uster® laboratory systems - description of all quality

June 2002 / Edition 2: September 2007 / Edition 3: July 2010 SE 562

USTER®

LABORATORY SYSTEMS APPLICATION REPORT Description of all quality parameters measured by Uster Technologies fiber and yarn testing equipment

THE STANDARD FROM FIBER TO FABRIC

Gabriela Peters, Sandra Meier


Copyright 2010 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\Laborsysteme \SE-562_Description of all quality parameters .

2 (24) USTER® PRODUCTS


Contents

1 Introduction ................................................................................ 4

2 USTER® HVI ................................................................................ 4

2.1 Length & Strength ........................................................................ 5

2.2 Micronaire .................................................................................... 6

2.3 Color & Trash ............................................................................... 7

3 USTER® AFIS .............................................................................. 7

3.1 Neps (USTER® AFIS-N)............................................................... 7

3.2 Length & Maturity (USTER® AFIS-L&M) ...................................... 8

3.3 Trash (USTER® AFIS-T) ............................................................ 10

4 USTER® TESTER ...................................................................... 10

4.1 Mass variations .......................................................................... 10

4.2 Hairiness .................................................................................... 12

4.3 Optical evaluation of yarns......................................................... 13

4.4 Dust and trash............................................................................ 13

5 Strength and elongation of yarns........................................... 14

5.1 Conventional strength and elongation (USTER® TENSORAPID)........................................................... 14

5.2 Ultra-high speed strength tests (USTER® TENSOJET) ............. 16

6 Classification of yarn faults (USTER® CLASSIMAT) ............ 16

7 Yarn twist (USTER® ZWEIGLE TWIST TESTER) .................... 18

7.1 Absolute twist ............................................................................. 19

7.2 Twist multiplier ........................................................................... 19

8 Hairiness length classification (USTER® ZWEIGLE HL 400)..................................................... 20

9 Friction (USTER® ZWEIGLE FRICTION TESTER) ................. 21

10 Yarn splices (USTER® ZWEIGLE SPLICE TESTER) .............. 22

11 Applicable standards............................................................... 22

USTER® PRODUCTS 3 (24)


1 Introduction It was 50 years ago that Uster Technologies put their first testing unit, the evenness tester GGP, on to the market. Since that time, a vast number of other testing instruments such as tensile testing installations and yarn clearers, for example, have been developed by Uster Technologies. Today, the USTER® TESTER 4, which was introduced in 1997, already represents the fifth generation of the "old" GGP. Aside from the measuring principle, however, the USTER® TESTER 4 has very little in common with the first GGP tester. A good 10 years ago, Uster Technologies entered the last field of textile testing in the spinning mill by extending their activities to fiber test-ing. Thanks to the wide range of testing instruments and computer-aided sys-tems, today’s quality assurance can count on a large number of quality pa-rameters. It is hard to believe, but there are well over 150 characteristics to describe the quality of a fiber or a yarn. In some cases, this great variety has resulted in confusion and communication problems, because some quality parameters are only distinguished by minor changes such as differ-ent prefixes. We hope that this paper, which describes and explains the test parameters of all laboratory tests carried out with Uster Technologies instruments, will provide the necessary information. It is intended as a reference that should make your daily work with test parameters a little easier. The individual chapters contain a brief description of the respective testing unit and its quality parameters. On the left hand side you will find the abbreviations, which you know from the test reports, and on the right the corresponding explanations of these abbreviations.

2 USTER® HVI The USTER® HVI testing system (High-Volume Instrument) uses the latest measurement technology for the testing of large quantities of cotton sam-ples within a minimum amount of time. It is a high-performance system that permits the annual classification of entire cotton crops. Particularly worth mentioning is the exclusive use of this system at the US Department of Agriculture (USDA). HVI systems are also used for the classification of en-tire inventories or complete lots at the cotton producer, at the merchant or in the spinning mill. The following information is, of course, also applicable if you use a product from our LVI family instead of a HVI installation.



