lab project: yarn processing

TT520- Oxenham

Lab Project: Yarn Processing

Fall 2008

of 51

Students Involved

Carding and Drawing

Clinton Coletrane

Leslie Eadie

Jonathan Halbur

Spinning

Rachel Davis

Brian Edwards

Physical Testing

Colin Holloway

Jennifer Woodson

*assistance from Nazan Erdumlu

Knitting

Prasad Muthusami

Sam Watson

Mounting

Ahmer Ghani

Brian Hamilton

of 51

Table of Contents

Yarn Preparation ................................................................................................................................... 4-10

Opening, Carding, Drawing with Testing and Results.............................................................................. 4

Combing / Roving with Testing and Results ............................................................................................ 7

Spinning ................................................................................................................................................ 11-31

Rotor Spinning ........................................................................................................................................ 11

Ring & Compact Spinning ...................................................................................................................... 15

Testing and Results ................................................................................................................................. 19

Knitting ................................................................................................................................................. 32-39

Processing ............................................................................................................................................... 32

Testing and Results ................................................................................................................................. 35

Mounting ............................................................................................................................................... 40-41

Final Conclusions ................................................................................................................................. 42-43

References .................................................................................................................................................. 44

Appendix ............................................................................................................................................... 45-51

I. ASTM Test Methods...................................................................................................................... 46

II. Physical Testing Raw Data ............................................................................................................ 48

III. Knitting Evaluation Raw Data ....................................................................................................... 49

IV. Mounting Samples ......................................................................................................................... 51

of 51

Yarn Preparation

The raw material used for this project was 100% Fibermax® cotton. This cotton was graded

prior to purchase and had the following specifications (Table 1):

Color 31

Leaf 3

Staple 35

Micronaire 3.3

Strength 28.5

Table 1: Specifications for Fibermax® cotton

The cotton was put through the following processes:

1. Monocylinder cleaner B4/1. This machine has a peg beater that is used to separate fiber

tufts. The trash that is taken out of the fibers falls down through to a separate section of

the machine. This machine runs at 700-800rpm

2. Mixing opener B3/3R. this machine contains a saw tooth beater and spiked apron lattice

3. ERM cleaning machine B5/5 (fine opener cleaner)

4. Card 1. This card has a delivery speed of 145m/min and the slivers coming out were

70gr/yd

The main operations in the first four processes are opening and cleaning. In a typical

blowroom, one would blend multiple bales of cotton so as to achieve the highest degree of

blending possible. For this lab, only Fibermax® cotton was used, which should decrease the

need for substantial blending. However, the cotton still must be opened and cleaned. As the

cotton went through the blowroom, the degree of opening and cleaning increased as it went from

the blunt peg beaters (Figure 1) found on the monocylinder cleaner B4/1 to the fine card wire

seen on the card. If opening and cleaning of the fibers was not done slowly using the three

of 51

machines prior to the card, the sharp card wire would rip and tear the cotton fibers from the tufts

rather than separating and orienting them.

Figure 1: Peg beater inside the cleaner

From this point on, materials were split, a portion going to produce carded yarn and the

remaining portion going to produce combed yarn.

Processes for the carded yarn:

1. Draw frame RSB851. Slivers coming out of this machine were 60gr/yd. the machine had

the following settings (Table 2):

Roll Settings 39mm front; 41mm back

Break Draft 1.28

Draw Ratio 7

Delivery Speed 250 m/min

Table 2: Settings for draw frame

of 51

Figure 2: Draft zone inside the draw frame

2. Draw frame RSB851 (with auto-leveler). 8 slivers (60gr/yd) were fed into this machine

and the sliver coming out was 60gr/yd. 9 cans were filled with 75 yards of sliver each and

one with 200 yards (for testing). This machine had the following settings (Table 3):

Roll Settings 41mm front; 42mm back

Break Draft 1.16

Delivery Speed 250m/min

Draft Ratio 8

*Calculations were done to set the auto-leveler which was finally set to 682

Table 3: Settings for draw frame

of 51

Figure 3: Autoleveler on the second drawframe

The purpose of the drawframe is twofold. A specific sliver count must be achieved that is

suitable to go to the roving frame, and in achieving that specific count the uniformity of the

sliver is also increasing. By running six slivers into the drawframe (Figure 2), the final effect of

any variation seen in any of the slivers is reduced. In addition, the autolevelers (Figure 3) found

on both drawframes allows the input sliver count to be automatically controlled and adjusted so

as to insure uniformity of the output.

Processes for the combed yarn:

1. Prep-draw. Settings were the same as for the carded going through the first draw frame,

but this time draw was set to 6.9

2. Lap winder

3. Comber

4. Breaker draw. There were 2 breakages observed during this process, but when delivery

speed was slowed down, no more breakages were observed.

5. Draw frame RSB581 (with auto-leveler). 8 slivers (60gr/yd) were fed into this machine

and the sliver coming out the machine was 60gr/yd. Settings on the machine were the

same as for carded, except the auto-leveler was set to 647 after calculations were done to

of 51

determine output. Two breakages were observed on the draw frame. 9 cans were filled

with 75yards of sliver and one with 200 yards of sliver (for testing).

