The Relationship Between Baer Diagram Hand Array Length And Almeter Length Measurements For Dehaired Cashmere

Abstract

The traditional method of assessing the length of processed animal fibres in a processing works is to use a hand array length more formally named a Baer Diagram. Over the past 40 years the Almeter, which measures fibre length indirectly by capacitance, has been the international standard for fibre length measurement. In the absence of published scientific literature on the accuracy or reliability of using Baer Diagrams for measuring fibre length the present study was undertaken to establish relationships between Baer Diagram and Almeter measurements in dehaired cashmere. The mean (SD) and range of Baer Diagram mid length, Almeter length after carding, fibre diameter and fibre curvature were: 38.1 (7.5), 28-50 mm; 27.1 (8.4), 15-44 mm; 16.9 (2.0), 14.1-21.0 micrometre; 56.4 (10.8), 29-71 degree/mm. The Baer diagram hand array mid length within sample average and range in variance was 0.61 mm (0.5 – 1.5) and average and range in coefficient of variation was 2.07 % (1.41 – 3.57). The 99% confidence limits for the mid length measurement was plus/minus 2 mm. There was a useful relationship between Baer Diagram hand array and a range of Almeter length measurements. The Baer Diagram hand array midpoint length explained 77% of the variation in cashmere length after carding (LAC). The regression equation indicated a slope no different from one and a regression constant of –11. In other words, to estimate LAC, 11 mm should be taken from the Baer Diagram midpoint length determination. The addition of other objective measurements such as mean fibre diameter or fibre curvature did not improve the predictive value of the relationships.