USTER TESTER 5-S800 · blowroom, spinning preparation and during the spinning process itself. The inevitable result is wear of needles, yarn carriers, sinkers and cams. The needle

USTER® TESTER 5-S800

APPLICATION REPORT The purpose of trash and dust measurement in spinning mills

THE YARN INSPECTION SYSTEM

S. Dönmez Kretzschmar, R. Furter November 2008 SE 628


Copyright 2008 by Uster Technologies AG All rights reserved. No part of this publication may be reproduced, stored in a re-trieval system, translated or transmitted in any form or by any means, electroni-cally, mechanically, photocopying, recording or otherwise, without the prior permis-sion in writing of the copyright owner. veronesi\TT\Schulung_Dokumente\Off-Line\UsterTester5 \SE-628_The purpose of trash and dust measurement in spinning mills

2 (24) USTER® TESTER 5-S800


Contents

1 Introduction ................................................................................ 5

1.1 Effect of trash and dust on the wear of machine parts ................. 5

2 Measurement of remaining dust and trash in yarns ............... 8

2.1 Measuring principle ...................................................................... 8

2.2 Trash and dust distribution diagram (trash histogram)................. 9

3 Trash and dust particles throughout the spinning process 13

3.1 Determination of trash and dust in raw cotton and in yarns ....... 13

3.2 Determination of trash and dust in yarn ..................................... 15

3.3 Influence of trash and seed-coat fragments on subsequent production processes ................................................................. 16

4 Initial findings from practical applications ............................ 17

4.1 Comparison of trash and dust measurements of yarns with different noil percentages........................................................... 17

4.2 Comparison of rotor yarns with different clearing efficiencies of the OE spin boxes...................................................................... 18

4.3 Influence of the winding speed on the trash and dust content of carded ring yarns ....................................................................... 19

5 Conclusion................................................................................ 21

6 Literature................................................................................... 22

USTER® TESTER 5-S800 3 (24)




1 Introduction With the application of chemicals in today’s cotton harvesting methods, it is possible to defoliate the cotton plants and open the bolls which are still closed at this point in time. However, the use of such chemicals also means that the harvest is limited to a short period and therefore requires a precise planning and scheduling of the harvesting process. This explains why fully automatic harvesting machines are often used today. These machines permit a time-saving harvest of the cotton plants and a simultaneous re-moval (spindle picking) of stalks and remaining pieces of leaves. Another automatic harvesting method (stripper) produces a yield of only 1/3 of cot-ton compared with 2/3 of stalks, pieces of leaves and sand, which subse-quently have to be removed in a very aggressive ginning process. It is a proven fact that the time-consuming manual harvest of cotton, which is still used with high-quality, long-staple cotton, actually stands out through a lower contamination of the raw cotton. This means that less aggressive cleaner settings are needed in the subsequent ginning process, because the hand-picking is aimed specifically at harvesting only cotton bolls, so there is no need for cleaning out pieces of leaves and stalk. With all har-vesting methods, however, the cotton seeds, together with the fibers, al-ways get into the ginning plant where it is broken up into trash and seed-coat fragments. This means that ginned cotton is always contaminated with trash and dust particles and that an intensive cleaning is only possible in the spinning mill. It has been shown in many publications that knowing the trash and dust content in the spinning process provides a great variety of information with regard to the machine settings, the wear of machine parts and the quality of the finished fabric. Trash and dust have a significant influence on wear of different machine parts. For example, increased dust content will certainly result in accelerated wear of the fiber or yarn guiding elements in the spin-ning process. High dust content also has an effect on the service life of the delivery nozzle in the spin box of the OE rotor spinning machine, the ring traveler on the ring spinning machine and the yarn guiding elements in the winding area. With the USTER TESTER 5-S800, Uster Technologies of-fers the OI (Optical - Impurities) sensor which detects trash and dust parti-cles in yarns and determines their number and size. In this article we will concentrate on the trials which show a number of possible applications for the OI sensor. The information on the trash content in a yarn for example is very helpful for a possible subsequent scouring process or can show the effectiveness of the combing process. 1.1 Effect of trash and dust on the wear of machine parts With all harvesting methods, the cotton seeds, together with the fibers, al-ways get into the ginning plant where it is broken up into trash and seed-coat fragments. This means that ginned cotton is always contaminated with trash and dust particles and that an intensive cleaning is only possible in the spinning mill.



