Wear of Various Textile Guide Materials:Part 5 : Effect of Cylinder Radius on Wear Rate

概要

論文の詳細を見る
The rate of wear of copper cylinders of different radii of curvature rubbed by running cotton yarn was measured on the test apparatus described in earlier paper, for the purpose of investigating the effect of the cylinder radius on the rate of wear and studying the mechanism of wear. The results of a test under a constant yarn tension but with the cylinder radius varied have shown that the rate of wear decreases with an increase in the cylinder radius. However, the results of a test under a constant normal pressure per unit length of contact have shown that the rate of wear is independent of the cylinder radius. The specific rate of wear is found to be not constant but to decrease with an increase in the cylinder radius. Hence the laws of wear explained in a previous instalment do not hold. The deviation from the laws of wear suggests that the surface condition has changed. Again, the effect of frictional heating is considered which softens and melts the natural lubricant contained in cotton fibers. The duration of contact of yarn with a cylinder is long if the cylinder is of a larger radius. The fact that cylinder of a larger radius wears less than does a cylinder of a small radius suggests that the duration of yarn-cylinder has a more predominant effect on softening and melting of cotton wax than the surface temperature of the cylinder. Thus it is considered that softened and molten wax is transferred more to a cylinder of a larg radius, thus protecting the cylinder surface against wear. As previously reported, frictional heating leads to thermal softening and melting of the cotton wax which is on the surface of cotton fibers. The molten wax is transferred to the surface of the cylinder and prevents the latter from wearing away. Then a question arises. What happens if the cylinder is rubbed by wax-free cotton? Hence it becomes very important to investigate the wear characteritics of a copper cylinder rubbed by a scoured yarn. Our test apparatus is run using a cheese or a cone of yarn. This prevents us from scouring a yarn in our laboratory. Therefore, we had the yarn scoured commercially in a bleaching mill, using caustic so da solution. The results of tests using the scoured yarn and a grey yarn were found to be almost the same. Also the entrance to of the cylinder wears more than the exit. Superficially, the scouring of a yarn does not affect the rate of wear of the cylinder or the coefficient of friction. This is not what we. anticipated. Here remains one thing to be taken into account. Many experts have reported that the coefficient of friction of a completely scoured yarn against various materials is much higher than that of the yarn having lubricants. From this fact we were led to conclude that the scoured yarn we used was not completely waxfree. This conclusion was proved by a soxhlet test. Usually, a small amount of lubricants changes the frictional behavior of a yarn markedly. Thus the remaining wax on a scoured yarn plays the same part in wear phenomena as the wax on a grey yarn. However, it is almost impossible for us to scour a large quantity of yarn completely in our laboratory. We have to resort to some other type of test machine which needs only a small quantity of yarn in order to study the effect of cotton wax further.
社団法人日本繊維機械学会の論文

Wear of Various Textile Guide Materials:Part 5 : Effect of Cylinder Radius on Wear Rate

スポンサーリンク

概要

著者

関連論文

スポンサーリンク