The sliver being prepared for combing goes through the same initial drawframe as the carded

sliver does, having the same two functions. However, after the initial drawframe, the sliver that

will be combed is wound into a lap on the lap winder for use on the comber. Both the lap winder

and comb use doublings similar to those found on the drawframes. As a result, a higher degree

of uniformity in the output from the comb should be achieved. When combing (Figures 4 & 5),

the removal of both trash content as well as short fiber content found in the laps is desirable. The

resultant combed sliver should be more uniform and oriented than the carded sliver. As a result

of the increased orientation and the resultant lack of cohesion, the comber’s drawframe adds a

small degree of crimp to the fibers to help increase inter-fiber cohesion.

Figure 4: Comber Figure 5: Close up of working parts of

the combing machine

Once the carded sliver and combed sliver had been appropriately drawn, samples were

tested in the physical testing lab on the Uster® Tester 3 and AFIS machines. The Uster® Tester

3 machine provides information describing the uniformity of the two slivers, namely the

of 51

coefficient of variation (CV). In addition to the CV, the Uster® Tester 3 machine also gives a

histogram that sums variant lengths. From the histogram, the lengths where there is the most

variation, can be determined. The AFIS machine was used to determine the fiber length

distributions and nep content of the combed and carded slivers. For each of the machines,

combed and carded sliver was tested three times so as to provide accurate and useful data.

Sliver Type %CVm

Carded Sliver 3.86

Combed Sliver 3.26

Table 4: %CVm results from Uster® Tester 3

As the data in Table 4 shows, combing the sliver did decrease the coefficient of variation

(CV%) by a small degree, as would be expected. This can be attributed to the removal of short

fiber content from the sliver during the combing process. In addition to the removal of short

fibers, the comber also doubles the input slivers and then redraws them after combing. The

doubling and redrawing of the slivers also reduces the coefficient of variation by reducing the

effect of variation seen in any one of the slivers fed into the comber. Although there was a

decrease in CV% in going from the carded to the combed sliver, neither sample had what would

be considered a good CV%. Given the high quality cotton used from the bale, the CV% would

have been expected to have lower values. One reason a slightly higher variation than normal

existed is because the samples were allowed to condition for 48 hours. As the sliver relaxes, the

coiler pattern becomes more defined within the sliver structure. This can be seen from the peak

on the histogram at 1 yard. Further analysis from the histogram shows a number of peaks at the

range from 1.5-2.5 inches. These peaks are drafting waves, and are a result of the drafting frame

and the natural variation in cotton fiber length within the sliver.

of 51

Carded Sliver Combed Sliver

Nep Content(9000 fibers) 80 59 (45)

Short Fiber Content%(w) 8.0 6.2 (5.65)

Average Length (in.) 1.0 1.02

Table 5: Sliver results from Uster® AFIS

As is indicated by the data in Table 5, both nep content and fiber length distribution of

the combed sliver was lower than that of the carded sliver. This is to be expected as the main

purpose of the combing machine is to remove both short fiber content and waste, such as neps,

from the carded sliver. Depending on the degree of uniformity desired in the combed sliver, the

desired level of trash removal can be increased or decreased. Thus, to a certain degree, one can

control the values of nep content and fiber length distribution in the combed sliver. As for the

carded sliver, nep content is mainly a result of the operating conditions seen in the card and the

fine opener prior to the card. These two processes utilize teeth so fine that snagging and fiber

breakage can occur, thus resulting in neps. The fiber length distribution of the carded sliver is a

function of the initial quality of the cotton that was used. However, the averaged combed data

looks worse than it actually is because one test showed a nep content of 86 and a short fiber

content (SFC) of 7.3. This was far worse than the other two and the average of the two runs can

be seen in parenthesis.

of 51

Spinning

The purpose of this exercise was to spin yarns using three different techniques: open end

spinning, ring spinning, and compact spinning. Open end spinning is used because it is

approximately ten times faster than ring spinning. It also requires less labor because the

equipment is more automated. Alternatively, ring spinning equipment is less expensive and the

yarns produced are stronger. Whereas, compact spinning takes place on the same equipment as

ring spinning, a few extra elements are added to the machine that makes the yarns much less

hairy.

Rotor Spinning

For rotor spinning (a method of open end spinning), the Reiter® R20 was used. The

machine must be warmed up prior to its use. Stray fibers should also be cleaned from the rotor

with a blast of compressed air. With the Reiter® R20, the sliver is fed from the can into the

machine via a feed roll. In this case, an OB20 M4 combing roll, at 700 rpm, was used to open

the fibers in the sliver and to allow trash to fall out. With cotton, it was necessary to use an

aggressive combing roll such as this. The fibers were then fed out of the combing roll and into

the fiber channel. From the fiber channel, the fibers were transported to the rotor (Figure 6). For

this exercise, a 32 mm rotor was used that spun at 92,100 rpm. The rotor had a standard groove

and a diamond coat finish. Centrifugal force forced the fiber into the groove and each rotation of

the rotor put one turn of twist into the yarn. The fibers then exited the rotor and entered the

nozzle (or navel). The nozzle used in this exercise had eight grooves, while others may have

spirals or lobes. It was also ceramic (Figure 7), which would not be the best choice if synthetic

fibers were being spun because steel nozzles dissipate heat more efficiently. The nozzle

provides false twist, which is beneficial because it creates spinning stability. Grooved nozzles

may increase hairiness, so a smooth nozzle may be used when the yarn is going to be woven.

