Important Measurement Point for Determining Fiber Quality

Determining Fiber Quality:
In yarn manufacturing process, it’s very important to know to determine fiber qualities and fiber properties. Because the lion share cost of yarn manufacturing goes to raw materials. So attaining quality garments is very argent to dignify raw material’s qualities. That’s why we have some specific measurement points by which we can specify actual yarn quality. Some of them are given below with a small description.

Some Important Measurement Point for Determining Fiber Quality

1. Uniformity Ratio:

………………………………..Mean fiber length            .100
Uniformity ratio = …………..……………………….. × ………
…………………………….Upper half mean length         .1

Mean length is the average length of all fibers approximately ¼’’ and longer, and upper half mean length is the estimate of the lengths of fibers in the upper half portion as measured by the fibrograph.

Rating of cotton fibers with respect to uniformity ratio

Uniformity Ratio	Rating
Above 80	Uniform
76-80	Average Uniform
71-75	Slight irregular
70 and below	Irregular

2. Coefficient of Variation (CV):
CV is a relative measure of the length variation. The larger the value, the greater the variation in fiber lengths, and, conversely the smaller the value, the more uniform are the fiber lengths.

Rating of cotton samples with regard to fiber length variation

CV%	Rating
Below 27	Low variability
27-34	Average variability
35 and above	High variability

3. Fibre Fineness rating in micrograms/ inch:

Fibre Fineness	Rating
Very fine	Below 3.0
Fine	3.0 to 3.9
Average	4.0 to 4.9
Course	5.0 to 5.9
Very course	6 and above

4. Maturity ratings:

Rating	Maturity Ratio
Very mature	Above 84%
Mature	77 to 84%
Average	68 to 76%
Immature	60 to 67%
Very Immature	Below 60%

5. Fiber strength rating is 1000lbs. per square inch:

Rating	Strength rating in 1000 lbs.
Superior	93 and above
Very superior	87 to 92
strong	81 to 86
Average	75 to 80
Fair	70 to 74
Weak	Below 70

6. Effect of short fibre in yarn:

For good spinning 14%, short fibre is accepted as allowable
Short  fibre%	8%	13%	15%
Break Factor	1904	1723	1620
Elongation	8.3	7.8	7.2
Break per 100	32	52	54.8
Spindle hourse

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