As it is mentioned before, trash and dust have a significant influence on wear of different machine parts. These are:

Wear of machine parts, especially on deflection parts and friction points

Yarn guiding elements in weaving and warping

Navels on OE rotor-spinning machines

Ring travelers on ring-spinning machines

Yarn guiding elements in winding

Needles, yarn carriers, sinkers and cams in knitting Trash and dust affect needles, yarn carriers, sinkers and cams on the knit-ting machine. The knitting needle is the most vital loop forming element of a knitting machine. Knitting needles require a weekly check for wear espe-cially if coarse or harsh yarn is used [5]. Depending on where they are cultivated, the harvesting method, weather conditions and gin treatment (cleaning process after harvesting), for exam-ple, cotton fibers can contain varying degrees of impurities. The natural fibers which contains foreign particles (Fig. 1) can induce needle wear. Some cotton is contaminated by sand dust which is not eliminated in the blowroom, spinning preparation and during the spinning process itself. The inevitable result is wear of needles, yarn carriers, sinkers and cams. The needle manufacturers recommend a careful selection of raw materials and intensive purification and dust removal during preparation for spinning and during the spinning process. Thus the abrasive effect can be minimized. The position of the abrasive particles in the yarn is of decisive importance in determining the degree of wear. A particle attached to the surface of the yarn will clearly exercise the most serious abrasive effect. For example, the yarns manufactured using the OE spinning method tends to demonstrate a greater degree of dust on the yarn surface. Where particles such as oxides or silicates (Fig. 2) which are harder than needle steel, are carried on the surface of the spun yarn, the needle surface becomes scratched, inevitably resulting in abrasion of the needle material [Groz-Beckert, 6]

Fig. 1 Trash and dust particles [Groz-Beckert, 6] Fig. 2 Dust particle in cotton [Groz-Beckert, 6]



The abrasive particles accumulate at the latch groove and the hook. During the knitting process, with every closing movement the latch hits the hook. As a result of the applied pressure and the friction, the needle steel is worn by the particles as illustrated below (Fig. 3) [Groz-Beckert, 6].

Hook Latch spoon Needle Line [4]

New hook New latch

Worn hooks Worn latch Effect of worn needles on knitted fabric

Fig. 3 Worn needles and effect on knitted fabric [Groz-Beckert, 6].

Consequences of worn hooks Consequences of worn latch

Needle lines Needle lines

Torn fibers and threads Holes in the fabric

Holes in the fabric Partially cut fibers and threads

Held loops Latch spoon breakage

Tuck stitches / double stitches Needle lines

Spliced threads Holes in the fabric Table 1

As we can see from the Fig. 3, the worn needles can cause a lot of quality problems during the knitting process. A very common problem is the forma-tion of the needle lines (Fig. 3, [4, 6]). Mostly the needle lines are not no-ticeable before finishing but especially after dyeing process, they become more pronounced. Exchanging only the worn needles can again cause new fabric faults because the stitch lengths of the loops formed by used needles are different than the stitch lengths of the loops formed by the new ones. In order to eliminate this fault, knitting machine and needle producers are rec-ommending, besides periodical maintenance and cleaning of the knitting machine, also the exchange of all the needles with the new ones periodi-cally [4,5].



2 Measurement of remaining dust and trash in yarns 2.1 Measuring principle The appearance of fabrics is considerably affected by remaining dust and trash particles in yarns. Therefore, the number and size of dust and trash particles can be considered as quality characteristics of yarns. The principles of operation of the sensor OI are shown in Fig. 4.