The yarn then passed through an Uster® electronic yarn clearer, a paraffin waxing device, and

onto a package. The threading, and rethreading, of the machine is performed by a robot. All

settings for this machine are adjusted via computer controls.

of 51

Figure 6: Interior of rotor spinning chamber

Figure 7:

Inside of front face plate of rotor

spinning machine. Combing takes

place inside the face plate. Ceramic

navel inserts false twist into yarn

exiting the rotor, while loose fibers

enter rotor from opening around

base of navel

of 51

The goal was to produce a yarn with an English cotton count of 18/1. The draft was set at

125, so that for every yard of sliver, 125 yards of yarn was produced. The delivery speed was

then set based on the following calculations:

turns/inch = [(cotton count)] (twist multiple) = [(18)] (4) = 16.97 turns/inch

turns/meter = (turns/inch) (39.37 inches/meter) = (16.97) (39.37) = 668.13 turns/meter

delivery speed = (rotor rpm) / (turns/meter) = (92,100) / (668.13) = 138 meters/min

First, 120 yards of each the combed and the carded yarn was spun for testing on the Scott

Tester (Figure 8). The Scott Tester measures the force (in pounds) required to break the yarn

(Figure 9). A 120 yard segment of the yarn is reeled into 40 loops for testing. Yarn count is

determined on a scale. By multiplying yarn count and the break force, the break factor can be

calculated. The break factor of the combed yarn was 2,123 and the break factor of the carded

yarn was 1,894. A break factor of greater than 1,200 suggests that the yarn is adequate for

knitting, while a break factor of greater than 2,000 suggests that the yarn is sufficient for

weaving. Upon verification that the cotton count was within 3% of 18, the machine was

restarted and the rest of the sliver was spun into yarn.

of 51

Figure 8: Scott Tester tests the

breaking strength of the yarns

Figure 9: Yarn breaking on Scott Tester

Three cans of carded sliver and three cans of combed sliver were spun because variation

exists between positions on the machine. Carded sliver was spun in positions 2, 4, and 6.

Combed sliver was spun in positions 14, 16, and 18. The total length of yarn produced from

each can of sliver is provided in Table 6 below. It is significant to note that the waxing device

on position 4 malfunctioned and was not spinning. Also, the yarn broke once at position 18. This

meant that in three hours of machine operation, there was only one break.

Table 6: Total length of yarn produced from each can of sliver

Position Meters

2 9150

4 8800

6 8950

14 8640

16 8720

18 8190

of 51

Ring and Compact Spinning

For ring and compact spinning, the Seussen Fiomax E1 was used (Figure 10). This

machine, like others, must be warmed up before it is used. The roving is hung overhead. The

end of the roving is fed through the drafting rollers, from which it exits. To thread the machine,

a guide yarn is wound around the bobbin, through the traveler, and is then fed through the

drafting rollers where it attaches to the drafted roving. Compact spinning is carried out on the

same machine, but the drafting rollers are different—they are designed to eliminate the majority

of the hairiness that is associated with ring spun yarns and make the yarn structure more

“compact” (Figure 11). The ring on this machine was 45 mm. The traveler that was initially

used was a #5. This machine has very little automation and yarn breaks must be pieced by hand.

Figure 10: Suessen Fiomax E1 ring frame with compact

spinning attachments and overhead roving

of 51

Figure 11: Compact spinning on left; groove under mesh provides suction that compacts

the yarn. Ring spinning on right; tubes underneath pull away waste fibers.

To determine the draft setting for the machine, the desired count (18) was divided by the

break draft (1.19). The calculated main draft was 15.12. The closest machine set-up was a total

draft of 15.10. To accomplish this, the NW gear inside the machine was changed to a 35 tooth

gear and the H2 gear was changed to a 45 tooth gear. To account for twist, the square root of the

desired count was multiplied by the twist multiple (4). The calculated turns/inch was 16.97. The

closest machine setting was 17.12. To achieve this, the DW gear was changed to a 30 tooth gear.

The Z1 and Z2 gears were also changed to 60 and 56 tooth gears, respectively. All gears were

changed manually (Figures 12 & 13).

Compact Spinning Ring Spinning

of 51

Figure 12 & 13: Gears for the ring spinning machine (gears must be changed manually)

The data produced once the yarn was tested, as described previously, on the Scott Tester

is provided below (Table 7). Four rovings, one of each spinning / preparation combination, were

spun.

Yarn Breaking Force (lbs.) Count Break Factor

Carded Compact 148 17.16 2540

Combed Compact 159 16.43 2612

Carded Ring 113 17.43 1970

Combed Ring 157 17.38 2729

Table 7: Four rovings, one of each spinning / preparation combination

of 51

The average yarn count from above was calculated to be 17.1. This is 5% difference

from the desired count of 18. Since a 3% difference is allowed, the machine settings needed to

be adjusted. The traveler was changed to a lighter #3 to improve the count (Figure 14). After

switching travelers the average count was 17.92. This is within the 3% tolerance. However, the

tension was still too high, so the machine was slowed down slightly and was run until all twenty-

four bobbins were full. No yarn breaks were recorded.

Figure 14: Replacing the traveler on the spindle

of 51

Testing and Results

Conditioning of Specimens (72 hours):

Relative Humidity 64%

Temperature 72°F

Specimens:

1. Carded Ring Spun Yarn (Table 8)

2. Combed Ring Spun Yarn (Table 9)

3. Carded Compact Yarn (Table 10)

4. Combed Compact Yarn (Table 11)

5. Carded Rotor Spun Yarn (Table 12)

6. Combed Rotor Spun Yarn (Table 13)

7. Carded Compact Roving (Table 14)

8. Combed Compact Roving (Table 14)

9. Combed Ring Spun Roving (Table 14)

10. Carded Ring Spun Roving (Table 14)

Testing Machines Utilized

Uster® Tester 3 – This machine is used to provide testing on various yarn and roving types

(Figure 15). Outputs found in printed reports provide detailed information on the test sample.

