BANGLADESH UNIVERSITY OF TEXTILESTEJGAON, DHAKA-1208

B.Sc. IN TEXTILE ENGINEERING, EXAM-2012

Project on

Effects of Different Parameters on Spirality of Single Jersey Knitted Fabric

SUPERVISING TEACHER

Md. Emdad Sarker

Lecturer,

Department of Fabric

Manufacturing Engineering,

Bangladesh University of Textiles.

Prepared By-

Rakib Ahmed. ID-20091050

Tanvir Ahmed. ID-20091085

Md. Nashirul Islam. ID-20091086

Sabbirul Islam. ID-20091100

Spirality is a dimensional distortion in circular plain knitted fabrics. The lengthwise rows of stitches, called wales or needle lines, should occupy a truly vertical line in the fabric and should always be at right angles to the cross wise courses of stitches. Many times the wales may skew to the right or left forming an angle, which appears in the form of a twilled surface. This geometrical defect has been termed spirality of knitting in circular fabrics

What is spirality?

Literature survey:

A research was done by M.D De ARAUJO, (Centro de Tecnologia Textil,

Universidade do Minho, Guimaraes 4800, Portugal)& G.W. Smith (College of

Textiles, North Carolina State University, Raleigh, North Carolina 27695,

U.S.A.) on the Effect of yarn spinning technology on spirality. They had

concluded that 50/50 blend yarns produce less spirality than 100% cotton

yarns.

Another research on the effect of yarn and fabric construction on spirality of

cotton single jersey fabric was done by JIANGTAO, R.C DHINGKA, E.K.

CHAN and M.S ABBAS in Institute of Textiles & Clothing, The Hong Kong

Polytechnic University.

Here, researchers derived some important equations representing spirality

like,

Spirality = 13.5 + 0.95 TF – 1.89 K,

Spirality= 9.8 + .82 TF – 2.84 K + 18.51 S

Here, the units of spirality, twist factor ( TF) and tightness factor (K) are

degree, √ tex X tpc and √ tex X cm-1, respectively.

Apparatus & machine Used:

GSM Cutter Wrap Reel

HATRA course length tester

Yarn tension meter

Machine Brand: Orizio

Origin: Italy

Machine Model: CMO 4A

Dia x Gauge: 32x28

Number of feeder: 96

Number of needle: 2820

Machine Brand: Wellknit

Origin: Taiwan

Machine Model: WS/3.0 F-B (BD)

Dia x Gauge: 30x28

Number of feeder: 90

Number of needle: 2640

Methodology:

We chose Epyllion fabric ltd and Padma poly cotton ltd for doing the job which

is related to our project.

We tried to find out the deviation of spirality with the deviation of different

machine related parameters such as machine speed, diameter, gauge and no. of

feeder. For this purpose we select knitting floor of Padma poly cotton. At first

we made grey knitted fabric by running the machine at different rpm using

same yarn and keeping the number of feeders and diameter, gauge fixed and

rpm of machine was recorded. Then we produced different knitted fabric by

varying the tension of feeding yarn. We recorded the yarn tension was given and

indicated the fabrics separately. These fabrics were scoured, bleached and finished

at Padma poly cotton. After relaxing, spirality was measured.

As spirality does not depend only machine parameters we had to find out

spirality variation according to different fabric related parameters so, for this

purpose we chose Epyllion fabric ltd to do the job. There we produced

several fabric samples with different stitch length when other parameters

were fixed. We made the same fabric with yarn of different count when

GSM and stitch length was within a range. Like the same process we were

able to produce knit fabric by changing GSM but keeping stitch length and

yarn count fixed.

These fabrics were scoured, bleached, dyed and finished separately with

running bulk production of factory order. After drying the fabric we

measured the spirality of different fabric and recorded. In some cases fabrics

were dried by tumble dryer as requirement of buyer.

Then we analysis these data and tried to find out the relation between

spirality and other parameters.

Measuring the spirality:

Spirality was measured in percentage. This measuring way was practiced in the industries of

Bangladesh. Fabric was cut from the roll at the measurement of (35cm´35cm). Three sides

are stitched. Then the stitched fabric pieces were washed with detergent for an hour and

then those were dried in tumble dryer. After conditioning half an hour in the lab

temperature, the spirality of the fabrics were measured. For measuring the spirality, at first

the displacement of the wales was measured, then the length of the wales was taken from

the displaced point to the top of the fabric piece.