Optical receiver

Lens

Measuring slot

Yarn withdust andtrash

Whiteplate

White hemisphere Light-emitting diodes

Fig. 4 Sensor for dust and trash

Dust and trash particles, also particles of small size, can be recognized in the measuring zone and generate an optical signal at the receiver. Dust and trash particles also weaken the yarn at the place where the parti-cles are embedded. In the knitting process it can lead to a break when the yarn has to move through the eye of a needle. Therefore, it is quite obvious that the spinner tries to minimize the number of dust and trash particles in a yarn. Fig. 5 shows 4 examples of seed coat fragments. The fibers of the seed coat fragments are embedded in the yarn body.

Fig. 5 Seed-coat fragments Fig. 6 Trash particles Fig. 6 shows 4 examples of trash particles which were spun into the yarn body.



The dust and trash particles are not contaminations of completely different origin. Particles smaller than 0,5 mm are by definition dust particles. For-eign matter larger than 0,5 mm are called trash particles. 2.2 Trash and dust distribution diagram (trash histogram) The trash histogram shows whether the trash and dust particle sizes are "normally" distributed or if there is an overabundance of certain sizes. The horizontal scale shows the size in mm, and the logarithmic vertical scale the amount of the particles. In order to compare the amount of dust and trash particles it is possible to print out a diagram which shows the amount of such particles. Fig. 7 to Fig. 12 demonstrates the dust and trash dia-grams of 100% cotton, Nec 30 yarns according to various spinning systems (Ring-carded, ring-combed, compact and OE–rotor,). As we can see from the examples in Fig. 7 to Fig. 12, the combing process was able to eliminate nearly all trash particles. Trash particles are dark blue, dust particles are light blue. The amount of trash particles are also reduced, particularly the coarse particles.

Fig. 7 Trash count values in Ring-spun yarn, carded, Ne 30, 100% cotton (Color code: shaded blue = dust, dark blue = trash)

The first example in Fig. 7 shows a less cleaned ring-spun, carded, which has a high trash and dust count. The trash count/km value is equal to 24.8 and the dust count/km value is equal to 1259. Fig. 8 and Fig. 9 show the USTER® STATISTICS with respect to the trash and dust values of carded, ring - spun material of 100% cotton. The above mentioned values in our example correspond to 95% level of the USTER® STATISTICS (Fig. 8 and Fig. 9)



Fig. 8 USTER® STATISTICS 2007, Cotton 100%, carded, Ne 30, ring-spun, for woven fabrics

Fig. 9 USTER® STATISTICS 2007, Cotton 100%, carded, Ne 30, ring-spun, for woven fabrics

Fig. 10 Trash count values in Ring-spun yarn, combed, Ne 30, 100% cotton (Color code: shaded blue = dust)



On the contrary the second example in Fig. 10 is of a yarn produced from well cleaned ring-spun, combed yarn. In this sample there is no trash parti-cle. The dust count/km value is equal to 53.2. These values correspond to less than 5% and 17% of the USTER® STATISTICS, respectively.

Fig. 11 Trash count values in OE-Rotor yarn, carded, Ne 30, 100% cotton (Color code: shaded blue = dust, dark blue = trash)

The third example, Fig 11, demonstrates OE-rotor yarn which has a high trash and dust count. The trash count/km value is equal to 13.6 and the dust count/km value is equal to 783.7. These values correspond to 86% and 83% of the USTER® STATISTICS, respectively.