2.1 Length & Strength

Characteristics Unit Description

Len 1 [mm or in] Mean length (HVI mode) = mean fiber length

Len 2 [mm or in] Upper half mean length (HVI mode) = mean length by weight of the longer 50% of fibers Fig. 1)

Unf [%] Uniformity Index = length uniformity of the fi-bers. The Uniformity Index is only valid for the HVI mode.

Uniformity2 Len

1001 Len

Index

Classification of the length uniformity:

Uniformity Index very low below 76 low 77 – 79 average 80 – 82 high 83 – 85 very high above 86

Strength [g/tex] Breaking force of the fiber bundle divided by fiber fineness

Assessment of the fiber strength (without long staple):

HVI 1/8 (HVICC) below 21 = very low 22 to 24 = low 25 to 27 = average 28 to 30 = high over 30 = very high

Elg [%] Breaking elongation of the fiber bundle

Amt Amount, Parameter describing the optically measured number of fibers in the bundle at the time of break

SFI [%] Short fiber index = percentage of fibers shorter than ½ inch or 12.7 mm

SCI Spinning consistency index. A coefficient is calculated by means of various quality charac-teristics by a multiple regression analysis. The main benefit of the SCI is a simplified selection of bales for a predetermined blend of fibers as well as the long-term check of the raw material blend.



Upper half mean length

Mean length

100%0% 50%

Length

Fibrogram

Fig. 1 USDA-mode / Fibrogram

The fibrogram is a non-endaligned staple diagram and is calculated from a randomly taken fiber bundle which is fixed in a measuring grip. 2.2 Micronaire


Mic Parameter describing cotton fiber fineness

Micronaire Ratings: below 3.0 = very fine 3.1 - 3.9 = fine 4.0 - 4.9 = average 5.0 - 5.9 = coarse over 6.0 = very coarse

Mat Parameter describing cotton maturity

Maturity Index Ratings: below 0.70 = uncommon 0.71 – 0.85 = immature 0.86 – 1.00 = mature above 1.01 = very mature



2.3 Color & Trash


Rd Reflectance of the fibers, higher Rd values mean a higher color grade

+b Yellowness of the fibers (Nickerson/Hunter scale)

C-Grade Color grade = Color classing parameter ac-cording to the American Grade Standards (USDA) for Upland and Pima cottons or ac-cording to a user-specific classification

Tr Area Area of the sample covered with trash particles

Tr Cnt Number of trash particles

Tr Trash Trash code = trash classing according to USDA

3 USTER® AFIS The USTER® AFIS (Advanced Fiber Information System) is used for the measurement of individual fibers. The fibers are opened and individualized with a pair of spiked rollers surrounded by carding segments. The fiber opening unit works by aero-mechanical separation to separate trash parti-cles and large seed-coat fragments from the fibers. These trash particles are extracted through the trash channel, while individual fibers and neps pass through the fiber channel. Both channels are equipped with opto-electrical sensors. The modular design of the USTER® AFIS provides ex-tensive information on important quality parameters and the respective fre-quency distribution. 3.1 Neps (USTER® AFIS-N)


Weight [g] Sample weight

Nep [µm] Mean nep size

Nep [Cnt/g] Number of neps per gram

SCN [µm] Mean seed-coat nep size

SCN [Cnt/g] Number of seed-coat neps per gram



3.2 Length & Maturity (USTER® AFIS-L&M)


n by number of fibers

w by fiber weight

L (n,w) [mm or in] Mean fiber length

L (n,w) CV [%] Coefficient of variation of the fiber length

SFC (n,w) [%] Short fiber content, percentage of fibers shorter than ½ inch or 12.7 mm (Fig. 2)

UQL (w) [mm or in] Upper quartile length = length exceeded by 25% of the fibers (Fig. 2)

5% (n) [mm] Length exceeded by 5% of the fibers (Fig. 2)

2.5% (n) [mm] Length exceeded by 2.5% of the fibers (Fig. 2)

Fine [mtex] Fiber fineness (linear density)

IFC [%] Immature fiber content = percentage of imma-ture fibers

Mat Ratio Maturity ratio

Fiber length

Short fiber content SFC (n, w)

100%

L½"

L (n,w)UQL(w)

L2,5%(n) L5%(n)

0% 25% 50% Fig. 2 Staple diagram



Fig. 3 and Fig. 4 show the definition of the measured values in relation to the maturity characteristics. The respective parameters can be explained using Fig. 3. Fig. 3 shows the cross-section of a cotton fiber.

