Here, Some theoretical knowledge has been discussed, Which may help one's corporate/ Industrial life.Every Textile Engineer (fabric major) should know these topics in spite of not having similarity that practical & theoretical result are not always same.practical results are best......................................

1. Some Important Collection for knittingSome Important Collection for knitting
Rasel Sheikh
Intake: 2nd

2. As per practical experience we know for Single Jersey fabric, if we knit the fabric with 30/s yarn
then the grey GSM will increase 15% to 20% after dyeing and finishing.
So, if we need 145 GSM S/J fabric with 30/s
Then we should keep the
Grey GSM = 145 – (15 to 20%), supposed it the percentage will be 18 then
Grey GSM = 145 – 18%
Grey GSM = 119 GSM
For single jersey fabric:
If the yarn count is 30/s then the grey gsm will be 20% to 15% less from the finished Gsm
If the yarn count is 26/s then the grey gsm will be 22% to 20% less from the finished Gsm
If the yarn count is 24/s then the grey gsm will be 24% to 23% less from the finished Gsm
If the yarn count is 20/s then the grey gsm will be 24% to 21% less from the finished Gsm
If we want to make RIB (1X1) finished fabric with 230 GSM to 250 GSM
then we must follow the below rules:
Required 230 GSM – to 250 GSM
Yarn count will be: 24/s comb or card
Stitch line will be: 2.70 – 2.95
Grey Gsm should be: 160 – 175 Gsm
Where:
1 cm = 16/17 Feeder
If we want to make RIB (1X1) finished fabric with 195 GSM to 225 GSM
then we must follow the below rules:
Required GSM – 195 to 225 GSM
Yarn count will be: 26/s comb or card
Stitch line will be: 2.70 – 2.95
Grey Gsm should be: 140 – 155 Gsm
Where:
1 cm = 16/17 Feeder

3. I thinkthe calculationforthe greyGSM fromthe dyedGSMwill be more accurate if the dyedGSMis
dividedbythe weight-increasefactor.Thus,if the greyfabricGSM increasesby20% on dyeing,thento
findoutthe greyGSM fromthe dyedGSM. Thusif the dyedGSMis 145, thendividingthisby1.20 (1+the
% increase inweight,here 20)=120.83 GSMshouldbe the grey GSM. To check,120.83+20% (weight
increase percentage)=144.99.So, inthe example statedinthe article the greyGSMcame to 119,
whereasbythe above methoditcomesto 120.83 ie 121.
Analysis:
The shape of a loop is not circular, but the yarn for that loop or stich length can be taken as equal
to the circumference of a circle (Figure 1). The point is that, loop shape is not circle but can be
assumed as a circle and that will help to formulate some equations.
So, it has been assumed that every loop is equivalent to a circle and then circumference of that
loop will be equal to Stitch Length.
Width of Fabric:

4. Fabric width is formed by courses that are laying crosswise (loops in horizontal direction).
According to this equation the width calculation should be easy and loop should stay like the
image cited below:
But every circle share part of circle of both sides. Fabric width from this equation will be less
than actual width because the loop circles placed consecutively shares both sides with preceding
and successive loops (Figure 3).
Now let’s make relation between values from this equation & actual values and see how much
closer they stay.

5. Table 1 shows that the actual width and the width from the equation always maintain
approximately same ratio among themselves.If this ratio can be considered as a constant actual
width of the fabric can easily be derived.
So the equations can be written as considering R as a constant as it shows in the Table 1.

6. The value of R for Single jersey is 1.25-1.30 and for 1*1Rib is about 1.00 and for others fabric
type’s value of R can be calculated.