Fig. 12 Trash count values in Com-pact yarn, combed, Ne 30, 100% cotton (Color code: shaded blue = dust, dark blue = trash)

On the contrary the fourth example, Fig. 12, represents a yarn produced as a compact yarn. The few trash particles it contains are just slightly over the 500 μm threshold level (average trash size 525 μm). The trash count/km value is equal to 0.2 and the dust count/km value is equal to 53.3. These values correspond to less than 5% and 26% of the USTER® STATISTICS, respectively. Fig. 13 demonstrates the trash counts by spinning systems. We can see the comparison of the trash contents of the selected 45 different carded and combed yarns. There is a significant difference between the trash counts of the carded yarns (ring-carded and OE-rotor) and the combed yarns (ring-combed and compact). While the highest trash count of carded yarns is 52 /km, the highest value of combed yarns is only 7 /km.



We can see that when the yarn gets thinner, the trash content of the se-lected 45 yarns decreases.

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Fig. 13 The comparison of the trash content in carded and combed yarns (45 yarns)

Fig. 14 demonstrates the dust count by spinning systems. Here we can see the comparison of the dust contents of the selected 45 different carded and combed yarns. There is a significant difference between the dust counts of the carded yarns (ring-carded and OE-rotor) and the combed yarns (ring-combed and compact). While the highest trash count of carded yarns is 4724 /km (OE-rotor), the highest value of combed yarns is only 1224 /km.

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Fig. 14 The comparison of the dust content in carded and combed yarns (45 yarns)

Table 2 shows a print-out of a combed cotton yarn, Nec 40. The table clearly demonstrates that the combers could eliminate most of the trash particles. There was no particle count anymore in five out of 10 bobbins. The dust counts are still considerable for all of the bobbins.



No. Trash Count/

km

Trash 1/g

Dust Count/

km

Dust 1/g

Trash size μm

Dust size

1 0.0 0.0 1287.0 43.1 189.7

2 0.0 0.0 1324.0 44.7 187.8

3 2.0 0.1 1319.0 44.4 506.3 188.5

4 1.0 0.0 1116.0 38.0 593.8 191.6

5 0.0 0.0 1471.0 49.4 188.0

6 3.0 0.1 1087.0 35.9 523.1 189.7

7 0.0 0.0 1212.0 40.7 191.9

8 0.0 0.0 967.0 33.0 187.4

9 1.0 0.0 1268.0 43.2 531.3 189.8

10 1.0 0.0 1274.0 43.5 506.3 191.3

Mean CV Q95 Max Min

0.8 129.1 0.7 3.0 0.0

0.0 127.8

0.0 0.1 0.0

1239 11.61 102.4 1471 967.0

41.6 11.51

3.4 49.4 33.0

532.1 6.79 44.8 593.8 506.3

189.6 0.86 1.2

191.9 187.4

Quality parameter

Explanation of terms

Trash Count/km Number of trash particles per km

Trash 1/g Number of trash particles per gram

Dust Count/km Number of dust particles per km

Dust 1/g Number of dust particles per gram

Trash size m Average size of the trash particles

Dust size Average size of the dust particles

Table 2 Print-out for dust and trash

3 Trash and dust particles throughout the spin-ning process

3.1 Determination of trash and dust in raw cotton and in

yarns A very important quality aspect, besides the information about the contami-nation of the raw cotton, is the knowledge of the variation of the contamina-tion level in the entire spinning process. Fig. 15 and Fig. 16 show the varia-tion of the trash and dust content in the spinning preparation process of a combed ring yarn. Fig. 15 represents an Indian cotton, micronaire 4.2, Up-per Half Mean Length 29 mm. Fig. 16 represents Pima cotton, Micronaire 3.9, Upper Half Mean Length 1 7/16 inch. (36,5 mm). Most of the dust and trash particles are removed in the blowroom, at the card and at the comber. The raw material in Fig. 15 was processed into a yarn of Ne 40 (15 tex). The count of this yarn, therefore, is equivalent to 15 grams per kilometer. Fig. 15 represents the amount of dust and trash particles per 15 grams per kilometer. The Pima cotton of Fig. 16 was processed into a yarn of Ne 80 (7,5 tex). The count of this yarn, therefore, is equivalent to 7,5 grams per kilometer. Fig. 16 represents the amount of dust and trash particles per 7,5 grams.



