(1)Fiber Maturity
5.1. Fiber Maturity:
Cotton fiber maturity denotes the degree of wall thickening of the fibers. In other words, it is
the measure of primary and secondary wall thickness. A fiber will be mature if the high
degree of wall thickening takes place during its growth.
1. Wax layer/cuticle, 2. Primary cell-wall, 3. Secondary cell-wall, 4. Tertiary wall, 5.
Lumen
5.2. Significance of maturity
1. Neps formation: Since thin walled immature fiber are more flexible than normal fiber
that’s why during processing they bend and make entanglement of fibers.
2. Dyeing fault: Owing to very poor wall thickening when dyed they appear much
lighter in shade than a simple fiber. It appears as white speeks on the treated dyed
fabric.
3. Reduction of yarn strength and increase hairiness.
4. Immaturity below a certain level leads to worst spinning and excessive end-breakage.
5. Produced an unstained area in the printed fabric
5.3. Fiber maturity depends on:
Weather
Types of soil
Plant diseases
Pests
Dead fibers etc
5.4. Normal, dead & immature fiber
Normal fiber: Normal fibre with a well developed cell wall and pronounced
convolutions in the raw state and become rod like after swelling. It is denoted
by “N”.
Dead fiber: Dead fibres are extremely immature fibre. If the cell wall is less
than one fifth of the fibre is termed as dead fibre. It is denoted by “D”.
Thin walled fibre: Thin walled fibres have the structure and characteristics
lying between normal and dead fibre. It is denoted by “T”.
5.5. Method of maturity determination
There are two methods are available right now-
1. Direct method: Counting the fibers directly after swelling by 18% NaOH solution in
the projection microscope.
2. Indirect method: Here, maturity is measure by determining the properties which are
affected by maturity. i.e. fineness.
5.6. Relationship between normal fiber, dead fiber & maturity ratio
Knowing the total number of fibers examined and the number of mature fibers the percentage
ofmature fibers can be calculated as below:
Percentage of Mature fibers = (Number of mature fibers / Total number of fibers examines) x
100
Maturity Ratio M:
The percentage of the three classes of fibers is combined into a single index termed the
maturity ratio and is approximately proportional to the degree of cell wall thickening.
i.e. Degree of cell wall thickening = 0.577M
Maturity ratio is calculated using the following equation:
M = (N - D) / 200 + 0.7
Where N = Percentage of normal fibers
D = Percentage of immature fibers
The value of N-D is known as immaturity count. From a sample of 100 fibers, it would be
abnormal to findthat all the fibers could be classed as normal fibers. If 100 fibers
are examined from the cotton crop grownunder the best conditions, the normal fibers (N)
expected would be 67% and the dead fibers (D or I) to be7%. Therefore for the chosen
standard of N-D of 67 - 7,
Maturity ratio M = (N - D) / 200 + 0.7 = 1
If, all the fibers are dead, then- D=100 and N=0
So, M= 0-100/200+0.7 =0.2
If, all are mature then, D=0 and N=100
So, M= 100-0/200+0.7=1.2
This means that, the theoretical range of value of M will be from 0.2 to 1.2 where 0.2 means
dead fiber, 1.2 means all are mature fiber.
It can also be calculated from the actual fiber weight per cm H and the standard fiber weight
per cm.Hs bythe relation.
M= H/Hs
Maturity coefficient Mc: (Maturity count)
The fiber maturity count is denoted by the percentages of the mature, half-mature and
immature fibers in a sample. It can be calculated using the formula,
Mc = (N + 0.6H + 0.4I)/100
Where N = percentage of mature fibers.
H - Percentage half-mature fibers
I - Percentage of immature fibers
For the chosen standard, N = 67% D or I = 7% and H = 26%.
Mc = (67 + 0.6(26) + 0.4(7))/100 = .85
Based on the maturity coefficient, the cottons are classed into different groups as shown
below:
Maturity Coefficient Rating
Below 0.06 Very immature
0.60 to 0.70 Immature
0.71 to 0.80 Average maturity
0.81 to 0.85 Good maturity
5.7. Introduction to HVI & AFIS
5.7.1 HVI: The term HVI holds for High Volume Instrument. With this machine, the
physical properties of textile fibers can be tested. The former version of HVI is MVI which
means Medium Volume Instrument. By adding some special module with MVI, HVI has
been developed with high testing facilities.
Specialty:
Fast speed
Act as quality standard
Offers almost all fiber properties testing
Parameters that can be tested by HVI:
Bale Tr. Tr. Tr. Len Unf SF Str Elg Mic Mat Rd + Mois C.
no Gr Are Cnt gth I b t G
a
0001 2 0.21 8 28.9 84.9 6.7 32. 6.8 3.54 0.85 79. 8. 8.1 21
6 1 6 2 -2
0001 1 0.08 9 29.9 81.8 6.9 29. 6.1 4.02 0.87 81. 8. 7.9 21
A 2 9 3 1 -1
0002 4 0.59 22 31.1 79.2 6.9 31 6.8 4.03 0.87 78. 8. 7.9 31
9 1 4 -1
0002 4 0.49 25 28.1 84.1 7.6 32. 6.6 3.98 0.87 77. 8 7.9 31
A 9 1 9 -1
Meanings:
Test result Abbreviation
Spinning Consistency Index SCI
Micronaire Mic
Maturity Index Mat
Upper Half Mean Length Len
Uniformity Index Unf
Short Fiber Index SFI
Strength Str
Elongation Elg
Moisture Moist
Reflectance Rd
Yellowness +b
Color grade C grade
Trash Count Tr cnt
Trash Area Tr area
Trash Grade Tr grade
Fluorescence UV
Neps Nep
Module Available:
A. Length and strength module
B. Microniare Module
C. Color and trash Module
5.7.2 AFIS: It holds for Advanced Fiber Information System. It is a fiber testing machine
which works based on Aero-mechanical principles. AFIS can be utilized for fiber, sliver and
roving testing from Ginning to yarn preparation stage. AFIS is especially used for Neps
testing and process controlling. Usually 5gm sample is tested which needs to be converted in
a definite form.
Modules:
A. Neps Module:
Test result Abbreviation
Nep count per gram Nep Cnt/g
Nep size (Micron) Nep size (micro meter)
Seed coat Nep count per gram SCN Cnt/g
Seed coat nep size (micron) SCN Size (Micro meter)
B. Length and Maturity Module:
Test Result Abbreviation
Mean Length by weight L (w)
Length variation by weight L (w) CV%
Upper Quartile length by weight UQL (w)
Short fibers content by weight SFC (w)
Mean length by number L (n)
Length variation by number L (n) CV%
5%- length by number L (n) 5%
Short fiber content by number SFC (n)
Fineness (militex) FINE (mtex)
Maturity Ratio Mat
Immature Fiber Content (%) IFC (%)
C. Trash Classification Module:
Test Result Abbreviation
Dust Count per gram Dust Cnt/g
Dust (micron) Dust Size (micrometer)
Trash Count per gram Trash Cnt/g
Trash size (micron) Trash Size (micrometer)
Visible Foreign Matter (%) VFM (%)