The characteristics tested were yarn, hairiness, CV%, count, neps, as well as yarn thickness.

These reports are very valuable within the industry for yarn comparisons. This may provide

insight into how to achieve better quality in processing. In terms of roving, this machine can

provide tests to determine CV% as well as a fully graphed chart of the variation within the

roving. This is beneficial in that workers can quickly test their roving outputs and make changes

accordingly. Pictured below is an Uster® Tester, similar to the one utilized in this experiment:

of 51

Figure 15: Uster® Tester 3

(Via USTER.COM)

Procedures: Uster® Tester 3

For each sample of yarn it was necessary to use the following steps to properly set up testing on

the Uster® Tester 3:

1. Yarn end of the package needs to be drawn through the yarn tensioner by means of a

drawing in needle. Depending on the diameter of the yarn (maximum allowed is 2.5

mm), the material can be drawn through the ceramic eyelet. If the yarn is coarse yarn, the

material must be drawn through the cross bored hole.

2. The yarn from the package is placed into the clamping plate of the yarn changer; the yarn

ends should not protrude more than 2-3 cm. (Figures 16 & 17).

For Ring Spun Yarns – it should be ensured that the yarn tensioner is always positioned

above the axis of the yarn package. The height of the yarn tensioner of the package

holder can be adjusted with the threaded flange.

For Yarns on Cylindrical Packages (OE, Rotor Spun) – the yarn tensioner lies above the

center of the package. The yarn should be drawn off such that the end of the yarn forms a

“P” with the yarn package.

of 51

Figures 16 & 17: Yarns placed below yarn guides and into clamping arrangement

3. Before beginning the measuring procedure for the sample, it is necessary to type in a

nominal count value of the yarn being tested. This is to be entered into the TEST

PARAMETERS key. This is so that measuring tests of the yarn can be accurate, if it is

unknown what the count is before testing, one should measure to ensure the best testing

results.

4. After the yarn has been secured in the yarn tensioner, and count has been entered into the

computer, make sure that the proper information regarding yarn type and test number has

of 51

been entered. If these steps have not been taken, it is not possible to hit the “Start” button

and begin the test.

5. As the start button is pressed, a suction jet suctions yarn off into a waste bin. At the start

of the measurement, the yarn is cut and accurately-defined yarn length is fed to the

balance (Figures 18 & 19). The yarn is then cut once again, after which it is suctioned off

into the waste bin until the measurement is completed. The weight of the material on the

balance is determined automatically, and finally the sample is ejected.

Figures 18 & 19: Specified yarn length is weighed on the balance

6. A multiple page report is then printed out that provides information on CV%, count,

hairiness, neps, and thin and thick places (Figure 20).

of 51

Figure 20: Yarn thickness being tested on Uster® Tester 3

For each roving sample, the following steps were taken on the Uster® Tester 3 (Figure 21):

1. Use a rotating spindle that the roving bobbin can easily wind off; place the roving bobbin

on this spindle. A spindle tensioner must also be used to control the speed at which the

unwinding from the bobbin occurs.

2. Before the roving is placed into the measuring slot, the 100% adjustment must be carried

out for the first test of a measuring series (in terms of this test, for each bobbin of roving

from each test). Press the “Start” button and then quickly press it again to initiate the

100% adjustment.

3. This is followed by a request to insert the yarn in the measuring slot.

4. Make sure that the machine is clear of debris as well as into the finger tensioner, and over

the roller into measuring slot 2, and is drawn off via the guide roller, and the rubber

covered rollers. The roving can run off onto the floor, or kept if waste percentages are

being calculated.

of 51

5. Once the yarn is measured, the roving must be taken out of the measuring field for at

least 2 seconds because between each measurement, an automatic 100% calibration is

carried out.

6. Similar to the above test for yarn, this test provides a print out of results that focus on

CV%

Figure 21: Roving thickness being tested on Uster® Tester 3

Uster® Tensorapid 3- This machine analyzes measured values from tensile testing. Yarn quality

can also be tested and analyzed with the Uster® Tensorapid (Figures 22 & 23). This machine

can be utilized to determine tenacity, elongation, and work of rupture. Outputs in printed reports

provide detailed information on the yarn test sample. The results from this test are useful in

determining the suitability of a particular yarn for its end use in knitting or weaving.

of 51

Figure 22: Uster® Tensorapid 3

(Via USTER.COM)

Figure 23: Uster® Tensorapid 3

of 51

Procedures: Uster® Tensorapid 3

For each sample of yarn it was necessary to use the following steps to properly set up testing on

the Uster® Tensorapid 3:

1. Yarn end of the package needs to be drawn through the yarn tensioner by means of a

drawing in needle. Depending on the diameter of the yarn (maximum allowed is 2.5

mm), the material can be drawn through the ceramic eyelet. If the yarn is coarse yarn, the

material must be drawn through the cross bored hole.

2. The yarn packages that are to be tested should be set up to the left of the machine on a

suitable package holder. The yarn is then pulled through the “pig tail” (Figure 24) and

placed into the clamping plate of the yarn changer, and should not protrude more than 2-3

cm.

