hvi

What is staple length in cotton? Complete definition.

Staple length is the major characteristic of cotton fiber on which cotton is traded and its price is determined. Staple length is the length of fiber. This parameter of cotton is so important that every consumer has to first decide what yarn he wants to produce and what staple length of cotton will be required to produce this yarn. In different origins staple length of fiber is spoken with different length scales like inches, MM milli meters and in USA mostly 32nds.

Here are a few staple lengths and their importance and definition also described for better understanding.

Staple length below 27 mm is considered short staple cotton and mostly used for yarn counts below 20/1 ring yarns or low quality or cheaper yarns like open end depending on the requirements of demands.

Major portion of global cotton consists of the staple length between the range of 27 to 30 mm fiber length. This sort of cotton is used to produce medium to good quality yarns. Count range mostly from 20/1 to 40/1 carded or combed for weaving or knitting.

Above this is long staple cotton with staple length 30mm to 33 mm. This cotton is used for producing fine quality yarns from 40/1 to 80/1 combed and compact yarns which are used for light weight fine quality fabrics.

Cotton with 33mm above is called ELS or Extra-long staple cotton used for very fine yarns, high strength or tenacity yarns.

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What is Uniformity Index UNF in cotton testing?

Uniformity Index of UNFI is a ration of mean length with upper half mean length. it is calculated by HVI or Fibrogram cotton testing instruments.

We are giving the following details for the ideal or poor counts of Uniformity.
1. Uniformity Index of Unf below 77 is considered very low or poor uniformity.
2. Uniformity index between the range of 77 to 80 is called low uniformity.
3. Uniformity Index Unf from 80 to 84 is considered medium level. Mostly normal quality cotton contains this range.
4. Uniformity Index 85 to 87 is considered high level uniformity.
5. Uniformity Index above 87 is considered a very high level of uniformity.

What is (SFI) Short Fiber Index In cotton HVI report.

SFI Short fiber index is a very important parameter in cotton results as it determined the ratio of short fiber in cotton. SFI indicates the %age of fiber having less than half inch length. This ratio is counted on High Volume Instrument HVI, one of the latest and best cotton testing instruments being used in the textile sector. The higher SFI is usually considered bad in cotton results.

SFI below 6.00 is an indication that cotton has very less short fiber which is good for cotton consumers. But this sort of cotton is rarely available.

Normally and mostly cotton contain SFI between the range of 6 to 9 and it’s acceptable for most cotton buyers.

SFI short fiber index from 10 to 13 is considered a little higher side ratio but to some extent acceptable for the cotton consumers.

SFI short fiber index above 14 is usually not acceptable for yarn manufacturers who want to make fine quality yarns and they avoid buying cotton with such high value of SFI.

What is Rd and +b in cotton and its definition?

Both Rd and +b are the color grade parameters for cotton. Rd describes the reflectance in cotton. Higher rd indicates the brightness in cotton while lower rd reflects the dullness or grey look in cotton. Cotton having higher rd is considered the better cotton and it also adds to its value and price.
While +b in cotton indicates the yellowness in cotton. Both these units are tested or measured on fiber testing machine HVI (High Volume Instrument) Earlier Fibro graph machine was used to test the cotton results but now a days majority of labs and mills use HVI machine with latest features.