Perimeter P

Area A1

Area A2

Lumen

Perimeter P

Fig. 3 Degree of thickening

To compute the mean degree of thickening theta, a circular cross-section of the measured fiber having a perimeter P is calculated, and subsequently area A1 is divided by area A2. Fig. 4 shows a maturity measurement using the USTER® AFIS as well as the values computed for theta.

Cumulative percent Theta Frequency

Mature fibers (R)

Thinwalled fibers

Immaturefibercontent (IFC)

Fig. 4 Histogram of AFIS maturity

For this example, the following apply: Mature fiber content R = 37.6% Immature fiber content IFC = 10.3%

Maturity (according to Lord): 0.83 0.7200

10.337.6 0.7

200IFC-R

M



3.3 Trash (USTER® AFIS-T)


Total [Cnt/g] Total number of particles per gram

Mean size [µm] Mean particle size

Dust [Cnt/g] Dust particles per gram (<500 m)

Trash [Cnt/g] Trash particles per gram (>500 m)

V.F.M. [%] Visible foreign matter

4 USTER® TESTER Mass variations, count variations and imperfections have a decisive influ-ence on the utility and market value of a yarn. The USTER® TESTER de-termines these quality parameters on yarns, rovings and slivers very quickly. The capacitive measuring system permits fast and reproducible measurements. Based on spectrograms and diagrams, it is easy to elimi-nate the sources of defects. In recent years, the hairiness measurement has become more and more important, because hairiness can also affect the quality a woven or knitted fabric. The modular design of the USTER® TESTER permits simultaneous testing of all parameters. With the USTER® TESTER 4 additional optical sensors have been introduced (sensors OM and OI). 4.1 Mass variations

Fig. 5 Mass variations / Irregularity U

Definition: U = L x

a

a = shaded area = mean value xi = mass value at a given point in time L = test length



Fig. 6 Mass variations / Coefficient of variation CV

Definition: CV = x

s

s = standard deviation = mean value L = test length


Um [%] Mean linear irregularity (now obsolete, CVm is more common today, Fig. 5)

CVm [%] Coefficient of variation of the yarn mass (Fig. 6)

CVm (L) [%] Coefficient of variation of the yarn mass at cut lengths of 1, 3, 10, 50, 100 m and in the Inert and Half Inert modes

Mass deviation m(max)= maximum mass m(min)= minimum mass

cut lengths for the calculation are 1, 3, 10 m or Half Inert

Index Ratio between the ideal and actual evenness of staple fiber strands

Imperfections Number of thin places, thick places and neps at selected sensitivity settings (staple fiber yarns only)

thin places: -30% , -40% , -50% , -60% thick places: +35% , +50% , +70%, +100% neps: +140% , +200% , +280%, +400%

Rel. count [%] Count deviation relating to the length of yarn tested, the mean corresponds to 100%

Abs. count [e.g. tex, Ne]

Linear density of the yarn unit length (yarn count)



4.2 Hairiness The receiver detects only the light transmitted by the protruding fibers (Fig. 7). The yarn body remains black and does not transmit light. The light intensity, at the receiver, therefore, measures the light intensity which is proportional to the hairiness of the yarn.

Fig. 7


Hairiness The hairiness H corresponds to the total length of protruding fibers divided by the length of the sensor of 1 cm. The hairiness is, therefore, a figure without a unit.

sh Standard deviation of hairiness

sh (L) Standard deviation of hairiness at cut lengths of 1, 3, 10, 50, 100 m

Hairiness deviation

h(max)= maximum hairiness h(min)= minimum hairiness cut lengths for the calculation are 1, 3, 10 m



4.3 Optical evaluation of yarns The following characteristics are evaluated by an optical sensor which illu-minates the yarn from 2 different directions and with an angle of 90' de-grees.