Experimental Data

Exp. No. Yarn count No. of feeder Stitch length

(mm)

Spirality angle

1 28 90 2.74 0.00%

2 28 90 2.75 1.00%

3 28 90 2.75 4.3%

4 28 90 2.78 4.5%

5 28 90 2.80 7.5%

Relation between spirality and stitch length:

0.00%

1.00%

4.30% 4.50%

7.50%

0.00%

1.00%

2.00%

3.00%

4.00%

5.00%

6.00%

7.00%

8.00%

2.74 2.75 2.75 2.78 2.8

Spirality%

Spirality angle

Spirality angle

Remarks:

Spirality gradually increases with the

stitch length as increasing stitch

length loosen the fabric structure and

knitted loops tend to deform more

after relaxation.

Relation between spirality and yarn count:

Exp. No. Dia x gauge Stitch length Yarn count(mm) Spirality angle

1 30x24 2.76 24 1.00%

2 30x24 2.75 26 2.29%

3 30x24 2.75 28 4.3%

4 30x24 2.75 30 5.14%

5 30x24 2.8 30 7.50%

1.00%

2.29%

4.30%

5.14%

7.50%

0.00%

1.00%

2.00%

3.00%

4.00%

5.00%

6.00%

7.00%

8.00%

24 26 28 30 30

Spirality

Spirality angle

Spirality angle

Remarks:

Spirality increases with yarn

count as we know TPI increases

with yarn counts and yarn tends

to twist back more after

relaxation of fabric.

Limitation:

Stitch length should be constant

in this experiment which we

couldn’t as stitch length is

changed due to changing of yarn

count.

Relation between Spirality and yarn count & stitch length:

From previous literature we have come to know, Spirality ∝ yarn count and Spirality ∝ stitch length so it is very obvious that spirality ∝ (yarn count × stitch length)

Exp. No. Dia x

Gauge

Yarn

count(Ne)

Stitch length

(mm)

Yarn count x

Stitch length

Spirality

angle

1 30x24 24 2.76 66.24 1.00%

2 30x24 26 2.75 71.5 2.29%

3 30x24 28 2.75 77 4.3%

4 30x24 30 2.75 82.5 5.14%

5 30x24 30 2.8 84 7.50%

1.00%

2.29%

4.30%5.14%

7.50%

0.00%

1.00%

2.00%

3.00%

4.00%

5.00%

6.00%

7.00%

8.00%

66.24 71.5 77 82.5 84

Spirality

Spirality angle

Spirality angle

Discussion:

In previous experiment we found

S.L changes with yarn count so

we tried to find out a relation

between these parameters &

spirality.

Remarks:

Spirality increases with the

increasing of count x S.L as it

loosen the fabric.

4.Relation between spirality and GSM:

Exp.

No.

Dia x

gauge

Yarn count

(Ne)

Stitch length

(mm)

GSM

(finished)

Spirality

angle %

1 30x24 28 2.78 160 4.50%

2 30x24 28 2.80 161 2.00%

3 30x24 28 2.80 163 1.00%

4 30x24 28 2.75 167 1.00%

5 30x24 28 2.80 168 1.00%

6 30x24 28 2.80 170 2.00%

0.00%

0.50%

1.00%

1.50%

2.00%

2.50%

3.00%

3.50%

4.00%

4.50%

5.00%

160 161 163 167 168 170

Sp

ira

lity

%

GSM

Spirality

Spirality angle %

Spirality angle %

Remarks:

Spirality decreases with the

increasing of GSM of knitted fabric

up to a certain limit then it could be

increased when stitch length is kept

within a range. The reason is higher

GSM means higher compactness of

the fabric, and higher compactness

allows less space for untwisting the

yarn resulting less spirality.

Limitation:

In this experiment we should keep

S.L and yarn count constant which

we could not as these are

interrelated.

Relation between spirality and GSM, yarn count and stitch length:

From previous literature we have come to know, Spirality ∝ yarn count; Spirality ∝ stitch length and Spirality ∝

.

