Comparison of Yarn Tenacity Data Obtained using the Uster Tensorapid, Dynamat II, and Scott Skein Testers

High speed yarn tensile testing machines increase production of yarn tensile data, but no comparisons with data from older, slow speed testing machines have been successful in determining whether these machines produce the same results. This work compares yarn tenacity data from three different machines. A family of five ring spun yarn sizes, each with five different twist factors, covers the entire range of spinning parameters for staple fibers. A new method used to analyze yarn data to determine the number of broken fibers and the effective fiber length acting in each yarn converts yarn tenacity into tenacity per broken fiber per effective fiber length. Converted yarn data from each machine show the effects of the time-to-break on tenacity and how the single strand yarn tensile test differs from one machine to another and with skein tensile test results.