For Ring Spun Yarns – it should be ensured that the yarn tensioner is always positioned

above the axis of the yarn package. The height of the yarn tensioner of the package

holder can be adjusted with the threaded flange.

For Yarns on Cylindrical Packages (OE, Rotor Spun) – the yarn tensioner lies above the

center of the package. The yarn should be drawn off such that the end of the yarn forms a

“P” with the yarn package.

Figure 24: Yarn being pulled through “pig-tail” on Uster® Tensorapid 3

of 51

3. After the yarn has been secured in the yarn tensioner, and count has been entered into the

computer, make sure that the proper information regarding yarn type and test number has

been entered. If these steps have not been taken, it is not possible to hit the “Start” button

and begin the test.

Figure 25: Yarn tension being tested on Uster® Tensorapid 3

4. A multiple page report is then printed that provides information on tenacity (gf/den),

elongation (%), time to break the yarn (seconds), and work of rupture (gf.cm) (Figure 25)

of 51

Results

*Three packages of each type of yarn were tested, and averages taken for the following results.

Table 8: Carded Ring Spun Yarn

PACKAGE 1 PACKAGE 2 PACKAGE 3 AVERAGE

Tenacity

(gf/den)

1.68 1.62 1.74 1.68

Elongation

(%)

7.56 7.35 7.52 7.48

Work of Rupture

(gf.cm)

499.9 463.6 511.9 491.8

Regularity

(CVm% 10yd)

2.17 2.47 2.45 2.36

Hairiness

7.26 7.53 7.07 7.29

Table 9: Combed Ring Spun


Tenacity

(gf/den)

1.90 1.88 1.83 1.87

Elongation

(%)

7.40 7.34 6.99 7.24

Work of Rupture

(gf.cm)

548.4 569.7 500.5 539.5

Regularity

(CVm %)

1.64 1.85 1.61 1.70

Hairiness

6.35 6.49 6.54 6.46

of 51

Table 10: Carded Compact Spun Yarn


Tenacity

(gf/den)

1.81 1.59 1.76 1.72

Elongation

(%)

7.79 6.98 7.70 7.49

Work of Rupture

(gf.cm)

547.9 434.2 521.6 501.23

Regularity

(CVm% 10yd)

2.06 2.30 2.11 2.16

Hairiness

6.43 5.38 6.25 6.02

Table 11: Combed Compact Yarn


Tenacity

(gf/den)

2.02 1.75 1.78 1.85

Elongation

(%)

7.94 7.15 7.49 7.53

Work of Rupture

(gf.cm)

619.1 514.5 522.3 551.97

Regularity

(CVm %)

1.97 1.80 1.37 1.71

Hairiness

4.47 5.03 4.65 4.72

Table 12: Carded Rotor Spun Yarn


Tenacity

(gf/den)

1.17 1.42 1.23 1.27

Elongation

(%)

7.72 8.07 7.83 7.87

Work of Rupture

(gf.cm)

402.8 440.0 398.7 413.83

Regularity

(CVm %)

1.92 1.95 1.82 1.90

Hairiness

5.03 5.22 5.06 5.10

of 51

Table 13: Combed Rotor Spun Yarn


Tenacity

(gf/den)

1.39 1.48 1.44 1.44

Elongation

(%)

7.78 8.31 8.04 8.04

Work of Rupture

(gf.cm)

447.6 481.5 474.7 467.93

Regularity

(CVm %)

1.56 2.44 2.11 2.04

Hairiness

4.99 5.13 4.98 5.03

Table 14: Rovings (only regularity is tested)

Regularity

(CVm% 10yd)

7. Carded Compact

6.29

8. Combed Compact Ring Spun

4.73

9. Combed Ring Spun

4.67

10. Carded Ring Spun

6.42

of 51

Results and Discussion

The results from the testing of the yarns and the rovings give an adequate indication as to

the suitability of each yarn for its designated end use. Overall, the combed compact yarn and the

combed ring spun yarn are the most consistent. The combed compact yarn received above

average results in the work of rupture, regularity, and tenacity tests. The combed compact yarn

was also not hairy, although this is consistent with compact spinning it is a trait which can be

deemed as desirable or undesirable depending on the end use. The combed ring spun yarn, while

a hairy yarn as compared to the others, was exceptionally regular, with high tenacity and work of

rupture results. The test results for the carded rotor spun yarn indicated that in all areas regarding

strength, with the exception of elongation, this yarn is deficient. The combed rotor spun yarn,

when rated against the other yarns, would be an average quality yarn. Its only exceptional

quality is in regard to elongation, where it outperformed all the other yarns tested. When making

comparisons with regard to spinning method, the compact spun yarns, according to the tests

performed, resulted in the most regular and uniform yarns. The rotor spun yarns, with the

exception of elongation rated below all the other yarns tested in every test. In comparing the

combed yarns against the carded yarns, after the different types of spinning were performed, the

combed yarns had a high tenacity rating, regularity, and work of rupture rating whereas the

carded yarns only indicated to have higher elongation ratings. In analyzing these yarns one can

see that the extra time and capital invested in producing combed yarns definitely produces a yarn

of higher quality. Although, is has already been noted: end use is the ultimate factor in

determining the appropriateness for a yarn in weaving or knitting.

of 51

Knitting

For further analyses purposes such as appearance, hand, and abrasion resistance, samples

of the combed rotor spun, combed compact spun, carded compact spun, carded rotor spun,

combed ring spun, and carded ring spun yarns were knitted on a Fiber Analysis Knitter (FAK).