So, it should be Spirality ∝

Exp. No. GSM Yarn count S.L NexSL/GSM Spirality

1 182 24 2.7 0.356044 1.00%

2 162 26 2.75 0.441358 1.43%

3 157 26 2.75 0.455414 2.29%

4 152 28 2.75 0.506579 4.30%

5 150 30 2.8 0.56 7.50%

0.00%

1.00%

2.00%

3.00%

4.00%

5.00%

6.00%

7.00%

8.00%

0.356044 0.441358 0.455414 0.506579 0.56

Sp

ira

lity

%

NexSL/GSM

Spirality

Spirality

spirality

Discussion:

As we have seen from previous experiment one

parameter can’t be changed by keeping other

fixed so we tried to find out a relation between

spirality and these parameters by changing all

of them.

Remarks:

Spirality increases with the increasing of the

value of (NexSL/GSM).

From the formula of GSM we know that, GSM=

So if WPI, CPI remains constant then Spirality ∝

Exp. No. GSM Yarn count

(Ne)

Stitch

length

(GSM x Yarn

count)/ Stitch

length

Spirality%

(mm)

1 125 32 2.7 1481.48 4.50%

2 157 26 2.75 1484.36 2.29%

3 180 24 2.88 1500.00 0.00%

4 162 26 2.75 1531.64 1.43%

5 152 28 2.75 1547.64 4.30%

6 182 24 2.76 1582.61 1.00%

7 150 30 2.8 1607.14 7.50%

8 160 28 2.78 1611.51 4.50%

9 188 24 2.76 1634.78 2.00%

0.00%

1.00%

2.00%

3.00%

4.00%

5.00%

6.00%

7.00%

8.00%

1481.48 1484.36 1500.00 1531.64 1547.64 1582.61 1607.14 1611.51 1634.78

Sp

ira

lity

%

(GSM × Count) ÷ SL

Spirality

Spirality%

Spirality

Remarks:

No significant result was not

found.

Relation between Spirality and Tightness factor:

As tightness factor indicates the looseness or tightness of a fabric. So spirality should be dependent on

tightness factor and we know, Tightness factor =

Exp. No. Yarn count

(Ne)

Yarn count

(Tex)

Stitch

length (mm)

Tightness

factor

Spirality %

1 20 29.52 3.80 14.3 1.00%

2 30 19.7 2.95 15.05 5.50%

3 36 16.4 2.67 15.17 3.00%

4 28 21.1 2.85 16.12 2.00%

5 28 21.1 2.80 16.4 1.00%

6 28 21.1 2.75 16.7 1.00%

0.00%

1.00%

2.00%

3.00%

4.00%

5.00%

6.00%

14.3 15.05 15.17 16.12 16.4 16.7

Sp

ira

lity

%

Tightness factor

Spirality

Spirality %

spirality

Remarks:

We can see from the frequency polygon

that spirality decreases with increasing of

Tightness factor as increasing tightness

factor allows lees space for yarn to twist

back to cause spirality.

Exp. No. GSM Yarn

count

(Ne)

Yarn count

(Tex)

Stitch

length

(mm)

Tightness

factor, ‘X’

(GSM x

Yarn

count)/

Stitch

length, ‘Y’

(GSM x

count)/ (SL x

Tightness

factor);

‘Y/X’

Spirality%

1 157 26 22.71 2.75 17.33 1484.36 85.65 2.29%

2 180 24 24.60 2.88 17.22 1500.00 87.09 0.00%

3 182 24 24.60 2.76 17.97 1582.61 88.06 1.00%

4 162 26 22.71 2.75 17.33 1531.64 88.38 1.43%

5 188 24 24.60 2.76 17.97 1634.78 90.96 2.00%

6 152 28 21.09 2.75 16.70 1547.64 92.68 4.30%

7 125 32 18.45 2.7 15.91 1481.48 93.12 4.50%

8 160 28 21.09 2.78 16.52 1611.51 97.55 4.50%

9 150 30 19.68 2.8 15.84 1607.14 101.43 7.50%

0.00%

1.00%

2.00%

3.00%

4.00%

5.00%

6.00%

7.00%

8.00%

85.65 87.09 88.06 88.38 90.96 92.68 93.12 97.55 101.43

Sp

ira

lity

%

(GSM x Yarn count)/(Stitch length x tightness factor)

Spirality

Spirality%

Spirality

Remarks:

Spirality doesn’t depend on (GSM x Yarn count)/ Stitch length.But we have found a

relation among GSM, stitch length, yarn

count and tightness factor. A proportional

relation is found between spirality and

(GSM x Yarn count)/(Stitch length x

tightness factor).

