3. GENERAL INTRODUCTION
• Fabric is a manufactured assembly of fibres and yarns that has substantial surface
area in relation to its thickness and sufficient cohesion to give the assembly
useful mechanical strength. Fabrics are most commonly woven or knitted but the
term includes assemblies produced by felting, lace making, net making, non woven
processes and tufting. Our project basically is on knitted fabric specification and
machines which are related to knitted fabric production.
• The title of our project work is Analysis of knitted fabric specification and other
related machine specification. There are problem in our industries to produce
knitted fabrics of required G.S.M. Other specification like fabric width, fabric
thickness is generally maintained in industries by previous data sheet. For this
reason there are problem if any order comes which didn’t produced in previous.
• Our target is to find out the easy process to get decision about yarn count selection,
loop length selection, machine Diameter selection & machine gauge selection.
• We strongly think that by this process we can get decision about yarn count, loop
length, machine gauge, and machine diameter for the single jersey, Rib and
interlock fabric.
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4. Aim of the project work
Find out relation between yarn count and
GSM.
Find out the logic of selection of stitch length
selection.
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5. LITERATURE REVIEW
• What is yarn
Yarn is a long continuous length of interlocked fibers,
suitable for use in the production of textiles, sewing,
crocheting, knitting, weaving, embroidery and rope
making.
• What is Fabric
Fabric or cloth is a flexible artificial material that is made
by a network of natural or artificial fibers. The example is
thread or yarn which is formed by weaving or knitting as
in textiles. Cloth is mostly used in the manufacturing of
clothing and household furnishings etc.
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6. Weaving
Weaving is a method of
fabric production in which
two distinct sets of yarns or
threads are interlaced at right
angles to form a fabric or
cloth. The longitudinal
threads are called the warp
and the lateral threads are
the weft or filling. The
method in which these
threads are inter woven
affects the characteristics of
the cloth. Fig. Interlacement of
warp & weft
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7. Knitting
Knitting is a method by
which thread or yarn may
be turned into cloth or
other fine crafts. Knitted
fabric consists of
consecutive rows of loops,
called stitches. As each
row progresses, a new
loop is pulled through an
existing loop. The active
stitches are held on a
needle until another loop
can be passed through
them. This process
eventually results in a
final product.
Fig. Looping diagram
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8. Course: A course is predominantly
horizontal row of needle loops
produced y adjacent needles during
the same knitting cycle.
Wales: A wale is a predominantly
vertical column of intermeshed needle
loops produced by the same needle
knitting at successive knitting cycle.
A wale commences as soon as an
empty needle starts to knit.
Stitch length: Is theoretically a single
length of yarn which includes one
needle loop and
adjacent needle loops on either side of
it
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9. GSM = Grams per Square Meter. A measurement system more
commonly seen in paper, but also seen in t-shirts, it measures
the weight of the sheet (of fabric, paper, etc.), which will give
you some indication of its thickness. There are two formulas
for calculating the GSM of knitted fabric:-
GSM =
• Course per inch x Stitch
length x 39.37 x 39.37 x Tex
=
1000 x 1000
GSM =
WPI x CPI x SL (mm) x 0.9155
=
Count (Ne)
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10. SOME MEASUREMENT NEED FOR
GSM CALCULATION
CALCULATION OF WALES PER INCH:
We calculated the number of wales in 10 inch fabric unraveling the
yarn. Then we divide the no. of total wales by 10 inch to getting the
wales per inch.
CALCULATION OF COURSE PER INCH:
We calculated the number of course in five inch with the help of
counting glass and needle. Then we divide the total no. of course by
five inch to getting the course per inch.
MEASUREMENT OF STITCH LENGTH:
In order to determine the stitch length, we count 100 no wales or
stitch and count its length by hanging the yarn on the stitch counter.
The reading is found in mm unit.
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11. MEASUREMENT OF YARN COUNT:
We have fallowed a different way to find out the count of
the yarn. At first we unravel a considerable no yarn from the
fabric. Then we measured the total length of the yarn and
measured the weight of that no of yarn. From these weights,
we find out the count of the yarn. The equation we followed
is as follow:-
n-1 x 453.6
Count =
Wt x 36 x 840
Where, n= number of yarn in bundle.
L= length of yarn.
Wt= weight of yarn.
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12. Yarn count is calculated in two systems:
a. Direct system
b. Indirect system
• Direct system:
In this system the the weight per unit length is the yarn count. This is use
for thrown silk, artificial silk, jute etc and count calculation formula is the
following
W x l
Count =
L
Here, W = weight of sample.
L = length of sample.
l = unit length in system.
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13. Indirect system:
In this system the count of yarn express the no of unit length per unit
weight. In this system higher the yarn count finer the yarn. It is generally
used for cotton, worsted, woolen, linen etc and the yarn count calculation
formula is the following:
L x w
Count=
W x l
Here, W = weight of sample.
L = length of sample.
w = unit weight in system.
l = unit length in system.