The FAK (Figure 26), made by Lawson-Hemphill, was used to knit the six yarn samples.

Figure 26: Fiber Analysis Knitter (FAK) used for the knitting of six yarn samples

The knit is a 28 cut gage. This means there are 28 needles per inch. One sample,

approximately half a yard in length, was knitted for each yarn with a small section of blue yarn

knitted between the samples. This allows for one continuous knitted sample with a distinguished

separation between yarn types. Each sample was assigned a number, and the number was

documented with the yarn type. This was done to ensure completely unbiased results. After all

of the samples were knitted, the samples were cut from the original continuous knit “sock” into

six individual samples corresponding to the six different yarn types (Figure 27).

of 51

Figure 27: Knitted samples

As mentioned previously, the samples were marked with numbers rather than the type of

yarn. This was done because a panel of judges was used for appearance and hand preferences of

the samples. Seven judges were asked to rate the knitted samples based on appearance and hand.

The backlight on a batching machine model no. H-450 made by Joseph Pernick MFG., Corp.,

(Figure 28), was used to aid in analyzing samples. This allowed each judge to easily see any

defects or irregularities.

Figure 28: Batching machine with backlight used to aid in analyzing samples

of 51

Each judge rated the samples individually. The judge first was asked to put the samples

in order of preference based solely on personal preference of appearance. The judge was then

asked to put the samples in order of preference based solely on personal preference of hand. The

judge was finally asked to place the samples in order of personal preference based on both

appearance and hand. The order for all three ratings was documented along with the reasoning

each judge used for placing the samples in a particular order.

of 51

Results and Discussion

Results based on appearance are shown below (Graph 1).

Graph 1: Number of times preferred in the top three choices based on appearance

The above graph indicates that Combed Rotor Spun yarn is in the top three most

preferred based solely on appearance from all of the judges. Four of the six different types of

yarns were in the top three of four or more judge’s votes. This showed that the appearance was

subjective to the particular judge. Most judges preferred the uniform appearance of the combed

samples despite the type of spinning process, and also the rotor spun sample despite whether or

not it was combed. When asked for the basis of the decisions, most stated that they preferred the

uniform appearance the most. Other preferences given were the most cover, evenness, and lack

of neps and trash.

Appearance

0

1

2

3

4

5

6

7

8

Combed Rotor

Spun

Carded Rotor

Spun

Combed Ring

Spun

Combed

Compact Spun

Carded Compact

Spun

Carded Ring

Spun

Type of Spinning

Nu

mb

er

of

Tim

es P

refe

rred

in

the T

op

Th

ree

Ch

oic

es

of 51

Results based on the hand of the fabric are shown below (Graph 2).

Graph 2: Number of times preferred in the top three choices based on hand

With the exception of one, all judges voted combed ring spun, carded ring spun, and

combed compact spun as his or her top three choices in regard to hand. Nobody voted combed

rotor spun or carded rotor spun as being in the top three choices for hand. It should also be noted

that the rotor spun yarns have a wax on the yarn that was applied during processing that the other

four yarns do not have on them, which may have been a factor in determining hand. When the

judges were asked what they based their decision on, all responded with a liking for softness or

hairiness. Some additional measurements were based on how thick the sample felt and the

smoothness of the surface. The true test was the combination of both characteristics being

judged.

Hand

0

1

2

3

4

5

6

7

8

Combed Ring

Spun

Carded Ring

Spun

Combed

Compact Spun

Carded Compact

Spun

Combed Rotor

Spun

Carded Rotor

Spun

Type of Spinning

Nu

mb

er

of

Tim

es P

refe

rred

in

th

e

To

p T

hre

e

Ch

oic

es

of 51

Results for judging on both appearance and hand are graphed along with the preference

of a combination of both characteristics (Graph 3). Appearance and hand are also graphed to

help show what preferences the judges favored in making their decisions.

Graph 3: Number of times preferred in the top three choices based on both

appearance, hand, and a combination of appearance and hand

This is the most important method of analysis because it most closely resembles a real

life decision when shopping for fabric or garments. This graph indicates that a combination of

appearance and hand is the most subjective preference of all. Every type of yarn was voted into

the top three choices at least once. Most judges showed a preference of hand over appearance as

shown with carded ring spun. Carded ring spun yarn was not voted into the top three preferences

by anyone according to appearance but, its softness overcomes its appearance and allows for it to

be one of the most preferred samples overall. The balance of appearance and hand was different

for everyone. Some judges were more willing to sacrifice one characteristic more than another.

More technical tests of the knitted samples were performed with the Martindale Pilling Test.

Preferences

012345678

Com

bed

Ring

Spu

n

Car

ded

Rin

g Spu

n

Com

bed

Com

pact

Spu

n

Com

bed

Rot

or S

pun

Car

ded

Com

pact S

pun

Car

ded

Rot

or S

pun

Type of Spinning

Nu

mb

er

of

Tim

es P

refe

rred

in

the T

op

Th

ree C

ho

ices

Combination of Appearance and

Hand- Number of Times Preferred

in the Top Three Choices

Hand- Number of Times Preferred

in the Top Three Choices

Appearance- Number of Times

Preferred in the Top Three Choices

of 51

Martindale Pilling Test

This test method covers the determination of the resistance to the formation of pills and

other related surface changes on textile fabrics using the Martindale Tester (Figure 29). The

Martindale Abrasion and Pilling Tester used here was manufactured by James H. Heal &

Company Ltd, Halifax, England. For the pilling resistance test the fabric samples, in sock form,

were slit-open along the length of the fabric. With each of those fabrics two circular samples of

38mm and 140mm diameter were cut using a circular cutter. One standard felt of 140mm

diameter and one fabric specimen of the same size were mounted on each of table of the tester.

