44809453 uster hvi spectrum measuring principles

Measuring principles

USTERUSTER®®

HVI SPECTRUMHVI SPECTRUM

2Edas/schulungsunterlagen/HVI SPECTRUM

Test Report


Measurements on cotton:

• Length, uniformity• Micronaire• Strength• Color• Trash

NEW on USTER® HVI SPECTRUM:• Maturity Index• Short Fiber Index• Moisture


Length & Strength MeasurementLength & Strength Measurement

HomePosition

Comb Fiber Beard

LED

Breaker Jaws

Breaker Jaws


Development of a fibrogram


Mean Length Mean Length --Principle of MeasurementPrinciple of MeasurementDeveloped from the fibrogram

Mean lengthML

100%0%

Length

Tangent from origin


Upper Half Mean Length Upper Half Mean Length --Principle of MeasurementPrinciple of MeasurementDeveloped from the fibrogram

Upper half mean lengthUHML

100%0% 50%

Length

Tangent from 50% amount


Comparison Mean Length - Upper Half Mean Length

Upper half mean length

Mean length

100%0% 50%

Length


Staple diagram

Fiber length

100%0% 50%


Comparison Fibrogram - Staple Diagram

Fibrogram• non end-aligned

diagram of the fiber length

• calculated from a randomly taken fiber bundle which is fixed in a measuring grip

Staple Diagram• end-aligned

diagram of the fiber length

• distribution curve (histogram) of all fiber lengths


Explanation to the length

1 inch = staple class 32 32:32 = 1

1 1/16 inch = staple class 34 34:32 = 1 1/16

1 1/2 inch = staple class 48 48:32 = 1 1/2


Relationship Between Staple Class Relationship Between Staple Class and HVI UHML Resultsand HVI UHML Results

Inches UHM [inches] UHM [mm] Code

below 13/16 < 0.79 < 20.1 2413/16 0.80 - 0.85 20.1 - 21.6 267/8 0.86 - 0.89 21.8 - 22.6 2829/32 0.90 - 0.92 22.9 - 23.4 2915/16 0.93 - 0.95 23.6 - 24.1 30

31/32 0.96 - 0.98 24.4 - 24.9 311 0.99 - 1.01 25.1 - 25.8 321 1/32 1.02 - 1.04 25.9 - 26.4 331 1/16 1.05 - 1.07 26.7 - 27.2 341 3/32 1.08 - 1.10 27.4 - 27.9 35

1 1/8 1.11 - 1.13 28.2 - 28.7 361 5/32 1.14 - 1.17 29.0 - 29.7 371 3/16 1.18 - 1.20 30.0 - 30.5 381 7/32 1.21 - 1.23 30.7 - 31.2 391 1/4 1.24 - 1.26 31.5 - 32.0 40

1 9/32 1.27 - 1.29 32.3 - 32.8 411 5/16 1.30 - 1.32 33.0 - 33.5 421 11/32 1.33 - 1.35 33.8 - 34.3 431 3/8 > 1.38 > 35.0 44


Uniformity Index

Indication of the distribution of fiber length within the fibrogram fiber length variation

ML = Mean LengthUHML = Upper Half Mean Length

Uniformity Index UI = ML x 100UHML


Length Uniformity Length Uniformity -- Evaluation criteriaEvaluation criteria

Uniformity IndexML/UHML Description

77 & lower very low

77 – 79 low

80 – 82 average

83 – 85 high

85 & higher very high


Short Fiber Index SFIAn indication of the amount of fibers that are less than 0.5 inch (12.7 mm) in length.

Short Fiber Index Description

Below 6 very low

6 to 9 low

10 to 13 average

14 to 17 high

18 and higher very high


Short Fiber Index SFICalculated with a proven algorithm

Fiber length (mm/inch)

Short fiber content SFC (%)

100%

L½"12.7 mm

0% 25% 50%

Frequency (%)

x %


Length & Strength MeasurementLength & Strength Measurement

Cotton Fiber Structure - genetically caused weak places


Bundle Fiber Strength Bundle Fiber Strength --Principle of MeasurementPrinciple of Measurement• The bundle strength is the breaking strength of the

cotton fibers in grams per tex. The fineness is calculated from the Micronaire value.

• The fiber beard is broken at a continuous deformationrate and with a 1/8-inch distance between the clamps.

• With the space of 1/8-inch, the fibers will break at their weakest spot, not at a predetermined breaking-point (clamp).


* Calibrated to HVI calibration cottons

Bundle Fiber Strength - Evaluation

Description Pressley 1/8"g/tex

Stelometer 1/8"g/tex

HVI 1/8"*g/tex

very low 21 & lower 17 & lower 21 & lowerlow 21 – 23 17 – 19 22 - 24average 24 – 26 20 – 22 25 – 27high 27 – 29 23 – 25 28 – 30very high 30 & higher 26 & higher 31 & higher


Bundle Fiber Strength - Evaluation

Strength (gram/tex) Description

Less than 21 very weak

22 to 24 weak

25 to 27 medium

28 to 30 strong

31 and higher very strong


Elongation MeasurementElongation Measurement

• Measurement of the elastic behavior of the fibers in the bundle

• The distance the fibers extend before they break is expressed as percent elongation


Determination of the elongation

Clamp

Clamp

= x 100ll0


Elongation Measurement Elongation Measurement -- EvaluationEvaluation

Elongation (%) Description

Less than 5.0 very low

5.1 to 5.8 low

5.9 to 6.7 average

6.8 to 7.6 high

7.7 and higher very high


Micronaire MeasurementMicronaire Measurement

Air measuring device

Pressurechangemeasuringdevice

Measuringchamber with fibers

Airflow



Air flow

coarse fibers,low air resistance

(high Micronaire value)

fine fibers,high air resistance

(low Micronaire value)



• A fiber sample of constant weight is measured by passing air through the fibers and measuring the drop in pressure.

