Processing of Classed Grower and Bulk Class Lots of Different Uniformity Index

Abstract

The UI was obtained using Multiple Regression Analysis and is based on measures of Coefficient of Variation of Staple Length (CVL), Coefficient of Variation of Staple Strength (CVS), Coefficient of Variation of Diameter (CVD), and variation in Position of Break (Uniformity of POB). In previous papers submitted to IWTO in 1997 and in 1998 it was demonstrated that there was a distinct identifiiable separation of Bulk Classed lots and Classed Grower lots using the Uniformity Index derived by AWTA Ltd. 

Earlier, Thompson, Whiteley, Black and Teasdale (1983) noted the slightly increased variability of Staple Length (SL) for Bulk Classed versus Classed Grower lots and suggested that these differences would produce no significant differences in processing performance. The Cooperative Research Centre (CRC) for Premium Quality Wool expressed an interest in assessing the effect, if any, the Uniformity Index had on the processing performance of wool lots. A feasibility trial was designed to investigate how mini consignments matched for measured raw wool characteristics, but with differences in Uniformity Index, would perform during early stage processing. This document reports on that trial.

The findings were:

• No real differences were noted between the wools with different UI’s in either their processing performance or in the quality of their tops for the quality characteristics measured.
• There were no differences between the preparation of the Sale Lots, i.e., whether Classed Grower or Bulk Class, in processing performance or product quality for the quality characteristics measured.
• The CV (Diameter) values of the Sale Lots which comprised each processing batch determined the CVD of the resulting tops, i.e. a raw wool blend composed of lots with low CVD’s produced a top with a low CVD and vice versa.
• All tops had a consistently lower CVD than the combination of the Greasy wool blend. This lower CVD may be due to the preferential removal of fine wool in combing.
• The Hauteur, CV (Hauteur) and romaine of the blends were all well predicted by the TEAM equations.

Citation

"Processing of Classed Grower and Bulk Class Lots of Different Uniformity Index", AWTA Ltd, CSIRO & The Woolmark Company, Report CTF 03, Commercial Technology Forum, Nice Meeting, November 2001