Measuring Fibre Curvature: Key Issues

Abstract

The capability of instruments such as SIROLAN-LASERSCAN™ (LASERSCAN) and OFDA100 to provide measurements of fibre curvature has resulted in increased interest, within Australia among wool producers and exporters, and among overseas top-makers and spinners. However, the metrology of fibre curvature measurement by these instruments is poorly understood. Standardised conditions for preparation, and measurement procedures that stabilise the curvature of the wool fibres prior to measurement by either instrument, are yet to be defined.

Based on its strong association with crimp frequency, wool fibre curvature measurement holds promise as a specification, which can be used to add value to wool in production, trading and processing. However, wool fibre shape (or curvature) is relatively unstable compared to other raw wool parameters such as mean fibre diameter, adding emphasis to the importance of defining standardised preparation procedures.

The stability of the fibre curvature measurement is affected by the sample preparation procedures currently used for both LASERSCAN and OFDA100. Preliminary results show that Shirley Analysing influences fibre curvature, as can the particular design of the OFDA100 spreader. The simple process of minicoring also increases measured fibre curvature. Results are presented highlighting the relationship between fibre curvature measurements by LASERSCAN and OFDA100. The need for a calibration system for these instruments for fibre curvature measurement is foreshadowed.

While it is encouraging to see breeders adopting new technologies, research is showing that breeders should be careful when using fibre curvature measurements in the implementation of their breeding plans. Breeders need to be aware of the limitations of the measurement of fibre curvature, and remember that the measurement should not be treated with the same level of confidence as that given to mean fibre diameter.

Citation

"Measuring Fibre Curvature: Key Issues", V.E. Fish, Paper 31, Wool Industry Science & Technology Conference, October 2002, Hamilton, Victoria, Australia