Report on the 2004/05 OFDA4000 and Almeter/OFDA100/Laserscan round trial

Abstract

This paper summarises the analyses of round trial performance, in 3 non-IWTO-licensed laboratories, of OFDA4000 instruments compared with reference measurements undertaken on OFDA100, Laserscan and Almeter instruments. A wide range of wools were used in the trials from 4 countries of origin, covering mean fibre diameters from 16 to 36 micron and Hauteur values from 47 to 104 mm.

The analyses were undertaken on 49 parameters, not all of which would be considered commercially important. They indicate that in this trial the OFDA4000's can be considered technically equivalent to the reference instruments in some parameters but, unsurprisingly, not all 49. In terms of the main measurements intended to be used for certification (MFD, SD, H and B), it is the author's opinion that the instrument provides sufficient levels of performance to be considered commercially equivalent.

With respect to the detailed length distribution data, some statistically significant biases were detected, but on the whole these were relatively small when compared with the precision of these measurements by either instrument. The OFDA4000s demonstrated similar precision to the Almeters on H distribution parameters, but their performance on B distributions was slightly poorer than the Almeters – however a similar situation has been previously seen in the AL2000 – AL100 comparisons. 

Citation

"Report on the 2004/05 OFDA4000 and Almeter/OFDA100/Laserscan round trial", Peter Baxter, Report 02, Sliver Group, Hobart Meeting, April 2005