What Performance Indicators Cotton Fibers Have？

 

Cotton is the most important natural textile fiber, as well as cellulosic textile fiber, in the world, used to produce apparel, home furnishings, and industrial products. Worldwide about 40% of the fiber consumed was cotton. But how much do you know about the testing indicators of cotton fibers in the production process?
Cilck Here to Find the Machine for Fiber Testing

Fiber length

Fiber length is largely influenced by variety, but the cotton plant’s exposure to extreme temperatures, water stress, or nutrient deficiencies may result in shorter fibers. Excessive cleaning or drying at the gin may also result in shorter fibers. Fiber length affects yarn strength, yarn evenness, and the efficiency of the spinning process. The fineness of the yarn that can be successfully produced from given fibers also is influenced by fiber length.
Therefore, it is necessary to detect the length of cotton fibers during the production process.

Main Indicators of Fiber Length
The main indicators for measuring cotton fiber length are as follows:
(1) Span length: The minimum length attained by a specified percentage of the fibers in a test beard, corresponding to a determined percentage of the optical density of the beard.
The first section of the length investigated, which is normally situated at a distance of 3,8 mm from the line of gripping of the comb, is taken as the reference base of 100 % optical density.
(2) Length uniformity: The ratio between two span lengths, the smaller value being expressed as a percentage of the higher value.
(3) Modal length: In the distribution of cotton fiber length, the fiber length that accounts for the most mass or quantity of fibers.
(4) Quality length: In the distribution of cotton fiber length, the weighted average length of each group of fibers above the modal length.
(5) Short fiber content: The percentage of short fiber mass (quantity) below a certain length range in cotton fibers to the total fiber mass (quantity)
(6) Average length of mass: The average length obtained by weighting the mass of each group of fibers in the cotton fiber length distribution.
Main Methods for Measuring Fiber Length
There are two main methods for measuring fiber length:
(1) Photoelectric method:Fibers are placed on combs in such a way that they are caught at random points along their lengths to form a beard. The beard is scanned photoelectrically from base to tip, the amount of light passing through the beard being used as a measure of the number of fibers that extend various distances from the combs.
​(2) Roller analyzer method: Organize the samples into neat cotton bundles at one end, and then use roller to control the length of fibers for equal distance grouping and weighing, determine the distribution of cotton fiber length, and calculate various length indicators.

Fiber fineness of cotton fibers

Fiber fineness affects processing performance and the quality of the end product in several ways. in the opening, cleaning, and carding processes, low-micronaire or fine-fiber cotton require slower processing speeds to prevent damage.
Main Indicators of Cotton Fiber Fineness
(1) Linear density: The mass per unit length of fibers or yarns.
(2) Micronaire value: A comprehensive indicator reflecting the fineness and maturity of cotton fibers. Micronaire value s are divided into three levels: A, B, and C.
Main Methods for Measuring Fiber Fineness
There are three main methods for measuring fiber fineness:
(1) Cut middles method: According to the definition of cotton fiber linear density, cut a certain length of fiber, weigh its mass, count its’ quantity, and calculate the average cotton fiber linear density.
(2) Method of Air-flow: Air is passed through a test specimen consisting of a plug of fibers. The permeability is indicated on a scale for recording variations in either the rate of flow through, or the pressure difference across, the plug. The mass and volume of the test specimen are either a constant for a given type of instrument or varied appropriately in relation to each other. The scale indicating variations in permeability can be calibrated in arbitrary units of micronaire value or marked in the appropriate absolute units of rate of flow or of pressure difference and a table or graph provided for conversion of the observed readings into micronaire values.
(3) Projection Microscope Method: Projection on a screen of the magnified images of the profiles of wool fiber pieces, and measurement of their width by means of a graduated scale. The operating technique assures a random sampling of the fibers to be measured.

More informations can be found here:https://fyitester.com/indicators-of-cotton-fiber/