All the measurements till roving were carried out with USTER® AFIS, the tests with bobbins and cones with the USTER® TESTER 5.

780

7875

42901695

240

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bale card mat card sliver ribbon lap combersliver

finishersliver

roving bobbin cone

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Fig. 15 Process analysis in the spinning process

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bale card mat card sliver ribbon lap combersliver

finishersliver

roving bobbin cone

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rash

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co

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t in

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m

Fig. 16 Process analysis in the spinning process

If we compare Fig. 15 and Fig. 16, we can notice the following:

It was easier to clean the cotton in Fig. 16 even if we compare it at the same amount of raw material.

The spinning machine and the winding machine also can remove a cer-tain amount of dust and trash particles.



3.2 Determination of trash and dust in yarn So what is the added benefit we can expect from determining the trash and dust particles in yarn? With the introduction of the optoelectronic OI sensor for the measurement of contaminants with the USTER TESTER 5-S800, it is possible for the first time to obtain information with routine laboratory tests about the trash and dust content in yarns together with the other qual-ity parameters. With the existing capacitive sensor, it was not possible to distinguish between neps and trash particles. The OI sensor, on the other hand, identifies trash and dust as separate objects. Seed-coat fragments are also counted as trash or dust depending on the size. An important advantage of the determination of the trash and dust particles at the very end of the spinning process is the objective assessment of the cleaning efficiency with regard to vegetable remains in yarn. In practice, this means that the cotton is purchased according to the usual criteria, i.e. the cotton is assessed and selected according to quality standards of the classing office. At the same time, this quality assessment is the most impor-tant factor for the pricing of raw cotton. After the raw material has been defined, the settings of cleaners in the blowroom and the machine settings in the spinning mill are specified ac-cordingly. Once they have been defined, the settings are usually left un-changed. With a certain statistical variation, a constant quality can be ex-pected with regard to the trash and dust content in the yarn, provided no changes have been made in the production process or the respective raw material. If these requirements are fulfilled and the trash and dust content in yarn increases, then this would indicate a fault in the production process and require an examination of the entire spinning process with the help of suitable fiber testing instruments, but especially with the USTER AFIS PRO 2 (Fig. 17 and Fig. 18). The main advantage of controlling the trash and dust content in the yarn is the immense time saving, because a quality control of the yarn at the end of the process is standard procedure in mod-ern spinning mills. In addition, the USTER TESTER 5-S800 permits an automatic monitoring of the measurement values with defined warning and control limits and therefore ensures a continuous monitoring of the test data.



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Fig. 17 Increase of the dust content in yarn


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Process control by means of fiber testing equipmentProcess control by means of fiber

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Fig. 18 Increase of the trash con-tent in yarn

3.3 Influence of trash and seed-coat fragments on subse-

quent production processes A high trash content in yarn will also have an effect on the subsequent pro-duction processes. The information on the trash content in a yarn, for ex-ample, is very helpful for a possible subsequent scouring process. At this finishing stage, vegetable contaminants are removed from yarns or from fabrics with the help of sodium hydroxide (NaOH) and supporting chemicals at a temperature of 98°C. If the degree of contamination is known, it is pos-sible to control this process by adjusting the concentration and duration accordingly.



Extensive tests with the USTER TENSOJET have also shown that trash particles and seed-coat fragments in yarn can cause dangerous weak places. Fig. 19 shows the different reasons for the 69 weak places detected in a rotor yarn of 100% cotton, Ne 30, which have been determined in a test series of two million breaks. The weak places have a mean specific tensile strength of 7.4 cN/tex (min. 2.8 cN/tex, max. 9 cN/tex) and a mean elonga-tion of 3.7% (min. 1.89 %; max. 6%). Because of the special yarn construc-tion of OE rotor yarns, with the twist being applied from the inside to the outside, there is a danger that trash particles disturb the twist application and, as a result, causing weak places.