2DØ [mm] Mean value of the two-dimensional diameter over the measured yarn length

s2D8mm [mm] Standard deviation of the diameter over the reference length of 8 mm

CV2D8mm [%] Coefficient of variation of the diameter over the reference length of 8 mm

CV2D0.3mm [%] Coefficient of variation of the diameter over the reference length of 0.3 mm

CV FS [%] Coefficient of variation of the fine structure, assessment of short-wave variations

CV1D0.3mm [%] Coefficient of variation of the one-dimensional yarn diameter, related to 0.3 mm

Shape Non-dimensional value between 0 and 1, which describes the roundness of a yarn (1 = circular, 0.5 = elliptical)

D [g/cm³] Mean yarn density related to the nominal count

4.4 Dust and trash The following characteristics are determined by a sensor which determines dust and trash in yarns.


Trash count [Cnt/km or yd] Trash particles per km or yard > 500 µm

Trash count spec. [Cnt/g] Trash particles per gram > 500 µm

Dust count [Cnt/km or yd] Dust particles per km or yard > 100 - 500 µm

Dust count spec. [Cnt/g] Dust particles per gram > 100 - 500 µm

Trash size [µm] Mean trash particles size

Dust size [µm] Mean dust particles size



5 Strength and elongation of yarns 5.1 Conventional strength and elongation

(USTER® TENSORAPID) In quality assurance, tensile testing of textile and technical yarns is one of the most important tests. The USTER® TENSORAPID operates in accor-dance with the CRE measuring principle. The abbreviation CRE stands for "Constant Rate of Extension". This means that the active clamp is moving at constant speed. The measuring unit is suitable for the testing of textile yarns (staple and filament yarns), technical yarns, woven fabrics and skeins. With the USTER® TENSORAPID, it is possible to process up to 40 samples automatically.


Pretension Force applied to the yarn at the beginning of the strength test to guarantee reproducible initial conditions. Standard pretension is 0.5 cN/tex.

Time to Br. [sec] Time elapsed between the start of the meas-urement and the breakage of the specimen (Fig. 8)

B-Force [cN] Breaking force = maximum tensile force meas-ured (Fig. 8)

Elongation [%] Breaking elongation = elongation at maximum force (Fig. 8)

Tenacity [cN/tex] Breaking force divided by the linear density of the specimen

B-Work [cNcm] Work to break = work at maximum force (area below the force/elongation curve drawn to the point of maximum force, (Fig. 8)

Work [cNcm] Partial work (area below the force/elongation curve drawn between two specified elongation values)

Ref. val. Reference values (maximum of 8 values)

F ...% [cN] Force at a specified elongation

E ...N [%] Elongation at a specified force

E (F-) [%] Elongation at a specified force drop

F (1.br.) [cN] Breaking force of the first filament at a defined force drop

M1 ...% [N/tex] Modulus (maximum of 8 values), either secant

M2 ...% [N/tex] Modulus or Young's modulus = slope of the force/elongation curve measured at a specified elongation



Elongation E (%)

Tensional force F (N, cN)

Breaking elongation

Elongation at rupture

Work done to break

FE-characteristic curve

Pre

-te

nsio

nal f

orc

e

Fo

rce

at r

uptu

re

Bre

aki

ng

forc

e

Fig. 8 Force-Elongation Curve

The software for filament testing provides the following additional parame-ters:


Y-Point Point at the end of the elastic range of filament yarn

Y-Point Load. [N] Force value at the end of the elastic range of filament yarn

Y-Point Stress [cN/tex] Tenacity referred to the fineness or diameter at the end of the elastic range of filament yarn

Y-Point Strain [%] Elongation at which the elastic range of a fila-ment yarn ends

Natural Draw Ratio (NDR)

Point at the end of the flow range

NDR Load [N] Force at the end of the flow range

NDR Stress [cN/tex] Tenacity referred to the fineness or diameter at the end of the flow range

