the knitted loop. Generally the longer the
stitch length, the fabric is more open and lighter.
3.
So by setting the loop length or stitch length, it is possible to knit fabric
as a particular gsm using different yarn counts and machine gauges.
4.
The density of the stitch is the next important parameter set in the knitting
and represents the total needle loop in the given area. Stitch density is the
product of courses per inch and wales per inch and is measured in units of
loops per square inch or cm.
5. The construction of knitted fabrics is the number of loops or stitches per inch.
6.
A wale corresponds to the warp of woven fabrics, while a course corresponds to
the weft.
7.
In General, the fabric which has more wales will shrink less in width, and
which has more courses that will shrink less in length.
8.
The fabric that has both more wales and courses will have better recovery from
stretching, while that with fewer wales and courses will be less rigid, stretch
more easily, fit the body contour better but have poor recovery.
9.
The knit fabric is defined as the number of courses per inch followed by the
number of wales per inch. A 30x30 fabric would contain 30 courses per inch and
30 wales per inch.
10.
Each wale is formed by a different knitting needle that knits that wale
throughout the length of the fabric.
11.
In each course, the adjacent loops are formed by the same thread but by
different needles. Therefore most, but not all, horizontally oriented defects
are yarn related while most, but not all, vertically oriented defects are
needle related.
12.
Yarns in thickness, yarn, blend, color, or tension are seen as horizontal lines in different fabrics.
13.
Needle damage such as a bent latch or a bent or broken hook is seen as vertical
lines or streaks in the fabric.
Quality control in knitting Fabric
1.
The main contribution of quality control is saving time and money. If any error
occurs, the knitting machine must be stopped to correct the error, which
reduces the time, which is uniform in the overall production process.
2.
Loop density is the most important factor in defining the quality of the
knitted fabric and it is directly related to the fabric presence, field weight
per unit, dimensional stability, fabric weight, tensile factor, drape, and many
other factors.
3.
Quality control in the knitting process are two main causes of inconsistency
that lead to fabric defects raw material management before the knitting
process and variation in parameters during the knitting process.
4.
The selection of yarn with a proper yarn count is important in determining the
knitted fabric quality since only the correct yarn count gives optimal knitting
performance for a specific machine gauge and structure.
5. An elastic yarn is easier to knit and results
in fewer knitting faults such as drop stitches, holes, and bad selvages.
6.
This refers to the irregularity and non-consistency of the yarn, which directly
affects the quality and weaving performance of the woven fabric.
7.
Quality control during the knitting process and precision in the settings of the
knitting machine during the whole knitting process are important to produce a
fruitless knitted fabric.
8.
By carefully controlling the knitting tension, the variations in loop length
can be minimized, and the quality of knitted fabric improved.
9.
The length of yarn in one stitch is another important factor that permanently
affects the quality of a knitted fabric.
Types of knitting
On the basis
of way, there are two types-
a. Weft
knitting
b. Warp
knitting
Weft knitting
The knitting technique
in which the yarn zigzags
along the width of the fabric is called warp knitting. In
weft knitting, the wales are perpendicular to the course of the yarn.
Weft knitted
fabric types-
1. Jersey
fabric
2. Double
knit
3. Circular
knit
4. Fair Isle
5. Cable knit
Warp knitting
Knitting
techniques, where yarn zigzags along the length of the fabric, are called warp
knitting. That is, instead of a single row or course, follow the adjacent
columns or wells related to knitting. Since the individual number of yarns
needed to weave a warp strand or end is equal to the number of stitches in a
row. Warp knitting is almost always done by a machine without hands.
Warp
knitted fabric types-
1.
Tricot
2.
Milanese knit
3.
Raschel knit
Type of knitting machine
On the basis
of beds, there are two types-
a. Flatbed
knitting M/C
b. Circular
bed knitting M/C
The knitting process has three basic
tasks
1. The active
stitches must be held so they don't drop
2. These
stitches must be released after secured
3.
Knit fabrication process
At
first, the yarn cone is fitted on a machine creel. Then fitter man set the yarn
for needle feed. Here needle is used for making a loop, and the sinker is used for holding
yarn. When you look closely at the knitted fabric it is made up of rows of
loops that interlock with neighboring rows that is what gives the fabric its
stretch. This technique allows the fabric to be shaped for the intended
purpose. If any yarn is a break, the instant machine is stopped. Then the yarn
joined and the machine ran for fabric making without any faults. Finally, get a
roll of fabric, cut off this roll, and then start the machine for getting the
next fabric roll. If need spandex fabric, spandex is used with yarn feed.
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