Abstract:

To evaluate the precision (the repeatability and the reproducibility errors) of raw silk size test using raw silk size tester, and find the affecting extent of heterogeneous material on test precision, and obtain the precision data of size test for different specifications of raw silk when the sampling size is 200 skeins with each skein having a length of 100 revolutions (112.5 meters), the study designed two different test schemes. The first scheme is that a cycling comparison trial among five labs is done on one same sample, the other is that five labs test five different samples from the same lot of raw silk respectively. The test data show that the precision level is very high when using the same sample, and the average coefficients of variation of the repeatability and reproducibility errors are less than 2%, while the average coefficients are above 10% when using different samples. Therefore, it can be concluded that the heterogeneity of material has great effect on the precision of raw silk size test, and the heterogeneity of material should be considered in evaluating and measuring the precision of raw silk size test in order to obtain the accurate precision level of the actual test.

Key words: raw silk, linear density test, accuracy, heterogeneity, sample size