Dimension of yarn twist, An Innovative Techniques

Abstract

This study presents a new technique for defining yarn twist that removes the disadvantages of the presently used ‘reversetwisting technique’. The new technique may be defined as a ‘two-end untwisting/twisting technique’. In this technique, the test sample of a yarn is subjected to untwisting and twisting by two clamps rotating in opposite directions. Pre-tension of the test sample is effected by loading it at its mid-length point, by virtue of which the sample takes the shape of a broken line instead of a straight line. Owing to the use of two rotating clamps and pre-loading the sample at its middle point, there is no ‘ballooning’ of the sample during testing. The ballooning phenomenon occurring in the reverse twisting technique is responsible for uncontrolled elongation of the test sample, due to slippage of the fibers. The two-end untwisting/twisting technique is much less sensitive to the amount of pre-tension applied to the test sample.