Thin places57%

Neps1%

Foreign fibers 6%

Spinning starter

4%

Seed-coat fragments

7%

Trash16%

Thick places9%

Fig. 19 Reasons for breaks of OE rotor-spun yarn, 100% carded cotton, Ne 30

4 Initial findings from practical applications 4.1 Comparison of trash and dust measurements of yarns

with different noil percentages Table 3 shows a comparison of two ring yarns which were spun with differ-ent noil percentages. For the calculation of the percentage decrease of imperfections, trash and dust particles, the yarn with the lower noil percent-age was taken as 100%.

Combing efficiency Thin -40% /km

Thin -50% /km

Thick+35%/km

Thick+50%/km

Neps +140%

/km

Neps+200%

/km

Neps +280%

/km

Trash >0.5 mm

/km

Dust <0.5 mm

/km

Noil percentage 10% 160.3 4.5 813.3 130.8 1125 250.5 44.8 5.1 557.5

Noil percentage 20% 65.6 1 318.9 26.4 320.5 55.1 7 1.3 186.4

Deviation in % -58% -77% -61% -80% -72% -78% -84% -75% -67%

Mean deviation in % -67.5% -70.5% -78% -71%

Table 3 Comparison of the imperfections and the trash and dust content of two yarns



This example illustrates that the removal of imperfections and of trash and dust particles can be controlled very specifically by adjusting the combing process, whereby the reductions in the individual classes show similar per-centages. The following illustrations in Fig. 20 show the histograms of the trash and dust distribution of the two yarns.

Distribution of trash and dust with a noil percent-age of 10%

Distribution of trash and dust with a noil percent-age of 20%

Fig. 20 The histograms of the trash and dust distribution of the two yarns with various noil percentages

The two diagrams (Fig. 20) show clearly how the overall level of trash and dust could in fact be lowered considerably by increasing the noil percent-age. The determination of an optimum noil percentage shall not be dealt with at this point. 4.2 Comparison of rotor yarns with different clearing effi-

ciencies of the OE spin boxes The following example compares four drawframe slivers and the respective yarns spun by two spinning mills which produce similar yarn counts.The comparison shows a noticeable difference in the dust content of the two drawframe slivers. With an optimum opening roller of the OE rotor spinning machine in spinning mill A, it was possible to achieve a dust reduction of 81% in the yarn Ne 5,6 and 87% in the yarn with Ne 6,75. The spinning mill B, on the other hand, produces a drawframe sliver with about half the dust content compared with spinning mill A.



In the subsequent spinning process, however, the high quality of this draw-frame sliver with regard to a reduced dust content can only be utilized to a limited extent. As shown very clearly in Fig. 21, the dust content of yarn B could hardly be reduced. This example illustrates how the degree of con-tamination of yarns can vary according to the clearing efficiency of the OE spin box.

OE-Yar

n, 1

05 te

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OE-Y

arn,

87

tex

OE-Yar

n, 1

07 te

x

OE-Y

arn,

91

tex

120

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t/g

Spinning mill A Spinning mill B

Fig. 21 Dust content in sliver and yarn

4.3 Influence of the winding speed on the trash and dust

content of carded ring yarns An additional trial series was carried out to examine the influence of the winding speed on the trash and dust content of carded yarns, which were wound at different speeds and then tested with the USTER® TESTER 4. The results are shown in the following diagrams. With regard to the trash content (Fig. 22) of ring yarns, one would assume that a reduction in the trash content could be expected, on the one hand, through the spinning process and, on the other hand, through the subsequent winding process. In the case of a winding speed of 1200 m/min, the two yarns show a trash reduction of 50%. In absolute terms, however, the trash reduction of yarn B is much higher than that of yarn A. The reason for this is the different structure of the trash particles such as seed-coat fragments and pure trash particles with no fibers attached. A comparison of these structures leads to the conclusion that loose trash particles are more likely to be thrown out in the winding process than seed-coat fragments, which are more strongly tied into the yarn body by the at-tached fibers.