NDR Extention [%] Elongation at the end of the flow range

NDR Ratio Ratio between NDR extension and Yield strain

Tensional force

Yield Point A

Elongation

B

C D

Fig. 9 Determination of the Yield Point



5.2 Ultra-high speed strength tests (USTER® TENSOJET) The USTER® TENSOJET is the first tensile testing installation which is ca-pable of measuring at speeds of 400 m/min. In one hour, the testing unit can carry out up to 30,000 tensile tests. The mechanism to load, elongate and finally break the test sample consists of two pairs of counter-rotating rollers, which are arranged at a distance of 500 mm. The measuring cycle is divided into four phases: continuous drawing-off of the yarn and interme-diate storage, insertion of the thread by an air jet, clamping and elongation until it is broken by the rollers and, finally, removal of the remaining pieces of thread into a waste container by compressed air. The USTER® TENSO-JET, like the USTER® TENSORAPID, operates in accordance with the CRE measuring principle.


B-Force [cN] Breaking force = maximum tensile force measured (Fig. 8)

Elongation [%] Breaking elongation = elongation at maxi-mum force (Fig. 8)

Tenacity [cN/tex] Breaking force divided by the linear density of the (Fig. 8)

B-Work [cN*cm] Work done to break = work at breaking force (area below the force/elongation curve drawn to the point of maximum force, Fig. 8)

Max values Maximum value of force, elongation, tenac-ity or work within one test series

Min values Minimum value of force, elongation, tenac-ity or work within one test series

Percentile values e.g. P. 0.01

0.01%, 0.05%, 0.1%, 0.5%, 1.0% of all measurements are below the reported value

6 Classification of yarn faults (USTER® CLASSIMAT)

There are basically two types of yarn faults. Firstly, there are the frequent yarn faults, better known as imperfections which are detected with an evenness tester. Secondly, there are rare yarn faults, which occur at such irregular intervals that at least 100 km of yarn has to be tested to ensure reliable detection. For open end yarns a test length of 1000 km is recom-mended. As a yarn fault classifying installation, the USTER® CLASSIMAT detects all seldom-occurring yarn faults and classifies these into the re-spective classes of the CLASSIMAT system.



Using the CLASSIMAT matrix, it is possible to define or control the most suitable yarn clearer settings.

Characteristics Description

Fault classification

0.1 1 2 4 8 32 64 [cm]

600

400

250

150

045

- 30

- 45

- 75

[%]

A1

A3

A2

A4

A0

B1

B3

B2

B4

B0

C 1

C 3

C 2

C 4

C 0

D1

D3

D2

D4

D0

E

F G

TB1

TB2

TC 1

TC 2

TD 1

TD 2

H1

H2

I1

I2

Mass

100

Mean

Fig. 10 Classing matrix of the Classimat

Fault lengths A: shorter than 1 cm B+TB: 1 to 2 cm C+TC: 2 to 4 cm D+TD: 4 to 8 cm E: longer than 8 cm F+H: 8 to 32 cm G+I: longer than 32 cm

Fault sizes 0: +45 to +100% 1: +100 to +150% 2: +150 to +250% 3: +250 to +400% 4: over +400% E: over +100% F+G: +45 to 100% TB1/TC1/TD1/H1/I1: -30 to -45% TB2/TC2/TD2/H2/I2: -45 to -75%

N channel for very short thick places S channel for short thick places L channel for long thick places T channel for long thin places C channel for count deviations

Sensitivity Reference length

N channel: +100% to +500%

S channel: +50% to +300% 1 to 10 cm

L channel: +10% to +200% 1 to 200 cm

T channel: -10% to -80% 10 to 200 cm

Fault channels of the clearers

C channel: ±5% to ±80% 12.8 m



7 Yarn twist (USTER® ZWEIGLE TWIST TESTER) The amount of twist placed in a staple spun yarn is important from a techni-cal viewpoint because of its effect on physical properties and performance, and on finished product appearance. It has an effect on fabric luster, hand, weight and strength. It is also important from a production standpoint be-cause with every turn of twist there is an accompanying reduction in pro-ductivity and an increase in cost. There are two possible twist directions, Z and S. Yarns twisted clockwise have S-twist, yarns twisted counter-clockwise have Z-twist. Most yarns worldwide have Z-twist (Fig. 11). Usually, the twist of a yarn is given in turns per meter or turns per inch, re-spectively. The amount of twist is determined mostly by the end use, and by the type and length of the fibers used.