7. Variation of R is related withtype of fabric construction, needles number, yarn types and
composition, machine tension, speed, and tightness factor.
WPI:
WPI can be calculated from this equation of width.
No of needles=no of wales, and width is expressed in inch.
So, No of wales per inch=Total no of wales or no of needles/Width of the fabric in inches.
t is to be mentioned that actual WPI can be less than the WPI found from this equation if any
needles are inactive.
Course Per Inch (CPI):
A knitted fabric is a combination of courses in horizontal direction with continuous yarn. A wale
is formed having courses as shown in figure 5. A loop contains a tail yarn of previous loop and a
head yarn of next loop [From figure 5], so effective height of every course is (d1-2dy) mm.

8. So, Course height is (d1 – 2dy) mm or { (d1 – 2dy)*39.36/1000 } inch
Let, n=no of courses required for 1 inch of fabric or CPI

9. This equation can be used to have idea of CPI or to determine required no of feeder/course.
GSM:
The equation for GSM can be formulated by using equation of WPI & CPI formulated here.
The general formula for calculating GSM is

10. Figure 6 shows the variation of Actual GSM and GSM from derived equation for single jersey
grey fabrics made of 100% cotton at standard condition.

11. Figure 7 shows a relative presentation of actual and calculated GSM when required GSM is
130.The analyzed data shows that the error percentage for calculated GSM is below 5% in most
of the time. And this variation of GSM is related with so many factors like: color, yarn count,
tightness factor, relaxation state, andprocessesoccurred onthe fabric.
The equationof GSM contains the constant ‘R’ &statistical analysis for the values of R for 100%
cotton single jersey fabric foundfrom analyzed data shows 1.46% standard deviation when mean
value is 1.273 at table 4.

12. On the other hand factory data for 120 GSM single jersey fabric productions from 100% cotton
yarn shows 5.46% standard deviation, which shows that equation derived here will give less
error then the existing ways of controlling GSM.
Results:
The equations for some knitting parameters of circular knitted fabric are

13. Where, R=constant that depends on fabric types.
D=Machine Diameter and G= Machine gauge
Sl=Stitch Length (mm)& Ne=Yarn count (English count)
Knitted fabric is dimensionally unstable fabric. Here value of ‘R’ can be different for different
types of
variables. So, a constant ‘R’ value (for S/J R=1.25-1.3) must be measured by maintaining a
standard procedure & standard parameters of all variables. A further study should be done to
identify the constant value of ‘R’ for all basic types of knitted fabric.
Conclusion & Remarks:
All the equation derived here got two specific variables, Stitch length and Yarn Count. The two
which are mainly responsible for determining parameters like width, WPI, CPI & GSM. The
existing equations for calculating parameters may need more variables or need to be calculated
after production. All the equation here is to have a prediction about WPI, CPI, Width and GSM,
and process of formulation is so easy to understand that nontechnical & technical persons both
will find it easy to absorb. The values from these equations show less standard deviation than the
present situation of production. The error can be less if ‘R’ value is more precise & standard
procedure can be followed.
Useful knitting link: https://www.scribd.com/doc/52320541/Calculation-in-Weft-Knitting

14. 𝑲𝒔 =
𝑮𝑺𝑴𝑿𝑺. 𝑳
𝑻𝑬𝑿
GSM:
GSM means the weight in gram persquare meter offabric.Fabric area density:Fabric area density can be
calculated bythe following formula,
Fabric width:
Fabric width can becalculated bythe following formula:
𝐹𝐴𝐵𝑅𝐼𝐶 𝑊𝐼𝐷𝑇𝐻 =
𝜋𝑋𝐷𝑋𝐺𝑋𝑆. 𝐿
𝐾 𝑊
Where, Stitch length isin cm
D =Machine diameter,
G =Machine Gauge and
KW
= 38 (for dry relaxed state)
=41 (forwet relaxed state)
=42.2 (forfinished relaxed sta
FABRIC TYPES COLOR VALUE OF KS
S/J AVG 19.55
SINGLE LACOSTE AVG 22.4
1X1 RIB AVG 24.5
2X1 RIB AVG 28.3
FLEECE AVG 40.92