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14. GSM DEPENDS ON
The main material for knitting process is yarn. The quality of knitted yarn should be like as
follows:
Parameter 30/1 Cotton Combed 30/1 Cotton Carded 30/1 Poly Cotton
Best Acceptable
limit
Best Acceptable
limit
Best Acceptable
limit
Uniformity % 9 – 9.5 9.7 – 10.2 11.5-12.1 12.8-13.5 9.5-9.8 10.4-10.7
Thin (-50%) 0 3 - 5 16-22 50-60 2-3 7-10
Thick (+50%) 7 - 12 32-43 75-90 250-300 15-20 34-42
Neps (+200%) 38 - 47 73 - 88 140-175 300-380 30-45 48-58
Hairiness 4.0 – 4.4 4.6 - 4.9 4.75-5.1 5.5-5.8 4-4.44 4.45-4.8
Tenacity
(CN/tex)
21.8 – 22.6 18.4 - 18.9 16.7-17.6 16.2-15.4 25.5-24 23.4-22.1
Elongation 6.7 – 6.9 6.2 - 6.4 7.3-7.08 6.6-6.4 14.7-13.7 11.8-11.2
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15. YARN COUNT
The following counts of yarn that are widely used for knitting
process are given:
• a) Cotton: 20/1, 24/1, 26/1, 28/1, 30/1, 34/1, 40/1 Ne.
• b) Terylene cotton: 20/1, 24/1, 26/1, 28/1, 30/1 Ne.
• c) CVC: 26/1, 28/1, 30/1, 34/1 Ne.
• d) Melange: 20/1, 22/1, 26/1, 30/1 Ne.
• e) Spandex: 40D, 70D.
• f) Polyester: 75D, 150D.
• g) Sewing thread: 40/2, 150D etc.
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16. RELATIONSHIP BETWEEN
KNITTING PARAMETERS
1. Stitch length increase with the decrease of GSM.
2. If stitch length increase then fabric width increase
and WPI decrease.
3. If machine gauge increase then fabric width
decrease.
4. If yarn count increase then fabric width increase.
5. If shrinkage increases then fabric width decrease
but GSM and WPI increase.
6. For finer gauge, finer count yarn should use.
7. Grey GSM should be less than finish GSM.
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17. The following equations for
the selection of yarn count to
get required G.S.M.
equations vary for fabric
types, fabric construction.
List of equations are
tabulated below:
• Single jersey
Yarn count = - 0.141 GSM + 50.22
• Pique
Yarn count = - 0.146 GSM + 57.16
• Double lacoste
Yarn count = - 0.167 GSM + 64.36
• 1 x 1 Rib
Yarn count = - 0.123 GSM + 54.57
• Lycra 1 x 1 Rib
Yarn count = - 0.119 GSM + 59.12
• Lycra 2 x 2 Rib
Yarn count = - 0.108 GSM + 56.62
• Interlock
Yarn count = - 0.206 GSM + 80.56
• Single jersey
GSM = -6.879yarn count + 350.4
• Lycra Single jersey
GSM = -4.9716 yarn count + 354.56
• Pique
GSM = -6.6737 yarn count + 386.44
• 1 x 1 Rib
GSM = -7.9731 yarn count + 437.66
• Lycra 1 x 1 Rib
GSM = -8.2839 yarn count + 494.08
• Lycra 2 x 2 Rib
GSM = -8.2839 yarn count + 494.08
• Interlock
GSM = -4.778 yarn count + 388
EQUATIONS FOR GETTING
REQUIRED GSM FROM THE
SPECIFIC YARN COUNT:
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18. Relation among GSM, stitch length and yarn count can be
derived from the following equation
1
GSM α (When Yarn count and Stitch length both
Yarn count x Stitch length are variable)
• Different properties were found in Different knit structures according to stitch
length, stitch density that means wales per inch, course per inch. Loose
structure that means higher loop length gives less GSM on fabric & compact
structure that means shorter loop length gives high GSM on fabric.
• In our project analysis, we observed that single jersey plain structure & 1×1
plain rib structure variation of calculated GSM with respect to actual GSM is
too small. But in single lacoste & polo-pique structure variation of calculated
GSM with respect to actual GSM is high. Because single lacoste & polo-pique
structure are made by combination of knit & tuck loops. They also analyzed
that one knit loop consumes 30% more yarn than tuck loop. So calculated GSM
is higher in single lacoste & polo-pique structure than single jersey plain
structure & 1×1 plain rib structure.
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20. RESULT & DISCUSSIONRESULT & DISCUSSION
From our project work we manage to find the following equations for the
selection of yarn count to get required G.S.M. equations vary for fabric
types, fabric construction. The equations are tabulated below:
Relation between the fabric GSM and the yarn count:
If the GSM of the fabric is “x” and the count of yarn is “y”, then the
equation for determining GSM and the Yarn count is as follows:
GSM, x = 332 - 5.88y &
Yarn count (Ne), y = 56 - 0.17x
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21. CONCLUSION
About this project learning thing is that fabric GSM change
during production. Different type of yarn and Yarn count has
vary the fabric GSM. It is also vary with stitch length, dyeing
and VDQ pulley. These parameters are responsible for GSM
change. From this project try to input some information for
how GSM depends on any other parameters.
So these things are should learn well to avoiding upcoming
problem and increase productivity.
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