Fig. 11 Illustration of a yarn with Z-twist and S-twist

The twist of a yarn can be described by the twist per unit length (per meter or per inch), and by the twist multiplier. Another decisive parameter for the twist characteristic of a yarn is the variation of the twist, which should be kept within small limits. For the twist character of a yarn only the twist multiplier is decisive, as it describes the angle of the twist in the yarn. A fine yarn needs more twist than a coarse yarn in order to have the same twist character. Therefore, the twist of a yarn is usually given as the coefficient of twist, also called twist multiplier in order to be able to compare different yarn counts. Fig. 12 shows the illustration of a yarn. It can be seen that although the twist per unit length is the same, the twist multiplier (the angle of the twist) varies, depending on the yarn count.

Fig. 12 Illustration of the yarn twist 1 = high twist 2 = low twist




7.1 Absolute twist The absolute twist is the amount of twist per meter or twist per inch, respec-tively. In general, one can say that within certain limits a yarn with a higher twist is stronger than the same yarn with a lower twist. Also, the yarn with the lower twist has a larger diameter. The conversion of turns per meter into turns per inch can be done accord-ing to the following formula:

Turns per inch = Turns per meter / 39.37 = Turns per meter x 0.0254

Turns per meter = Turns per inch x 39.37

The number of turns in the yarn highly affects the production level of the spinning machine. As the spindle speed is usually already set to the maxi-mum, the amount of twist can only be influenced by the reduction of the delivery, which consequently also results in a reduction of productivity.

Twist per meter = revolution of the spindle per minute / delivery in m per min

7.2 Twist multiplier The most common term used to express a twist level is the twist multiplier as it is independent of the yarn count. It is used for the comparison of cer-tain yarn characteristics of yarns with different counts. A finer yarn, e.g. needs more twist in order to reach the same character as a coarse one. The larger the twist multiplier, the higher the number of turns per meter (or per inch) in the yarn for a given count. For a given twist multiplier, the yarn count gets finer and the turns per meter (per inch) increase. The following formula shows the calculation for the twist multiplier:

English twist multiplier: e = turns per inch / Nec

Metric twist multiplier: m = turns per meter / Nm

Conversion of e and m:

e = m : 30.3

m = e x 30.3


The twist per meter of a yarn is dependent on the yarn count. A fine yarn requires more twist than a coarse yarn for the same application. Therefore, the English twist multiplier takes this into account, e.g. a statement such as: “The twist multiplier of 3.7 for a combed yarn is valid for the entire count range.” There are certain relationships in regard of the twist multiplier:

The twist multiplier should be as low as possible, but as high as neces-sary.

The higher the twist multiplier, the lower the production level. Due to the high twist, the production rate of the spinning machine will decrease.

A low twist multiplier will lead to a lower strength level in the yarn with a softer handle.


Twist [1/m] Twist of the yarn per meter

Twist [1/inch] Twist of the yarn per inch

English twist multiplier

[-] Twist per inch/Nec. Twist value inde-pendent of count.

Metric twist multiplier

[-] Twist per meter/Nm. Twist value inde-pendent of count.

Metric twist multiplier

[-] Twist per meter tex. Twist value in-dependent of count.