Then, a 38mm diameter disk of 3mm polyurethane foam and a 38mm diameter specimen of the

same fabric were mounted in its respective holders. The holders were placed over the specimen

such that the face of the specimen is rubbed against the face of the same fabric in the holder.

The holders were held in position with pegs which normally tends to give a pressure as low as

3kPa. When the machine is switched on, it starts off in a particular straight line which gradually

becomes a widening ellipse until it forms another straight line. The machine was run for 500,

1000, 2000 and 3000 cycles and number of pills on each fabric was counted and documented for

each trial. The degree of the fabric pilling for the different samples were compared with visual

standards which may be actual fabrics or photographs of fabrics showing a range of pilling

resistance, and given a rating on a scale of 1-5 (1-high pilling and 5-no pilling) at the end of the

test. The results of the testing have been tabulated below (Table 15).

Type of Spinning Number of Pills

500 cycles 1000 cycles 2000 cycles 3000 cycles

Combed Rotor Spun 20 32 35 32

Combed Compact Spun 42 48 49 41

Carded Compact Spun 45 49 49 33

Carded Rotor Spun 24 28 26 23

Combed Ring Spun 38 45 50 35

Carded Ring Spun 32 41 41 26

Table 15: Results from Martindale Pilling Test

of 51

Based on the number of pills and in comparison to the visual standards the samples were given a

numerical rating. The results are given below (Table 16).

Sample Rating

Combed Rotor Spun (waxed) 4

Combed Compact Spun 3

Carded Compact Spun 3

Carded Rotor Spun (waxed) 4

Combed Ring Spun 2

Carded Ring Spun 2

Table 16: Ratings assigned to knitted samples after pilling test

The results indicate that rotor spun yarns have better resistance to pilling over the other types of

yarn and ring spun yarns have the least pilling resistance standards among the given types. It

should be noted that rotor yarns are waxed during the spinning process while other yarn samples

are not waxed, and hence the results are biased to a certain extent.

Figure 29: Martindale Pilling / Abrasion Testing Machine

of 51

Mounting

Samples of all of the rovings, yarns, and fabrics can be found in Appendix IV. The

varying samples have been mounted amongst their counterparts so that variances between them

can be seen. For the rovings and yarns, contrasting backgrounds of black and white are utilized

to allow the eye to pick up different details. For example, it is much easier to detect the different

levels of hairiness in the yarns and rovings against the black background while impurities tend to

be easier to spot when the background is white. The fabric samples have been affixed so that the

bottom is unattached to the paper, making the hand easier to determine.

Scanning the mounted samples into a computer makes it possible for very precise

viewing of the samples. In the scanned images of rovings and yarns, it is possible to make

qualitative assessments that may be difficult to make with the naked eye.

When looking at the scan of the rovings, against the black background, the two combed

rovings certainly appear to be less hairy than the carded samples. This must be due to the

removal of short fibers during the combing process. In fact, on closer inspection, it can be

observed that the combed samples have much less short fibers than do the carded samples. The

combed fibers also look more regular in width from top to bottom than do the carded rovings,

and this assessment is consistent with the quantitative analysis that was done on the samples.

Against the white background, two things stand out. First, the two combed samples have a bit

more twist in them than the carded samples; this is intentional, as the combed rovings need the

twist to boost cohesion. Second, the combed roving samples have less visible dirt than the

carded samples. This makes sense as cleaning is one of the perks of cotton combing.

of 51

The yarn sample scans (Figure 30) provide insight into their qualities that may not be

apparent at first glance. At the top of the mounting, against the black background, the two ring

spun yarns are unmistakably hairier than the other four samples. This is to be expected and is

consistent with the testing results. The combed compact spun yarn appears to be the least hairy

of the samples. Regularity is difficult to access on such a short and thin sample, but the combed

compact and combed ring-spun samples appear to be the most uniform as far as linear density is

concerned. When making observations against the white background, the level of cleanliness in

all of the combed yarns is once again apparent when contrasted with the carded samples.

Figure 30: Scanned yarn samples

Mounting provides a way to accentuate the visual aspects of the samples that were

created during this lab. It takes away many variables when comparing the different yarns or

rovings. The samples are juxtaposed to each other on the same board, lying in the same

direction, against the same background, and likely receiving the same lighting. This means that

the viewer is free to observe and make educated comparisons.

A B D E C F

A- Carded Ring Spun

B- Combed Ring Spun

C- Carded Compact

D- Combed Compact

E- Carded Rotor

F- Combed Rotor

of 51

Final Conclusions

The world of yarns is nothing if not bountiful, consisting of an array of options; be they

natural or synthetic. This abundance in choices means that there should be a yarn suitable for

any end use one might have in mind, for the end use is the real driver behind the determination of

which yarn to select. Different fibers, processes, and process variables should all be explored as

each can impact the qualities of the final product.

