Top 3 Effective method of Fiber length measurement

FIBER LENGTH:

Fiber length means the distance between two ends of the fiber in straight condition. Different Setting point gauging, machine distance, beating points speed, draft, twist of yarn depends on the fiber length. To be a textile fiber,

Fiber Length : Diameter = 5000 : 1

Effect or Impact of Fiber Length :

1. Yarn Regularity
2. Thick & Thinness
3. Twist
4. Breaking Strength

Importance of Fiber Length :

1. Directly related to spinning performance
2. Longer cotton can be spun into finer counts. [ The longer the yarn , The finer the yarn]
3. Machinery arrangements, speed & setting of various stages designed based on the length of the fiber.
4. In the blow room, the number of cleaning points, settings between beater and gride bars, feed roller and beater depends upon the length of fiber.
5. Cards have to work slower with open settings for longer cotton and faster with close setting for short staple.
6. In draw frame, simplex and ring frame, the distance between nips of the drafting rollers will be wide for long staple and close for shorter staple.
7. With respect to twist, higher twist multipliers are used for long fiber.

Different types of Fiber Length:

1. Staple Length:

Technically, staple length is characterized as the most important fiber length. In short, the average length  of spinnable fiber is called staple length. In case of cotton , the staple length varies from 16 mm to 52 mm    depending upon the type of cotton .

Grading of Cotton according to staple length:

2. Effective Length:

The length at the main bulk of the longer fiber is called effective length.

For American Cotton :

Staple Length = 0.91 × Effective Length

For Egyptian Cotton :

Staple Length = Effective Length

3. Span Length:

It is the distance from a line where the fibers are randomly caught to a point, where only a certain percentage of fiber extends or remain. For example, the most popular 2.5% span length is the distance from the clamp on a fiber beard to a point up to which only 2.5% of the fibers extend.

4. Modal Length:

The mode of a frequency distribution is the value of the class with the highest frequency. On the other words, most frequently occurring length of fiber or length of group of fiber, where more number of fiber will be having equal length.

5. Mean Length:

Average length of all fibers in the sample is called mean length.

Uniformity Ratio:

The ratio between 50% span length and 2.5% span length express in percentage.

So, Uniformity Ratio= (50% span length/2.5% span length) X 100

Different Methods of Fiber Length Measurement :

1. The Technician & graders method
2. The Breeders Method
3. The Technologist Method
   1. Direct Method:
      • Single Fibers.
      • Group Fibers. Examples : Bear Sorter, Shirley Comb Sorter
   2. Semi-Direct Method :
      • Ball Sledge Sorter
   3. Indirect Method:
      • Fibro Graph. Examples : Uster Staples

Determination Of Fiber Length By Comb Sorter Analysis:

Different Fiber length is obtained by a geometrical construction on the Sorter Diagram. It includes the following steps:

1. Q is the midpoint of OA; OQ= (1/2) X OA.
2. From Q, draw QP’ parallel to OB to cut the curve at P’.
3. Drop the perpendicular P’P.
4. Mark off OK equal to 1/4 of OP and erect the perpendicular KK’.
5. S is the midpoint of KK’.
6. From S draw SR’ parallel to OB to cut the curve at R’.
7. Drop the perpendicular R’R.
8. Mark off OL equal to 1/4 of OR and erect the perpendicular LL’.

Effective Length:

From the Comb Sorter Diagram, LL’ is the effective length.

Mean Length:

This is the average length of all fibers in the sample. From the Comb Sorter Diagram,

Mean Length= (Area under the curve OAB)/ OB

Percentage Of Short Fiber:

This is the percentage of fibers, the length of which are equal to or less than half of the effective length.

So, Percentage Of Short Fiber= (Area RR’B/Area OAB) X 100= RB/OB X 100

Modal Length:

This is the length of the group of fibers where more number of fibers will be having equal length. From the Comb Sorter Diagram, LL’ is the Modal length.

Dispersion:

It represents the variation in length of fibers and is the interquartile range expressed in a percentage of effective length. In short the ratio of interquartile range and effective length is called Dispersion. From the Comb Sorter Diagram, LL’ is the upper quartile and MM’ is the lower quartile. Difference between LL’ and MM’ is NL’ is the interquartile range.

So, Dispersion= (NL’/LL’) X 100

Determination Of Fiber Length By Uster Technologies:

Uster Technologies offers fiber length measurement using instruments like the HVI 1000 and LVI series, which analyze cotton fibers for length, length uniformity, and short fiber content, providing data for cotton classification and trading. 

Key Uster Instruments for Fiber Length Measurement:

Uster HVI 1000:

This is the standard for cotton classification and trading, measuring fiber length, length uniformity, strength, color, and trash. 

Uster LVI Series (LVI 920, LVI 930, LVI 960, LVI 975, LVI 940):

These instruments focus on cotton fiber analysis, providing data on length, length uniformity, and short fiber content. 

Uster AFIS Pro 2:

This instrument is used for measuring fiber length, short fiber content, and other fiber properties, including neps and trash, according to Uster Technologies. 

How Fiber Length is Measured By Uster Technologies:

1. Sample Preparation: The fibro gram method is preferred for preparing samples for fiber length estimation, using a fibro sampler to create a “beard” of fibers with varying lengths. 
2. Optical Scanning: Instruments like the HVI scan a fiber comb to generate a fibro gram, which shows the length distribution of the fibers, including parameters like 2.5% and 50% span lengths. 
3. Data Analysis: The instruments analyze the data to determine various fiber length parameters, including average length, length uniformity, and short fiber content. 

Uster Technologies’ Testing Services:

Uster Technologies offers textile testing services for cotton fibers and blends, as well as staple and filament yarns, covering the entire production process from fiber to yarn. 

References:

1. Principles of Textile Testing by J E Booth.
2. Handbook of Textile Testing and Quality Control by E. B. Grover, Elliot Brown Grover, Dame Scott Hamby.
3. Physical Testing of Textiles by B.P. Saville.

To learn more on textile testing and laboratory accreditation you can check on the following article:

1. Testing Of Textiles: Why Is It Important For The Textile And Apparel Industries?
2. 10 comprehensive steps in textile fiber sampling method
3. 5 EFFECTIVE insights of moisture regain in textile fiber
4. Fabric Abrasion Resistance: Martindale Abrasion Testing Process
5. Fabric Hand feel evaluation by Fabric Touch Tester (FTT)
6. Color Fastness test
7. Washing fastness test method: ISO 105 C06
8. ISO/IEC 17025 Laboratory Accreditation Process
9. ISO/IEC 17025 Laboratory Accreditation Advantages
10. KEY STEPS FOR CONDUCTING AN EFFECTIVE QMS INTERNAL AUDIT