Coefficient of varia-tion

[%] Coefficient of variation of the twist value

8 Hairiness length classification (USTER® ZWEIGLE HL 400)

Besides the traditional yarn parameters like evenness, imperfections, strength and elongation, the hairiness plays also an important role in the evaluation of a yarn. The hairiness influences the performance of subse-quent processes like weaving, knitting or dyeing as well as the appearance and end use of the final fabric or garment. The factors influencing hairiness can be sub-divided into 3 major groups:

Fiber properties

Yarn parameters

Process parameters



The hairiness length classification gives detailed hairiness information for various applications in the spinning process and also its subsequent proc-esses. This information is especially interesting for:

Compact spinning

Machine maintenance

Knitting

Weaving


Hairiness Hairiness Number of protruding fibers at a defined length from the yarn body. Individual count of fibers in 9 length zones: the numbers of protruding fibers are meas-ured in intervals of: 1, 2, 3, 4, 6, 8, 10, 12, and 15 mm. This means that the measuring range is from 1 – 15 mm.

S3 value S3 The S3 value is the sum of all fiber classes 3 mm and longer (cumulative). This value describes the long protruding fibers of a yarn.

S1+2 value S1+2 The S1+2 value is the sum of all fibers with the length of 1 and 2 mm This value describes the amount of short protruding fibers of a yarn.

9 Friction (USTER® ZWEIGLE FRICTION TESTER) Yarns experience friction either between themselves or against metallic surfaces before being processed into a fabric in weaving and knitting ma-chinery. Yarn friction is important with respect to the running behavior of a yarn in post spinning processes. Yarn friction is a quality parameter which can affect the yarn performance and especially the knittability and weave-ability of a yarn. The monitoring and measurement of yarn friction allows the optimum wax-ing of yarns on winding machines. It also allows the measurement of influ-ences of chemical additives on running properties of single and plied grey and dyed yarns.




Friction µ Yarn friction between the yarn and a metal surface of a yarn tensioner. Range between 0 and 1.

Coefficient of variation CV Variation of the friction.

10 Yarn splices (USTER® ZWEIGLE SPLICE TESTER) A yarn must have a certain minimum tensile strength and a minimum elon-gation in order to stand up to the processes subsequent to spinning. This is also and especially valid for splices that join together two ends of a yarn. Besides the quality aspect that needs to be fulfilled by the yarn, its process-ing quality depends to a certain extent also on the quality of the splices. Today, approximately one splice per kilometer has to be expected in a cone. Considering the costs for a yarn break in knitting, warping, sizing or weaving, the splices play an important role in this respect as well. The number of splices must be kept at a low level, but the potential weak places (splice) must have the highest strength possible. This is only possible by checking the strength of the splices regularly by means of an instrument.


Strength [cN] Breaking strength of a splice

Elongation [%] Breaking elongation of a splice

11 Applicable standards Most fiber and yarn testing methods are covered by national or international standards. Since fiber testing instruments are mainly developed in the United States, ASTM standards apply in most cases. Yarn testing is cov-ered by DIN, EN or ISO standards and Japan Industrial Standards.



The following standards apply to USTER® PRODUCTS: 1. USTER® HVI

ASTM D-1448, ISO 2403 Micronaire reading of cotton fibers ASTM D-1447 Fibrograph measurement of length and length

uniformity ASTM D-1445 Breaking strength and elongation (flat bundle

method) ASTM D-2253 Nickerson/Hunter colorimeter ASTM D-2812 Non-lint content of cotton ASTM D-5867 High-volume instrument testing 2. USTER® AFIS

ASTM D-5866 AFIS nep testing 3. USTER® TESTER

ISO 2060, DIN 53 830 Determination of yarn count ISO 2649, DIN 53 817, Determination of yarn evenness ASTM 1423 4. USTER® TENSORAPID

ISO 2062, DIN 53 834, Single-end tensile testing ASTM D-1578, JIS 5. USTER® ZWEIGLE TWIST TESTER

ISO 2061 Determination of twist in yarn – direct count-ing method

ASTM 1423 Twist in yarns by direct counting 6. Environmental conditions

Since most measurements on textile products are affected by both the temperature and the relative humidity, textile testing should be performed under constant standard atmospheric conditions. ISO 139, EN 20 139, Standard atmosphere for conditioning and

testing DIN 53 802



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H-8610 Uster / Switzerland C Phone +41 43 366 36 36 Fax +41 43 366 36 37 www.uster.com [email protected]


uster® laboratory systems - description of all quality

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