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Fig. 22 Influence of the winding speed on the trash content [Trash/km]

Fig. 23 shows the reduction in the number of dust particles resulting from the winding process. A comparison of the dust content of the bobbins, again at the winding speed of 1200 m/min, results in a calculated reduction of about 30%.

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Fig. 23 Influence of the winding speed on the dust content [Dust/km]

Up to a winding speed of 1200 m/min, there are no differences with regard to the yarn evenness, the imperfections and the tensile properties. A loss of quality in the yarn evenness, imperfections and tensile properties can be observed only at winding speeds of 1400 m/min and up. The yarn hairiness increases with every winding process.


5 Conclusion With the installation of the OI (Optical - Impurities) sensor in the USTER TESTER 5-S800, Uster Technologies has completed the quality assess-ment of a yarn. In addition to the known quality parameters such as even-ness, imperfections, hairiness and yarn count, with the help of OI-sensor the detection of the trash and dust particles in yarns and the determination of their numbers and sizes are also possible. As it is mentioned before, trash and dust have a significant influence on the wear of different machine parts. For example, increased dust content will certainly result in acceler-ated wear of the production parts in the spinning process. High dust content also has an effect on the service life of the delivery nozzle in the spin box of the OE rotor spinning machine, the ring traveler on the ring spinning ma-chine and the yarn guiding elements in the winding area. The trials have shown that there are a number of possible applications for the OI sensor. It could be shown, for example, that the opening rollers of the OE rotor machines can have a considerable influence on the trash and dust removal. In addition, and against all expectations, it turned out that, with regard to trash and dust, the winding process has a „cleaning“ effect on the yarn, because a high winding speed results in a reduction of the trash and dust content. Unfortunately, it is not possible to select just any high winding speed because of the other quality parameters involved. The information on the trash content in a yarn for example is very helpful for a possible subsequent scouring process or can show the effectiveness of the combing process.



6 Literature

1. Frey, M., Schneider, U. ., “Possibilities of removing seed fragments with adherent fibers in the spinning mill”, Melliand Textile Reports 5/89.

2. USTER NEWS BULLETIN No. 38, page 20, M. Frey, R. Furter, R. Meier, W. Schneiter, Ed. White, Uster Technologies.

3. Weber, A., “Analysis of weak places with capacitive and optical sensors on the USTER® TENSOJET”, thesis 1995, Fachhochschule für Technik und Wirtschaft, Reutlingen.

4. Iyer, C., Mammel, B., Schach, W., 1995, “Circular Knitting”, Bam-berg, Meisenbach

5. Ajgaonkar, D.B.,”Principles of Knitting XXXIII”, The Indian Textile Journal,163-170, October 1975.

6. GROZ-BECKERT Technical Information, Knitting 2,” The Influence of Spun Yarns on Needle Life”, © 09/2003 GROZ-BECKERT KG

7. USTER® TESTER 5 Application Handbook: “Laboratory system for the measurement of yarns, rovings and slivers”, V1.2, 410 106-04020, June 2007.

8. USTER® News Bulletin No 44: USTER® TESTER 5: “A Multi-purpose Laboratory System for the analysis of spun yarns”, October 2005.

9. Söll, W., Peters, G., “Determination of the trash and dust content in yarns with the USTER® TESTER 5-S800” USTER® TESTER 5, Ap-plication Report, SE 556, September 1999 / Edition 2: July 2008.

10. Söll, W. “Determination of the yarn quality with revolutionary sensor technology”, USTER® TESTER 5, Application Report, SE 555, Sep-tember 2005 / Edition 2: July 2008.




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USTER® TESTER 5-S800

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USTER TESTER 5-S800 · blowroom, spinning preparation and during the spinning process itself. The inevitable result is wear of needles, yarn carriers, sinkers and cams. The needle