This lab focused on the processes and the process variables, using cotton as a constant

fiber choice. Cotton’s journey from bale to yarn can consist of many different routes. Six such

routes were explored in this lab, leading to six different yarns, which, in turn, became six pieces

of fabric. The assessments of these yarns and fabrics, both qualitative and quantitative, showed

how this one material can be customized to excel in a multitude of varying end uses. The

characteristics of the six yarns are displayed graphically in the figure below (Graph 4).

For someone making cotton processing decisions, the data presented below (Graph 4),

can be a tremendous asset. It takes a collection of numbers and assessments for six different

yarns and combines them into one comprehensible display. The carded compact yarn, for

example, is situated completely toward the center of the octagon, not excelling in a single area.

The combed ring spun yarn, on the other hand, resides almost exclusively on the two outermost

octagonal grades, with elongation being its solitary downfall. Once it is determined which

characteristics are required of the cotton’s end use, these qualities can be matched with those

produced by a particular process route.

of 51

Graph 4: Web comparing important aspects when determining an end use for a yarn

0

1

2

3

4

5

6Tenacity

Elongation

Work ofRupture

Regularity

Hairiness

Hand

Appearance

Pills(after3000

cycles)

Carded Ring Spun

Combed Ring Spun

Carded Compact

Combed Compact

Carded Rotor Spun

Combed Rotor Spun

of 51

References

Davis, Brian Knitting Lab

Long, Stan Knitting Lab

Oxenham, William Professor

Pegram, Jan Physical Testing Lab

Pleasants, Tim Rieter Lab

White, Teresa Physical Testing Lab

of 51

Appendix

of 51

Appendix I:

ASTM Test Methods

ASTM D 1425-96: Standard Test Method for Unevenness of Textile Strands Using

Capacitance Testing Equipment

This test method covers the indirect measuring of unevenness of textile strands by means of

continuous runs using capacitance testing equipment. The test method provides a value of

“short-term unevenness”, a single value expressing the complicated strand property that is

unevenness. Properties of a strand vary along the length; these variations are termed “strand

irregularity”. The variation of linear density is “unevenness”—this is what this test method is

concerned with. This test method is applicable to all yarns, rovings, slivers, and tops (exceptions

apply).

During testing, a yarn or roving will pass through the sensing device of the evenness tester at a

constant speed. The Uster® Tester 3 is equipped with an integrator that calculates the

unevenness automatically. The value for the variations as determined by the Uster® Tester 3 is

designated as a “CVm%”, which is related to the unevenness of the strand. A low unevenness

number is preferred, as higher unevenness numbers generally indicate the specimen will be

difficult to process, have lower strength, and will have poorer fabric appearance.

of 51

ASTM D 2256-97: Standard Test Method for Tensile Properties of Yarns by the Single-

Strand Method

This test method covers the determination of tensile properties of monofilament and spun yarns.

This test method also covers the measurement of breaking force and elongation of yarns and

includes directions for the calculation of breaking tenacity, initial modulus, chord modulus, and

breaking toughness. Specimens are to be handled in such a way that changes in twist or

stretching are avoided.

During testing single strand yarn specimens are broken on a tension testing machine, in this case

the Uster® Tensorapid 3, at a predetermined elongation rate and the breaking force and the

elongation break are determined. This test method determines the breaking tenacity and

elongation of a yarn which are fundamental properties that are widely used to establish

limitations on yarn processing or conversion and on their end-use applications. Elongation

results provide an indication of the likely stretch behavior of garment stress areas (i.e. knees or

elbows) and stretch behavior of reinforcement items (i.e. hose or tires). Also, the breaking

strength is tested. The breaking strength of a yarn influences the breaking strength of a fabric

made from the yarn.

of 51

Appendix II:

Physical Testing Raw Data

of 51

Appendix III:

Knitting Evaluation Raw Data

Characteristic Person A Person B Person C Person D Person E Person F Person G

Appearance- Top

(Most Preferred) to

Bottom (Least

Preferred)

4 1 1 2 5 1 1

1 4 4 5 2 4 4

2 5 5 1 1 5 2

5 6 2 4 4 2 5

6 2 6 3 3 3 6

3 3 3 6 6 6 3

Hand- Top (Most

Preferred) to Bottom

(Least Preferred)

5 2 6 2 5 6 6

2 5 5 6 2 3 5

6 6 2 5 6 5 2

3 3 3 3 3 2 1

4 4 1 4 1 4 4

1 1 4 1 4 1 3

Combination of

Appearance And

Hand- Top (Most

Preferred) to Bottom

(Least Preferred)

5 1 2 2 5 1 6

6 2 5 5 2 4 5

1 6 6 6 3 5 2

4 5 3 3 1 2 1

2 3 1 4 4 3 4

3 4 4 1 6 6 3

1= Combed Rotor Spun 4= Carded Rotor Spun

2= Combed Compact Spun 5= Combed Ring Spun

3= Carded Compact Spun 6= Carded Ring Spun

of 51

Type of Spinning

Appearance-

Number of Times

Preferred in the

Top Three

Choices

Hand- Number of

Times Preferred

in the Top Three

Choices

Combination of

Appearance and

Hand- Number of

Times Preferred

in the Top Three

Choices

Combed Ring Spun 5 7 6

Carded Ring Spun 0 7 5

Combed Compact Spun 4 6 5

Combed Rotor Spun 7 0 3

Carded Compact Spun 0 1 1

Carded Rotor Spun 5 0 1

of 51

Appendix IV:

Mounting Samples

lab project: yarn processing

Documents