• Maturity has an influence on micronaire results.


Micronaire - Influences

• Genetic factors of the cotton, which have an influence on the diameter of the fiber. For example Pima cotton has a lower micronaire value than Upland cotton.

• Environmental influences, e.g. soil, fertilizer, humidity and temperature, duration of growing period


Micronaire - Consequences

Low Micronaire• Can tend to the

formation of neps in yarn and fabric

• If they are mature, they are fine and strong

• If they are immature, they are weak

• Immature fibers absorb less dye and can lead to problems in dyeing (shiny neps)

High Micronaire• Mostly mature and

strong fibers• Limits the yarn count• Fine yarns cannot be

spun.


Micronaire Micronaire -- Evaluation Evaluation

Micronaire Description

Less than 3.0 very fine

3.0 to 3.6 fine

3.7 to 4.7 medium

4.8 to 5.9 coarse

6.0 and higher very coarse


Maturity IndexMaturity Index

• The maturity index is a relative value calculated from the HVI measurements of

- micronaire - strength - elongation

• Indicates the degree of cell wall thickness


Maturity Index Maturity Index -- EvaluationEvaluation

Maturity Index Description

Below 0.7 uncommon

0.70 to 0.85 immature

0.86 to 1.00 mature

above 1.00 very mature


Micronaire & Maturity- Evaluation

smaller than 3.0 = very finesmall perimeter and mature or largeperimeter and very immature

3.1 to 3.9 = finedifferent degrees of maturity and/ortypes, but often little mature

4.0 to 4.9 = averagemedium degree of maturity

5.0 to 5.9 = coarselarge perimeter, mostly immature

greater than 6.0 = very coarsemature fibers


Micronaire & Maturity

Low Micronaire &“fairly mature”

Medium Micronaire &“less mature”

Medium Micronaire &“fairly mature”

High Micronaire &“well mature”


Color & Trash MeasurementColor & Trash Measurement


Color Range of CottonColor Range of Cotton


HVI Color HVI Color

GradesGrades

forfor

Upland Upland

CottonCotton


HVI ColorHVI Color

GradesGrades

forfor

Upland Upland

CottonCotton


HVI Color HVI Color GradesGradesfor for Pima Pima CottonCotton


U.S. Upland U.S. Upland Cotton Cotton Standard Standard DescriptionDescriptionforfor Color Color and Leafand Leaf

Color Grade Symbols Code Leaf CodeWhiteGood MiddlingStrict MiddlingMiddlingStrict Low MiddlingLow MiddlingStrict Good OrdinaryGood Ordinary

GMSMMidSLMLMSGOGO

11213141516171

1234567

Light SpottedGood MiddlingStrict MiddlingMiddlingStrict Low MiddlingLow MiddlingStrict Good Ordinary

GM Lt SpSM Lt SpMid Lt SpSLM Lt SpLM Lt SpSGO Lt Sp

122232425262

123456

SpottedGood MiddlingStrict MiddlingMiddlingStrict Low MiddlingLow MiddlingStrict Good Ordinary

GM SpSM SpMid SpSLM SpLM SpSGO Sp

132333435363

123456

TingedStrict MiddlingMiddlingStrict Low MiddlingLow Middling

SM TgMid TgSLM TgLM Tg

24344454

2345

Yellow StainedStrict MiddlingMiddling

SM YSMid YS

2535

23


Color Measurement

• Reflectance (Rd):This value expresses the whiteness of the light that is reflected by the cotton fibers. It corresponds to the Nickerson/Hunter color chart.

• Yellowness (+b):This value expresses the yellowness of the light that is reflected by the cotton fibers. It corresponds to the Nickerson/Hunter color chart.

• The Color Grade (CG) results from these two values.

The color is defined by the Reflectance (Rd) and the Yellowness (+b) of the cotton fibers:


Trash MeasurementTrash Measurement

Video image

analysis

results in:

Trash % Area (covered)

Trash (Particle)Count


Trash Measurement • Trash Count (TC)

Sample is illuminated from underneath the glass window, and a black and white CCD camera analyzes the changes in the pixels. A trash particle is counted, if it exceeds the grayness threshold set in the camera.

• Trash Area (TA)The area that is covered by a trash particle. The result is expressed in relation to the entire measuring area of the glass window and is expressed as “% Area”.Resulting from the TA, the Trash Code (T) is determined.


Relationship of Trash Measurement to Relationship of Trash Measurement to ClasserClasser’’s Leaf Grade*s Leaf Grade*

Classer‘sLeaf Grade

TrashMeasurement

(% area)

12345678

<= 0.08<= 0.12<= 0.18<= 0.34<= 0.55<= 0.86<= 1.56> 1.56

* 1999 USDA crop data (4 year average)* 1999 USDA crop data (4 year average)


Automated Moisture MeasurementAutomated Moisture Measurement

Moisture is the amount (%) of water that is present in the sample being tested.

Patented resistance moisture sensor

Direct measurement

Sensor located underneath color/ trash hand

Consistent pressure ensures repeatable moisture results

No customer calibration required


Moisture - Evaluation

Moisture Content % Description

< 4% very low

4 – 6% low

6 – 8% medium

8 – 11% high

> 11% very high

44809453 uster hvi spectrum measuring principles

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