Relation between Spirality and GSM, Count, Stitch length, Tightness factor:

Exp.

No.

GSM Yarn

count

(Ne)

Yarn

count

(Tex)

Stitch

length

(mm)

Tightness

factor,X

(GSM x

Yarn

count)/

Stitch

length, Y

(GSM x

count)/ (SL

x Tightness

factor);

Y/X

Spirality%

1 163 28 21.09 2.8 16.40 1630.00 99.38 1.00%

2 167 28 21.09 2.75 16.70 1700.36 101.82 1.00%

3 168 28 21.09 2.8 16.40 1680.00 102.43 1.00%

4 170 28 21.09 2.85 16.11 1670.18 103.65 2.00%

5 128 36 16.40 2.67 15.17 1725.84 113.78 3.00%

0.00%

0.50%

1.00%

1.50%

2.00%

2.50%

3.00%

3.50%

99.38 101.82 102.43 103.65 113.78

Sp

ira

lity

%

(GSM x count)/ (SL x Tightness factor)

Spirality

Spirality%

Spirality

Relation between Spirality and GSM, Count, Stitch length, Tightness factor (after

tumbling):

Remarks:

Spirality doesn’t depend on (GSM x Yarn count)/ Stitch length but we have found a

relation among GSM, stitch length, yarn

count and tightness factor. A proportional

relation is found between spirality and

(GSM x Yarn count)/(Stitch length x

tightness factor) even after tumble

drying.

Relation between spirality and yarn tension:

Exp. No. Yarn tension

(cN)

Stitch length No. of feeder Spirality

angle%

1 6.5 2.73 96 3.33%

2 7.5 2.73 96 1.43%

3 8.0 2.73 96 1.44%

4 8.5 2.73 96 5.03%

5 9.0 2.73 96 2.85%

6 10.0 2.73 96 2.14%

0.00%

1.00%

2.00%

3.00%

4.00%

5.00%

6.00%

6.5 7.5 8 8.5 9 10

Sp

ira

lity

%

Yarn tension

Spirality

spirality

Spirality angle%

Relation between spirality and machine rpm:

Exp. No. Cylinder

rotation

direction

Yarn count

(Ne)

RPM Spirality%

1 Clockwise 30 20 3.33%

2 Clockwise 30 26 1.43%

3 Clockwise 30 30 1.44%

4 Clockwise 30 35 5.03%

5 Clockwise 30 40 2.85%

6 Clockwise 30 45 2.14%

0.00%

1.00%

2.00%

3.00%

4.00%

5.00%

6.00%

20 26 30 35 40 45

Sp

ira

lity

%

RPM

Spirality

Spirality%

Spirality

Result & Findings:

From the research we can infer-

•The loop length has an effect on spirality. For minimizing spirality, loop length or stitch

length should not be also high so that the yarns have more space to be untwisted.

•Spirality% increases with yarn count as we know TPI increases with yarn counts& yarn

tends to twist back more after relaxation of fabric.

•Spirality shows a relation with the product of stitch length and count (Stitch length x Yarn count)•Spirality decreases with the increasing of GSM of knitted fabric up to a certain limit

then it could be increased when stitch length is kept within a range.

•Tried to find a term (Stitch length x Yarn count)/ GSM& make relationship with

spirality, get proportional relation.

•Spirality decreases with increasing of tightness factor.

•Develop a term (GSM x Yarn count)/(Stitch length x tightness factor), & spirality

increases with the value of this term. And there would be no spirality if the value of

(GSM x Yarn count)/(Stitch length x tightness factor)is around 87.

•No significant effect of feeding yarn tension has been found on spirality

•Machine RPM does not show any significant effect on spirality.

Limitation:

•This project will be much more accurate if we produced fabric

considering different parameters on a single machine. But we couldn’t manage a single machine in the factory that they were letting us to use on

our purpose. In that reason we rely on different machine of our

predetermined parameters. Result may be different in case of

experimenting fabric spirality produced on same machine.

•We couldn’t maintain same dyeing and finishing process & condition.

•We should use yarn of same lot. But we could not produce the fabrics

by the yarn of same lot.

•We tried to find the effect of one factor (stitch length or gsm or count)

on spirality while strictly maintaining the other factors constant. But in

some cases we couldn’t maintain that premises because they are closely

interrelated and in that cases we kept our factor data in a small range.