F05: Single Fibre Length

AWTA TEST CODE

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F05

OTHER NAMES

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TEST METHODS

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AWC 212
BS 6176
ISO 6989
IWTO 5

IMAGE

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Closeup of the single fibre length instrument

Single fibre length Instrument 

APPLICATION

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This method is applicable to any stage of processing from raw fibre to yarns. Whilst the method is applied mainly to wool fibres, it may also be applied to cut or stretch broken man-made fibres (ASTM-D3661) with lengths from 25 to 250mm.

PRINCIPLE

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A fibre is gripped at one end by means of a pair of forceps and is led through or under a stop mechanism, thus preventing the stop switch acting. The forceps holding the fibre end are led by a turning screw along a scale indicating the distance from the stop mechanism, the screw stops and the point at which the forceps stop is an indication of the length of that fibre.

A number of fibres are tested and the mean fibre length, the standard deviation and the coefficient of variation calculated.

SAMPLES REQUIRED FOR TESTING

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From loose fibre - 40 handfuls taken at random from the whole bulk; slivers (card, top, etc.) - a 1m length randomly selected;
rovings and yarns - 10m length randomly selected.

Subsampling of the sample is a very important and time consuming operation which must be performed with great accuracy.

The number of fibres individually measured varies depending on the limits or error able to be tolerated for a given degree of confidence in the results obtained. For man-made fibres (ASTM-D3661), the number is usually 100. For wool, the number can be up to 32000, but usually a minimum of 600.

INTERPRETATION

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Results obtained should be compared with the nominal values.

SERVICE TARGET

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6 days.

COST

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See Fee List.